14 research outputs found
Introducing Einstein's Relativity: A deeper understanding
No full textThere is little doubt that Einstein's theory of relativity captures the imagination. Not only has it radically altered the way we view the universe, but the theory also has a considerable number of surprises in store. This is especially so in the three main topics of current interest that this book reaches, namely: black holes, gravitational waves, and cosmology. The main aim of this textbook is to provide students with a sound mathematical introduction coupled to an understanding of the physical insights needed to explore the subject. Indeed, the book follows Einstein in that it introduces the theory very much from a physical point of view. After introducing the special theory of relativity, the basic field equations of gravitation are derived and discussed carefully as a prelude to first solving them in simple cases and then exploring the three main areas of application. This new edition contains a substantial extension content that considers new and updated developments in the field. Topics include coverage of the advancement of observational cosmology, the detection of gravitational waves from colliding black holes and neutron stars, and advancements in modern cosmology. Einstein's theory of relativity is undoubtedly one of the greatest achievements of the human mind. Yet, in this book, the author makes it possible for students with a wide range of abilities to deal confidently with the subject. Based on both authors' experience teaching the subject this is achieved by breaking down the main arguments into a series of simple logical steps. Full details are provided in the text and the numerous exercises while additional insight is provided through the numerous diagrams. As a result this book makes an excellent course for any reader coming to the subject for the first time while providing a thorough understanding for any student wanting to go on to study the subject in depth<br/
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No full textThe author wishes to acknowledge the contributions of Mercedes Reaves and Raymon
Cleanup Memory in Biologically Plausible Neural Networks
No full textI hereby declare that I am the sole author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public. ii During the past decade, a new class of knowledge representation has emerged known as structured distributed representation (SDR). A number of schemes for encoding and manipulating such representations have been developed; e.g. Pol-lack’s Recursive Auto-Associative Memory (RAAM), Kanerva’s Binary Spatter Code (BSC), Gayler’s MAP encoding, and Plate’s Holographically Reduced Rep-resentations (HRR). All such schemes encode structural information throughout the elements of high dimensional vectors, and are manipulated with rudimentary algebraic operations. Most SDRs are very compact; components and compositions of components are all represented as fixed-width vectors. However, such compact compositions are unavoidably noisy. As a result, resolving constituent components requires a cleanup memory. In its simplest form, cleanup is performed with a list of vectors that are sequentially compared using a similarity metric. The closest match is deemed the cleaned codevector. While SDR schemes were originally designed to perform cognitive tasks, none of them have been demonstrated in a neurobiologically plausible substrate. Po-tentially, mathematically proven properties of these systems may not be neurally realistic. Using Eliasmith and Anderson’s 2003 Neural Engineering Framework, I construct various spiking neural networks to simulate a general cleanup memory that is suitable for many schemes. Importantly, previous work has not taken advantage of parallelization or the high-dimensional properties of neural networks. Nor have they considered the ef-iii fect of noise within these systems. As well, additional improvements to the cleanup operation may be possible by more efficiently structuring the memory itself. In this thesis I address these lacuna, provide an analysis of systems accuracy, capac-ity, scalability, and robustness to noise, and explore ways to improve the search efficiency. i
Transformative Liminality: A Reading of Genevieve L. Asenjo’s “Pangungumusta mula sa Balaan Bukid”
No full textIn 2021, Filipino writer Genevieve L. Asenjo published her short story collection titled Ang Itim na Orkidyas ng Isla Boracay. Hailed as “Best Book of Short Fiction in Filipino” during the 40th National Book Awards, it consists of narratives that delve into the entanglement of the Philippines, the United States of America, and South Korea. Specifically, in the story “Pangungumusta mula sa Balaan Bukid” (“Pangungumusta” from hereon), South Korea is imagined as a liminal space for the “migratory,” namely, the migrant workers and refugees. In postcolonial thought, a liminal space is perceived as a threshold, a doorway, or a portal where waiting happens, interactions are exchanged, and decisions are made; and as such, in The Location of Culture, theorist Homi K. Bhabha describes it as an “in-between” space of ambivalence, a “third space” where there is neither self nor other. While existing discussions on migrant workers and refugees tend to focus on identity and mobility, the novelty of this paper lies in its problematization of the transformative point of their interaction: What happens when an Overseas Filipino Worker (OFW) gets entangled with a Palestinian refugee in Seoul? How does their interaction offer new perspective on what a liminal space is? The primary method is a textual analysis of “Pangungumusta” through a postcolonial lens. The author argues that in such entanglement a liminal space becomes transformative; and so, it is that which “naghatid . . . sa isang uri ng kaluwalhatian” (ushered in a kind of glory; Asenjo, 2021: 69). This paper is composed of three primary sections: an introduction of Asenjo and her works, a presentation of the plot of “Pangungumusta” and commentary on its postmodern form, and a discussion of liminal space as imagined in the narrative, concluding that liminality is indeed transformative, that is, as the liminal space spatially brings the characters together, it at the same time spells out their ideological differences, which makes transformation possible.
