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1. Evaluating the Potential for Solar-Plus-Storage Backup Power as Homes Become More Efficient, Flexible, and Electrified

Author

Gorman, Will, Barbose, Galen, Miller, Chandler, White, Philip, Carvallo, JP, and Baik, Sunhee

Subjects
Backup power, electric resilience, electrification, energy efficiency, load flexibility, solar+storage, Fluid Mechanics and Thermal Engineering, Engineering, Electrical Engineering, Mechanical Engineering, Affordable and Clean Energy, Electric resilience, Energy efficiency, Load flexibility, Electrification, Solar, Storage, Resources Engineering and Extractive Metallurgy, Interdisciplinary Engineering, Energy, Electrical engineering, Fluid mechanics and thermal engineering, Mechanical engineering
Abstract

Adoption of residential behind-the-meter solar photovoltaic-plus-storage systems (PVESS) is driven, in part, by customer demand for backup power. However, there is limited understanding of how these systems perform over a range of building stock conditions that will evolve with future efficiency and electrification trends, posing challenges for identifying optimal electric resiliency investments. This study quantifies how residential energy consumption impacts the capability of PVESS to provide home backup power during long-duration power interruptions. We model statistically representative distributions of the residential building stock and estimate storage sizes required to provide backup power as a series of building envelope efficiency, load flexibility, and electrification measures are applied. For the baseline building stock, median storage size requirements range from 10 kWh in temperate weather conditions to 90 kWh in hot climates for a 3-day power interruption. Applying energy efficiency and temperature set-point adjustments reduce storage size requirements by 2–45 kWh (16%–53 %). In hot locations, heat pump retrofits reduce median storage sizing by an additional 10–30 kWh while in cold locations, they drive 10–50 kWh of storage capacity increase. Our results suggest that bi-directional EV charging may be essential to enabling PVESS backup of heating and cooling, given their typically large kWh sizes.

Published
2024

3. Solar+Storage for Household Back-up Power: Implications of building efficiency, load flexibility, and electrification for backup during long-duration power interruptions

Author

Gorman, Will, Barbose, Galen L, Miller, Cesca, Carvallo, Juan Pablo, Baik, Sun Hee, and White, Philip

Abstract

The study analyzes the evolving role of solar+storage for home backup power during long-duration power interruptions. In particular, it evaluates how required storage sizing is impacted as homes become more efficient, flexible, and electrified. The study relies on NREL’s ResStock building modeling platform to create statistically representative distributions of the existing building stock in ten locations across the United States. It then shows how the amount battery storage required for backup power rises or falls as a series of building envelope efficiency, load flexibility, and electrification measures are applied across the building stock in each region. The study also includes sensitivities to show how backup power requirements are impacted by the timing and duration of power interruptions, and explores variation in backup power requirements across the building stock within each study location.The results demonstrate the value of pairing solar+storage with efficiency upgrades, smart home controls, and (in mild winter climates) efficient heat pump retrofits. That value comes in the form of reducing the amount of storage required and/or extending the range of interruption conditions over which a given system can provide backup power (i.e., more extreme weather and/or longer interruptions). Heat pumps in cold-weather climates can pose a challenge for solar+storage backup power, given the amount of storage required, though are a vast improvement over electric-resistance heating. Retaining existing fossil-based heating systems for occasional use during power interruptions, as either the primary or supplementary source of heat, can mitigate this challenge. Other forms of building electrification (e.g., cooking and water heating) generally have marginal impacts on backup battery sizing, given their relatively small energy demand.

Published
2023

4. Pointwise density estimation on metric spaces and applications in seismology

Author

Cleanthous, Galatia, Georgiadis, Athanasios G., and White, Philip A.

Subjects
Mathematics - Statistics Theory, Statistics - Applications
Abstract

We are studying the problem of estimating density in a wide range of metric spaces, including the Euclidean space, the sphere, the ball, and various Riemannian manifolds. Our framework involves a metric space with a doubling measure and a self-adjoint operator, whose heat kernel exhibits Gaussian behaviour. We begin by reviewing the construction of kernel density estimators and the related background information. As a novel result, we present a pointwise kernel density estimation for probability density functions that belong to general H\"{o}lder spaces. The study is accompanied by an application in Seismology. Precisely, we analyze a globally-indexed dataset of earthquake occurrence and compare the out-of-sample performance of several approximated kernel density estimators indexed on the sphere.

