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Impacts of Nighttime Hypoxia on the Physiological Performance of Red Sea MacroalgaeAlamoudi, Taiba 11 1900 (has links)
Marine deoxygenated areas are expanding, and more hypoxic zones emerge globally. Climate change induced warming and stratification can extrapolate the biological oxygen demand, more predominantly at coastal areas and reefs with dense vegetation and high metabolic activity. The diurnal oxygen fluctuation can reach a critically low oxygen level at nighttime, exposing aquatic organisms to severe hypoxia that could interfere with viable ecosystem functions. Little is known about the impact of hypoxia on marine primary producers macroalgae, mainly the physiological adaptation of the Red Sea macroalgae under climate change scenarios is understudied.
Here we investigate hypoxia thresholds at night time for conspicuous Red Sea macroalgae species calcareous Halimeda opuntia and Padina boryana and noncalcifying brown algae Sargassum latifolium. We utilized a computer-based gas system to expose the samples to different oxygen treatments (normoxia, hypoxia, and severe hypoxia) that mimic in situ water chemistry at 32 °C. We monitored algal physiological response during 12 hours of exposure to different oxygen levels in the dark by measuring photochemical efficiency, respiration rates, and cellular viability.
For the duration of our experiments (12h), we did not detect lethal thresholds. In all tested species, severe hypoxia significantly decreased photochemical efficiency, and hypoxia had a limited impact on photochemical efficiency. However, both low oxygen treatments significantly decreased respiration rates and induced changes in cellular activity. We concluded a sublethal O$_2$ thresholds SLC$_{(50)}$ of 1.2 ±0.1, 1.5 ±0.1, and 1.7 ±0.1 mg O$_2$ L$^{−1}$ ±SD for H. opuntia, P. boryana, and S. latifolium responses, respectively. We also found that during 12 hours of treatments, the median time to observe a 50% reduction in photochemical efficiency under severe hypoxia treatment relative to control was 6.3 ±1.4, 3.5 ±1.0, and 0.8 ±1.3 hours ±SD for H. opuntia, P. boryana, and S. latifolium responses, respectively.
This study is the first assessment of Red Sea macroalgae response to hypoxia and the first dark nighttime algal adaptation of its kind for our proposed species. Further investigation is needed to assess daytime recovery, recurring dark hypoxia, and synergic or sequential effects of other environmental stressors on hypoxia thresholds.
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The Predictive Power of Machiavellianism, Emotional Manipulation, Agreeableness, and Emotional Intelligence on Counterproductive Work BehaviorsWalters, Ryan L. 09 June 2021 (has links)
No description available.
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Constraints on dark matter models using a fast simulation of the ATLAS detectorTaylor, Samantha H. 13 August 2021 (has links)
Data collected at the LHC are analyzed by the ATLAS collaboration for evidence
of dark matter. In this thesis, a fast simulation of the ATLAS detector response using
the Delphes software is assessed for dark matter models with a leptonically decaying
Z boson and a pair of dark matter particles in the final state. Limits for the Two
Higgs Doublet plus pseudoscalar dark matter model are obtained using simplified
systematics, and found to be nearly indistinguishable to limits obtained using the
more complex standard ATLAS analysis. / Graduate
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Decreasing nighttime fears in children: a thesis ...McMenamy, Carol J. 01 January 1987 (has links)
The purpose of the study was to find out if children ages 4- 5 who were experiencing nighttime fears could be taught coping behaviors to decrease their fears. Five children and their parents participated in the study. A treatment package consisting of teaching the children brave self- statements, relaxation exercises, and the introduction of a token economy was used. Results indicate a reduction in fear behavior at post treatment, and further decreases in fear related measures at follow- up.
