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Report to the President for year ended June 30, 2025, MIT Health
No full textThis report contains the following sections: Introduction; About MIT Health; Key Updates; Employment Updates; MIT Health utilization; MIT Health Patient Population; and MIT Student Health Insurance Plan Enrollment
Countervailing Effects of Extreme Maximum and Minimum Temperature Days on Conflict in Mainland Southeast Asia
No full textWe exploit 0.5◦ × 0.5◦ raster data to document how exceedances of the local 90th percentile thresholds for daily maximum and minimum temperatures affect conflict in mainland
Southeast Asia. We show that conflict incidence increases with extreme high maximum
temperature days and decreases with extreme high minimum temperature days. This implies that failing to control for extreme minimums understates the effects of extreme maximums. Moreover, as the frequency of extreme maximums and minimums is expected to
increase together with average temperatures, the countervailing effects at both tails of
the temperature distribution offset one another in mean-temperature regressions, helping
to explain earlier inconclusive findings for the region. We also show that the effects of
extreme maximums and minimums differ by conflict type, actors involved and affected
populations. Thus, even in the absence of an aggregate mean-temperature effect, a rising frequency of extreme temperature days may generate complex distributional conflict
incidence
The Phase Transition for Recovering a Random Hypergraph from its Edge Data
No full textThe weighted projection of a hypergraph is the weighted undirected graph with the same vertex set and edge weight equal to the number of hyperedges that contain the edge; the projection is the unweighted graph with the same vertex set and edge set consisting of edges with weight at least one. For d ≥ 3, after observing the unweighted and weighted projection of a random d-uniform hypergraph that is sampled using a generalization of the Erdős–Rényi random model, we study the recovery of a fraction of the hyperedges and the entire hypergraph. For both cases, we show that there is a sharp phase transition in the feasibility of recovery based on the density of the hypergraph, with recovery possible only when the hypergraph is sufficiently sparse. Particularly, we resolve numerous conjectures from [5]. Furthermore, we display an efficient algorithm that is optimal for both exact and partial recovery. We also analyze the phase transition for exact recovery by exhibiting a regime of probabilities that is below the exact recovery threshold by a polylogarithmic factor for which exact recovery is possible.M.Eng
Development and Characterization of Electrochemically Machined Tungsten Extractor Electrodes for Electrospray Thrusters
No full text39th International Electric Propulsion Conference, Imperial College London, London, United Kingdom 14-19 September 2025This work explores electrochemically machined (ECM) tungsten extractors as an alternative to microfabricated silicon, in order to benefit from manufacturability, improved
ion optics through chamfered apertures, reduced secondary electron emission, and the potential for thinner geometries. A custom ECM fabrication process employing a linearly
oscillating cathodic paddle in sodium hydroxide was designed to manufacture extractors
and increase aperture uniformity. Using through-mask ECM, a 76.2 µm thick tungsten
extractor was fabricated, achieving a mean aperture diameter of 368 µm with a standard
deviation of 29 µm. The extractor was integrated with a modified version of the MIT
ion electrospray propulsion system (iEPS) to form a complete thruster. Characterization
included current-voltage sweeps, angular beam scans, and retarding potential analysis.
Measured efficiencies are comparable to previous iEPS thrusters, with intercepted currents ranging approximately between 1–2% of emitted current. These results demonstrate
that ECM tungsten extractors can deliver at least similar performance to existing designs
while offering improved manufacturability and scalability for future electrospray propulsion
systems
Search for a cH signal in the associated production of at least one charm quark with a Higgs boson in the diphoton decay channel in pp collisions at TeV
No full textThis paper presents the first search for a cH signal sensitive to the coupling of the charm quark (c) to the Higgs boson (H) in the associated production of at least one charm quark with a Higgs boson decaying to two photons. The results are based on a data set of proton-proton collisions at a center-of-mass energy of 13 TeV collected with the CMS experiment at the LHC, corresponding to an integrated luminosity of 138 fb−1. Assuming the standard model (SM) rates for all other Higgs boson production processes, the observed (expected) upper limit at 95% confidence level on the cH signal strength is 243 (355) times the SM prediction. Under the same assumption, the observed (expected) allowed interval on the Higgs boson to charm quark coupling modifier, κc, is |κc| < 38.1 (|κc| < 72.5) at 95% confidence level
Topical application of Lactobacilli successfully eradicates Pseudomonas aeruginosa biofilms and promotes wound healing in chronic wounds