Published
2023

5. County-level assessment of behind-the-meter solar and storage to mitigate long duration power interruptions for residential customers

Author

Gorman, Will, Barbose, Galen, Carvallo, Juan Pablo, Baik, Sunhee, Miller, Cesca, White, Philip, and Praprost, Marlena

Subjects
Affordable and Clean Energy, Backup power, Built environment and design, Distributed generation, Economics, Electrical Engineering, Electricity reliability, Electricity resilience, Energy, Engineering, Solar, Storage
Abstract

Customer concerns over electric system resilience could drive early adoption of behind-the-meter solar-plus-storage (BTM PVESS), especially as wildfire, hurricane, and other climate-driven risks to electric grids become more pronounced. However, the resilience benefits of BTM PVESS are poorly understood, especially for residential customers, owing to lack of data and methodological challenges, making it difficult to forecast adoption trends. In this paper, we develop a methodology to model the performance of BTM PVESS in providing backup power across a wide range of customer types, geography / climate conditions, and long duration power interruption scenarios, considering both whole-building backup and backup of specific critical loads. We combine novel, disaggregated end-use load profiles across the continental United States with temporally and geospatially aligned solar generation estimates. We then implement a PVESS dispatch algorithm to calculate the amount of load served during interruptions. We find that PVESS with 10 kWh of storage can meet a limited set of critical loads in most United States counties during any month of the year, though this capability drops to meeting only 86% of critical load, averaged across all counties and months, when heating and cooling are considered critical. Backup performance is lowest in winter months where electric heat is common (southeast and northwest U.S.) and in summer months in places with large cooling loads (southwest and southeast U.S.). Winter backup performance varies by roughly 20% depending on infiltration rates, while summer performance varies by close to 15% depending on the efficiency of the central air-conditioning system. Differences in temperature set-points in Harris County correspond to a 40% range in winter backup performance and a 20% range in summer performance. Economic calculations show that a customer's resilience value of PVESS must be high to motivate adoption of these systems.

Published
2023

6. Joint Multivariate and Functional Modeling for Plant Traits and Reflectances

Author

White, Philip A., Christensen, Michael F., Frye, Henry, Gelfand, Alan E., and Silander Jr, John A.

Subjects
Statistics - Applications, Statistics - Methodology
Abstract

The investigation of leaf-level traits in response to varying environmental conditions has immense importance for understanding plant ecology. Remote sensing technology enables measurement of the reflectance of plants to make inferences about underlying traits along environmental gradients. While much focus has been placed on understanding how reflectance and traits are related at the leaf-level, the challenge of modelling the dependence of this relationship along environmental gradients has limited this line of inquiry. Here, we take up the problem of jointly modeling traits and reflectance given environment. Our objective is to assess not only response to environmental regressors but also dependence between trait levels and the reflectance spectrum in the context of this regression. This leads to joint modeling of a response vector of traits with reflectance arising as a functional response over the wavelength spectrum. To conduct this investigation, we employ a dataset from a global biodiversity hotspot, the Greater Cape Floristic Region in South Africa.

Published
2022

7. Nonseparable Space-Time Stationary Covariance Functions on Networks cross Time

Author

Porcu, Emilio, White, Philip A., and Genton, Marc G.

Subjects
Statistics - Methodology, Mathematics - Statistics Theory
Abstract

The advent of data science has provided an increasing number of challenges with high data complexity. This paper addresses the challenge of space-time data where the spatial domain is not a planar surface, a sphere, or a linear network, but a generalized network (termed a graph with Euclidean edges). Additionally, data are repeatedly measured over different temporal instants. We provide new classes of nonseparable space-time stationary covariance functions where {\em space} can be a generalized network, a Euclidean tree, or a linear network, and where time can be linear or circular (seasonal). Because the construction principles are technical, we focus on illustrations that guide the reader through the construction of statistically interpretable examples. A simulation study demonstrates that we can recover the correct model when compared to misspecified models. In addition, our simulation studies show that we effectively recover simulation parameters. In our data analysis, we consider a traffic accident dataset that shows improved model performance based on covariance specifications and network-based metrics.

