1,965 results on '"Connor T."'
Search Results
2. Coerced consent in clinical research: study protocol for a randomized controlled trial
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Connor T. A. Brenna, Nancy Walton, Melanie Cohn, Urooj Siddiqui, Ella Huszti, and Richard Brull
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Coercion ,Voluntariness ,Research consent ,Clinical trials ,Perioperative research ,Medicine (General) ,R5-920 - Abstract
Abstract Background Despite the low-risk nature of participation in most clinical anesthesia trials, subject recruitment on the same day as surgery is often restricted due to the concerns of researchers and local research ethics boards that same-day consent may not afford adequate time and opportunity for patients to weigh and make decisions, as well as perceptions of patient vulnerability immediately prior to surgery that could impact the voluntary nature and the rigor of the informed consent process. However, specialties such as anesthesiology, critical care, interventional radiology, and emergency medicine have a varied pattern of practice and patient acquaintance that does not typically afford the luxury of time or, in many cases, advance consent for participation in research. Indeed, the initial encounter between anesthesiologists and patients undergoing elective procedures routinely occurs on the day of surgery. Concerns of coercion related to same-day consent for clinical anesthesia research trials have not been borne out in the literature, and represent a significant obstacle to clinical researchers, as well as to the patients who are denied opportunities for potential benefit through participation in research studies. Methods We describe the protocol for a prospective randomized controlled trial examining the voluntariness of patient consent, solicited either in advance of surgery or on the same day, to participate in an anesthesia research study at Women’s College Hospital. One hundred fourteen patients scheduled to undergo ambulatory anterior cruciate ligament repair facilitated by general anesthesia with an adductor canal block will be randomized for recruitment either (a) in the pre-operative assessment clinic before the day of surgery or (b) on the day of surgery, to be approached for consent to participate in a fabricated research study of adjunct medications in adductor canal blocks. Regardless of allocation, patients in both groups will receive the same routine standard of care and will complete a post-operative questionnaire to signal perceptions of undue influence in the process of providing informed consent for the fabricated trial. Discussion This study will inform trial design and practice guidelines surrounding the amount of time patients ought to be afforded in order to make durable decisions to participate (or not) in clinical research studies. This is expected to impact trial recruitment in a variety of clinical settings where researchers have only brief opportunities to interface with patients. Trial registration The trial was registered prospectively on the Open Science Framework (OSF), registration #46twc, on 2023-Mar-17.
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- 2024
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3. Machine learning-enabled forward prediction and inverse design of 4D-printed active plates
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Xiaohao Sun, Liang Yue, Luxia Yu, Connor T. Forte, Connor D. Armstrong, Kun Zhou, Frédéric Demoly, Ruike Renee Zhao, and H. Jerry Qi
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Science - Abstract
Abstract Shape transformations of active composites (ACs) depend on the spatial distribution of constituent materials. Voxel-level complex material distributions can be encoded by 3D printing, offering enormous freedom for possible shape-change 4D-printed ACs. However, efficiently designing the material distribution to achieve desired 3D shape changes is significantly challenging yet greatly needed. Here, we present an approach that combines machine learning (ML) with both gradient-descent (GD) and evolutionary algorithm (EA) to design AC plates with 3D shape changes. A residual network ML model is developed for the forward shape prediction. A global-subdomain design strategy with ML-GD and ML-EA is then used for the inverse material-distribution design. For a variety of numerically generated target shapes, both ML-GD and ML-EA demonstrate high efficiency. By further combining ML-EA with a normal distance-based loss function, optimized designs are achieved for multiple irregular target shapes. Our approach thus provides a highly efficient tool for the design of 4D-printed active composites.
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- 2024
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4. Synergistic effects of climate and urbanisation on the diet of a globally near threatened subtropical falcon
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Mohammod Foysal and Connor T. Panter
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Bangladesh ,climate change ,Falco chicquera ,raptor ,red‐necked falcon ,trophic ecology ,Ecology ,QH540-549.5 - Abstract
Abstract Understanding how human activities affect wildlife is fundamental for global biodiversity conservation. Ongoing land use change and human‐induced climate change, compel species to adapt their behaviour in response to shifts in their natural environments. Such responses include changes to a species' diet or trophic ecology, with implications for the wider ecosystem. This is particularly the case for predatory species or those that occupy high positions within trophic webs, such as raptors. Between 2002 and 2019, we observed 1578 feeding events of the globally near threatened and understudied, Red‐necked Falcon (Falco chicquera) in Bangladesh. We explored the effects of mean monthly temperature, precipitation, temperature differences, and urban land cover on (a) mean prey weights and (b) dietary composition of 15 falcon pairs. Falcons hunted smaller prey items during months with increased temperatures and precipitation, and in more urban areas. However, during months with increased temperature differences, falcons tended to prey on larger prey items. Being specialist aerial hunters, these dietary patterns were largely driven by the probabilities of bats and birds in the diet. Falcons were more likely to prey on bats during warmer and wetter months. Furthermore, urban pairs tended to prey on bats, whereas more rural pairs tended to prey on birds. Mean monthly temperature difference, i.e., a proxy for climate change, was better at explaining the probability of bats in the falcon diet than mean monthly temperature alone. Anthropogenic dietary shifts can have deleterious effects on species with declining populations or those of conservation concern. The effects of urbanisation and human‐induced climate change are expected to continue into the foreseeable future. Therefore, our findings represent a cornerstone in our understanding of how falcons respond to an increasingly human‐dominated world.
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- 2024
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5. High-Fidelity Two-Qubit Gates between Fluxonium Qubits with a Resonator Coupler
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Emma L. Rosenfeld, Connor T. Hann, David I. Schuster, Matthew H. Matheny, and Aashish A. Clerk
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Physics ,QC1-999 ,Computer software ,QA76.75-76.765 - Abstract
We take a bottom-up first-principles approach to designing a two-qubit gate between fluxonium qubits for minimal error, speed, and control simplicity. Our proposed architecture consists of two fluxoniums coupled via a resonator. The use of a simple linear coupler has many practical benefits, including the possibility of material optimization for suppressing loss, reducing fabrication complexity, and increasing yield by circumventing the need for Josephson junctions. Crucially, a resonator-as-coupler approach also suggests a clear path to increased connectivity between fluxonium qubits, by reducing capacitive loading when the coupler has a high impedance. After performing analytic and numerical analyses of the circuit Hamiltonian and gate dynamics, we tune circuit parameters to destructively interfere sources of coherent error, revealing an efficient fourth-order scaling of coherent error with gate duration. For component properties from the literature, we predict an open-system average controlled-Z (cz) gate infidelity of 1.86×10^{−4} in 70 ns.
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- 2024
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6. Autistic adults exhibit highly precise representations of others’ emotions but a reduced influence of emotion representations on emotion recognition accuracy
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Connor T. Keating, Eri Ichijo, and Jennifer L. Cook
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Medicine ,Science - Abstract
Abstract To date, studies have not yet established the mechanisms underpinning differences in autistic and non-autistic emotion recognition. The current study first investigated whether autistic and non-autistic adults differed in terms of the precision and/or differentiation of their visual emotion representations and their general matching abilities, and second, explored whether differences therein were related to challenges in accurately recognizing emotional expressions. To fulfil these aims, 45 autistic and 45 non-autistic individuals completed three tasks employing dynamic point light displays of emotional facial expressions. We identified that autistic individuals had more precise visual emotion representations than their non-autistic counterparts, however, this did not confer any benefit for their emotion recognition. Whilst for non-autistic people, non-verbal reasoning and the interaction between precision of emotion representations and matching ability predicted emotion recognition, no variables contributed to autistic emotion recognition. These findings raise the possibility that autistic individuals are less guided by their emotion representations, thus lending support to Bayesian accounts of autism.
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- 2023
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7. Safety of hyperbaric oxygen therapy in patients with heart failure: A retrospective cohort study
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Simone Schiavo, Connor T. A. Brenna, Lisa Albertini, George Djaiani, Anton Marinov, and Rita Katznelson
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Medicine ,Science - Published
- 2024
8. Zebra finches have style: Nest morphology is repeatable and associated with experience
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Benjamin A. Whittaker, Liam Nolet-Mulholland, Anna Nevoit, Deborah Yun, Connor T. Lambert, Sara C. Blunk, and Lauren M. Guillette
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Biological sciences ,Ornithology ,Evolutionary biology ,Science - Abstract
Summary: We investigated whether birds build nests in repeatable styles and, if so, whether styles were associated with past nest-building experience. Laboratory, captive bred zebra finches in an Experimental group were given nest-building experience, whereas, birds in a Control group were not. Each pair (n = 20) then built four nests that underwent image analyses for nest size, geometric shape and entrance orientation. Birds built nests in repeatable styles, with lower morphometric variation among nests built by the same pair and higher morphometric variation among nests built by different pairs. Morphology was not associated with construction time, body weight, nor age of birds. We found lower morphometric variation among nests built by the Experimental group, which also used less material to build nests compared to the Control group. Prior experience may therefore have been advantageous, as learning to reduce material usage while achieving a similar product (nest) may have lowered building costs.
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- 2023
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9. An ethical analysis of clinical triage protocols and decision-making frameworks: what do the principles of justice, freedom, and a disability rights approach demand of us?
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Jane Zhu, Connor T. A. Brenna, Liam G. McCoy, Chloë G. K. Atkins, and Sunit Das
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Resource allocation ,COVID-19 ,Clinical triage protocols ,Disability rights ,Justice ,Positive freedoms ,Medical philosophy. Medical ethics ,R723-726 - Abstract
Abstract Background The expectation of pandemic-induced severe resource shortages has prompted authorities to draft and update frameworks to guide clinical decision-making and patient triage. While these documents differ in scope, they share a utilitarian focus on the maximization of benefit. This utilitarian view necessarily marginalizes certain groups, in particular individuals with increased medical needs. Main body Here, we posit that engagement with the disability critique demands that we broaden our understandings of justice and fairness in clinical decision-making and patient triage. We propose the capabilities theory, which recognizes that justice requires a range of positive capabilities/freedoms conducive to the achievement of meaningful life goals, as a means to do so. Informed by a disability rights critique of the clinical response to the pandemic, we offer direction for the construction of future clinical triage protocols which will avoid ableist biases by incorporating a broader apprehension of what it means to be human. Conclusion The clinical pandemic response, codified across triage protocols, should embrace a form of justice which incorporates a vision of pluralistic human capabilities and a valuing of positive freedoms.