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Origins for dark matter particles : from the "WIMP miracle" to the "FIMP wonder" / Origines pour les particules de matière noire : du "miracle WIMP" à une "merveille FIMPDutra, Maíra 19 February 2019 (has links)
Cela fait plus de 80 ans que nous avons des preuves qu'environ 26% de la densité d'énergie de l'univers actuel se présente sous la forme de matière noire, qui interagit avec la matière ordinaire strictement par gravitation. Avec les neutrinos massifs, l’existence de particules de matière noire (DM) indique qu’il faut étendre le modèle standard de la physique des particules (SM) pour en tenir compte. Dans cette thèse, nous explorons la relation étroite entre la nature des couplages reliant la DM aux particules du SM et la production de l'abondance de la DM dans l'univers primordial. Nous commençons par examiner la classe la plus prédictive de candidats DM, les particules massives à interaction faible (WIMP). Leurs masses et couplages sont comparables à ceux du SM, et donc les deux secteurs ont déjà été en équilibre thermique, et l'abondance de DM respecte automatiquement les limites cosmologiques -- le "miracle WIMP". Les limites expérimentales actuelles repoussent l'espace paramétrique viable des modèles WIMP vers des limites complexes, rendant nécessaire l'ajout de particules supplémentaires dans le secteur sombre et la vérification plus précise de la condition de découplage. Après avoir considéré le statut phénoménologique d'une gamme significative de modèles pour les WIMP avec des masses dans l'intervalle 10-10⁴ GeV, nous examinons la phénoménologie d'une DM sur l'échelle MeV dans un modèle de portail Z'. En plus de chercher à améliorer la recherche de WIMPs, il convient de considérer le cas dans lequel DM et SM interagissent si faiblement qu’ils n’ont jamais atteint l’équilibre. Les particules massives à interaction faible (FIMP) sont des candidats DM produits à partir du SM dans des processus hors d'équilibre, un mécanisme appelé freeze-in. Nous montrons que si des champs lourds (10¹⁰-10¹⁶ GeV) interviennent dans les interactions DM-SM, le freeze-in est une possibilité naturelle qui fournit la bonne abondance de DM sans qu'il soit nécessaire d'imposer couplages extrêmement petits. Ces champs lourds sont en fait nécessaires dans des scénarios à hautes énergies théoriquement bien motivés tels que le GUT, le see-saw, la leptogénèse et l’inflation -- nous appelons cette coïncidence intéressante la "merveille FIMP". Nous explorons différentes réalisations de cette possibilité, avec des modèles impliquant des moduli, fermions, bosons de jauge et champs de spin-2 comme les médiateurs lourds. Nous montrons enfin dans quels cas la production de DM pendant le reheating après inflation a un impact sur l’espace paramétrique de tels modèles. / For more than eighty years, we face evidence that about 26% of the energy budget of the universe today is in the form of dark matter, whose interaction with ordinary matter is felt only gravitationally. Along with massive neutrinos, the existence of dark matter particles (DM) indicate that we must extend the standard model of particle physics (SM) in order to account for them. In this thesis, we explore the close relationship between the nature of couplings connecting DM to the SM sector and the production of the DM relic density in the Early Universe. We start by considering the most predictive class of DM candidates, the weakly interacting massive particles (WIMPs). Their masses and couplings are comparable to the SM ones, which ensure that both sectors were once in thermal equilibrium and automatically render the DM relic density within the inferred range -- the so-called "WIMP miracle". The current experimental bounds push the viable parameter space of WIMP models to complex corners, making necessary to add extra particles in the dark sector and to check the decoupling condition more carefully. After reviewing the phenomenological status of a comprehensive spectrum of models for WIMPs with masses in the range 10-10⁴ GeV, we consider the challenging phenomenology of an MeV DM in a Z' portal model. Besides seeking to improve the search for WIMPs, it is worth considering the case in which DM and SM interact so feebly that they had never reached equilibrium. Feebly interacting massive particles (FIMPs) are DM candidates produced from the SM thermal bath in out-of-equilibrium processes, a mechanism called freeze-in. We show that if heavy fields (10¹⁰-10¹⁶ GeV) mediate the DM-SM interactions, the freeze-in is a natural possibility that provide the right amount of DM in the universe without the need of extremely small gauge, yukawa or quartic couplings. Such heavy fields are actually needed in theoretically well motivated high-energy scenarios like for instance GUT, seesaw, leptogenesis and inflation -- we call this interesting coincidence the "FIMP wonder". We explore different realizations of such possibility, with models involving moduli, fermions, gauge bosons and spin-2 fields as heavy mediators. We finally show in which cases the DM production during reheating have impact on the parameter space of such models.
