192 research outputs found
Estimating the value of demand-side management in low-cost, solar micro-grids
No full textDemand-side management has the potential to reduce the cost of solar based community micro-grids and solar home systems for electricity access. This paper presents a methodology for optimal least-cost sizing of generation assets while meeting explicit reliability constraints in micro-grids that are capable of active demand management. The battery management model considers kinetic constraints on battery operation and represents dispatch in the field to regulate the depth of discharge. The model allows consideration of the trade-off between depth of discharge, cycle life, and calendar lifetime in lead-acid batteries. Separate reliability targets for disaggregated, residential load profiles at hourly timesteps are considered to evaluate the performance and cost reduction potential of demand-side management capabilities — with economic results and sensitivity analyses around key input assumptions subsequently presented. We find that demand-side management can reduce the number and cost of requisite solar panels and batteries with the integration of real-time management and controls – a key result for justifying next generation micro-grids for electricity access. Keywords: Micro-grids, Electricity access, Demand-side management, Reliability, Asset selection, Off-grid, Techno-economic model, CostMassachusetts Institute of Technology. Tata Center for Technology and Desig
A novel PCM1-PDGFRB fusion in a patient with a chronic myeloproliferative neoplasm and an ins(8;5)
No full textEarly and late-onset veno-occlusive disease/sinusoidal syndrome post allogeneic stem cell transplantation – a real-world UK experience
No full textClassical veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is a serious complication post allogeneic hematopoietic stem cell transplantation (HSCT). Before the recently revised EBMT criteria, the Baltimore and modified Seattle criteria failed to recognize the syndrome of late-onset VOD. We present real-world experience from a large UK transplant center reporting on VOD/SOS in consecutive HSCT adult patients (n = 530), transplanted for hematological cancers. We identified 27 patients treated with Defibrotide for VOD/SOS diagnosis, where detailed data were available for final analysis. Using standard definitions including EBMT criteria, around 30% (n = 8/27) of cases classified as late-onset VOD presenting at median of 46 (22-93) days but with D100 survival (63% vs 58%, Log-rank; P = 0.81) comparable to classical VOD. Hazard ratio for D100 mortality was 2.82 (95% CI: 1.74-4.56, P <.001, Gray test) with all VOD/SOS events. Twenty percent (n = 2/8) of late-onset VOD patients were anicteric and 42% (n = 8) classical VOD patients presented with refractory thrombocytopenia, while less than half met EBMT criteria for classical VOD in adults, highlighting gaps in real-world diagnostic limitations using EBMT criteria. However, challenges remain about underrecognition and difficulties related to early defibrotide access for treatment of late-onset VOD in current treatment guidelines. Our report strongly supports early Defibrotide for the treatment of severe VOD/SOS in adults regardless of time of onset.</p
Optimal sizing of solar and battery assets in decentralized micro-grids with demand-side management
No full textThesis: S.M. in Technology and Policy, Massachusetts Institute of Technology, School of Engineering, Institute for Data, Systems, and Society, Technology and Policy Program, 2017.Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.Cataloged from PDF version of thesis.Includes bibliographical references (pages 199-209).Solar-based community micro-grids and individual home systems have been recognized as key enablers of electricity provision to the over one billion people living without energy access to-date. Despite significant cost reductions in solar panels, these options can still be cost-prohibitive mainly due over-sizing of generation assets corresponding with a lack of ability to actively manage electricity demand. The main contribution shared is the methodology and optimization approach of least-cost combinations of generation asset sizes, in solar panels and batteries, subject to meeting reliability constraints; these results are based on a techno-economic modeling approach constructed for assessing decentralized micro-grids with demand-side management capabilities. The software model constructed is implemented to represent the technical characteristics of a low-voltage, direct current network architecture and computational capabilities of a power management device. The main use-case of the model presented is based on serving representative, aggregated, household-level load profiles combined with simulated power output from solar photovoltaic modules and the kinetic operating constraints of lead-acid batteries at hourly timesteps over year-long simulations. The state-space for solutions is based on available solar module and battery capacities from distributors in Jharkhand, India. Additional work presented also extends to real-time operation of such isolated micro-grids with requisite local computation. First, for load disaggregation and forecasting purposes, clustering algorithms and statistical learning techniques are applied on quantitative results from inferred load profiles based on data logged from off-grid solar home systems. Second, results from an optimization approach to accurately parametrize a lead-acid battery model for potential usage in real-time field implementation are also shared. Economic results, sensitivity analyses around key technical and financial input assumptions, and comparisons in cost reductions due to the optimization of solar and battery assets for decentralized micro-grids with demand-side management capabilities are subsequently presented. The work concludes with insights and policy implications on establishing differentiated willingness-to-pay, tiers of service, and dynamic price-setting in advanced micro-grids.by Varun Mehra.S.M. in Technology and PolicyS.M
Essays in Finance and Macroeconomics: Household Financial Obligations and the Equity Premium
No full textabstract: This dissertation is a collection of three essays relating household financial obligations to asset prices. Financial obligations include both debt payments and other financial commitments.
In the first essay, I investigate how household financial obligations affect the equity premium. I modify the standard Mehra-Prescott (1985) consumption-based asset pricing model to resolve the equity risk premium puzzle. I focus on two channels: the preference channel and the borrowing constraints channel. Under reasonable parameterizations, my model generates equity risk premiums similar in magnitudes to those observed in U.S. data. Furthermore, I show that relaxing the borrowing constraint shrinks the equity risk premium.
