1983 research outputs found
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Implications of a Future Biofuels Market for Economic Development and International Trade. Report of a workshop held at the Kennedy School of Government, Harvard University, 9 May 2007
No full textVersion of Recor
D-instantons and String Field Theory
No full textIn this thesis, we study D-instanton contributions to supergraviton scattering amplitudes in ten-dimensional type IIB superstring theory beyond the leading non-perturbative order. Our computation is based on the Neveu-Schwarz-Ramond (NSR) formalism with picture changing operators and vertical integration. In the first chapter, we determine the single D-instanton contribution to maximal R-symmetry violating (MRV) amplitudes with arbitrary momenta at the first subleading order in string coupling, as well as the effects of a D-/anti-D-instanton pair at leading nontrivial order in the momentum expansion. These results confirm a number of predictions of S-duality, and unveil some previously unknown pieces of type IIB string amplitudes.
The naive on-shell prescription for D-instanton mediated amplitudes, based on integration over the moduli space of worldsheet geometries as well as that of D-instanton boundary conditions, suffers from potential open string divergences and regularization ambiguities. In the second chapter, we employ the framework of open+closed superstring field theory (SFT) to address such issues. From this, we are able to unambiguously compute a part of the momentum-independent constant that appears at first subleading order in the string coupling, which serves as a highly nontrivial consistency check on spacetime supersymmetry and soft relations
A Market for Impact
No full textThere are two fundamental problems in philanthropy: 1) information aggregation, to allow for the broad assessment of the wide range of charities, and 2) incentive alignment, to better incentivize philanthropists to donate to effective charities. This paper address these two problems through the design of a novel market for impact. We define three classes of contracts that will be traded for a given charity, the units they will be traded in, and provide the full specification of how such a market would be implemented in practice. We then consider equilibrium conditions of the market under specified individual belief distributions and simulate market participant demand to show that the equilibrium price equals the mean belief of market participants. This result suggests that the market is efficient. Finally, we develop numerous techniques to approximate other attributes of the contracts including volatility and the distributions of the true values themselves
“Strength is a Product of Trust”: An Ethnographic Study of Trauma-Informed Weight Lifting in the United States
No full textSince the initial recognition of post-traumatic stress disorder (PTSD) by the American Psychiatric Association in 1980, a growing repertoire of evidence-based therapeutic options have become available for people impacted by trauma. In the past few years, several American gyms have served as generative sites for people impacted by trauma to share their experiences of healing through weight lifting. Committed to increasing access to weight lifting as therapy, a community of weight lifting coaches and psychotherapists have begun to offer trauma-informed weight lifting— an emerging approach to addressing the impacts of trauma premised upon the perceived therapeutic aspects of weight lifting. As its central question, this research asks: what is trauma-informed weight lifting, and how might it reconfigure both the bodies and embodied subjectivities of people who have experienced trauma? Through 34 months of ethnographic fieldwork, this research explores what possibilities for healing emerge when weight lifting becomes the medium through which trauma is processed, interpersonal bonds are formed, and new forms of embodiment are accessed
Novel Agonist TREM2 Monoclonal Antibodies Activate Syk-Associated Cell Signaling Pathways
No full textTriggering receptor expressed on myeloid cells 2 (TREM2), a protein expressed on the surface of microglia, is genetically linked to, and a therapeutic target for Alzheimer’s disease (AD). As a myeloid cell receptor, TREM2 binds a variety of ligands, including AD-related proteins apolipoprotein E (ApoE) and β-amyloid. Upon stimulation, TREM2 activates various cell signaling pathways that drive microglial functions capable of ameliorating or accelerating AD progression and pathology (Ennerfelt et al., 2022; Gratuze et al., 2018; Leyns et al., 2017; Price et al., 2020; Takahashi et al., 2007; Takahashi et al., 2005; Wang et al., 2015; Wang et al., 2016; Wang et al., 2020; Zhao et al., 2018). Characterization of TREM2 signaling pathways mediating these functions, however, is incomplete. Further investigation of these signaling cascades is required to understand the function of TREM2 in AD beyond its genetic component. The goal of this research was to generate novel agonist monoclonal antibodies to activate cells in vitro in a TREM2-dependent manner, and to examine the phosphorylation state of potential downstream targets. We screened a library of rabbit host monoclonal antibodies that were raised against the ectodomain of human or mouse TREM2 by western blot to identify clones that were target specific. We then identified several clones that could activate cell signaling pathways downstream of TREM2 in vitro. These pathways include the activation of spleen tyrosine kinase (Syk), which