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- 2022
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10. Speech Recording for Dietary Assessment: A Systematic Literature Review
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Connor T. Dodd, Marc T. P. Adam, and Megan E. Rollo
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Automatic speech recognition ,dietary assessment ,food recording ,natural language processing ,systematic literature review ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Traditional methods of capturing people’s dietary intake are complex and labour-intensive, requiring a high level of literacy and time. Speech recording has potential to reduce these barriers, and recent technological advances have greatly increased the viability of this approach. The aim of this paper is to establish the current state of research on the usage of speech records in dietary assessment. To this end, we performed a systematic literature review and summarised the current state of research along a conceptual framework that captures the components involved in using speech records for dietary assessment. Six databases from the nutrition and computing domains were interrogated, resulting in 21 relevant papers. Speech recording in an unstructured format was preferred when compared against other methods by all three studies reporting comparisons. High technological satisfaction and ease of use were noted by all eight studies reporting user acceptance. When recording data, 78% of studies focused on collecting prospective food records. The choice of device reflected this, with 15 of 18 studies reporting a form of handheld, portable collection device intended to be always available. To process data, nine studies performed automated speech transcription achieving an average accuracy of 83%, seven of which utilized a readily available commercial service. Of the five studies that used natural language processing to further automate analysis, an average accuracy of 82% was reported. Further research is required to adapt these prototypes to address practical challenges in dietary assessment and monitoring (e.g. self-monitoring for low-literacy users).
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- 2022
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11. Increased circulating butyrate and ursodeoxycholate during probiotic intervention in humans with type 2 diabetes
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Paul J. McMurdie, Magdalena K. Stoeva, Nicholas Justice, Madeleine Nemchek, Christian M. K. Sieber, Surabhi Tyagi, Jessica Gines, Connor T. Skennerton, Michael Souza, Orville Kolterman, and John Eid
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Anaerobutyricum hallii ,Akkermansia muciniphila ,Bile acids ,Butyrate ,Clostridium butyricum ,Metabolomics ,Microbiology ,QR1-502 - Abstract
Abstract Background An increasing body of evidence implicates the resident gut microbiota as playing a critical role in type 2 diabetes (T2D) pathogenesis. We previously reported significant improvement in postprandial glucose control in human participants with T2D following 12-week administration of a 5-strain novel probiotic formulation (‘WBF-011’) in a double-blind, randomized, placebo controlled setting (NCT03893422). While the clinical endpoints were encouraging, additional exploratory measurements were needed in order to link the motivating mechanistic hypothesis - increased short-chain fatty acids - with markers of disease. Results Here we report targeted and untargeted metabolomic measurements on fasting plasma (n = 104) collected at baseline and end of intervention. Butyrate and ursodeoxycholate increased among participants randomized to WBF-011, along with compelling trends between butyrate and glycated haemoglobin (HbA1c). In vitro monoculture experiments demonstrated that the formulation’s C. butyricum strain efficiently synthesizes ursodeoxycholate from the primary bile acid chenodeoxycholate during butyrogenic growth. Untargeted metabolomics also revealed coordinated decreases in intermediates of fatty acid oxidation and bilirubin, potential secondary signatures for metabolic improvement. Finally, improvement in HbA1c was limited almost entirely to participants not using sulfonylurea drugs. We show that these drugs can inhibit growth of formulation strains in vitro. Conclusion To our knowledge, this is the first description of an increase in circulating butyrate or ursodeoxycholate following a probiotic intervention in humans with T2D, adding support for the possibility of a targeted microbiome-based approach to assist in the management of T2D. The efficient synthesis of UDCA by C. butyricum is also likely of interest to investigators of its use as a probiotic in other disease settings. The potential for inhibitory interaction between sulfonylurea drugs and gut microbiota should be considered carefully in the design of future studies.
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- 2022
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12. Pulmonary function following hyperbaric oxygen therapy: A longitudinal observational study
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Connor T. A. Brenna, Shawn Khan, George Djaiani, Darren Au, Simone Schiavo, Mustafa Wahaj, Ray Janisse, and Rita Katznelson
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Medicine ,Science - Abstract
Hyperbaric oxygen therapy (HBOT) is known to be associated with pulmonary oxygen toxicity. However, the effect of modern HBOT protocols on pulmonary function is not completely understood. The present study evaluates pulmonary function test changes in patients undergoing serial HBOT. We prospectively collected data on patients undergoing HBOT from 2016–2021 at a tertiary referral center (protocol registration NCT05088772). Patients underwent pulmonary function testing with a bedside spirometer/pneumotachometer prior to HBOT and after every 20 treatments. HBOT was performed using 100% oxygen at a pressure of 2.0–2.4 atmospheres absolute (203–243 kPa) for 90 minutes, five times per week. Patients’ charts were retrospectively reviewed for demographics, comorbidities, medications, HBOT specifications, treatment complications, and spirometry performance. Primary outcomes were defined as change in percent predicted forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and forced mid-expiratory flow (FEF25-75), after 20, 40, and 60 HBOT sessions. Data was analyzed with descriptive statistics and mixed-model linear regression. A total of 86 patients were enrolled with baseline testing, and the analysis included data for 81 patients after 20 treatments, 52 after 40 treatments, and 12 after 60 treatments. There were no significant differences in pulmonary function tests after 20, 40, or 60 HBOT sessions. Similarly, a subgroup analysis stratifying the cohort based on pre-existing respiratory disease, smoking history, and the applied treatment pressure did not identify any significant changes in pulmonary function tests during HBOT. There were no significant longitudinal changes in FEV1, FVC, or FEF25-75 after serial HBOT sessions in patients regardless of pre-existing respiratory disease. Our results suggest that the theoretical risk of pulmonary oxygen toxicity following HBOT is unsubstantiated with modern treatment protocols, and that pulmonary function is preserved even in patients with pre-existing asthma, chronic obstructive lung disease, and interstitial lung disease.
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- 2023
13. The host galaxies of radio-loud quasars at z>5 with ALMA
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Mazzucchelli, C., Decarli, R., Belladitta, S., Bañados, E., Meyer, R. A., Connor, T., Momjian, E., Rojas-Ruiz, S., Eilers, A. -C., Khusanova, Y., Farina, E. P., Drake, A. B., Walter, F., Wang, F., Onoue, M., and Venemans, B. P.
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Astrophysics - Astrophysics of Galaxies - Abstract
The interaction between radio-jets and quasar host galaxies plays a paramount role in quasar/galaxy co-evolution. However, very little has been known so far about this interaction at very high-z. Here, we present new Atacama Large Millimeter/submillimeter Array (ALMA) observations in Band 7 and Band 3 of six radio-loud quasars' host galaxies at $z > 5$. We recover [CII] 158 $\mu$m line and underlying dust continuum emission at $>2\sigma$ for five sources, while we obtain upper limits for the CO(6-5) emission line and continuum for the remaining source. At the spatial resolution of our observations ($\sim$1.0"-1.4"), we do not recover perturbed/extended morphologies or kinematics, signatures of potential mergers. These galaxies already host large quantities of gas, with [CII]-based star formation rates of $30-400 M_{\odot} $yr$^{-1}$. Building their radio/sub-mm spectral energy distributions (SEDs), we find that in at least four cases the 1mm continuum intensity arises from a combination of synchrotron and dust emission, with an initial estimation of synchrotron contribution at 300 GHz of $\gtrsim$10%. We compare the properties of the sources inspected here with a large collection of radio-quiet sources from the literature, as well as a sample of radio-loud quasars from previous studies, at comparable redshift. We recover a potential mild decrease in $L_{\rm [CII]}$ for the radio-loud sources, which might be due to a suppression of the cool gas emission due to the radio-jets. We do not find any [CII]-emitting companion galaxy candidate around the five radio-loud quasars observed in Band 7: given the depth of our dataset, this result is still consistent with that observed around radio-quiet quasars. Further higher-spatial resolution observations, over a larger frequency range, of high-z radio-loud quasars hosts will allow for a better understanding of the physics of such sources., Comment: 20 pages; 11 figures; accepted for publication in A&A
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- 2024
14. Encoding Multi-level Dynamics in Effect Heterogeneity Estimation
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Zhu, Fucheng Warren, Jerzak, Connor T., and Daoud, Adel
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Statistics - Machine Learning ,Computer Science - Machine Learning ,I.4.7 ,I.4.9 - Abstract
Earth Observation (EO) data are increasingly used in policy analysis by enabling granular estimation of treatment effects. However, a challenge in EO-based causal inference lies in balancing the trade-off between capturing fine-grained individual heterogeneity and broader contextual information. This paper introduces Multi-scale Concatenation, a family of composable procedures that transform arbitrary single-scale CATE estimation algorithms into multi-scale algorithms. We benchmark the performance of Multi-scale Concatenation on a CATE estimation pipeline combining Vision Transformer (ViT) models fine-tuned on satellite images to encode images of different scales with Causal Forests to obtain the final CATE estimate. We first perform simulation studies, showing how a multi-scale approach captures multi-level dynamics that single-scale ViT models fail to capture. We then apply the multi-scale method to two randomized controlled trials (RCTs) conducted in Peru and Uganda using Landsat satellite imagery. In the RCT analysis, the Rank Average Treatment Effect Ratio (RATE Ratio) measure is employed to assess performance without ground truth individual treatment effects. Results indicate that Multi-scale Concatenation improves the performance of deep learning models in EO-based CATE estimation without the complexity of designing new multi-scale architectures for a specific use case., Comment: 27 pages, 13 figures
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- 2024
15. Hybrid cat-transmon architecture for scalable, hardware-efficient quantum error correction
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Hann, Connor T., Noh, Kyungjoo, Putterman, Harald, Matheny, Matthew H., Iverson, Joseph K., Fang, Michael T., Chamberland, Christopher, Painter, Oskar, and Brandão, Fernando G. S. L.
