Pure Nash Equilibria in Concurrent Deterministic Games

We study pure-strategy Nash equilibria in multi-player concurrent deterministic games, for a variety of preference relations. We provide a novel construction, called the suspect game, which transforms a multi-player concurrent game into a two-player turn-based game which turns Nash equilibria into winning strategies (for some objective that depends on the preference relations of the players in the original game). We use that transformation to design algorithms for computing Nash equilibria in finite games, which in most cases have optimal worst-case complexity, for large classes of preference relations. This includes the purely qualitative framework, where each player has a single omega-regular objective that she wants to satisfy, but also the larger class of semi-quantitative objectives, where each player has several omega-regular objectives equipped with a preorder (for instance, a player may want to satisfy all her objectives, or to maximise the number of objectives that she achieves.)Comment: 72 page

Effect of Media and Estrogen on Morphological Change in Candida albicans

Introduction: Candida albicans (C. albicans), an opportunistic pathogen, lives symbiotically within the intestine of its human host. Temperature and chemical factors have been shown to induce a morphological change in C. albicans from yeast to filamentous form turning C. albicans pathogenic. In this study, we investigated the intestinal cues that might be responsible for the change. We found that different solid media impact the morphological phenotype so we focused on characterizing these before further testing. We tested Estradiol (E2) because of its known linkage to sepsis and higher levels during infections. Experiments were conducted to compare solid agar plates of YEPD, Minimal Media (MM), and Spider Media (SP) for C. albicans growth to choose the best one for further testing with E2 and other factors that could be prone to causing morphological changes. Methods: C. albicans was inoculated through streak method on different solid media (YEPD, MM, SP) and incubated at 30℃. The effect of 0.1nM E2 on C. albicans morphology was also tested. Morphological changes were assayed through bright-field microscopy. Results: Using the three different medias, we found three distinctive phenotypes: A, B, and C. Out of 6 experiments of 14 MM plates, the expressed phenotype was 86% A and 14% inconclusive of the time. 8 experiments of 17 SP plates showed 100% of phenotype B. 6 experiments of 14 YEPD plates presented phenotype C 92% of the time and 8% inconclusive. For E2 trials, 2 experiments, 6 MM plates showed 50% phenotype A and 50% inconclusive. 4 experiments, 10 SP plates had phenotype B 100%. YEPD 2 experiments, 2 plates had phenotype C at 100%. Conclusion: We have established experimental conditions of media controls for further testing whether E2 and other cues, such as inflammatory cytokines, have inhibitory or positive effects on the growth of C. albicans

The Ethics of Eliminating Harmful Species: The Case of the Tsetse Fly

Wildlife species harmful to humans are often targets of control and elimination programs. A contemporary example is the tsetse fly, a vector of sleeping sickness and African animal trypanosomosis. Tsetse flies have recently been targeted by a pan-African eradication campaign. If it is successful, the campaign could push the entire tsetse family to extinction. With the emergence of effective and efficient elimination technologies, ethical assessment of proposed elimination campaigns is urgently needed. We examine the ethics of tsetse fly elimination by considering arguments predicated on both the instrumental and the intrinsic values of the species at local and global scales. We conclude that, although global eradication of tsetse flies is not ethically justified, localized elimination campaigns targeting isolated populations are ethically defensible. We urge assessments of this kind be conducted regularly and in context, so that all relevant factors underlying decisions on species elimination are routinely laid bare for evaluation

Testing Environmental Cues on Candida albicans Morphology

Introduction C. albicans is a commensal fungus which under certain environmental cues (e.g., pH, oxidative stress) shifts morphology from spores to filamentous and becomes invasive within the human body. This work aims to identify the environmental gut cues responsible for this morphological shift. Estrogen (E2) becomes elevated during sepsis, thus the guiding hypothesis states that E2 may represent a factor responsible for the morphological change in C. albicans. Methods A calibration curve of growth of C. albicans in liquid minimal media (MM) was established using a spectrophotometer and correlating optical density with cell counts measured with a hematocyter. Liquid MM was inoculated in quadruplets of three different amounts of C. albicans. To test the effect of estrogen at 1nM concentration, E2 was added at the time of inoculation to one of each tube set, and fetal bovine serum was the positive control in another tube. All tubes were anaerobically grown over 3 nights in a shaking incubator at 30℃. Morphological changes were assayed using bright-field microscopy. Results C. albicans was inoculated in amounts of 1, 2, and 4 million cells into sets of 4 tubes each based on the established growth curve. The MM relationship between OD and number of cells is described by the following equation: 1.06×106 + 1.83×10 7x + 1.68×10 7x 2 , R 2= 0.867. Adding E2 at 1 nM to the liquid media appeared to induce filamentous growth and budding, as with positive control 10% FBS. Conclusion Our preliminary experiments indicate that regardless of initial cell amount, tubes containing E2 seem to induce more filamentous growth in MM, as observed with FBS (positive control). Further experiments to determine effects of E2 at other concentrations would bring more insight, as well as trials combining E2 and FBS to explore if there is an additive or inhibitory effect on filamentation