is suggested to be downstream of TREM2/DAP12 microglial activation (Ennerfelt et al., 2022; Gratuze et al., 2018; Jay et al., 2017; McQuade et al., 2020; Schlepckow et al., 2020; Wang et al., 2020; Zhao et al., 2018). Syk activation was characterized using phospho-specific anti-Syk monoclonal antibodies. Having established tools to activate TREM2, we screened other downstream proteins related to Syk signaling that may also be engaged by TREM2 activation. Based on our findings, we suggest that Syk phosphorylation is indeed a reliable readout for TREM2-dependent microglia activation. We further suggest that the antibodies validated herein can be leveraged to further characterize signaling events and cellular responses (phagocytosis, inflammation, proliferation, etc.) downstream of TREM2. Full characterization of TREM2 signaling cascades can be applied to AD therapeutic research, targeting the benefits of upregulating or downregulating TREM2-dependent microglial activation to attenuate AD pathology
How Pindar’s Homer Might Save From Harm the Heroic Glory of Ajax
No full textIn this essay I attempt to explain, though only in its barest outlines, Pindar’s poetic project of picturing ‘Homer’ as a potential savior of the glory deserved by Ajax, hero of Salamis—despite this Homer’s generally indiscriminate taste, it is claimed, for greedily savoring all the delicacies of all the myths cooked up for him by way of epic poetry—I use the word ‘myths’ here only for the moment in rendering the original Greek word, mûthoi. For Pindar, as a master of lyric song in the earlier part of the fifth century BCE, the mûthoi of epic poetry are harmful because of their inherent relativism—a relativism that results, supposedly, from uncritical and indiscriminate inclusions of localized variations in epic storytelling. Such variations, which tend to contradict each other in content, are blamed on a ‘Homer’ who is imagined in Pindar’s songs as a prototypical master poet of all epic poetry. In terms of Pindar’s songs, the relativism of mûthoi in the epic poetry of this proto-poet Homer threatens to shade over the unified alḗtheia or absolute ‘truth’ of heroic glory as supposedly illuminated in Pindar’s own lyric songs. It is in the light of such a selective lyric program that Pindar’s songs focus on the desperate feelings of Ajax in that agonizing moment when this hero’s own fellow Achaeans awarded the arms of the fallen super-hero Achilles, the best of the Achaeans, to Odysseus and not to Ajax. Reacting to the indignity that he has just suffered, Ajax expresses his cosmic desperation by committing suicide. He skewers himself on a sword that he had received as a gift, once upon a time, from his admiring martial opponent Hector. This suicide of Ajax is blamed in Pindar’s songs on shameless distortions of truth—yes, distortions made possible by way of Homer’s shamelessly indiscriminate inclusions of all too many tasty epic variations that this prototypical poet of epic, as pictured in Pindar’s lyric song, was savoring all too greedily. And yet, despite such a negative picturing of epic repertoire, it is also claimed in Pindar’s song that the despair of Ajax might be mitigated, that there might still be hope, genuine hope, for saving the heroic glory deserved by Ajax. Such a hoped-for salvation might still be achieved, it is claimed, by way of judicious selectivity in rethinking Homer’s menu, as it were, and even in a rethinking of Homer himself. Pindar’s Homer, as represented in his own lyric song, thus becomes an improved Homer who must be more discriminating, more selective, in viewing the heroes of the epic past.The ClassicsVersion of Recor
The Life-Long Learning Compass: Curating Collective Wisdom for Action Towards a Shared North Star for the Future of Work and Learning
No full textThe Future of Work and Learning looks bleak to some, incites worry in others and signals an opportunity for widespread education and workforce innovations and invention in others. Unfortunately, the latter are counted among the few. With staggering realities that more than 50% of jobs will be forever transformed by automation. Or the fact that 65% of the jobs that Generation Alpha will work in don’t even exist today; many are grappling with ‘how will we prepare learners for the Future of Work and Learning, if we do not know what to expect?’ How do we ensure that our most vulnerable people are not disproportionately devastated by the rapid innovations and changes? What is a solution that is accessible to- and inclusive of many communities no matter their resource constraints?
The future is surely bright, not bleak, and here is a solution. First, we ignite and accept a paradigm shift in education which will bring with it new mental models for thinking about learning and even workers. This paradigm shift calls for us to see learning as lifelong, continuous and a journey. Given the inevitable changes and amount of unknowns that comes with rapid development, technological advancements —and just about any journey— we then anchor in the only variable that remains constant throughout all of this uncertainty, which is the human being and the essence of our humanity. The solution is to equip ourselves for this journey the way we would prepare for any other. By identifying and locating our ‘true north star’ and equipping ourselves with a compass to navigate the uncertainty that lies ahead. Just as with any journey, we can navigate individually, in small teams or as an entire community, the point is that we are prepared with The Lifelong Learning Compass in hand.