In the Second essay, I test the predictability of excess market returns using the household financial obligations ratio. I show that deviations in the household financial obligations ratio from its long-run mean is a better forecaster of future market returns than alternative prediction variables. The results remain significant using either quarterly or annual data and are robust to out-of-sample tests.
In the third essay, I investigate whether the risk associated with household financial obligations is an economy-wide risk with the potential to explain fluctuations in the cross-section of stock returns. The multifactor model I propose, is a modification of the capital asset pricing model that includes the financial obligations ratio as a ``conditioning down" variable. The key finding is that there is an aggregate hedging demand for securities that pay off in periods characterized by higher levels of financial obligations ratios. The consistent pricing of financial obligations risk with a negative risk premium suggests that the financial obligations ratio acts as a state variable.Dissertation/ThesisDoctoral Dissertation Economics 201
HAPLOIDENTICAL TRANSPLANT WITH POST-TRANSPLANT CYCLOPHOSPHAMIDE FOR ACUTE MYELOID LEUKAEMIA AND MYELODYSPLASTIC SYNDROMES PATIENTS: THE ROLE OF PREVIOUS LINES OF THERAPY.
No full textBackground: Allogeneic haematopoietic stem-cell transplant is a potentially curative option for high-risk acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS) patients. Post-transplant cyclophosphamide administration allows for selection of haploidentical donors in patients who are eligible for the procedure, but do not have a fully matched donor, since it can overcome the HLA barrier. There is still an active debate on whether intensification of the conditioning regimen is necessary with haploidentical donors when peripheral blood stem cells are used as the source of the graft.
Herein we report our decennial experience of haploidentical stem-cell transplant using peripheral blood stem cells at King’s College Hospital.
Objectives: The primary objective was to evaluate overall survival (OS) for patients with less than two previous lines of therapy. Secondary objectives were total OS, OS according to cytomegalovirus (CMV) reactivation, incidence of transplant-related mortality (TRM), graft-versus-host disease (GVHD) and GVHD-relapse-free survival (GRFS).
Results: One-year and three-year total OS were 62% and 43%, respectively, with a median OS of 22 months. One-year and three-year OS for patients with ≤2 and in patients with >2 previous lines of therapy were 72% and 55%, and 60% and 22%, respectively (p-value=0.04). The median OS in patients with >2 previous lines of therapy and ≤2 lines of therapy was 16 and 49 months, respectively. Cumulative incidence (CI) of relapse was 25% with a median time to relapse of 5 months (range 1 – 38 months).
Conclusions: Haploidentical haematopoietic stem-cell transplant is potentially curative in chemo-sensitive AML and MDS and offers a high rate of prolonged remission. Our cohort further confirms the role of consolidative haploidentical transplant in patients in complete remission and highlights that patients with heavily pre-treated disease may not benefit from this strategy.
FLUDARABINE-MELPHALAN-CAMPATH FOLLOWED BY UNMANIPULATED PERIPHERAL-BLOOD HAEMATOPOIETIC STEM CELLS CAN STILL CURE LYMPHOMA.
No full textBackground: The second decade of this millennium was characterized by a widespread availability of chimeric antigen receptor T-cell (CAR-T)therapies to treat relapsed and refractory lymphomas.
As expected, the role and indication of allogeneic haematopoietic stem cell transplant(allo-HSCT)in the management of lymphoma changed. Currently a not unneglectable proportion of patients will be considered candidate for an allo-HSCT and the debate of which transplant platform should be offered is still active.
Objectives:to report the outcome of patients affected with relapsed/refractory lymphoma and transplanted following reduced intensity conditioning at King’s College Hospital, London, between January 2009 and April2021. Methods: Conditioning was with fludarabine 150mg/m2 and melphalan 140mg/m2. The graft was unmanipulated G-CSF mobilized peripheral blood haematopoietic stem cells(PBSC). Graft-versus-host disease (GVHD) prophylaxis consisted of pre-transplant Campath at the total dose of 60 mg in unrelated donors and 30 mg in fully matched sibling donors, and ciclosporin.
Results: One year and five years OS were87% and79.9%, respectively and median OS was not reached. Cumulative incidence of relapse was 16%.Incidence of acute GVHD was 48%(only grade I/II); no cases of grade III/IV were diagnosed. Chronic GVHD occurred in 39% of patients. TRM was 12%, with no cases developed within day 100 and 18months after the procedure.
Conclusions:The outcomes of heavily pretreated lymphoma patients are favorable with median OS and survival not reached after a median of 49months. In conclusion, even if some lymphoma subgroups can’t be treated (yet) with advanced cellular therapies, this study confirms the role of allo-HSCT as a safe and curative strategy
The Romanticization of Mental Illness and Substance Abuse in Young Adult Media
No full textabstract: The following creative project defends that, whether intentionally or not, mental illness and substance abuse are inevitably romanticized in young adult media and discusses the dangers of this romanticization. This project is divided into three parts. The first part consists of psychological evaluations of the main characters of two popular, contemporary forms of young adult media, Catcher in the Rye by J.D Salinger and Euphoria by Sam Levinson. These evaluations use textual evidence and the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) to determine what symptoms of psychopathology the characters appear to display. The second part consists of a self-written short story that is meant to accurately depict the life of a young adult struggling with mental illness and substance abuse. This story contains various aesthetic techniques borrowed from the two young adult media forms. The final part consists of an aesthetic statement which discusses in depth the aesthetic techniques employed within the short story, Quicksand by Anisha Mehra. (abstract
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