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Quantum Physics - Abstract
Dissipative cat qubits are a promising physical platform for quantum computing, since their large noise bias can enable more hardware-efficient quantum error correction. In this work we theoretically study the long-term prospects of a hybrid cat-transmon quantum computing architecture where dissipative cat qubits play the role of data qubits, and error syndromes are measured using ancillary transmon qubits. The cat qubits' noise bias enables more hardware-efficient quantum error correction, and the use of transmons allows for practical, high-fidelity syndrome measurement. While correction of the dominant cat Z errors with a repetition code has recently been demonstrated in experiment, here we show how the architecture can be scaled beyond a repetition code. In particular, we propose a cat-transmon entangling gate that enables the correction of residual cat X errors in a thin rectangular surface code, so that logical error can be arbitrarily suppressed by increasing code distance. We numerically estimate logical memory performance, finding significant overhead reductions in comparison to architectures without biased noise. For example, with current state-of-the-art coherence, physical error rates of $10^{-3}$ and noise biases in the range $10^{3} - 10^{4}$ are achievable. With this level of performance, the qubit overhead required to reach algorithmically-relevant logical error rates with the cat-transmon architecture matches that of an unbiased-noise architecture with physical error rates in the range $10^{-5} - 10^{-4}$., Comment: 13+14 pages, 8+9 figures
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- 2024
16. Preserving phase coherence and linearity in cat qubits with exponential bit-flip suppression
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Putterman, Harald, Noh, Kyungjoo, Patel, Rishi N., Peairs, Gregory A., MacCabe, Gregory S., Lee, Menyoung, Aghaeimeibodi, Shahriar, Hann, Connor T., Jarrige, Ignace, Marcaud, Guillaume, He, Yuan, Moradinejad, Hesam, Owens, John Clai, Scaffidi, Thomas, Arrangoiz-Arriola, Patricio, Iverson, Joe, Levine, Harry, Brandão, Fernando G. S. L., Matheny, Matthew H., and Painter, Oskar
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Quantum Physics - Abstract
Cat qubits, a type of bosonic qubit encoded in a harmonic oscillator, can exhibit an exponential noise bias against bit-flip errors with increasing mean photon number. Here, we focus on cat qubits stabilized by two-photon dissipation, where pairs of photons are added and removed from a harmonic oscillator by an auxiliary, lossy buffer mode. This process requires a large loss rate and strong nonlinearities of the buffer mode that must not degrade the coherence and linearity of the oscillator. In this work, we show how to overcome this challenge by coloring the loss environment of the buffer mode with a multi-pole filter and optimizing the circuit to take into account additional inductances in the buffer mode. Using these techniques, we achieve near-ideal enhancement of cat-qubit bit-flip times with increasing photon number, reaching over $0.1$ seconds with a mean photon number of only $4$. Concurrently, our cat qubit remains highly phase coherent, with phase-flip times corresponding to an effective lifetime of $T_{1,\text{eff}} \simeq 70$ $\mu$s, comparable with the bare oscillator lifetime. We achieve this performance even in the presence of an ancilla transmon, used for reading out the cat qubit states, by engineering a tunable oscillator-ancilla dispersive coupling. Furthermore, the low nonlinearity of the harmonic oscillator mode allows us to perform pulsed cat-qubit stabilization, an important control primitive, where the stabilization can remain off for a significant fraction (e.g., two thirds) of a $3~\mathrm{\mu s}$ cycle without degrading bit-flip times. These advances are important for the realization of scalable error-correction with cat qubits, where large noise bias and low phase-flip error rate enable the use of hardware-efficient outer error-correcting codes., Comment: Comments welcome!
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- 2024
17. Hardware-efficient quantum error correction using concatenated bosonic qubits
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Putterman, Harald, Noh, Kyungjoo, Hann, Connor T., MacCabe, Gregory S., Aghaeimeibodi, Shahriar, Patel, Rishi N., Lee, Menyoung, Jones, William M., Moradinejad, Hesam, Rodriguez, Roberto, Mahuli, Neha, Rose, Jefferson, Owens, John Clai, Levine, Harry, Rosenfeld, Emma, Reinhold, Philip, Moncelsi, Lorenzo, Alcid, Joshua Ari, Alidoust, Nasser, Arrangoiz-Arriola, Patricio, Barnett, James, Bienias, Przemyslaw, Carson, Hugh A., Chen, Cliff, Chen, Li, Chinkezian, Harutiun, Chisholm, Eric M., Chou, Ming-Han, Clerk, Aashish, Clifford, Andrew, Cosmic, R., Curiel, Ana Valdes, Davis, Erik, DeLorenzo, Laura, D'Ewart, J. Mitchell, Diky, Art, D'Souza, Nathan, Dumitrescu, Philipp T., Eisenmann, Shmuel, Elkhouly, Essam, Evenbly, Glen, Fang, Michael T., Fang, Yawen, Fling, Matthew J., Fon, Warren, Garcia, Gabriel, Gorshkov, Alexey V., Grant, Julia A., Gray, Mason J., Grimberg, Sebastian, Grimsmo, Arne L., Haim, Arbel, Hand, Justin, He, Yuan, Hernandez, Mike, Hover, David, Hung, Jimmy S. C., Hunt, Matthew, Iverson, Joe, Jarrige, Ignace, Jaskula, Jean-Christophe, Jiang, Liang, Kalaee, Mahmoud, Karabalin, Rassul, Karalekas, Peter J., Keller, Andrew J., Khalajhedayati, Amirhossein, Kubica, Aleksander, Lee, Hanho, Leroux, Catherine, Lieu, Simon, Ly, Victor, Madrigal, Keven Villegas, Marcaud, Guillaume, McCabe, Gavin, Miles, Cody, Milsted, Ashley, Minguzzi, Joaquin, Mishra, Anurag, Mukherjee, Biswaroop, Naghiloo, Mahdi, Oblepias, Eric, Ortuno, Gerson, Pagdilao, Jason, Pancotti, Nicola, Panduro, Ashley, Paquette, JP, Park, Minje, Peairs, Gregory A., Perello, David, Peterson, Eric C., Ponte, Sophia, Preskill, John, Qiao, Johnson, Refael, Gil, Resnick, Rachel, Retzker, Alex, Reyna, Omar A., Runyan, Marc, Ryan, Colm A., Sahmoud, Abdulrahman, Sanchez, Ernesto, Sanil, Rohan, Sankar, Krishanu, Sato, Yuki, Scaffidi, Thomas, Siavoshi, Salome, Sivarajah, Prasahnt, Skogland, Trenton, Su, Chun-Ju, Swenson, Loren J., Teo, Stephanie M., Tomada, Astrid, Torlai, Giacomo, Wollack, E. Alex, Ye, Yufeng, Zerrudo, Jessica A., Zhang, Kailing, Brandão, Fernando G. S. L., Matheny, Matthew H., and Painter, Oskar
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Quantum Physics - Abstract
In order to solve problems of practical importance, quantum computers will likely need to incorporate quantum error correction, where a logical qubit is redundantly encoded in many noisy physical qubits. The large physical-qubit overhead typically associated with error correction motivates the search for more hardware-efficient approaches. Here, using a microfabricated superconducting quantum circuit, we realize a logical qubit memory formed from the concatenation of encoded bosonic cat qubits with an outer repetition code of distance $d=5$. The bosonic cat qubits are passively protected against bit flips using a stabilizing circuit. Cat-qubit phase-flip errors are corrected by the repetition code which uses ancilla transmons for syndrome measurement. We realize a noise-biased CX gate which ensures bit-flip error suppression is maintained during error correction. We study the performance and scaling of the logical qubit memory, finding that the phase-flip correcting repetition code operates below threshold, with logical phase-flip error decreasing with code distance from $d=3$ to $d=5$. Concurrently, the logical bit-flip error is suppressed with increasing cat-qubit mean photon number. The minimum measured logical error per cycle is on average $1.75(2)\%$ for the distance-3 code sections, and $1.65(3)\%$ for the longer distance-5 code, demonstrating the effectiveness of bit-flip error suppression throughout the error correction cycle. These results, where the intrinsic error suppression of the bosonic encodings allows us to use a hardware-efficient outer error correcting code, indicate that concatenated bosonic codes are a compelling paradigm for reaching fault-tolerant quantum computation., Comment: Comments on the manuscript welcome!
- Published
- 2024
18. Using web-sourced photographs to examine temporal patterns in sex-specific diet of a highly sexually dimorphic raptor
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Connor T. Panter and Arjun Amar
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Accipiter nisus ,citizen science ,Eurasian sparrowhawk ,prey selection ,reversed size dimorphism ,sparrowhawk ,Science - Abstract
Traditional methods to study raptor diet are usually limited temporally, e.g. prey remains at nesting sites, and are unsuitable to examine dietary changes throughout the year. Using web-sourced photography, we explore temporal patterns in prey size and key prey species between sexes of the sexually dimorphic Eurasian sparrowhawk (Accipiter nisus) throughout the United Kingdom. We examined 666 photographs of sparrowhawk on prey and identified the prey species involved, together with sparrowhawk sex. Changes in prey size and proportions of key prey species over time (seasonally and monthly) were explored for each sex. Prey weight was substantially higher for females than males. However, on average, prey size for both sexes declined during the summer period (May–June) being the lowest in June, which is the main nestling-rearing month for both sparrowhawks and their prey. Compared with summer, rock doves (Columba livia) were more important prey for female sparrowhawk in winter. Whereas, for males, Eurasian blackbirds (Turdus merula) were more important in spring compared with autumn. Web-sourced photography can overcome several limitations of previous methods used to study raptor diet including the ability to quantify diet between the sexes throughout the entire year, however, may also introduce a prey-size bias toward larger prey items.