Distinctly crafted with dual-transformational aspirations (transform people to transform systems and vice-versa) The Lifelong Learning Compass was designed to guide, support and develop the unique characteristics and competencies of each worker and learner. It begins by asking “who are we serving (through teaching and learning)?” To tailor and personalize the learning experience. Then it proceeds to ask why we are learning? And how do we support learner and worker individual and collective development? It is through the magnetization of these human centered cardinal points, that are anchored in an holistic view of those we serve, that we begin to navigate the journey ahead. The Lifelong Learning Compass illuminates that the journey forward calls for our eyes to be fixed with fidelity to our collective ‘true north.’ Which is that throughout learning and life; people should be seen, affirmed, ‘in-powered’ and protected, to activate the most powerful bi-directional force on earth, which is love
Payment Discrepancies and Access to Primary Care Physicians for Dual-eligible Medicare-Medicaid Beneficiaries
No full textImportance: Dual-eligible Medicare-Medicaid beneficiaries represent 1-in-5 Medicare beneficiaries, but providers receive less than 100% of the Medicare fee for them because of reimbursement caps in many states.
Objective: To examine how this payment differential impacts the availability of primary care physicians (PCPs) for dual vs. non-dual Traditional Medicare (TM) beneficiaries, we leverage the Affordable Care Act (ACA) primary care fee bump that temporarily eliminated this differential in 2013-2014.
Design: We used the Medicare Physician and Other Supplier Public Use File (2012-2017) to enumerate TM beneficiaries each provider billed for annually by dual status and calculate dual caseloads as a percentage of a physicians’ TM patients. We examined differences in PCPs’ Medicare dual caseloads in states with and without dual reimbursement differentials using multivariate regression models, adjusted for provider and area-level traits. We also used a triple difference approach to examine the effects of temporary and extended fee bumps vs. no bump on PCP’s dual caseloads compared with caseloads of selected specialists unexposed to the fee bump.
Setting: Traditional Medicare
Participants: PCPs and a comparison specialty group of cardiologists, orthopedic surgeons, and general surgeons
Exposure: State dual reimbursement policies and changes over time due to the ACA fee bump
Main outcome measures: Medicare dual caseloads of at least 20% (the national average) or 10% (81% of PCP’s).
Results: In 2012, prior to the fee bump, PCPs in states with lower reimbursement for duals vs. minimal differences were less likely to have a dual caseload of at least 10% (e.g., difference=-4.83 percentage points (pp) (95% CI: -7.22 to -2.44) for states with temporary fee bumps). Despite the constant proportion of dual beneficiaries, the proportion of PCPs with dual caseloads of at least 10% or 20% decreased between 2012-2017, and the fee increase was not consistently associated with increases in the likelihood of PCPs exceeding these thresholds.
Conclusions: Pre-ACA, state reimbursement caps for dual-eligibles were associated with a lower proportion of duals on PCPs’ Medicare panels. Despite the ACA’s fee bump, the proportion of physicians treating duals declined over time, raising concerns of worsening access for duals.Accepted Manuscrip
Towards upright city halls: Mechanisms of corruption at the local level in Spain
No full textA considerable amount of literature points to the fact that corruption is especially relevant at the local level of government in several countries. However, academia has not paid sufficient attention to the factors that can explain variation in local corruption, at least compared to corruption at the country level.
This research aims to shine new light on the debate around the explanatory factors of local corruption in Spain and explore the causal mechanisms behind these factors. Departing from the assertion that anti-corruption norms and regulations are mostly homogeneous at the regional or state levels, I show evidence of which demographic, political and economic factors can facilitate corruption in cities and towns.
The study uses a mixed methods research approach based on a statistical analysis of different variables that the literature has found to be related to local corruption and, based on these results, a qualitative comparative analysis of corruption in six cities.
The results of the research suggest that longevity in the local government of the same party and strong leadership mayors are risk factors for corruption, as much as a high dependence of the city council on the construction and real estate sectors. The analysis also indicates that anti-corruption controls could be failing in small municipalities, especially when there is a lack of alternation in power. These findings have implications for future anti-corruption strategies. In particular, they may help policymakers to increase the efficiency of public integrity tools by considering these risk factors and reviewing which controls are failing in specific contexts