Published
2022

8. Two-cardinal ideal operators and indescribability

Author

Cody, Brent and White, Philip

Subjects
Mathematics - Logic, 03E35, 03E55
Abstract

A well-known version of Rowbottom's theorem for supercompactness ultrafilters leads naturally to notions of two-cardinal Ramseyness and corresponding normal ideals introduced herein. Generalizing results of Baumgartner [7, 8], Feng [22] and the first author [16, 17], we study the hierarchies associated with a particular version of two-cardinal Ramseyness and a strong version of two-cardinal ineffability, as well as the relationships between these hierarchies and a natural notion of transfinite two-cardinal indescribability., Comment: Made updates suggested by referee

Published
2022

9. Evaluating the Capabilities of Behind-the-Meter Solar-plus-Storage for Providing Backup Power during Long-Duration Power Interruptions

Author

Gorman, Will, Barbose, Galen L, Carvallo, Juan Pablo, Baik, Sunhee, Miller, Cesca, White, Philip, and Prapost, Marlena

Abstract

The study estimates the performance of behind-the-meter solar PV-plus-energy-storage-systems (PVESS) in providing critical-load or whole-building backup across a wide range of geographies, building types, and power interruption conditions. The study also considers a set of 10 historical long-duration power outage events and evaluates how PVESS could have performed in providing backup power during those specific events. The analysis is the first in what will be a series of studies by Berkeley Lab, in collaboration with the National Renewable Energy Laboratory, on the use of PVESS for backup power. This initial study, which relies on simulated end-use level building loads, solar generation, and storage dispatch, is intended to provide a baseline set of performance estimates and to illustrate key performance drivers.

Published
2022

13. Improving Performance in Upper-Division Electricity and Magnetism with Explicit Incentives to Correct Mistakes

Author

Mason, Andrew J., McCardell, Jessica M., White, Philip A., and Colton, John S.

Abstract

This study seeks to determine whether giving an explicit incentive to students in an upper-division first-semester electromagnetism course (EM1), in the form of partial credit for reworking unit exam problems, will improve their problem-solving skills as measured by performance on identical problems on the final exam. Three problems--a primarily algorithmic problem, a primarily conceptual problem, and a problem that blended conceptual with algorithmic--were selected and analyzed over the course of three consecutive sections of EM1, for which each student could freely choose whether or not to rework mistakes on each one of the given problems in exchange for the aforementioned partial credit. Regression models were chosen for quantitative analysis, with the covariate being unit exam performance and whether the student reworked the problem. Results indicate that overall, students who choose to rework problems perform better on the final exam attempt, at a level that often does not correlate strongly with unit exam performance, whereas students who decline to rework problems have a stronger correlation between unit exam and final exam performances. The results show a clear difference between the two stages of problem-solving, namely, invoking the correct principles and applying the principles, where the latter showed a more significant effect with a much larger effect size. Qualitative analysis of a sample of students interviewed about their exam solutions showed that reworking an exam problem for some students did result in more expertlike problem-solving trends; that being said, there were instances of persistent novicelike trends regardless of reworking, as well as instances of students independently reviewing unit exam problems in preparation for the final even though the partial credit incentive was declined at the time of the unit exam. Thus, while the intervention showed overall benefits insofar as exam performance is concerned, the usage of more well-defined scaffolding, e.g., tutorials, may prove a more thorough and definite benefit for improving problem-solving skills.

Published
2023
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17. Medical management and surgery versus medical management alone for symptomatic cerebral cavernous malformation (CARE): a feasibility study and randomised, open, pragmatic, pilot phase trial