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- 2022
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19. Liver Kinase B1 Regulates Remodeling of the Tumor Microenvironment in Triple-Negative Breast Cancer
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Connor T. King, Margarite D. Matossian, Jonathan J. Savoie, Khoa Nguyen, Maryl K. Wright, C. Ethan Byrne, Steven Elliott, Hope E. Burks, Melyssa R. Bratton, Nicholas C. Pashos, Bruce A. Bunnell, Matthew E. Burow, Bridgette M. Collins-Burow, and Elizabeth C. Martin
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LKB1 ,breast cancer ,stem cells ,collagen remodeling ,tumor micoenvironment ,Biology (General) ,QH301-705.5 - Abstract
Liver kinase B1 (LKB1) is a potent tumor suppressor that regulates cellular energy balance and metabolism as an upstream kinase of the AMP-activated protein kinase (AMPK) pathway. LKB1 regulates cancer cell invasion and metastasis in multiple cancer types, including breast cancer. In this study, we evaluated LKB1’s role as a regulator of the tumor microenvironment (TME). This was achieved by seeding the MDA-MB-231-LKB1 overexpressing cell line onto adipose and tumor scaffolds, followed by the evaluation of tumor matrix-induced tumorigenesis and metastasis. Results demonstrated that the presence of tumor matrix enhanced tumorigenesis in both MDA-MB-231 and MDA-MB-231-LKB1 cell lines. Metastasis was increased in both MDA-MB-231 and -LKB1 cells seeded on the tumor scaffold. Endpoint analysis of tumor and adipose scaffolds revealed LKB1-mediated tumor microenvironment remodeling as evident through altered matrix protein production. The proteomic analysis determined that LKB1 overexpression preferentially decreased all major and minor fibril collagens (collagens I, III, V, and XI). In addition, proteins observed to be absent in tumor scaffolds in the LKB1 overexpressing cell line included those associated with the adipose matrix (COL6A2) and regulators of adipogenesis (IL17RB and IGFBP4), suggesting a role for LKB1 in tumor-mediated adipogenesis. Histological analysis of MDA-MB-231-LKB1-seeded tumors demonstrated decreased total fibril collagen and indicated decreased stromal cell presence. In accordance with this, in vitro condition medium studies demonstrated that the MDA-MB-231-LKB1 secretome inhibited adipogenesis of adipose-derived stem cells. Taken together, these data demonstrate a role for LKB1 in regulating the tumor microenvironment through fibril matrix remodeling and suppression of adipogenesis.
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- 2022
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20. Causes, temporal trends, and the effects of urbanization on admissions of wild raptors to rehabilitation centers in England and Wales
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Connor T. Panter, Simon Allen, Nikki Backhouse, Elizabeth Mullineaux, Carole‐Ann Rose, and Arjun Amar
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birds of prey ,conservation ,morbidity ,mortality ,threats ,wildlife rescue centers ,Ecology ,QH540-549.5 - Abstract
Abstract Data from wildlife rehabilitation centers (WRCs) can provide on‐the‐ground records of causes of raptor morbidity and mortality, allowing threat patterns to be explored throughout time and space. We provide an overview of native raptor admissions to four WRCs in England and Wales, quantifying the main causes of morbidity and mortality, trends over time, and associations between threats and urbanization between 2001 and 2019. Throughout the study period, 14 raptor species were admitted totalling 3305 admission records. The Common Buzzard (Buteo buteo; 31%) and Tawny Owl (Strix aluco; 29%) were most numerous. Relative to the proportion of breeding individuals in Britain and Ireland, Peregrine Falcons (Falco peregrinus), Little Owls (Athene noctua), and Western Barn Owls (Tyto alba) were over‐represented in the admissions data by 103%, 73%, and 69%, respectively. Contrastingly Northern Long‐eared Owls (Asio otus), Western Marsh Harriers (Circus aeruginosus), and Merlin (Falco columbarius) were under‐represented by 187%, 163%, and 126%, respectively. Across all species, vehicle collisions were the most frequent anthropogenic admission cause (22%), and orphaned young birds (10%) were most frequent natural cause. Mortality rate was highest for infection/parasite admissions (90%), whereas orphaned birds experienced lowest mortality rates (16%). For one WRC, there was a decline in admissions over the study period. Red Kite (Milvus milvus) admissions increased over time, whereas Common Buzzard and Common Kestrel admissions declined. There were significant declines in the relative proportion of persecution and metabolic admissions and an increase in orphaned birds. Urban areas were positively associated with persecution, building collisions, and unknown trauma admissions, whereas vehicle collisions were associated with more rural areas. Many threats persist for raptors in England and Wales, however, have not changed substantially over the past two decades. Threats associated with urban areas, such as building collisions, may increase over time in line with human population growth and subsequent urban expansion.
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- 2022
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21. The Effects of Dexmedetomidine on Perioperative Neurocognitive Outcomes After Noncardiac Surgery
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Amara Singh, BSc, Jeremy Broad, MBBS, Connor T. A. Brenna, MD, Lilia Kaustov, PhD, and Stephen Choi, MD
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Surgery ,RD1-811 - Abstract
Objective:. The purpose of this review is to examine the effect of dexmedetomidine on delayed neurocognitive recovery (dNCR; cognitive dysfunction ≥1 week postoperative) after major noncardiac surgery. Background:. Dexmedetomidine (DEX) effectively reduces delirium in the intensive care unit and reportedly attenuates cognitive decline following major noncardiac surgery. Ascertaining the true effect on postoperative cognition is difficult because studies are limited by suboptimal selection of cognitive assessment tools, timing of testing, and criteria for defining significant cognitive decline Methods:. Prospective randomized trials comparing perioperative DEX to placebo for major noncardiac surgery assessing cognitive function ≥1 week postoperative were included. Pediatric, nonhuman, and non-English trials, and those where executive function was not assessed were excluded. Data were abstracted by 3 reviewers independently and in parallel according to PRISMA guidelines. The a priori binary primary outcome is dNCR defined as cognitive function declining by the minimal clinically important difference or accepted alternate measure (eg, Reliable Change Index ≥1.96). Bias was assessed with the Cochrane Collaboration tool. Data were pooled using a random effects model. Results:. Among 287 citations identified, 26 (9%) met criteria for full-text retrieval. Eleven randomized trials (1233 participants) were included for qualitative analysis, and 7 trials (616 participants) were included for meta-analysis of dNCR. Dexmedetomidine did not reduce the incidence of dNCR significantly (OR 0.57, 95% CI 0.30–1.10, P = 0.09) compared with placebo. There was no difference in the incidence of delirium (OR 0.94, 95% CI 0.55–1.63, P = 0.83) and a higher incidence of hemodynamic instability (OR 2.11, 95% CI 1.22–3.65, P = 0.008). Conclusions:. Dexmedetomidine does not reduce dNCR 1 week after major noncardiac surgery. This meta-analysis does not yet support the use of perioperative DEX to improve short term cognitive outcomes at this time; trials underway may yet change this conclusion while larger trials are needed to refine the point estimate of effect and examine long-term cognitive outcomes.
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- 2022
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22. Cross-resonance control of an oscillator with a fluxonium ancilla
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Zheng, Guo, Lieu, Simon, Rosenfeld, Emma L., Noh, Kyungjoo, and Hann, Connor T.
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Quantum Physics - Abstract
The conditional displacement (CD) gate between an oscillator and a discrete-variable ancilla plays a key role in quantum information processing tasks, such as enabling universal control of the oscillator and longitudinal readout of the qubit. However, the gate is unprotected against the propagation of ancilla decay errors and hence not fault-tolerant. Here, we propose a CD gate scheme with fluxonium as the ancilla, which has been experimentally demonstrated to have a large noise bias and millisecond-level lifetimes. The proposed gate is applied cross-resonantly by modulating the external flux of the fluxonium at the frequency of the target oscillator, which requires minimal hardware overhead and does not increase sensitivity to decoherence mechanisms like dephasing. We further provide a perturbative description of the gate mechanism and identify the error budget. Additionally, we develop an approximate procedure for choosing device and gate parameters that optimizes gate performance. Following the procedure for multiple sets of fluxonium parameters from the literature, we numerically demonstrate CD gates with unitary fidelity exceeding 99.9% and gate times of hundreds of nanoseconds.
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- 2024
23. Effect Heterogeneity with Earth Observation in Randomized Controlled Trials: Exploring the Role of Data, Model, and Evaluation Metric Choice
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Jerzak, Connor T., Vashistha, Ritwik, and Daoud, Adel
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Statistics - Methodology ,62P20 ,G.3 ,I.5.4 - Abstract
Many social and environmental phenomena are associated with macroscopic changes in the built environment, captured by satellite imagery on a global scale and with daily temporal resolution. While widely used for prediction, these images and especially image sequences remain underutilized for causal inference, especially in the context of randomized controlled trials (RCTs), where causal identification is established by design. In this paper, we develop and compare a set of general tools for analyzing Conditional Average Treatment Effects (CATEs) from temporal satellite data that can be applied to any RCT where geographical identifiers are available. Through a simulation study, we analyze different modeling strategies for estimating CATE in sequences of satellite images. We find that image sequence representation models with more parameters generally yield a greater ability to detect heterogeneity. To explore the role of model and data choice in practice, we apply the approaches to two influential RCTs -- Banerjee et al. (2015), a poverty study in Cusco, Peru, and Bolsen et al. (2014), a water conservation experiment in Georgia, USA. We benchmark our image sequence models against image-only, tabular-only, and combined image-tabular data sources, summarizing practical implications for investigators in a multivariate analysis. Land cover classifications over satellite images facilitate interpretation of what image features drive heterogeneity. We also show robustness to data and model choice of satellite-based generalization of the RCT results to larger geographical areas outside the original. Overall, this paper shows how satellite sequence data can be incorporated into the analysis of RCTs, and provides evidence about the implications of data, model, and evaluation metric choice for causal analysis.