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Neutrinos from Dark Matter Annihilation in the SunHansen, Fredrik, Holmgren, Erik January 2013 (has links)
Dark Matter (DM) is believed to consist ofWeakly Interactive Massive Particles (WIMPs) which interact only through gravity and the weak nuclear force. These particles can become trapped in gravitational wells such as the Sun and a theoretical value of the capture rate can be calculated. At high particle density the WIMPs annihilating spontaneously into Standard Model (SM) particles. Due to particle equilibrium the total annihilation rate can be related to the capture rate by a simple expression. This report will focus on calculating the capture rate and the related annihilation rate as well as calculating the neutrino ux of the Sun. At rst we will give a brief introduction to cosmology and a theoretical argument for the WIMPs as the prime DM candidate. Then we will look at the theoretical background and the mechanism through which WIMPs become trapped and evaporate or annihilate. Finally we will perform a numerical analysis of the WIMP cycle within the Sun and calculate the capture rate for a variety of theoretical WIMP masses. We will look at the capture rate due to scattering both by hydrogen nucleii and by more massive elements. The Scattering by hydrogen will be the prime contributor to the total capture rate and is the only spin dependent contribution.
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Mörka personlighetsdrag hos Sveriges studenter : – En enkätundersökning om machiavellism, narcissism och psykopati / Dark Personality Traits in Students in Sweden : – A Survey about Machiavellianism, Narcissim and PsychopathyFlood Hörberg, Henric, Olsson, Emil January 2022 (has links)
The purpose of this study was to examine whether differences were found in occurrence of three personality traits from the Dark Triad, Machiavellianism, narcissism and psychopathy, in regards to students within different educations in universities and colleges in Sweden. Previous research and findings have shown that students with different educations tend to show traits from the Dark Triad of varying degrees. Data to the study was collected through a self-assessment survey named Short Dark Triad (SD3). The survey was translated to Swedish, then sent to 22 different educations at 33 Swedish universities and colleges. 1055 participants were gathered in the study with a distribution of 709 women and 346 men. The results were mostly supported by previous research, however a few results were not supported by previous research. For example, economy students did not get higher scores on Machiavellianism when compared to students at law and political science.
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Dark matter in and around starsSivertsson, Sofia January 2009 (has links)
There is by now compelling evidence that most of the matter in the universe is in the form of dark matter, a form of matter quite different from the matter we experience in every day life. The gravitational effects of this dark matter have been observed in many different ways but its true nature is still unknown. In most models dark matter particles can annihilate with each other into standard model particles. The direct or indirect observation of such annihilation products could give important clues for the dark matter puzzle. For signals from dark matter annihilations to be detectable, typically high dark matter densities are required. Massive objects, such as stars, can increase the local dark matter density both via scattering off nucleons and by pulling in dark matter gravitationally as the star forms. Dark matter annihilations outside the star would give rise to gamma rays and this is discussed in the first paper. Furthermore dark matter annihilations inside the star would deposit energy inside the star which, if abundant enough, could alter the stellar evolution. Aspects of this are investigated in the second paper. Finally, local dark matter overdensities formed in the early universe could still be around today; prospects of detecting gamma rays from such clumps are discussed in the third paper. / Introduktionsdelen till en sammanläggningsavhandling
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Spelares upplevelser av mörka designmönster i MMORPG spel / Players' experiences of dark design patterns in MMORPG gamesÖstling, David, Sundström, Isak January 2021 (has links)