Criticism of Raymon Panikkar's cosmoteandism
No full textWydział Teologii, Instytut Nauk Teologicznych; promotor rozprawy doktorskiej: o. dr hab. Ireneusz S. Ledwoń, prof. KULCelem niniejszej pracy jest krytyka myśli Raimona Panikkara z pozycji katolickiej. Raiomon Panikkar to jeden z najważniejszych teologów dialogu międzyreligijnego, który swą myśl ujął w system określający wzajemne relacje Boga, człowieka i kosmosu, czyli kosmoteandryzm, mający stanowić intelektualne uzasadnienie dla spotkania religii i ich przekształcenia, To przekształcenie dokonało się najpierw u teologa, który zaczynał swą pracę naukową jako ksiądz katolicki poszukujący obecności Chrystusa w hinduizmie, a skończył jako międzyreligijny intelektualista przypisujący sobie cztery tożsamości: chrześcijańską, hinduistyczną, buddyjską i ateistyczną, które - jego zdaniem - nie wykluczały się. Kosmoteandryzm dostarcza uzasadnienia dla tak radykalnie pojętego pluralizmu religijnego. Pierwszy rozdział pokazał źródła systemu Panikkara w myśli zachodniej, z jej przeświadczeniem o kryzysie świata, które autor ten czyni uzasadnieneim swoich refleksji. Odpowiedzią na kryzys jest przemyślenie idei religijnych, a zwłaszcza Trójcy, pokazaną na przykładzie Boskości, człowieka i kosmosu, które autor łączy z trzema jej Osobami, czemu w pracy tej odpowiadają rozdziały 2, 3 i 4. Ostatni rozdział zawiera krytykę tego systemu w odniesieniu do metody teologii katolickiej, kościelnego wyznania wiary, a także Karla Poppera krytyki historycyzmów.The purpose of this work is to criticize the ideas of Raimon Panikkar from Catholic position. Raimon Panikkar is one of the most important theologians of interreligious dialogue, who put his thought into a system defining the mutual relations between God, man and the cosmos, i.e. cosmoteandism, which was to constitute an intellectual justification for the meeting of religions and their transformation. This transformation took place first within the Panikkar himself, who began his scientific work as a catholic priest seeking the presence of Christ in Hinduism but ended up as an interreligious intelectual who ascribed four identities: Christian, Hindu, Buddhist and atheistic, which in his opinion were not mutually exclusive. Cosmoteandrism provides justification for such a claim, as well as for his radical religious pluralism. The first chapter showed the cosmoteandrism in Western thought, with its conviction of a world crisis that this author uses as justification for his mindset, as he tries to answer to the crisis with rethinking of religious ideas, especially the Trinity. He connects Divinity, man and the cosmos, with the three Persons, which in this work corresponds to chapter 2, 3, and 4. The last chapter contains a critique of Panikkar's system from a perspective of Catholic theology, church faith and Karl Popper's criticism of historicism
The economic and law of rent control
No full textThe authors construct a model of second-generation rent control, describing a regime that does not permit rent increases for sitting tenants--or their eviction. When an apartment becomes vacant, however, the landlord is free to negotiate a new contract with a higher rent. They argue that this stylized system is a good (though polar) approximation of rent control regimes that exist in many cities in India, the United States, and elsewhere. Under such a regime, if inflation exists, landlords prefer to rent to tenants who plan to stay only a short time. The authors assume that there are different types of tenants (where"type"refers to the amount of time tenants stay in an apartment) and that landlords are unable to determine types before they rent to a tenant. Contracts contingent on departure date are forbidden, so a problem of adverse selection arises. Short stayers are harmed by rent control while long-term tenants benefit. In addition, the equilibrium is Pareto inefficient. The authors show that when tenant types are determined endogenously (when a tenant decides how long to stay in one place based on market signals) in the presence of rent control, there may be multiple equilibria, with one equilibrium Pareto-dominated by another. In other words, many lifestyle choices are made based on conditions in the rental housing market. One thing rent control may do is decrease the mobility of the labor force, because tenants may choose to remain in a city where they occupy rent-controlled apartments rather than accept a higher-paying job in another city. The authors show that abolishing the rent control regime can do two things: shift the equilibrium to a better outcome and result in lower rents, across the board.International Terrorism&Counterterrorism,Economic Theory&Research,Health Economics&Finance,Housing&Human Habitats,Payment Systems&Infrastructure,International Terrorism&Counterterrorism,Banks&Banking Reform,Economic Theory&Research,Health Economics&Finance,Housing&Human Habitats