Author

Eriksson, Madeleine, Hayat, Raza, Kinsella, Elaine, Lewis, Katherine, White, David CS, Boyd, Julia, Bullen, Alastair, Maclean, Morag, Stoddart, Andrew, Phair, Sandra, Evans, Helen, Noakes, Jo, Alexander, Debra, Keerie, Catriona, Linsley, Christopher, Milne, Garry, Norrie, John, Farrar, Nicola, Realpe, Alba X, Donovan, Jenny L, Bunch, Janet, Douthwaite, Kathryn, Temple, Simon, Hogg, James, Scott, David, Spallone, Pat, Stuart, Ian, Wardlaw, Joanna M, Palmer, Jeb, Sakka, Eleni, Mukerji, Nitin, Cirstea, Emanuel, Davies, Susan, Giannakaki, Venetia, Kadhim, Ammar, Kennion, Oliver, Islam, Moidul, Ferguson, Lucie, Prasad, Manjunath, Bacon, Andrew, Richards, Emma, Howe, Jo, Kamara, Christine, Gardner, Jonathan, Roman, Madalina, Sikaonga, Mary, Cahill, Julian, Rossdeutsch, Alex, Cahill, Varduhi, Hamina, Imron, Chaudhari, Kishor, Danciut, Mihai, Clarkson, Emma, Bjornson, Anna, Bulters, Diederik, Digpal, Ronneil, Ruiz, Winnington, Taylor, Mirriam, Anyog, Divina, Tluchowska, Katarzyna, Nolasco, Jackson, Brooks, Daniel, Angelopoulou, Kleopatra, Welch, Bethany, Broomes, Nicole, Fouyas, Ioannis, MacRaild, Allan, Kaliaperumal, Chandru, Teasdale, Jessica, Coakley, Michelle, Brennan, Paul, Sokol, Drahoslav, Wiggins, Anthony, MacDonald, Mairi, Risbridger, Sarah, Bhatt, Pragnesh, Irvine, Janice, Majeed, Sohail, Williams, Sandra, Reid, John, Walch, Annika, Muir, Farah, van Beijnum, Janneke, Leach, Paul, Hughes, Tom, Makwana, Milan, Hamandi, Khalid, McAleer, Dympna, Gunning, Belinda, Walsh, Daniel, Wroe Wright, Oliver, Patel, Sabina, Gurusinghe, Nihal, Raza-Knight, Saba, Cromie, Terri-Louise, Brown, Allan, Raj, Sonia, Pennington, Ruth, Campbell, Charlene, Patel, Shakeelah, Colombo, Francesca, Teo, Mario, Wildman, Jack, Smith, Kerry, Goff, Elizabeth, Stephens, Deanna, Borislavova, Borislava, Worner, Ruth, Buddha, Sandeep, Clatworthy, Philip, Edwards, Richard, Clayton, Evangeline, Coy, Karen, Tucker, Lisa, Dymond, Sandra, Mallick, Andrew, Hodnett, Rebecca, Spickett-Jones, Francesca, Grover, Patrick, Banaras, Azra, Tshuma, Sifelani, Muirhead, William, Scott Hill, Ciaran, Shah, Rupal, Doke, Thomas, Hall, Rebecca, Coskuner, Sonny, Aslett, Laura, Vindlacheruvu, Raghu, Ghosh, Anthony, Fitzpatrick, Teresa, Harris, Lauren, Hayton, Tom, Whitehouse, Arlo, McDarby, Andrew, Hancox, Rebecca, Auyeung, Claudia Kate, Nair, Ramesh, Thomas, Rhys, McLachlan, Heather, Kountourgioti, Athanasia, Orjales, Guillelme, Kruczynski, Jan, Hunter, Sophie, Bohnacker, Niamh, Marimon, Rosette, Parker, Lydia, Raha, Oishik, Sharma, Puneet, Uff, Christopher, Boyapati, Geetha, Papadopoulos, Marios, Kearney, Siobhan, Visagan, Ravindran, Bosetta, Ellaine, Asif, Hasan, Helmy, Adel, Chapas, Liliana, Tarantino, Silvia, Caldwell, Karen, Guilfoyle, Mathew, Agarwal, Smriti, Brown, Daniel, Holland, Sarah, Tajsic, Tamara, Fletcher, Clare, Sebyatki, Aisha, Ushewokunze, Shungu, Ali, Sarah, Preston, John, Chambers, Carole, Patel, Mohammed, Holsgrove, Daniel, McLaughlan, Danielle, Marsden, Tracey, Cawley, Kathryn, Raffalli, Hellen, Lee, Stephanie, Israni, Anil, Dore, Rachael, Anderson, Taya, Hennigan, Dawn, Mayor, Shelley, Glover, Samantha, Chavredakis, Emmanuel, Brown, Debbie, Sokratous, Giannis, Williamson, John, Stoneley, Cathy, Brodbelt, Andrew, Farah, Jibril Osman, Illingworth, Sarah, Konteas, Anastasios Benjamin, Davies, Deborah, Owen, Carol, Kerr, Loretta, Hall, Peter, Al-Shahi Salman, Rustam, Forsyth, Laura, Lewis, Steff C, Loan, James JM, Neilson, Aileen R, Stephen, Jacqueline, Kitchen, Neil, Harkness, Kirsty A, Hutchinson, Peter JA, Mallucci, Conor, Wade, Julia, and White, Philip M

