Genomic evaluation of male reproductive adaptations and responses to dehydration in Peromyscus eremicus (Cactus mouse)

Research elucidating the genetic architecture of physiological mechanisms enabling survival and reproduction in extreme environments is becoming prominent in evolutionary biology. The desert, in particular, poses numerous challenges for its endemic species, and mammals (and often, rodents) have been the focus for survival adaptations pertaining to water-limitation. However, desert rodent adaptation research has focused predominantly on survival, while potential physiological reproductive adaptations to dehydration have received less attention, aside from research evaluating water as reproductive cue. The fact that we do not know the physiological mechanisms enabling reproduction during dehydration is surprising, as desert rodents must possess adaptations to successfully reproduce in their water-limited habitats. The cactus mouse (Peromyscus eremicus), a desert-specialist in the Southwest United States, is the focus of my genetic exploration of reproductive adaptations to dehydration. My dissertation describes three research studies that 1) characterize male cactus mouse reproductive tissue transcriptomes and find signatures of positive selection in these tissues relative to other rodent species, 2) describe differential expression of genes responding to water-limitation within testes, providing candidate genes for future studies exploring the impacts of acute and chronic drought on P. eremicus reproduction, and 3) generate a seminal vesicle proteome representative of proteins present in hydrated and dehydrated conditions experienced by the cactus mouse. These three studies contribute comprehensive genetic data critical to future research exploring the effects of water-limitation on reproduction as well as the genetic mechanisms for potential male reproductive adaptations in this desert-adapted rodent. Research on desert adaptations is particularly timely, as climate change will result in more frequent stochastic drought events and elevated temperatures. These increasing abiotic shifts will exacerbate clinical challenges for global health; thus, an enhanced understanding of mammalian desert-specialist adaptations may improve our ability to address these physiological demands in humans

A quantum advantage over classical for local max cut

We compare the performance of a quantum local algorithm to a similar classical counterpart on a well-established combinatorial optimization problem LocalMaxCut. We show that a popular quantum algorithm first discovered by Farhi, Goldstone, and Gutmannn [1] called the quantum optimization approximation algorithm (QAOA) has a computational advantage over comparable local classical techniques on degree-3 graphs. These results hint that even small-scale quantum computation, which is relevant to the current state-of the art quantum hardware, could have significant advantages over comparably simple classical computation

Approximation Algorithms for Quantum Max-dd-Cut

We initiate the algorithmic study of the Quantum Max-$d$-Cut problem, a quantum generalization of the well-known Max-$d$-Cut problem. The Quantum Max-$d$-Cut problem involves finding a quantum state that maximizes the expected energy associated with the projector onto the antisymmetric subspace of two, $d$-dimensional qudits over all local interactions. Equivalently, this problem is physically motivated by the $SU(d)$-Heisenberg model, a spin glass model that generalized the well-known Heisenberg model over qudits. We develop a polynomial-time randomized approximation algorithm that finds product-state solutions of mixed states with bounded purity that achieve non-trivial performance guarantees. Moreover, we prove the tightness of our analysis by presenting an algorithmic gap instance for Quantum Max-d-Cut problem with $d \geq 3$.Comment: 42 page

On infinite products

Call number: LD2668 .R4 1966 S53

Model Based Prediction Approach for Internal Machine Tool Heat Sources on the Level of Subsystems

AbstractModern machine tools are highly sophisticated mechatronic systems. Each subsystem's energy efficiency is important regarding thermal effects of the machine: Losses in the subsystems are mainly heat sources, causing temperature gradients and thermal elongation. Knowledge about the internal heat sources is therefore mandatory for high precision machining, as well as for the design of compensation strategies. This paper presents a modeling approach to estimate the heat release of machine tool subsystems and predict boundary conditions for thermal models. The simulation results are verified by measurements on an internal cooling system of a lathe.Video abstrac

