Obama, Trump, and Xi: Three South China Sea Strategies in the U.S.-China Battle for Global Hegemony

The South China Sea is one of the world\u27s largest regions of untapped resources and fisheries. Moreover, one-third of all global trade flows through its waters. Due to its rapid ascension to great power status, China has been able to aggressively expand into the region and both build new islands and lay claim to already existing ones. With no other countries capable of or willing to push back against Beijing, the United States stepped in. The purpose of this thesis is to examine the strategies undertaken by the Obama administration and the Trump administration in the face of China’s expansion as a whole, and then specifically related to the South China Sea. The thesis also examines Xi Jinping’s rise to power and how his foreign policy has challenged both American presidents’ approaches. This qualitative study concludes with assessing the effectiveness of the three presidents’ strategies and how they situate in the greater rivalry, and provides an outlook for what the future of the South China Sea conflict and greater Sino-U.S. relations will look like

From Observers to Participants: Joining the Scientific Community

In this essay, we have integrated the voices of our mentors and students to explore 45 years of undergraduate research experiences and their role in shaping our scientific community. In considering our collective experiences, we see undergraduate involvement in research as a rich source of community development, one that has both touched our lives and influenced our teaching

Global dynamic optimization

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2004.Includes bibliographical references (p. 247-256).(cont.) on a set composed of the Cartesian product between the parameter bounds and the state bounds. Furthermore, I show that the solution of the differential equations is affine in the parameters. Because the feasible set is convex pointwise in time, the standard result that a convex function composed with an affine function remains convex yields the desired result that the integrand is convex under composition. Additionally, methods are developed using interval arithmetic to derive the exact state bounds for the solution of a linear dynamic system. Given a nonzero tolerance, the method is rigorously shown to converge to the global solution in a finite time. An implementation is developed, and via a collection of case studies, the technique is shown to be very efficient in computing the global solutions. For problems with embedded nonlinear dynamic systems, the analysis requires a more sophisticated composition technique attributed to McCormick. McCormick's composition technique provides a method for computing a convex underestimator for for the integrand given an arbitrary nonlinear dynamic system provided that convex underestimators and concave overestimators can be given for the states. Because the states are known only implicitly via the solution of the nonlinear differential equations, deriving these convex underestimators and concave overestimators is a highly nontrivial task. Based on standard optimization results, outer approximation, the affine solution to linear dynamic systems, and differential inequalities, I present a novel method for constructing convex underestimators and concave overestimators for arbitrary nonlinear dynamic systems ...My thesis focuses on global optimization of nonconvex integral objective functions subject to parameter dependent ordinary differential equations. In particular, efficient, deterministic algorithms are developed for solving problems with both linear and nonlinear dynamics embedded. The techniques utilized for each problem classification are unified by an underlying composition principle transferring the nonconvexity of the embedded dynamics into the integral objective function. This composition, in conjunction with control parameterization, effectively transforms the problem into a finite dimensional optimization problem where the objective function is given implicitly via the solution of a dynamic system. A standard branch-and-bound algorithm is employed to converge to the global solution by systematically eliminating portions of the feasible space by solving an upper bounding problem and convex lower bounding problem at each node. The novel contributions of this work lie in the derivation and solution of these convex lower bounding relaxations. Separate algorithms exist for deriving convex relaxations for problems with linear dynamic systems embedded and problems with nonlinear dynamic systems embedded. However, the two techniques are unified by the method for relaxing the integral in the objective function. I show that integrating a pointwise in time convex relaxation of the original integrand yields a convex underestimator for the integral. Separate composition techniques, however, are required to derive relaxations for the integrand depending upon the nature of the embedded dynamics; each case is addressed separately. For problems with embedded linear dynamic systems, the nonconvex integrand is relaxed pointwise in timeby Adam Benjamin Singer.Ph.D

Pick-a-Pic: An Open Dataset of User Preferences for Text-to-Image Generation

The ability to collect a large dataset of human preferences from text-to-image users is usually limited to companies, making such datasets inaccessible to the public. To address this issue, we create a web app that enables text-to-image users to generate images and specify their preferences. Using this web app we build Pick-a-Pic, a large, open dataset of text-to-image prompts and real users' preferences over generated images. We leverage this dataset to train a CLIP-based scoring function, PickScore, which exhibits superhuman performance on the task of predicting human preferences. Then, we test PickScore's ability to perform model evaluation and observe that it correlates better with human rankings than other automatic evaluation metrics. Therefore, we recommend using PickScore for evaluating future text-to-image generation models, and using Pick-a-Pic prompts as a more relevant dataset than MS-COCO. Finally, we demonstrate how PickScore can enhance existing text-to-image models via ranking