Published
2024
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23. Response to Hansen Wheat et al.: Additional analysis further supports the early emergence of cooperative communication in dogs compared to wolves raised with more human exposure

Author

Salomons, Hannah, Smith, Kyle C. M., Callahan-Beckel, Megan, Callahan, Margaret, Levy, Kerinne, Kennedy, Brenda S., Bray, Emily E., Gnanadesikan, Gitanjali E., Horschler, Daniel J., Gruen, Margaret, Tan, Jingzhi, White, Philip, vonHoldt, Bridgett M., MacLean, Evan L., and Hare, Brian

Published
2023
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24. Addressing barriers and identifying facilitators to support informed consent and recruitment in the Cavernous malformations A Randomised Effectiveness (CARE) pilot phase trial: insights from the integrated QuinteT recruitment intervention (QRI)

Author

Mallucci, Conor, White, Philip M., Eriksson, Madeleine, Hayat, Raza, Kinsella, Elaine, Lewis, Katherine, Neilson, Aileen R., White, David C.S., Boyd, Julia, Bullen, Alastair, Maclean, Morag, Stoddart, Andrew, Phair, Sandra, Evans, Helen, Noakes, Jo, Alexander, Debra, Keerie, Catriona, Linsley, Christopher, Milne, Garry, Norrie, John, Bunch, Janet, Douthwaite, Kathryn, Temple, Simon, Hogg, James, Scott, David, Spallone, Pat, Stuart, Ian, Wardlaw, Joanna M., Palmer, Jeb, Sakka, Eleni, Mukerji, Nitin, Cirstea, Emanuel, Davies, Susan, Giannakaki, Venetia, Kadhim, Ammar, Kennion, Oliver, Islam, Moidul, Ferguson, Lucie, Prasad, Manjunath, Bacon, Andrew, Richards, Emma, Howe, Jo, Kamara, Christine, Gardner, Jonathan, Roman, Madalina, Sikaonga, Mary, Cahill, Julian, Rossdeutsch, Alex, Cahill, Varduhi, Hamina, Imron, Chaudhari, Kishor, Danciut, Mihai, Clarkson, Emma, Bjornson, Anna, Bulters, Diederik, Digpal, Ronneil, Ruiz, Winnington, Taylor, Mirriam, Anyog, Divina, Tluchowska, Katarzyna, Nolasco, Jackson, Brooks, Daniel, Angelopoulou, Kleopatra, Welch, Bethany, Broomes, Nicole, Fouyas, Ioannis, MacRaild, Allan, Kaliaperumal, Chandru, Teasdale, Jessica, Coakley, Michelle, Brennan, Paul, Sokol, Drahoslav, Wiggins, Anthony, MacDonald, Mairi, Risbridger, Sarah, Bhatt, Pragnesh, Irvine, Janice, Majeed, Sohail, Williams, Sandra, Reid, John, Walch, Annika, Muir, Farah, van Beijnum, Janneke, Leach, Paul, Hughes, Tom, Makwana, Milan, Hamandi, Khalid, McAleer, Dympna, Gunning, Belinda, Walsh, Daniel, Wright, Oliver Wroe, Patel, Sabina, Gurusinghe, Nihal, Raza-Knight, Saba, Cromie, Terri-Louise, Brown, Allan, Raj, Sonia, Pennington, Ruth, Campbell, Charlene, Patel, Shakeelah, Colombo, Francesca, Teo, Mario, Wildman, Jack, Smith, Kerry, Goff, Elizabeth, Stephens, Deanna, Borislavova, Borislava, Worner, Ruth, Buddha, Sandeep, Clatworthy, Philip, Edwards, Richard, Clayton, Evangeline, Coy, Karen, Tucker, Lisa, Dymond, Sandra, Mallick, Andrew, Hodnett, Rebecca, Spickett-Jones, Francesca, Grover, Patrick, Banaras, Azra, Tshuma, Sifelani, Muirhead, William, Hill, Ciaran Scott, Shah, Rupal, Doke, Thomas, Hall, Rebecca, Coskuner, Sonny, Aslett, Laura, Vindlacheruvu, Raghu, Ghosh, Anthony, Fitzpatrick, Teresa, Harris, Lauren, Hayton, Tom, Whitehouse, Arlo, McDarby, Andrew, Hancox, Rebecca, Auyeung, Claudia Kate, Nair, Ramesh, Thomas, Rhys, McLachlan, Heather, Kountourgioti, Athanasia, Orjales, Guillelme, Kruczynski, Jan, Hunter, Sophie, Bohnacker, Niamh, Marimon, Rosette, Parker, Lydia, Raha, Oishik, Sharma, Puneet, Uff, Christopher, Boyapati, Geetha, Papadopoulos, Marios, Kearney, Siobhan, Visagan, Ravindran, Bosetta, Ellaine, Asif, Hasan, Helmy, Adel, Chapas, Liliana, Tarantino, Silvia, Caldwell, Karen, Guilfoyle, Mathew, Agarwal, Smriti, Brown, Daniel, Holland, Sarah, Tajsic, Tamara, Fletcher, Clare, Sebyatki, Aisha, Ushewokunze, Shungu, Ali, Sarah, Preston, John, Chambers, Carole, Patel, Mohammed, Holsgrove, Daniel, McLaughlan, Danielle, Marsden, Tracey, Cawley, Kathryn, Raffalli, Hellen, Lee, Stephanie, Israni, Anil, Dore, Rachael, Anderson, Taya, Hennigan, Dawn, Mayor, Shelley, Glover, Samantha, Chavredakis, Emmanuel, Brown, Debbie, Sokratous, Giannis, Williamson, John, Stoneley, Cathy, Brodbelt, Andrew, Farah, Jibril Osman, Illingworth, Sarah, Konteas, Anastasios Benjamin, Davies, Deborah, Owen, Carol, Kerr, Loretta, Wade, Julia, Farrar, Nicola, Realpe, Alba X., Donovan, Jenny L., Forsyth, Laura, Harkness, Kirsty A., Hutchinson, Peter J.A., Kitchen, Neil, Lewis, Steff C., Loan, James J.M., Stephen, Jacqueline, and Al-Shahi Salman, Rustam

