L’objectif de cette thèse était d'évaluer la force d’impact dans des conditions proches de la pratique des Sports de Combat et des Arts Martiaux (SCAM) à l'aide d'un ergomètre composé d’un bloc-cible instrumenté avec un accéléromètre et un dynamomètre, et monté sur une lame flexible fixée verticalement sur le sol. La force d'impact a été calculée à partir des trois composantes mesurées par le dynamomètre, d'une part, et à partir de l'accélération du bloc-cible, grâce à un modèle mécanique original, d'autre part. Les mesures dynamiques ont été associées à des mesures cinématiques 3D à haute vitesse afin de caractériser les gestes de frappe de quatre boxeurs en situation d'entraînement, et d'en identifier les paramètres d'optimisation : gamme des énergies cinétiques pic et incidente du membre supérieur, gamme des pics de force d’impact, et forces intra articulaires au poignet, au coude et à l'épaule, calculées par dynamique inverse. Parallèlement, l’évaluation mécanique de quelques protections de boxe française (gants et bandages) et de karaté (gants, protège-pieds et protège-tibias) a montré que le test défini par la norme NF EN 13277-2 était insuffisant pour caractériser leurs propriétés amortissantes. Les résultats des mesures en situation et en laboratoire ont mis en évidence la qualité discutable de certains gants de boxe française et l'absence d’effet protecteur des bandages. La Fédération Française de Boxe Française (FFSBFDA) doit encore tirer toutes les conclusions de ces résultats. Les résultats des protections de karaté ont permis à la Fédération Française de Karaté (FFKDA) d'en définir les caractéristiques souhaitables, qui ont été approuvées par la Fédération Mondiale de Karaté (WKF). Au-delà de ces conséquences pratiques, la cible-ergomètre conçue, fabriquée et mise en oeuvre dans cette thèse, et le modèle mécanique associé présentent des avantages expérimentaux et ergonomiques qui ouvrent des perspectives d’évaluation de la force d'impact de nombreuses techniques de frappe utilisées dans les Sports de Combat et les Arts Martiaux. / The purpose of this thesis was to assess the impact force in conditions close to the practice of Fighting Sports and Martial Arts using an ergometer composed of a target-block instrumented with an accelerometer and a dynamometer, and mounted on a flexible lath vertically fixed on the floor. The impact force was computed from the three components measured by the dynamometer, and also from the acceleration of the target-block, using an original mechanical model. The dynamic measurements have been combined with those of a 3-D high speed kinematic analysis in order to characterize the striking movements of four French Boxers in training conditions, and to identify their optimization parameters : range of maximal and incident linear kinetic energies, range of impact force peaks, and joint forces at the wrist, the elbow and the shoulder, computed by inverse dynamics. Concurrently, the mechanical evaluation of some protective gears for French Boxing (gloves and handwraps) and Karate (gloves, leg-protections and shin protections) has shown that the test defined by the NF EN 13277-2 norm was not sufficient for assessing their damping properties. The results of practice and laboratory measurements exhibited the doubtful quality of some French Boxing gloves and the lack of damping effect of handwraps. The French Federation of French Boxing (FFSBFDA) should still draw all the conclusions of these results. The results of the Karate protective gears have allowed the French Karate Federation (FFKDA) to define their desirable characteristics, which have been approved by the World Karate Federation (WKF). Beyond these practical outcomes, the striking ergometer, designed, built and used in this thesis, and the associated mechanical model have / possess experimental and ergonomic advantages, which open wide perspectives for assessing the impact force of many striking techniques used in Fighting Sports and Martial Arts.

Detection of both biological and chemical environmental toxicants is essential in the assessment of risk to human health. Cell-based biosensors are capable of activity- based detection of toxicity. Chromatophore cells, responsible for the pigmentation of poikilothermic animal, have shown immense potential as cell-based biosensors in the detection of a broad range of environmental toxicants. Chromatophore cells possess the motile pigment granules that intracellularly aggregate or disperse in response to external stimuli. Previous studies have assessed chromatophore cells isolated from red Betta splendens and grey Oncorhynchus tschawytscha fish for use as a biosensor. The objective of this study was to describe blue B. splendens chromatophore cells in tissue culture. Blue B. splendens chromatophore cells were assessed for their longevity in tissue culture and their responses to previously established control agents. Blue B. splendens chromatophore cells were exposed to select chemicals and pathogenic bacteria to assess their ability to respond to environmental toxicants. Three concentrations of mercuric chloride, methyl mercuric chloride, paraquat, sodium arsenite, sodium cyanide chemicals were tested. Bacillus cereus, Bacillus subtilis, Salmonella enterica serovar Enteritidis, and Salmonella enterica serovar Typhimurium were tested. Red B. splendens chromatophore cells were subjected to the select chemical and bacterial toxicants, and observed for their responses. The data collected in this and previous studies were compiled to compare chromatophore cell responses to a broad range of environmental toxicants. Chromatophore cells isolated from both blue and red B. splendens were responsive to methyl mercuric chloride and sodium arsenite. Grey O. tschawytscha chromatophore cells have shown responsiveness to mercuric chloride and sodium arsenite. Blue and red B. splendens chromatophore cells were both responsive to B. cereus and both Salmonella serovars. Grey O. tschawytscha have previously been shown to respond to B. cereus as well. In conclusion, this study reports the chromatophore cells isolated from blue B. splendens in tissue culture and showed similar responsiveness to the selected chemical and bacterial environmental toxicants as chromatophore cells isolated from red and grey colored fish. This study provides compelling evidence that the chromatophore response is not dependent on fish color and that chromatophore cells used for a cell-based detection system may be isolated from different colored fish. / Graduation date: 2012