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- 2024
24. The legume information system and associated online genomic resources
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Joel Berendzen, Anne V. Brown, Connor T. Cameron, Jacqueline D. Campbell, Alan M. Cleary, Sudhansu Dash, Samuel Hokin, Wei Huang, Scott R. Kalberer, Rex T. Nelson, Sven Redsun, Nathan T. Weeks, Andrew Wilkey, Andrew D. Farmer, and Steven B. Cannon
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comparative genomics ,CoNekT ,determinacy ,gene families ,genome context viewer ,InterMine ,Plant culture ,SB1-1110 - Abstract
Abstract The Legume Information System (LIS; https://legumeinfo.org) houses genetic and genomic data, integrated in various online tools to allow comparative genomic analyses. The website and database maintain data for more than two dozen species, particularly focusing on crop and model species and holding data for other diverse species of taxonomic interest. Major analysis features include genome browsers, sequence‐search tools, legume‐focused gene families and a phylogenetic tree viewer, a gene annotation service (which places a submitted gene into a gene family and phylogenetic tree), an interactive microsynteny and pan‐genome viewer, a novel viewer of genetic variant data, genetic maps and viewers, a Data Store for data sets such as assemblies and annotations, InterMine instances for querying genetic and genomic data, and a tool for viewing geographic distributions of germplasm accessions. LIS also integrates with several other legume data resources and tools, including PeanutBase (https://peanutbase.org), SoyBase (https://soybase.org), Medicago Hapmap (https://medicagohapmap2.org), Alfalfa Breeder's Toolbox (https://alfalfatoolbox.org), and the Legume Federation (https://legumefederation.org).
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- 2021
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25. A Scoping Review of Earth Observation and Machine Learning for Causal Inference: Implications for the Geography of Poverty
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Sakamoto, Kazuki, Jerzak, Connor T., and Daoud, Adel
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Computer Science - Machine Learning ,Computer Science - Computer Vision and Pattern Recognition ,Statistics - Methodology ,Statistics - Machine Learning ,62H11 ,I.2.6 ,I.5.4 - Abstract
Earth observation (EO) data such as satellite imagery can have far-reaching impacts on our understanding of the geography of poverty, especially when coupled with machine learning (ML) and computer vision. Early research in computer vision used predictive models to estimate living conditions, especially in contexts where data availability on poverty was scarce. Recent work has progressed beyond using EO data to predict such outcomes -- now also using it to conduct causal inference. However, how such EO-ML models are used for causality remains incompletely mapped. To address this gap, we conduct a scoping review where we first document the growth of interest in using satellite images and other sources of EO data in causal analysis. We then trace the methodological relationship between spatial statistics and ML methods before discussing five ways in which EO data has been used in scientific workflows -- (1) outcome imputation for downstream causal analysis, (2) EO image deconfounding, (3) EO-based treatment effect heterogeneity, (4) EO-based transportability analysis, and (5) image-informed causal discovery. We consolidate these observations by providing a detailed workflow for how researchers can incorporate EO data in causal analysis going forward -- from data requirements to choice of computer vision model and evaluation metrics. While our discussion focuses on health and living conditions outcomes, our workflow applies to other measures of sustainable development where EO data are informative., Comment: To appear as: Sakamoto, Kazuki, Connor T. Jerzak, and Adel Daoud. "A Scoping Review of Earth Observation and Machine Learning for Causal Inference: Implications for the Geography of Poverty." In Geography of Poverty, edited by Ola Hall and Ibrahim Wahab. Edward Elgar Publishing (Cheltenham, UK), 2025
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- 2024
26. Designing high-fidelity two-qubit gates between fluxonium qubits
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Rosenfeld, Emma L., Hann, Connor T., Schuster, David I., Matheny, Matthew H., and Clerk, Aashish A.
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Quantum Physics - Abstract
We take a bottom-up, first-principles approach to design a two-qubit gate between fluxonium qubits for minimal error, speed, and control simplicity. Our proposed architecture consists of two fluxoniums coupled via a linear resonator. Using a linear coupler introduces the possibility of material optimization for suppressing its loss, enables efficient driving of state-selective transitions through its large charge zero point fluctuation, reduces sensitivity to junction aging, and partially mitigates coherent coupling to two-level systems. Crucially, a resonator-as-coupler approach also suggests a clear path to increased connectivity between fluxonium qubits, by reducing capacitive loading when the coupler has a high impedance. After performing analytic and numeric analyses of the circuit Hamiltonian and gate dynamics, we tune circuit parameters to destructively interfere sources of coherent error, revealing an efficient, fourth-order scaling of coherent error with gate duration. For component properties from the literature, we predict an open-system average CZ gate infidelity of $1.86 \times 10^{-4}$ in 70ns., Comment: Changes from peer review
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- 2024
27. Cognitive decline among older adults: A hidden preexisting condition and its role in ‘brain‐at‐risk’ surgical patients
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Connor T. A. Brenna, Beverley A. Orser, Sinziana Avramescu, Andrew Fleet, Lilia Kaustov, and Stephen Choi
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anesthesia ,cognitive assessment screening instrument ,mild neurocognitive disorder ,neurocognitive tests ,postoperative cognitive disorder ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Published
- 2021
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28. Post-Mortem Pedagogy: A Brief History of the Practice of Anatomical Dissection
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Connor T. A. Brenna
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anatomy ,dissection ,epistemic frameworks ,history ,medical education ,Medicine ,Medicine (General) ,R5-920 - Abstract
Anatomical dissection is almost ubiquitous in modern medical education, masking a complex history of its practice. Dissection with the express purpose of understanding human anatomy began more than two millennia ago with Herophilus, but was soon after disavowed in the third century BCE. Historical evidence suggests that this position was based on common beliefs that the body must remain whole after death in order to access the afterlife. Anatomical dissection did not resume for almost 1500 years, and in the interim anatomical knowledge was dominated by (often flawed) reports generated through the comparative dissection of animals. When a growing recognition of the utility of anatomical knowledge in clinical medicine ushered human dissection back into vogue, it recommenced in a limited setting almost exclusively allowing for dissection of the bodies of convicted criminals. Ultimately, the ethical problems that this fostered, as well as the increasing demand from medical education for greater volumes of human dissection, shaped new considerations of the body after death. Presently, body bequeathal programs are a popular way in which individuals offer their bodies to medical education after death, suggesting that the once widespread views of dissection as punishment have largely dissipated.
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- 2021
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29. ERK5 Is Required for Tumor Growth and Maintenance Through Regulation of the Extracellular Matrix in Triple Negative Breast Cancer
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Van T. Hoang, Margarite D. Matossian, Deniz A. Ucar, Steven Elliott, Jacqueline La, Maryl K. Wright, Hope E. Burks, Aaron Perles, Fokhrul Hossain, Connor T. King, Valentino E. Browning, Jacob Bursavich, Fang Fang, Luis Del Valle, Akshita B. Bhatt, Jane E. Cavanaugh, Patrick T. Flaherty, Muralidharan Anbalagan, Brian G. Rowan, Melyssa R. Bratton, Kenneth P. Nephew, Lucio Miele, Bridgette M. Collins-Burow, Elizabeth C. Martin, and Matthew E. Burow
- Subjects
ERK5 kinase ,triple negative breast cancer (TNBC) ,clustered regularly interspaced short palindromic repeats (CRISPR) knockout ,extracelluar matix ,metastasis ,epithelial–mesenchymal–transition ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Conventional mitogen-activated protein kinase (MAPK) family members regulate diverse cellular processes involved in tumor initiation and progression, yet the role of ERK5 in cancer biology is not fully understood. Triple-negative breast cancer (TNBC) presents a clinical challenge due to the aggressive nature of the disease and a lack of targeted therapies. ERK5 signaling contributes to drug resistance and metastatic progression through distinct mechanisms, including activation of epithelial-to-mesenchymal transition (EMT). More recently a role for ERK5 in regulation of the extracellular matrix (ECM) has been proposed, and here we investigated the necessity of ERK5 in TNBC tumor formation. Depletion of ERK5 expression using the CRISPR/Cas9 system in MDA-MB-231 and Hs-578T cells resulted in loss of mesenchymal features, as observed through gene expression profile and cell morphology, and suppressed TNBC cell migration. In vivo xenograft experiments revealed ERK5 knockout disrupted tumor growth kinetics, which was restored using high concentration Matrigel™ and ERK5-ko reduced expression of the angiogenesis marker CD31. These findings implicated a role for ERK5 in the extracellular matrix (ECM) and matrix integrity. RNA-sequencing analyses demonstrated downregulation of matrix-associated genes, integrins, and pro-angiogenic factors in ERK5-ko cells. Tissue decellularization combined with cryo-SEM and interrogation of biomechanical properties revealed that ERK5-ko resulted in loss of key ECM fiber alignment and mechanosensing capabilities in breast cancer xenografts compared to parental wild-type cells. In this study, we identified a novel role for ERK5 in tumor growth kinetics through modulation of the ECM and angiogenesis axis in breast cancer.