Updates in emergency department laceration management

Lacerations are a common reason for patients to seek medical attention, and are often acutely managed in the emergency department. Recent studies pertaining to closure techniques, sedation and analgesia, advances in wound care, and various other topics have been published, which may enhance our understanding of this injury and improve our management practices. This article will review pertinent studies published in the past few years relevant to laceration management. Understanding the current literature and appreciating which areas warrant further investigation will help us optimize outcomes for patients who sustain laceration injuries

Incidence, causes and outcomes of lameness cases in a working military horse population: a field study

Reasons for performing study: Lameness is a common problem in the horse. Despite this, information on the incidence of lameness in horses in the UK is restricted to studies of lameness in performance horses, racehorses or referral hospital populations. Objectives: To determine the overall incidence and common causes of lameness in a working horse population and incidence, duration and outcome of conditions observed. Study design: Prospective questionnaire study. Methods: Questionnaires were used to record lameness episodes in 294 horses in an equine military establishment. Information recorded included age, years of service, type of work, causal lesion, time taken to return to work and outcome. Lameness problems could be reported by any staff involved in the horses' care and were diagnosed by a veterinary surgeon or qualified farrier. Trends between lame and nonlame populations were compared using Chi-square analysis. Lameness diagnoses were grouped and analysed by disease category. Results: Completed questionnaires for 273 horses were analysed. The mean monthly incidence of lameness was 2.1%, equivalent to an annual rate of 25.4 cases per 100 horses per annum, with a mean of 1.2 lameness episodes per horse in the lame population. Horse age and duration of service were not significantly different between lame and nonlame populations. The most common diagnoses were cellulitis (18.6%), skin wounds (16.3%) and foot/shoeing problems (11.6%) and 88% of cases had returned to previous levels of work by the conclusion of the study. Conclusions: This initial field study showed that lameness is a common occurrence in this working military horse population and the majority of cases make a full return to work. The most common causes of lameness identified in this study and outcomes of these conditions differ from existing literature. Potential relevance: This study highlights the need for further studies of lameness in the wider horse population

The Birth and Death of Toxins with Distinct Functions: A Case Study in the Sea Anemone Nematostella

The cnidarian Nematostella vectensis has become an established lab model, providing unique opportunities for venom evolution research. The Nematostella venom system is multimodal: involving both nematocytes and ectodermal gland cells, which produce a toxin mixture whose composition changes throughout the life cycle. Additionally, their modes of interaction with predators and prey vary between eggs, larvae, and adults, which is likely shaped by the dynamics of the venom system. Nv1 is a major component of adult venom, with activity against arthropods (through specific inhibition of sodium channel inactivation) and fish. Nv1 is encoded by a cluster of at least 12 nearly identical genes that were proposed to be undergoing concerted evolution. Surprisingly, we found that Nematostella venom includes several Nv1 paralogs escaping a pattern of general concerted evolution, despite belonging to the Nv1-like family. Here, we show two of these new toxins, Nv4 and Nv5, are lethal for zebrafish larvae but harmless to arthropods, unlike Nv1. Furthermore, unlike Nv1, the newly identified toxins are expressed in early life stages. Using transgenesis and immunostaining, we demonstrate that Nv4 and Nv5 are localized to ectodermal gland cells in larvae. The evolution of Nv4 and Nv5 can be described either as neofunctionalization or as subfunctionalization. Additionally, the Nv1-like family includes several pseudogenes being an example of nonfunctionalization and venom evolution through birth-and-death mechanism. Our findings reveal the evolutionary history for a toxin radiation and point toward the ecological function of the novel toxins constituting a complex cnidarian venom.publishedVersio

Sale of UK’s Vaccine Manufacturing and Innovation Centre

Amid a surge of infections from the omicron coronavirus variant, revelations about high profile breaches of pandemic restrictions, and deepening tensions between Ukraine and Russia, a puzzling announcement has escaped the attention of many commentators—the UK government has put its Vaccine Manufacturing and Innovation Centre (VMIC) up for sale