Published
2024
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28. Spatial Functional Data Modeling of Plant Reflectances

Author

White, Philip A., Frye, Henry, Christensen, Michael F., Gelfand, Alan E., and Silander Jr, John A.

Subjects
Statistics - Applications, Statistics - Methodology
Abstract

Plant reflectance spectra - the profile of light reflected by leaves across different wavelengths - supply the spectral signature for a species at a spatial location to enable estimation of functional and taxonomic diversity for plants. We consider leaf spectra as "responses" to be explained spatially. These spectra/reflectances are functions over a wavelength band that respond to the environment. Our motivating data are gathered for several families from the Cape Floristic Region (CFR) in South Africa and lead us to develop rich novel spatial models that can explain spectra for genera within families. Wavelength responses for an individual leaf are viewed as a function of wavelength, leading to functional data modeling. Local environmental features become covariates. We introduce wavelength - covariate interaction since the response to environmental regressors may vary with wavelength, so may variance. Formal spatial modeling enables prediction of reflectances for genera at unobserved locations with known environmental features. We incorporate spatial dependence, wavelength dependence, and space-wavelength interaction (in the spirit of space-time interaction). We implement out-of-sample validation to select a best model, discovering that the model features listed above are all informative for the functional data analysis. We then supply interpretation of the results under the selected model., Comment: 20 pages main manuscript, 20 pages supplement

Published
2021

29. Flexible Validity Conditions for the Multivariate Mat\'ern Covariance in any Spatial Dimension and for any Number of Components

Author

Emery, Xavier, Porcu, Emilio, and White, Philip

Subjects
Statistics - Methodology, Mathematics - Statistics Theory
Abstract

This paper addresses the problem of finding parametric constraints that ensure the validity of the multivariate Mat{\'e}rn covariance for modeling the spatial correlation structure of coregionalized variables defined in an Euclidean space. To date, much attention has been given to the bivariate setting, while the multivariate setting has been explored to a limited extent only. The existing conditions often imply severe restrictions on the upper bounds for the collocated correlation coefficients, which makes the multivariate Mat{\'e}rn model appealing for the case of weak spatial cross-dependence only. We provide a collection of sufficient validity conditions for the multivariate Mat{\'e}rn covariance that allows for more flexible parameterizations than those currently available, and prove that one can attain considerably higher upper bounds for the collocated correlation coefficients in comparison with our competitors. We conclude with an illustration on a trivariate geochemical data set and show that our enlarged parametric space yields better fitting performances.