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- 2020
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30. Building a Fault-Tolerant Quantum Computer Using Concatenated Cat Codes
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Christopher Chamberland, Kyungjoo Noh, Patricio Arrangoiz-Arriola, Earl T. Campbell, Connor T. Hann, Joseph Iverson, Harald Putterman, Thomas C. Bohdanowicz, Steven T. Flammia, Andrew Keller, Gil Refael, John Preskill, Liang Jiang, Amir H. Safavi-Naeini, Oskar Painter, and Fernando G.S.L. Brandão
- Subjects
Physics ,QC1-999 ,Computer software ,QA76.75-76.765 - Abstract
We present a comprehensive architectural analysis for a proposed fault-tolerant quantum computer based on cat codes concatenated with outer quantum error-correcting codes. For the physical hardware, we propose a system of acoustic resonators coupled to superconducting circuits with a two-dimensional layout. Using estimated physical parameters for the hardware, we perform a detailed error analysis of measurements and gates, including cnot and Toffoli gates. Having built a realistic noise model, we numerically simulate quantum error correction when the outer code is either a repetition code or a thin rectangular surface code. Our next step toward universal fault-tolerant quantum computation is a protocol for fault-tolerant Toffoli magic state preparation that significantly improves upon the fidelity of physical Toffoli gates at very low qubit cost. To achieve even lower overheads, we devise a new magic state distillation protocol for Toffoli states. Combining these results together, we obtain realistic full-resource estimates of the physical error rates and overheads needed to run useful fault-tolerant quantum algorithms. We find that with around 1000 superconducting circuit components, one could construct a fault-tolerant quantum computer that can run circuits, which are currently intractable for classical computers. Hardware with 18 000 superconducting circuit components, in turn, could simulate the Hubbard model in a regime beyond the reach of classical computing.
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- 2022
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31. Comparative Genomics and Proteomic Analysis of Assimilatory Sulfate Reduction Pathways in Anaerobic Methanotrophic Archaea
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Hang Yu, Dwi Susanti, Shawn E. McGlynn, Connor T. Skennerton, Karuna Chourey, Ramsunder Iyer, Silvan Scheller, Patricia L. Tavormina, Robert L. Hettich, Biswarup Mukhopadhyay, and Victoria J. Orphan
- Subjects
sulfur pathway ,sulfate reduction ,anaerobic oxidation of methane ,ANME ,syntrophy ,sulfate adenylyltransferase ,Microbiology ,QR1-502 - Abstract
Sulfate is the predominant electron acceptor for anaerobic oxidation of methane (AOM) in marine sediments. This process is carried out by a syntrophic consortium of anaerobic methanotrophic archaea (ANME) and sulfate reducing bacteria (SRB) through an energy conservation mechanism that is still poorly understood. It was previously hypothesized that ANME alone could couple methane oxidation to dissimilatory sulfate reduction, but a genetic and biochemical basis for this proposal has not been identified. Using comparative genomic and phylogenetic analyses, we found the genetic capacity in ANME and related methanogenic archaea for sulfate reduction, including sulfate adenylyltransferase, APS kinase, APS/PAPS reductase and two different sulfite reductases. Based on characterized homologs and the lack of associated energy conserving complexes, the sulfate reduction pathways in ANME are likely used for assimilation but not dissimilation of sulfate. Environmental metaproteomic analysis confirmed the expression of 6 proteins in the sulfate assimilation pathway of ANME. The highest expressed proteins related to sulfate assimilation were two sulfite reductases, namely assimilatory-type low-molecular-weight sulfite reductase (alSir) and a divergent group of coenzyme F420-dependent sulfite reductase (Group II Fsr). In methane seep sediment microcosm experiments, however, sulfite and zero-valent sulfur amendments were inhibitory to ANME-2a/2c while growth in their syntrophic SRB partner was not observed. Combined with our genomic and metaproteomic results, the passage of sulfur species by ANME as metabolic intermediates for their SRB partners is unlikely. Instead, our findings point to a possible niche for ANME to assimilate inorganic sulfur compounds more oxidized than sulfide in anoxic marine environments.
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- 2018
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32. Resilience of Quantum Random Access Memory to Generic Noise
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Connor T. Hann, Gideon Lee, S.M. Girvin, and Liang Jiang
- Subjects
Physics ,QC1-999 ,Computer software ,QA76.75-76.765 - Abstract
Quantum random access memory (QRAM)—memory which stores classical data but allows queries to be performed in superposition—is required for the implementation of numerous quantum algorithms. While naive implementations of QRAM are highly susceptible to decoherence and hence not scalable, it has been argued that the bucket-brigade QRAM architecture [Giovannetti et al., Phys. Rev. Lett. 100, 160501 (2008)] is highly resilient to noise, with the infidelity of a query scaling only logarithmically with the memory size. In prior analyses, however, this favorable scaling followed directly from the use of contrived noise models, thus leaving open the question of whether experimental implementations would actually enjoy the purported scaling advantage. In this work, we study the effects of decoherence on QRAM in full generality. Our main result is a proof that this favorable infidelity scaling holds for arbitrary error channels (including, e.g., depolarizing noise and coherent errors). Our proof identifies the origin of this noise resilience as the limited entanglement among the memory’s components, and it also reveals that significant architectural simplifications can be made while preserving the noise resilience. We verify these results numerically using a novel classical algorithm for the efficient simulation of noisy QRAM circuits. Our findings indicate that QRAM can be implemented with existing hardware in realistically noisy devices, and that high-fidelity queries are possible without quantum error correction. Furthermore, we also prove that the benefits of the bucket-brigade architecture persist when quantum error correction is used, in which case the scheme offers improved hardware efficiency and resilience to logical errors.
- Published
- 2021
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33. Quantum algorithms: A survey of applications and end-to-end complexities
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Dalzell, Alexander M., McArdle, Sam, Berta, Mario, Bienias, Przemyslaw, Chen, Chi-Fang, Gilyén, András, Hann, Connor T., Kastoryano, Michael J., Khabiboulline, Emil T., Kubica, Aleksander, Salton, Grant, Wang, Samson, and Brandão, Fernando G. S. L.
- Subjects
Quantum Physics - Abstract
The anticipated applications of quantum computers span across science and industry, ranging from quantum chemistry and many-body physics to optimization, finance, and machine learning. Proposed quantum solutions in these areas typically combine multiple quantum algorithmic primitives into an overall quantum algorithm, which must then incorporate the methods of quantum error correction and fault tolerance to be implemented correctly on quantum hardware. As such, it can be difficult to assess how much a particular application benefits from quantum computing, as the various approaches are often sensitive to intricate technical details about the underlying primitives and their complexities. Here we present a survey of several potential application areas of quantum algorithms and their underlying algorithmic primitives, carefully considering technical caveats and subtleties. We outline the challenges and opportunities in each area in an "end-to-end" fashion by clearly defining the problem being solved alongside the input-output model, instantiating all "oracles," and spelling out all hidden costs. We also compare quantum solutions against state-of-the-art classical methods and complexity-theoretic limitations to evaluate possible quantum speedups. The survey is written in a modular, wiki-like fashion to facilitate navigation of the content. Each primitive and application area is discussed in a standalone section, with its own bibliography of references and embedded hyperlinks that direct to other relevant sections. This structure mirrors that of complex quantum algorithms that involve several layers of abstraction, and it enables rapid evaluation of how end-to-end complexities are impacted when subroutines are altered., Comment: Survey document with wiki-like modular structure. 337 pages, including bibliography and sub-bibliographies. Comments welcome
- Published
- 2023
34. Degrees of Randomness in Rerandomization Procedures
- Author
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Jerzak, Connor T. and Goldstein, Rebecca
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Statistics - Methodology ,62Kxx, 62Pxx - Abstract
Randomized controlled trials are susceptible to imbalance on covariates predictive of the outcome. Rerandomization and deterministic treatment assignment are two proposed solutions. This paper explores the relationship between rerandomization and deterministic assignment, showing how deterministic assignment is an extreme case of rerandomization. The paper argues that in small experiments, both fully randomized and fully deterministic assignment have limitations. Instead, the researcher should consider setting the rerandomization acceptance probability based on an analysis of covariates and assumptions about the data structure to achieve an optimal alignment between randomness and balance. This allows for the calculation of minimum p-values along with valid permutation tests and fiducial intervals. The paper also introduces tools, including a new, open-source R package named fastrerandomize, to implement rerandomization and explore options for optimal rerandomization acceptance thresholds., Comment: For accompanying software, see https://github.com/cjerzak/fastrerandomize-software
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- 2023
35. CausalImages: An R Package for Causal Inference with Earth Observation, Bio-medical, and Social Science Images
- Author
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Jerzak, Connor T. and Daoud, Adel
- Subjects
Computer Science - Machine Learning ,Statistics - Methodology ,62-07, 68U10 ,I.4 - Abstract
The causalimages R package enables causal inference with image and image sequence data, providing new tools for integrating novel data sources like satellite and bio-medical imagery into the study of cause and effect. One set of functions enables image-based causal inference analyses. For example, one key function decomposes treatment effect heterogeneity by images using an interpretable Bayesian framework. This allows for determining which types of images or image sequences are most responsive to interventions. A second modeling function allows researchers to control for confounding using images. The package also allows investigators to produce embeddings that serve as vector summaries of the image or video content. Finally, infrastructural functions are also provided, such as tools for writing large-scale image and image sequence data as sequentialized byte strings for more rapid image analysis. causalimages therefore opens new capabilities for causal inference in R, letting researchers use informative imagery in substantive analyses in a fast and accessible manner., Comment: For accompanying software, see https://github.com/AIandGlobalDevelopmentLab/causalimages-software
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- 2023
36. High-Fidelity Measurement of Qubits Encoded in Multilevel Superconducting Circuits
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Salvatore S. Elder, Christopher S. Wang, Philip Reinhold, Connor T. Hann, Kevin S. Chou, Brian J. Lester, Serge Rosenblum, Luigi Frunzio, Liang Jiang, and Robert J. Schoelkopf
- Subjects
Physics ,QC1-999 - Abstract
Qubit measurements are central to quantum information processing. In the field of superconducting qubits, standard readout techniques are limited not only by the signal-to-noise ratio, but also by state relaxation during the measurement. In this work, we demonstrate that the limitation due to relaxation can be suppressed by using the many-level Hilbert space of superconducting circuits: In a multilevel encoding, the measurement is corrupted only when multiple errors occur. Employing this technique, we show that we can directly resolve transmon gate errors at the level of one part in 10^{3}. Extending this idea, we apply the same principles to the measurement of a logical qubit encoded in a bosonic mode and detected with a transmon ancilla, implementing a proposal by Hann et al. [Phys. Rev. A 98, 022305 (2018)PLRAAN2469-992610.1103/PhysRevA.98.022305]. Qubit state assignments are made based on a sequence of repeated readouts, further reducing the overall infidelity. This approach is quite general, and several encodings are studied; the codewords are more distinguishable when the distance between them is increased with respect to photon loss. The trade-off between multiple readouts and state relaxation is explored and shown to be consistent with the photon-loss model. We report a logical assignment infidelity of 5.8×10^{-5} for a Fock-based encoding and 4.2×10^{-3} for a quantum error correction code (the S=2, N=1 binomial code). Our results not only improve the fidelity of quantum information applications, but also enable more precise characterization of process or gate errors.