Effect of Media and Estrogen on Morphological Change in Candida albicans

Introduction: Candida albicans (C. albicans), an opportunistic pathogen, lives symbiotically within the intestine of its human host. Temperature and chemical factors have been shown to induce a morphological change in C. albicans from yeast to filamentous form turning C. albicans pathogenic. In this study, we investigated the intestinal cues that might be responsible for the change. We found that different solid media impact the morphological phenotype so we focused on characterizing these before further testing. We tested Estradiol (E2) because of its known linkage to sepsis and higher levels during infections. Experiments were conducted to compare solid agar plates of YEPD, Minimal Media (MM), and Spider Media (SP) for C. albicans growth to choose the best one for further testing with E2 and other factors that could be prone to causing morphological changes. Methods: C. albicans was inoculated through streak method on different solid media (YEPD, MM, SP) and incubated at 30℃. The effect of 0.1nM E2 on C. albicans morphology was also tested. Morphological changes were assayed through bright-field microscopy. Results: Using the three different medias, we found three distinctive phenotypes: A, B, and C. Out of 6 experiments of 14 MM plates, the expressed phenotype was 86% A and 14% inconclusive of the time. 8 experiments of 17 SP plates showed 100% of phenotype B. 6 experiments of 14 YEPD plates presented phenotype C 92% of the time and 8% inconclusive. For E2 trials, 2 experiments, 6 MM plates showed 50% phenotype A and 50% inconclusive. 4 experiments, 10 SP plates had phenotype B 100%. YEPD 2 experiments, 2 plates had phenotype C at 100%. Conclusion: We have established experimental conditions of media controls for further testing whether E2 and other cues, such as inflammatory cytokines, have inhibitory or positive effects on the growth of C. albicans

Effects of Environmental Factors on Candida albicans Morphology: A Focus On Estrogen and Microgravity

C. albicans is one of the commensal fungi living in the human intestinal tract in a harmless spore form. In its filamentous form, C. albicans becomes invasive and penetrates the human body, which can cause serious health issues. In vitro factors such as change in temperature or pH are known to induce morphology shift in C. albicans. Interestingly, microgravity has been reported to decrease the human immunity and increase gene virulence expression in C. albicans. During sepsis, high levels of estrogen are reported and the risk of candidiasis also increases. Within present work, we tested the effect of microgravity and estrogen on the shift of morphology (spore to filamentous). C. albicans were grown in minimum media for 3 days in presence or absence of 0.1 nM estrogen. In addition, two other groups of C. albicans were subjected to microgravity for 3 days, using a clinostat, in presence or in absence of estrogen. For each condition, 5 random pictures were taken and scored 1 for the presence and 0 for absence of filament. Experiments were conducted in duplicate. Our results show that subjecting C. albicans to microgravity significantly increase the number of filaments compared to control (9.59±2.77 versus 1.68±1.93, P\u3c0.001, unpaired t-test), whereas estrogen did not significantly affect the number of filaments compared to control (2.66±1.61 versus 1.68±1.93, p=0.6, unpaired t-test). Finally, there was no significant effect of estrogen found on the number of filament when C. albicans was exposed to microgravity plus estrogen versus microgravity alone (8.0±2.76 versus 9.59±2.77). In conclusion, we have found that simulated microgravity dramatically increases the number of filaments, and estrogen at 0.1 nM has no effect on the number of filaments in our experimental conditions

Environmental Cues and Fungi Morphology

Candida albicans, a symbiotic yeast in the human gut, and Neurospora crassa, a filamentous bread mold, are distinct in habitat, morphology, and behavior. However, both fungi are equally susceptible to the ongoing flow of stimuli present within the environment. The objective of our research is to understand how different fungi respond to specific cues found within or outside their natural environment. Four stimuli were tested on C. albicans: estradiol (E2), media morphology, and irradiated and non-radiated plastic microfibers. Three stimuli were tested on N. crassa: plastic non-radiated microfibers, simulated microgravity, and cold shock. C. albicans was tested only on solid agar plates, while N. crassa was tested on both liquid and solid agar media. Specialized minimal media plates containing microfibers were made to test irradiated and non-radiated microfiber exposure. While C. albicans expressed no sensitivity to 0.1nM E2, it displayed three types of morphology when grown on either minimal, Spider, or YEPD media. N. crassa showed no sensitivity towards microfibers, but C. albicans exhibited varying degrees of inhibition for colony formation. Under simulated microgravity, N. crassa did not show significant morphological differences besides a possible increase in the amount of conidia present, however, results are inconclusive

Effects of Environmental Factors on Candida albicans Morphology: A Focus on Estrogen and Microgravity

During body invasion, C.albicans change their morphology from yeast to filamentous, but the environmental factors responsible for the change in morphology are not well characterized. During Sepsis, high levels of estrogen (E2) are recorded (~0.1 nM), in addition during spaceflight it has been shown that C.albicans become virulent. In this study, we aimed at characterizing the effect of estrogen and microgravity as environmental factors inducing filamentous growth. In our experiments, we grow C.albicans in minimum liquid media and use brightfield microscopy to observe the morphology. Microgravity is simulated using a clinostat. In an experimental series, we tested the effect of FBS (positive control) and estrogen on filamentous growth. We found that in the control only 1 out of 10 slides showed filaments. In the presence of FBS, we found filamentous growth in 10 out of 10 slides. In the presence of estrogen, filaments were observed in 8 out of 10 slides. In addition to FBS, the combination of FBS + E2 we found filament growth in 10 out 10 of the slides. However, in the presence of microgravity, we observed filaments in 9 out of 10 slides, meanwhile, we only observed 4 out of 10 slides without microgravity. In addition to microgravity, the combination of E2 + Microgravity, filaments were observed in 3 out of 10 slides. Meanwhile, we only observed 4 out of 10 slides with just E2. In conclusion, estrogen does not inhibit filament growth stimulated by FBS, but it prevents filamentous growth in microgravity