Historically black united negro college fund college/university alumni to increase student retention, 1986
No full textThis study was conducted to identify some retention strategies utilized by alumni to reduce the attrition of students so as to insure stable enrollments and the basis for fiscal stability at United Negro College Fund HBCU's. Since there was no known instrument to measure the concepts in the study, a questionnaire was constructed by the writer and field-tested by a panel of experts who gave valuable feedback for test improvement of the instruments. The data were analyzed by using correlation coefficients and the F-ratio. The following are major findings of the study; 1.That taken individually or collectively, alumni strategies in recruitment, financial aid, activities for student retention, and alumni affairs had some, but relatively little, effect on student retention? 2.That a combination of the four previously mentioned alumni strategies likewise had little impact on retention strategies; 3.That there were twenty-one states that were identified as strong recruitment possibilities but the three top areas for the UNCF/HBCO's are Illinios, Texas, and the District of Columbia. In light of the findings, the following conclusions were drawni 1.Although at this particular time period, the impact of alumni retention activities was almost nil. 2.That alumni can begin to build up even stronger recruitment possibilities in the cities mentioned. 3.That directors of alumni affairs play a key role in the student retention process and should work along with the registrars to keep abreast of retention statistics. 4.That alumni must try many strategies in order to be highly effective in the retention of students
Learning and monetary policy shifts
No full textThis paper estimates a dynamic stochastic equilibrium model in which agents use a Bayesian rule to learn about the state of monetary policy. Monetary policy follows a nominal interest rate rule that is subject to regime shifts. The following results are obtained. First, the author's policy regime estimates are consistent with the popular view that policy was marked by a shift to a high-inflation regime in the early 1970s, which ended with Volcker's stabilization policy at the beginning of the 1980s. Second, while Bayesian posterior odds favor the "full-information" version of the model in which agents know the policy regime, the fall of inflation and interest rates in the disinflation episode in the early 1980s is better captured by the delayed response of the "learning" specification. Third, the author examines the magnitude of the expectations-formation effect of monetary policy interventions in the "learning" specification by comparing impulse responses to a version of the model in which agents ignore the information contained in current and past monetary policy shocks about the likelihood of a regime shift.Equilibrium (Economics) ; Monetary policy ; Macroeconomics ; Inflation (Finance) ; Forecasting
Evofosfamide sensitizes esophageal carcinomas to radiation without increasing normal tissue toxicity
No full textBackground and purpose: Esophageal cancer incidence is increasing and is rarely curable. Hypoxic tumor areas cause resistance to conventional therapies, making them susceptible for treatment with hypoxia-activated prodrugs (HAPs). We investigated in vivo whether the HAP evofosfamide (TH-302) could increase the therapeutic ratio by sensitizing esophageal carcinomas to radiotherapy without increasing normal tissue toxicity.Materials and methods: To assess therapeutic efficacy, growth of xenografted esophageal squamous cell (OE21) or adeno (OE19) carcinomas was monitored after treatment with TH-302 (50 mg/kg, QD5) and irradiation (sham or 10 Gy). Short- and long-term toxicity was assessed in a gut mucosa and lung fibrosis irradiation model, sensitive to acute and late radiation injury respectively. Mice were injected with TH-302 (50 mg/kg, QD5) and the abdominal area (sham, 8 or 10 Gy) or the upper part of the right lung (sham, 20 Gy) was irradiated. Damage to normal tissues was assessed 84 hours later by histology and blood plasma citrulline levels (gut) and for up to 1 year by non-invasive micro CT imaging (lung).Results: The combination treatment of TH-302 with radiotherapy resulted in significant tumor growth delay in OE19 (P = 0.02) and OE21 (P = 0.03) carcinomas, compared to radiotherapy only. Irradiation resulted in a dose-dependent decrease of crypt survival (P <0.001), mucosal surface area (P <0.01) and citrulline levels (P <0.001) in both tumor and non-tumor bearing animals. On the long-term, irradiation increased CT density in the lung, indicating fibrosis, over time. TH-302 did not influence the radiation-induced short-term and long-term toxicity, confirmed by histological evaluation.Conclusion: The combination of TH-302 and radiotherapy might be a promising approach to improve the therapeutic index for esophageal cancer patients. (C) 2019 The Author(s). Published by Elsevier B.V.</p