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- 2020
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37. Genetic Monogamy in Socially Monogamous Mammals Is Primarily Predicted by Multiple Life History Factors: A Meta-Analysis
- Author
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Connor T. Lambert, Anne C. Sabol, and Nancy G. Solomon
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genetic monogamy ,social monogamy ,extra-pair paternity ,mammals ,paternal care ,social structure ,Evolution ,QH359-425 ,Ecology ,QH540-549.5 - Abstract
Background: We still do not understand the key drivers or prevalence of genetic monogamy in mammals despite the amount of attention that the evolution of mammalian monogamy has received. There have been numerous reviews of the hypotheses proposed to explain monogamy, some of which focused on animals in general, while others focused on particular classes like birds or mammals, or on specific orders within a class. Because monogamy is rare in mammals overall but relatively common in some of the orders in which it has been observed (e.g., Primates, Macroscelidea, and Carnivora), mammals provide a unique taxon in which to study the evolution and maintenance of monogamy However, the term “monogamy” encompasses related but separate phenomena; i.e., social monogamy (pair-living by opposite-sex conspecifics) and genetic monogamy or reproductive monogamy (mating exclusivity). A recent review of mammalian monogamy reported that 226 species (9%) in 9 orders (35%) were socially monogamous, although socially monogamous mammals are not necessarily genetically monogamous.Methods: Since factors that predispose socially monogamous mammals to be genetically monogamous are still subject to debate, we conducted meta-analyses using model selection to determine the relative importance of several life history, demographic, and environmental factors in predicting genetic monogamy.Results: We found sufficient data to include 41 species in our analysis, about 2x more than have been included in previous analyses of mammalian genetic monogamy. We found that living as part of a socially monogamous pair vs. in a group was the best predictor of genetic monogamy, either by itself or in combination with high levels of paternal care. A male-biased sex ratio and low population density were inversely related to the number of pairs that were genetically monogamous, but not to the production of intra-pair young or litters.Conclusion: Our results agree with the results of some previous analyses but suggest that more than one factor may be important in driving genetic monogamy in mammals.
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- 2018
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38. Engineering Breast Cancer Microenvironments and 3D Bioprinting
- Author
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Jorge A. Belgodere, Connor T. King, Jacob B. Bursavich, Matthew E. Burow, Elizabeth C. Martin, and Jangwook P. Jung
- Subjects
extracellular matrix ,tumor models ,cancer microenvironments ,3D bioprinting ,cell-ECM interactions ,biophysical properties ,Biotechnology ,TP248.13-248.65 - Abstract
The extracellular matrix (ECM) is a critical cue to direct tumorigenesis and metastasis. Although two-dimensional (2D) culture models have been widely employed to understand breast cancer microenvironments over the past several decades, the 2D models still exhibit limited success. Overwhelming evidence supports that three dimensional (3D), physiologically relevant culture models are required to better understand cancer progression and develop more effective treatment. Such platforms should include cancer-specific architectures, relevant physicochemical signals, stromal–cancer cell interactions, immune components, vascular components, and cell-ECM interactions found in patient tumors. This review briefly summarizes how cancer microenvironments (stromal component, cell-ECM interactions, and molecular modulators) are defined and what emerging technologies (perfusable scaffold, tumor stiffness, supporting cells within tumors and complex patterning) can be utilized to better mimic native-like breast cancer microenvironments. Furthermore, this review emphasizes biophysical properties that differ between primary tumor ECM and tissue sites of metastatic lesions with a focus on matrix modulation of cancer stem cells, providing a rationale for investigation of underexplored ECM proteins that could alter patient prognosis. To engineer breast cancer microenvironments, we categorized technologies into two groups: (1) biochemical factors modulating breast cancer cell-ECM interactions and (2) 3D bioprinting methods and its applications to model breast cancer microenvironments. Biochemical factors include matrix-associated proteins, soluble factors, ECMs, and synthetic biomaterials. For the application of 3D bioprinting, we discuss the transition of 2D patterning to 3D scaffolding with various bioprinting technologies to implement biophysical cues to model breast cancer microenvironments.
- Published
- 2018
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39. Demonstrating a long-coherence dual-rail erasure qubit using tunable transmons
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Levine, Harry, Haim, Arbel, Hung, Jimmy S. C., Alidoust, Nasser, Kalaee, Mahmoud, DeLorenzo, Laura, Wollack, E. Alex, Arrangoiz-Arriola, Patricio, Khalajhedayati, Amirhossein, Sanil, Rohan, Moradinejad, Hesam, Vaknin, Yotam, Kubica, Aleksander, Hover, David, Aghaeimeibodi, Shahriar, Alcid, Joshua Ari, Baek, Christopher, Barnett, James, Bawdekar, Kaustubh, Bienias, Przemyslaw, Carson, Hugh, Chen, Cliff, Chen, Li, Chinkezian, Harut, Chisholm, Eric M., Clifford, Andrew, Cosmic, R., Crisosto, Nicole, Dalzell, Alexander M., Davis, Erik, D'Ewart, J. Mitch, Diez, Sandra, D'Souza, Nathan, Dumitrescu, Philipp T., Elkhouly, Essam, Fang, Michael, Fang, Yawen, Flammia, Steven T., Fling, Matthew J., Garcia, Gabriel, Gharzai, M. Kabeer, Gorshkov, Alexey V., Gray, Mason J., Grimberg, Sebastian, Grimsmo, Arne L., Hann, Connor T., He, Yuan, Heidel, Steven, Howell, Sean, Hunt, Matthew, Iverson, Joseph K., Jarrige, Ignace, Jiang, Liang, Jones, William M., Karabalin, Rassul, Karalekas, Peter J., Keller, Andrew J., Lasi, Davide, Lee, Menyoung, Ly, Victor, MacCabe, Gregory S., Mahuli, Neha, Marcaud, Guillaume, Matheny, Matthew H., McArdle, Sam, McCabe, Gavin, Merton, Gabe, Miles, Cody, Milsted, Ashley, Mishra, Anurag, Moncelsi, Lorenzo, Naghiloo, Mahdi, Noh, Kyungjoo, Oblepias, Eric, Ortuno, Gerson, Owens, John Clai, Pagdilao, Jason, Panduro, Ashley, Paquette, J. -P., Patel, Rishi N., Peairs, Gregory A., Perello, David J., Peterson, Eric C., Ponte, Sophia, Putterman, Harald, Refael, Gil, Reinhold, Philip, Resnick, Rachel, Reyna, Omar A., Rodriguez, Roberto, Rose, Jefferson, Rubin, Alex H., Runyan, Marc, Ryan, Colm A., Sahmoud, Abdulrahman, Scaffidi, Thomas, Shah, Bhavik, Siavoshi, Salome, Sivarajah, Prasahnt, Skogland, Trenton, Su, Chun-Ju, Swenson, Loren J., Sylvia, Jared, Teo, Stephanie M., Tomada, Astrid, Torlai, Giacomo, Wistrom, Mark, Zhang, Kailing, Zuk, Ido, Clerk, Aashish A., Brandão, Fernando G. S. L., Retzker, Alex, and Painter, Oskar
- Subjects
Quantum Physics - Abstract
Quantum error correction with erasure qubits promises significant advantages over standard error correction due to favorable thresholds for erasure errors. To realize this advantage in practice requires a qubit for which nearly all errors are such erasure errors, and the ability to check for erasure errors without dephasing the qubit. We demonstrate that a "dual-rail qubit" consisting of a pair of resonantly coupled transmons can form a highly coherent erasure qubit, where transmon $T_1$ errors are converted into erasure errors and residual dephasing is strongly suppressed, leading to millisecond-scale coherence within the qubit subspace. We show that single-qubit gates are limited primarily by erasure errors, with erasure probability $p_\text{erasure} = 2.19(2)\times 10^{-3}$ per gate while the residual errors are $\sim 40$ times lower. We further demonstrate mid-circuit detection of erasure errors while introducing $< 0.1\%$ dephasing error per check. Finally, we show that the suppression of transmon noise allows this dual-rail qubit to preserve high coherence over a broad tunable operating range, offering an improved capacity to avoid frequency collisions. This work establishes transmon-based dual-rail qubits as an attractive building block for hardware-efficient quantum error correction., Comment: 9+13 pages, 16 figures
- Published
- 2023
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40. Systems Architecture for Quantum Random Access Memory
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Xu, Shifan, Hann, Connor T., Foxman, Ben, Girvin, Steven M., and Ding, Yongshan
- Subjects
Quantum Physics ,Computer Science - Hardware Architecture - Abstract
Operating on the principles of quantum mechanics, quantum algorithms hold the promise for solving problems that are beyond the reach of the best-available classical algorithms. An integral part of realizing such speedup is the implementation of quantum queries, which read data into forms that quantum computers can process. Quantum random access memory (QRAM) is a promising architecture for realizing quantum queries. However, implementing QRAM in practice poses significant challenges, including query latency, memory capacity and fault-tolerance. In this paper, we propose the first end-to-end system architecture for QRAM. First, we introduce a novel QRAM that hybridizes two existing implementations and achieves asymptotically superior scaling in space (qubit number) and time (circuit depth). Like in classical virtual memory, our construction enables queries to a virtual address space larger than what is actually available in hardware. Second, we present a compilation framework to synthesize, map, and schedule QRAM circuits on realistic hardware. For the first time, we demonstrate how to embed large-scale QRAM on a 2D Euclidean space, such as a grid layout, with minimal routing overhead. Third, we show how to leverage the intrinsic biased-noise resilience of the proposed QRAM for implementation on either Noisy Intermediate-Scale Quantum (NISQ) or Fault-Tolerant Quantum Computing (FTQC) hardware. Finally, we validate these results numerically via both classical simulation and quantum hardware experimentation. Our novel Feynman-path-based simulator allows for efficient simulation of noisy QRAM circuits at a larger scale than previously possible. Collectively, our results outline the set of software and hardware controls needed to implement practical QRAM.