Despite documented benefits, the processes described in the new product development literature often prove difficult to follow in practice. A principal source of such difficulties is the phenomenon of fire fighting the unplanned allocation of resources to fix problems discovered late in a product's development cycle. While it has been widely criticized, fire fighting is a common occurrence in many product development organizations. To understand both its existence and persistence, in this article I develop a formal model of fire fighting in a multi-project development environment. The major contributions of this analysis are to suggest that: (1) fire fighting can be a self-reinforcing phenomenon; and (2) multi-project development systems are far more susceptible to this dynamic than is currently appreciated. These insights suggest that many of the current methods for aggregate resource and product portfolio planning, while necessary, are not sufficient to prevent fire fighting and the consequent low performance. / MIT Center for Innovation in Product Development under NSF Cooperative Agreement Number EEC-9529140, the Harley-Davidson Motor Company and the Ford Motor Company

Background: Multidirectional interactions in social networks can have a profound effect on mate choice behavior; e.g., Poecilia mexicana males show weaker expression of mating preferences when being observed by a rival. This may be an adaptation to reduce sperm competition risk, which arises because commonly preferred female phenotypes will receive attention also from surrounding males, and/or because other males can copy the focal male's mate choice. Do P. mexicana males indeed respond to perceived sperm competition risk? We gave males a choice between two females and repeated the tests under one of the following conditions: (1) an empty transparent cylinder was presented (control); (2) another ("audience") male inside the cylinder observed the focal male throughout the 2nd part, or (3) the audience male was presented only before the tests, but could not eavesdrop during the actual choice tests (non-specific sperm competition risk treatments); (4) the focal male could see a rival male interact sexually with the previously preferred, or (5) with the non-preferred female before the 2nd part of the tests (specific sperm competition risk treatments). Results: The strength of individual male preferences declined slightly also during the control treatment (1). However, this decrease was more than two-fold stronger in audience treatment (2), i.e., with non-specific sperm competition risk including the possibility for visual eavesdropping by the audience male. No audience effect was found in treatments (3) and (5), but a weak effect was also observed when the focal male had seen the previously preferred female sexually interact with a rival male (treatment 4; specific sperm competition risk). Conclusion: When comparing the two 'non-specific sperm competition risk' treatments, a very strong effect was found only when the audience male could actually observe the focal male during mate choice [treatment (2)]. This suggests that focal males indeed attempt to conceal their mating preferences so as to prevent surrounding males from copying their mate choice. When there is no potential for eavesdropping [treatment (3)], non-specific specific sperm competition risk seems to play a minor or no role. Our results also show that P. mexicana males tend to share their mating effort more equally among females when the resource value of their previously preferred mate decreases after mating with a rival male (perceived specific sperm competition risk), but this effect is comparatively weak.

We aim to develop knowledge of how new technology, in this case social media, can contribute to how sports fans interact with their idols. Therefore our framing of a question is to present how fans experience their contact with mixed martial arts (MMA) & ultimate fighting championship (UFC) through social media platforms. To specify our study, we also have a supplement question with in which way sports fans uses social media.We have chosen to conduct a qualitative study consisting of interviews and data observations of websites, related to the organization UFC, to approach our main question. We have interviewed nine randomly selected people with one common interest - MMA/UFC. With an implant of theories, consisting of social media, fandom and lurking, on the result of the interview and website data, we try to come closer to a conclusion for our intention with this thesis.Our conclusion is that the interviewed fans express that through the usage of social media, they feel like they have come closer to UFC. They have developed a deeper knowledge about the sport, the members and other fans that shares the same interest. Most of our respondents have a lurking attitude towards the social media usage, which means that they are more like observers and soak in the information and media material. They are active in the searching of material related to UFC, but they are not active in the way of contributing with comments, discussions or material.

This thesis presents a prototype of Unmanned Cooperative Fire-Seeking and -Fighting Robots (UCSFRs) which have a new way to climb up the stairs or traverse over obstacles with a ball screw. There are three unmanned vehicles (one Mother Vehicle (MV) and two Daughter Vehicles (DVs)) presented in this research. The MV can carry two DVs to climb stairs. They can communicate with each other using Bluetooth communication modules. The core system of the UCSFRs is a PIC 16F877 microcontroller on a 2840 development board. The software is written in C language and the interface is established through Hyper Terminal built in Windows XP. UCSFRs are low cost unmanned vehicles compared with other commercial ones. The double-deck structure is applied on the DVs. The body of the MV can be extended for special purposes. In this research, there are three tests used to verify the functionality of the UCSFRs: (1) MV?s finding and stopping fire, (2) Communication between the MV and the DVs, and (3) the MV?s climbing stairs. In the second test, the DVs run in the opposite direction to assist MV detect fire. By cooperative work, they can save time finding the fire. The MV will go to the hightemperature area according to the data sent by the DVs. Because of the features mentioned above, UCSFRs can be used to perform dangerous tasks instead of fire-fighters.