Denna studie utfördes för att undersöka konceptet om mörka designmönster i MMORPG (Massive Multiplayer Online Role Playing Games) spel och för att ta reda på vad spelarna tyckte om dem. Detta gjordes för att utöka kunskapen kring ämnet och för att lysa ett ljus på hur spelare blir påverkade av mörka designmönster. Denna studie gjordes dessutom för att det ännu inte finns några undersökningar om spelarnas upplevelser och åsikter kring mörka designmönster i datorspel. Vi valde att fokusera på spelet Runescape då det är ett av de mest populära MMORPG spelen just nu. Dessutom liknar detta spel många andra MMORPG spel i hur det är designat. Definitionerna på mörka designmönster i denna studie kommer huvudsakligen från José Zagals studie om mörka designmönster i spel som publicerades 2013. Denna undersökning utfördes genom att publicera en enkät på några olika Runescape-forum. Enkäten innehöll frågor till spelarna om deras åsikter och syner på de olika mörka designmönster som kan hittas i spelet. Studien visade att spelare har blandade åsikter och att det fanns många spelare som var generellt sett positiva mot de mörka designmönstren i spelet. Många var också väl medvetna om de problematiska aspekterna av dessa och hade negativa åsikter om dem. Trots det tolererade spelarna dem eftersom att de fortsatte spendera väldigt många timmar i spelet. Några av dem med negativa åsikter beskrev hur deras beroende av spelet fick dem att fortsätta spela även fast de tyckte illa om de mörka designmönstren. / This study was performed in order to investigate the concept of dark design patterns in MMORPG (Massive Multiplayer Online Role Playing Games) games and what players think about them. This was done in order to deepen the knowledge surrounding this topic and to get more insight to how players are affected by dark design patterns since there are currently no studies on players' opinions on dark design patterns in video games. For the purpose of this study we focused on the game Runescape as it is currently one of the most popular MMORPG games. The game is also very similar to many other MMORPG games when it comes to its design. The definitions of the dark design patterns present in this study primarily come from José Zagals study on dark patterns in games from 2013. Our study was conducted by posting a survey asking the players about their opinions on the dark design patterns that could be identified in Runescape. The survey was posted on a couple of Runescape discussion-forums. The study showed that players had mixed opinions and that many players had a general non-negative view on the dark design patterns present in the game. At the same time, many were also well aware of the problematic aspects of the dark patterns and had negative opinions on them but nevertheless tolerated them as they kept putting many hours into the game. A few of the ones with negative opinions described how their addiction to the game made them keep playing despite disliking the dark design patterns.
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'Dark triad' personality traits and risky sexual behaviourMauda, Lesley Takalani January 2013 (has links)
Thesis (M.A. ( Clinical Psychology)) -- University of Limpopo, 2013 / This study investigated the relationship between the ‘dark triad’ personality traits and risky sexual behaviour (sociosexuality), and the effect of gender on the relationship. Participants consisted of two hundred and twenty-two (222) University of Limpopo students. Correlation analysis results indicate that, among males, primary psychopathy is positively associated with overall sociosexuality and secondary psychopathy is negatively associated with the behavioural component of sociosexualiy. Primary, secondary and overall psychopathy was positively related to risky sexual behaviour (sociosexuality). However, Machiavellianism, narcissism and overall psychopathy were not related to all dimensions of sociosexuality. Regression analysis results revealed that very few ‘dark triad’ personality traits have the capacity to predict risky sexual behaviour (sociosexuality). High risk socio-sexual behavioural features were predicted by the ‘dark triad’ personality traits mostly among females than among males. There were comparatively more factors associated with risky sexual behaviour among females than males in this sample. Generally, the ‘dark triad’ personality traits varied in relating with features of risky sexual behaviour. The nature of the relationship of ‘dark triad’ personality traits depends on the particular type of risky sexual behaviour. This is contrary to previous empirical findings that suggest that, when measured in a normal sample, correlates of the ‘dark triad’ personality traits will be the same. Recommendations were made on the basis of the results.
Key words: ‘dark triad’, narcissism, psychopathy, Machiavellianism, sociosexuality.
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