- Published
- 2023
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41. Coerced consent in clinical research: study protocol for a randomized controlled trial
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Brenna, Connor T. A., Walton, Nancy, Cohn, Melanie, Siddiqui, Urooj, Huszti, Ella, and Brull, Richard
- Published
- 2024
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42. Machine learning-enabled forward prediction and inverse design of 4D-printed active plates
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Sun, Xiaohao, Yue, Liang, Yu, Luxia, Forte, Connor T., Armstrong, Connor D., Zhou, Kun, Demoly, Frédéric, Zhao, Ruike Renee, and Qi, H. Jerry
- Published
- 2024
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43. The Dose-Response Relationship between Opioid Agonist Therapy and Alterations in Pain Pathways in Patients with Opioid Use Disorders: A Cross-Sectional Study
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Lang-Illievich, Kordula, Lang, Johanna, Rumpold-Seitlinger, Gudrun, Dorn, Christian, Brenna, Connor T. A., Klivinyi, Christoph, and Bornemann-Cimenti, Helmar
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- 2024
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44. Erratum for Skennerton et al., 'Methane-Fueled Syntrophy through Extracellular Electron Transfer: Uncovering the Genomic Traits Conserved within Diverse Bacterial Partners of Anaerobic Methanotrophic Archaea'
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Connor T. Skennerton, Karuna Chourey, Ramsunder Iyer, Robert L. Hettich, Gene W. Tyson, and Victoria J. Orphan
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Microbiology ,QR1-502 - Published
- 2017
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45. Methane-Fueled Syntrophy through Extracellular Electron Transfer: Uncovering the Genomic Traits Conserved within Diverse Bacterial Partners of Anaerobic Methanotrophic Archaea
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Connor T. Skennerton, Karuna Chourey, Ramsunder Iyer, Robert L. Hettich, Gene W. Tyson, and Victoria J. Orphan
- Subjects
ANME ,AOM ,anaerobic oxidation of methane ,extracellular electron transfer ,SEEP-SRB1 ,methane seeps ,Microbiology ,QR1-502 - Abstract
ABSTRACT The anaerobic oxidation of methane by anaerobic methanotrophic (ANME) archaea in syntrophic partnership with deltaproteobacterial sulfate-reducing bacteria (SRB) is the primary mechanism for methane removal in ocean sediments. The mechanism of their syntrophy has been the subject of much research as traditional intermediate compounds, such as hydrogen and formate, failed to decouple the partners. Recent findings have indicated the potential for extracellular electron transfer from ANME archaea to SRB, though it is unclear how extracellular electrons are integrated into the metabolism of the SRB partner. We used metagenomics to reconstruct eight genomes from the globally distributed SEEP-SRB1 clade of ANME partner bacteria to determine what genomic features are required for syntrophy. The SEEP-SRB1 genomes contain large multiheme cytochromes that were not found in previously described free-living SRB and also lack periplasmic hydrogenases that may prevent an independent lifestyle without an extracellular source of electrons from ANME archaea. Metaproteomics revealed the expression of these cytochromes at in situ methane seep sediments from three sites along the Pacific coast of the United States. Phylogenetic analysis showed that these cytochromes appear to have been horizontally transferred from metal-respiring members of the Deltaproteobacteria such as Geobacter and may allow these syntrophic SRB to accept extracellular electrons in place of other chemical/organic electron donors. IMPORTANCE Some archaea, known as anaerobic methanotrophs, are capable of converting methane into carbon dioxide when they are growing syntopically with sulfate-reducing bacteria. This partnership is the primary mechanism for methane removal in ocean sediments; however, there is still much to learn about how this syntrophy works. Previous studies have failed to identify the metabolic intermediate, such as hydrogen or formate, that is passed between partners. However, recent analysis of methanotrophic archaea has suggested that the syntrophy is formed through direct electron transfer. In this research, we analyzed the genomes of multiple partner bacteria and showed that they also contain the genes necessary to perform extracellular electron transfer, which are absent in related bacteria that do not form syntrophic partnerships with anaerobic methanotrophs. This genomic evidence shows a possible mechanism for direct electron transfer from methanotrophic archaea into the metabolism of the partner bacteria.
- Published
- 2017
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46. Linking Datasets on Organizations Using Half A Billion Open-Collaborated Records
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Libgober, Brian and Jerzak, Connor T.
- Subjects
Computer Science - Social and Information Networks ,68 ,H.3.3 - Abstract
Scholars studying organizations often work with multiple datasets lacking shared identifiers or covariates. In such situations, researchers usually use approximate string ("fuzzy") matching methods to combine datasets. String matching, although useful, faces fundamental challenges. Even where two strings appear similar to humans, fuzzy matching often struggles because it fails to adapt to the informativeness of the character combinations. In response, a number of machine learning methods have been developed to refine string matching. Yet, the effectiveness of these methods is limited by the size and diversity of training data. This paper introduces data from a prominent employment networking site (LinkedIn) as a massive training corpus to address these limitations. By leveraging information from the LinkedIn corpus regarding organizational name-to-name links, we incorporate trillions of name pair examples into various methods to enhance existing matching benchmarks and performance by explicitly maximizing match probabilities. We also show how relationships between organization names can be modeled using a network representation of the LinkedIn data. In illustrative merging tasks involving lobbying firms, we document improvements when using the LinkedIn corpus in matching calibration and make all data and methods open source., Comment: To appear in: Political Science Methods and Research (PSRM)
- Published
- 2023
47. Integrating Earth Observation Data into Causal Inference: Challenges and Opportunities
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Jerzak, Connor T., Johansson, Fredrik, and Daoud, Adel
- Subjects
Statistics - Machine Learning ,Computer Science - Machine Learning ,Statistics - Applications ,62D20 ,J.4 - Abstract
Observational studies require adjustment for confounding factors that are correlated with both the treatment and outcome. In the setting where the observed variables are tabular quantities such as average income in a neighborhood, tools have been developed for addressing such confounding. However, in many parts of the developing world, features about local communities may be scarce. In this context, satellite imagery can play an important role, serving as a proxy for the confounding variables otherwise unobserved. In this paper, we study confounder adjustment in this non-tabular setting, where patterns or objects found in satellite images contribute to the confounder bias. Using the evaluation of anti-poverty aid programs in Africa as our running example, we formalize the challenge of performing causal adjustment with such unstructured data -- what conditions are sufficient to identify causal effects, how to perform estimation, and how to quantify the ways in which certain aspects of the unstructured image object are most predictive of the treatment decision. Via simulation, we also explore the sensitivity of satellite image-based observational inference to image resolution and to misspecification of the image-associated confounder. Finally, we apply these tools in estimating the effect of anti-poverty interventions in African communities from satellite imagery., Comment: arXiv admin note: substantial text overlap with arXiv:2206.06410
- Published
- 2023
48. Deriving Entity-Specific Embeddings from Multi-Entity Sequences.
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Connor T. Heaton and Prasenjit Mitra
- Published
- 2024
49. PEaCE: A Chemistry-Oriented Dataset for Optical Character Recognition on Scientific Documents.
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Nan Zhang, Connor T. Heaton, Sean Timothy Okonsky, Prasenjit Mitra, and Hilal Ezgi Toraman
- Published
- 2024
50. γPNA FRET Pair Miniprobes for Quantitative Fluorescent In Situ Hybridization to Telomeric DNA in Cells and Tissue
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Alexander Orenstein, April S. Berlyoung, Elizabeth E. Rastede, Ha H. Pham, Elise Fouquerel, Connor T. Murphy, Brian J. Leibowitz, Jian Yu, Tumul Srivastava, Bruce A. Armitage, and Patricia L. Opresko
- Subjects
telomere ,γPNA ,hybridization probe ,fluorescent imaging ,Organic chemistry ,QD241-441 - Abstract
Measurement of telomere length by fluorescent in situ hybridization is widely used for biomedical and epidemiological research, but there has been relatively little development of the technology in the 20 years since it was first reported. This report describes the use of dual gammaPNA (γPNA) probes that hybridize at alternating sites along a telomere and give rise to Förster resonance energy transfer (FRET) signals. Bright staining of telomeres is observed in nuclei, chromosome spreads and tissue samples. The use of FRET detection also allows for elimination of wash steps, normally required to remove unhybridized probes that would contribute to background signals. We found that these wash steps can diminish the signal intensity through the removal of bound, as well as unbound probes, so eliminating these steps not only accelerates the process but also enhances the quality of staining. Thus, γPNA FRET pairs allow for brighter and faster staining of telomeres in a wide range of research and clinical formats.
- Published
- 2017
- Full Text
- View/download PDF
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