A power assessment of machining tools

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2002.Includes bibliographical references (p. 75-76).Energy conservation is becoming a more important ideal in today's society, due to the increasing awareness of environmental and economic impacts. This project experimentally measures the power consumption, which is related to the energy consumption, of machines in the Laboratory for Manufacturing and Productivity, in order to determine the energy cost of the machines. This project then compares the results found experimentally to the theoretical minimum energy consumption in order to reference the measurements to the ideal energy consumption. Finally, this project attempts to find documentation of these energy costs in order to project the results found experimentally onto machines not physically available for measurement. This project found that the machines in the Laboratory for Manufacturing and Productivity used more energy than was necessary while running, due to the sometimes large amount of power needed to run the idle machines. The specifications given by the machine's manufacturers were adequate to estimate the maximum power requirements. Combining these estimates with the motor properties allowed one to estimate the power requirements of both unloaded operation (while the machine was idle) as well as loaded operation.by David N. Kordonowy.S.B

A comparative study on the Sayan languages (Turkic; Russia and Mongolia)

In this study, the grammar and basic lexicon of the Sayan languages (Turkic), spoken in Russia and Mongolia, are compared by means of the features found in WALS (Dryer & Haspelmath 2013). The main goal of this thesis is to provide a comparative study on four Sayan languages, namely Tuvan, Tofa, Soyot, and Dukha. Tuba, the fifth Sayan language, became extinct before it was described and studied and, therefore, it is excluded from the linguistic study. The data in this study came from the grammars by Anderson & Harrison (1999 and 2006, Tuvan), Rassadin (1971, 1978 and 2010, Tofa and Soyot) and Ragagnin (2011, Dukha). Another question that will be discussed in this thesis is the reason why Tuvan is not moribund, while its sister and daughter languages are. To answer this question, I looked at the history of the Sayan peoples and their current social status. Of all Sayan languages, Tofa showed the least Mongolian influences. This is probably because the Tofa people moved away from the Tuva Basin before the Mongols had a linguistic influence on the Tuvan language. Together with data from the grammars and historical information, a Sayan tree diagram is reconstructed. From the history and the current social status of the Sayan peoples could be concluded that the number of speakers and isolation together form the reason why Tuvan is not extinct and flourishes, while the other Sayan languages struggle to survive

“How do assignments dispose students toward research? Answer-getting and problem-exploring in first-year writing” Composition Forum

This study explores the relationship between the dispositions toward research that writing teachers convey through their assignments and those that their students express in their reflective writing. We applied the term problem-exploring to a set of dispositions described by the ACRL Framework and coded each clause of instructor assignment text and student reflective writing from six FYW sections, half of which were working with a librarian to incorporate core concepts from the Framework. We found a strong correlation between the proportion of instructors’ problem-exploring assignment language and students’ expressions of problem-exploring at end of term. The rates of problem-exploring were significantly higher for instructors and students in sections working with the Framework. Our results offer a new lens through which to view research-assignment design, provide evidence of how assignments can foster problem-exploring, and support the value of pedagogical collaboration with librarians.https://compositionforum.com/issue/48/answer-getting.phpPublished versio

Dynamic Data Driven Methods for Self-aware Aerospace Vehicles

A self-aware aerospace vehicle can dynamically adapt the way it performs missions by gathering information about itself and its surroundings and responding intelligently. Achieving this DDDAS paradigm enables a revolutionary new generation of self-aware aerospace vehicles that can perform missions that are impossible using current design, flight, and mission planning paradigms. To make self-aware aerospace vehicles a reality, fundamentally new algorithms are needed that drive decision-making through dynamic response to uncertain data, while incorporating information from multiple modeling sources and multiple sensor fidelities.In this work, the specific challenge of a vehicle that can dynamically and autonomously sense, plan, and act is considered. The challenge is to achieve each of these tasks in real time executing online models and exploiting dynamic data streams–while also accounting for uncertainty. We employ a multifidelity approach to inference, prediction and planning an approach that incorporates information from multiple modeling sources, multiple sensor data sources, and multiple fidelities