Fires in buildings are dangerous in many ways, one big hazard is the risk of building collapse. This is a hazard both to occupants in the building and to the fire service, who might have to enter the building for their firefighting. The consequences of a building collapse can become severe, both in terms of damage to the building and in terms of injuries to people. Despite this, there are few methods to determine how stable a construction is, when exposed to stress from a fire. This thesis has tried to find connections between occurred events where buildings have collapsed, both by a literature study and by looking into some occurred collapses. This has been done by analysing some specific events more deeply, to find out what went wrong in that specific case, and by looking into a broader base of occurred building collapses which has been presented as statistics. Finally contact with personnel from two different fire brigades was taken, to perform a questionnaire and collect information of how they work with the dangers in reality. All of these studies has shown that there are some connections between which buildings collapse more often than others, one example is that small houses collapse more frequently than residential buildings and that roofs is the part of the building which collapses most often. This is confirmed by some of the people from the fire brigades, who thinks it reflects their own experiences regarding building fires. Even though some connections like these can be shown, they can have several explanations as for example, there are many more small houses than residential buildings in Sweden which makes it natural to believe that they collapse more often. Still, some connections are clear and this information can be used to base further studies on and perhaps gain more knowledge to be able to make better judgements on whether a construction is stable or not.

Research regarding youth involvement in physical fighting and suicidal ideation has been primarily conducted in western countries, such as the U.S., and limited information is available on this subject in sub-Saharan Africa. This study used data from the Global School-Based Student Health Survey (GSHS) to analyze the prevalence and correlates (i.e., bullying victimization, loneliness, having no friends, sadness, alcohol use, and drug use) of physical fighting and suicidal ideation among students, both boys and girls in Uganda. In this study, 10.1% of urban students and 15.2% of rural students reported engaging in both physical fighting and suicidal ideation. Rural students overall have a higher prevalence of physical fighting, being bullied, suicidal ideation, alcohol use and drug use when compared to urban students. Other risk factors vary among boys and girls in urban and rural settings. Gender and urban/rural differences indicate that interventions among boys and girls and urban and rural students should be adapted to address the needs of the specific groups.

In the zebra finch (Taeniopygia guttata), song and its social context play an important role in female mate selection. The song of the zebra finch is unique in that it can only be produced by males, which makes the species ideal for analyzing the components of male song that influence female song preference and mate selection. There are three consistent features of zebra finch song that affect female mate preference: 1) the amount of time a male sings, 2) the size and complexity of his song repertoire, and 3) the structural conformation to species or population norms (reviewed in Nowicki et al. 2002). During courtship, male zebra finches often express ‘static-visual’ and ‘dynamic-visual’ elements in sync with song (Morris 1954), which would suggest that such behaviors also play a role in influencing female mate preference. However, with courtship comes the competition between males for the attention of potential mates. These agonistic interactions between males act settle disputes over access to mates, and as such, are also likely to influence female mate selection. As follows, we predict that, at the initial onset of courtship, there would be a higher prevalence of male-to-female courting interactions and singing behavior in comparison to male-to-male agonistic tendencies if female mate selection is fundamentally determined by song preference. However if female mate selection is more complicated than simple song preference, we would expect to initially observe a higher number of agonistic interactions between males as they compete for dominance. This hypothesis was tested by recording and analyzing the behavioral interactions between male and female zebra finches in the context of song complexity. We found that different males scored higher for song complexity than those for expression of courtship behaviors, which indicates that different elements of male courtship display likely influence female mate preference. Our data comparing male-to-male interactions and male-to-female interactions within the first 30 minutes after introduction was statistically insignificant, suggesting that female mate selection is more complicated than simple song preference. This preliminary research can be used as a basis for future studies using quantitative movement tracking analysis, which would further strengthen these initial observations. By increasing our understanding of the influence the male song has on female mate selection, we can better expound upon the nature and function of the favored traits that male songbirds possess and the benefits that females and their progeny might gain from choosing a male with these particular attributes.

Game theory models predict that individuals involved in contests adjust their strategy appropriate to the current value of the contested resource and the resource holding potential (RHP) of their opponent. In this investigation, I examined interactively operating, multiple contest asymmetries on dyadic disputes for precopulatory guarding positions in the crab spider Misumenoides formosipes. In contests between equally sized opponents with no previous contest experience, residents had clear advantages in fighting success over intruders. In the remaining two experiments, asymmetries in experience predicted outcome when tested against residency and size asymmetries. Data from this investigation suggest crab spiders learn strategies through experience rather than rely solely on the assessment of their opponent’s RHP before determining contest effort. / Department of Biology