No full textChronic wounds are difficult to treat due to the presence of biofilm which prevents wound healing. Pseudomonas aeruginosa is one of the most common pathogens found in chronic wounds and conventional treatment strategies have been ineffective in the eradication of its biofilm, without harming the surrounding healthy tissue at the same time. Here, we introduced an innovative approach applying the probiotic product Bio-K+ (containing three lactobacilli) topically as an antimicrobial and antibiofilm agent. We identified lactic acid as the main active component. While antibiotics and antiseptics such as silver-ions only demonstrated limited efficacy, Bio-K+ was able to completely eradicate mature P. aeruginosa biofilms established in an in-vitro and ex-vivo human skin model. Furthermore, it demonstrated biocompatibility in the co-culture with human dermal fibroblasts and accelerated the migration of fibroblasts in a cell migration assay promoting wound healing. To enhance clinical practicability, we introduced Bio-K+ into the hydrocolloid dressing Aquacel, achieving sustained release of lactic acid and biofilm eradication. This new treatment approach applying probiotics could represent a major improvement in the management of chronic wounds and can be extended in treating other biofilm-associated infections
CoRE MOF DB: A curated experimental metal-organic framework database with machine-learned properties for integrated material-process screening
No full textWe present an updated version of the Computation-Ready, Experimental (CoRE) Metal-Organic Framework (MOF) database, which includes a curated set of computation-ready MOF crystal structures designed for high-throughput computational materials discovery. Data collection and curation procedures were improved from the previous version to enable more frequent updates in the future. Machine-learning-predicted properties, such as stability metrics and heat capacities, are included in the dataset to streamline screening activities. An updated version of MOFid was developed to provide detailed information on metal nodes, organic linkers, and topologies of an MOF structure. DDEC6 partial atomic charges of MOFs were assigned based on a machine-learning model. Gibbs ensemble Monte Carlo simulations were used to classify the hydrophobicity of MOFs. The finalized dataset was subsequently used to perform integrated material-process screening for various carbon-capture conditions using high-fidelity temperature-swing adsorption (TSA) simulations. Our workflow identified multiple MOF candidates that are predicted to outperform CALF-20 for these applications
The Passive Regolith Sampler: From Concept to Delivery to the Lunar Surface
No full textThis paper outlines the development and testing of two light-weight, low-cost, passive sensors developed by the MIT Space Enabled Research Group that were delivered to the moon in 2023 onboard the Rashid-1 rover as part of the Emirates Lunar Mission. The Passive Regolith Sampler (PRS) is a simple device mounted to the wheels of the rover, containing an aluminum tray with a cover plate of perforated holes of varying size and spacing. The device uses the motion of the rover wheel to press the device into the lunar surface, capturing small samples of lunar regolith in the holes. The Passive Wax Thermometer (PWT) is a collection of 10 wax samples, contained in individual capsules covered with sapphire windows. Each wax sample is an alkane with a different melting temperature determined by its chemical formula. Each wax sample undergoes temperature-dependent changes in opacity, providing a method for inferring temperature via image analysis. In preparation for lunar surface operations, the Space Enabled team performed a series of laboratory experiments and analytical analyses aiming to replicate conditions expected to be encountered during the mission. These experiments and analyses explored the physical mechanisms of the rover/regolith interaction, the lighting and thermal conditions at the landing site, and the quality of images captured from the rover mast camera. This paper outlines the results of these experiments and analyses, and their influence on the design and operations planning for the two payloads. Due to landing anomalies, the 2023 mission did not complete lunar surface operations; further work is planned to explore future operational opportunities
Report to the President for year ended June 30, 2025, Institute for Data, Systems, and Society
No full textThis report contains the following sections: Faculty & Leadership, Academic Programs, Research, Events, External Relations, Resource Development and Fundraising, and IDSSx
GDSVD: Scalable k-SVD via Gradient Descent
No full textWe show that a gradient-descent with a simple, universal rule for step-size selection provably finds k-SVD, i.e., the k ≥ 1 largest singular values and corresponding vectors, of any matrix, despite nonconvexity. There has been substantial progress towards this in the past few years where existing results are able to establish such guarantees for the exact-parameterized and over-parameterized settings, with choice of oracle-provided step size. But guarantees for generic setting with a step size selection that does not require oracle-provided information has remained a challenge. We overcome this challenge and establish that gradient descent with an appealingly simple adaptive step size (akin to preconditioning) and random initialization enjoys global linear convergence for generic setting. Our convergence analysis reveals that the gradient method has an attracting region, and within this attracting region, the method behaves like Heron’s method (a.k.a. the Babylonian method). Empirically, we validate the theoretical results. The emergence of a modern compute infrastructure for iterative optimization coupled with this work is likely to provide a means of solving k-SVD for very large matrices.M.Eng