Published
2021

30. Cerebral Edema in Patients With Large Hemispheric Infarct Undergoing Reperfusion Treatment

Author

Ng, Felix C, Yassi, Nawaf, Sharma, Gagan, Brown, Scott B, Goyal, Mayank, Majoie, Charles BLM, Jovin, Tudor G, Hill, Michael D, Muir, Keith W, Saver, Jeffrey L, Guillemin, Francis, Demchuk, Andrew M, Menon, Bijoy K, San Roman, Luis, Liebeskind, David S, White, Philip, Dippel, Diederik WJ, Davalos, Antoni, Bracard, Serge, Mitchell, Peter J, Wald, Michael J, Davis, Stephen M, Sheth, Kevin N, Kimberly, W Taylor, Campbell, Bruce CV, and Collaborators, for the HERMES

Subjects
Biomedical Imaging, Heart Disease, Cardiovascular, Neurosciences, Heart Disease - Coronary Heart Disease, Stroke, Clinical Research, Brain Disorders, Brain Edema, Brain Infarction, Endovascular Procedures, Humans, Reperfusion, Reperfusion Injury, Thrombectomy, edema, infarction, ischemic stroke, reperfusion, thrombectomy, HERMES Collaborators, Cardiorespiratory Medicine and Haematology, Clinical Sciences, Neurology & Neurosurgery
Abstract

Background and purposeWhether reperfusion into infarcted tissue exacerbates cerebral edema has treatment implications in patients presenting with extensive irreversible injury. We investigated the effects of endovascular thrombectomy and reperfusion on cerebral edema in patients presenting with radiological evidence of large hemispheric infarction at baseline.MethodsIn a systematic review and individual patient-level meta-analysis of 7 randomized controlled trials comparing thrombectomy versus medical therapy in anterior circulation ischemic stroke published between January 1, 2010, and May 31, 2017 (Highly Effective Reperfusion Using Multiple Endovascular Devices collaboration), we analyzed the association between thrombectomy and reperfusion with maximal midline shift (MLS) on follow-up imaging as a measure of the space-occupying effect of cerebral edema in patients with large hemispheric infarction on pretreatment imaging, defined as diffusion-magnetic resonance imaging or computed tomography (CT)-perfusion ischemic core 80 to 300 mL or noncontrast CT-Alberta Stroke Program Early CT Score ≤5. Risk of bias was assessed using the Cochrane tool.ResultsAmong 1764 patients, 177 presented with large hemispheric infarction. Thrombectomy and reperfusion were associated with functional improvement (thrombectomy common odds ratio =2.30 [95% CI, 1.32–4.00]; reperfusion common odds ratio =4.73 [95% CI, 1.66–13.52]) but not MLS (thrombectomy β=−0.27 [95% CI, −1.52 to 0.98]; reperfusion β=−0.78 [95% CI, −3.07 to 1.50]) when adjusting for age, National Institutes of Health Stroke Score, glucose, and time-to-follow-up imaging. In an exploratory analysis of patients presenting with core volume >130 mL or CT-Alberta Stroke Program Early CT Score ≤3 (n=76), thrombectomy was associated with greater MLS after adjusting for age and National Institutes of Health Stroke Score (β=2.76 [95% CI, 0.33–5.20]) but not functional improvement (odds ratio, 1.71 [95% CI, 0.24–12.08]).ConclusionsIn patients presenting with large hemispheric infarction, thrombectomy and reperfusion were not associated with MLS, except in the subgroup with very large core volume (>130 mL) in whom thrombectomy was associated with increased MLS due to space-occupying ischemic edema. Mitigating cerebral edema-mediated secondary injury in patients with very large infarcts may further improve outcomes after reperfusion therapies.

Published
2021

31. Prediction of Outcome and Endovascular Treatment Benefit

Author

Venema, Esmee, Roozenbeek, Bob, Mulder, Maxim JHL, Brown, Scott, Majoie, Charles BLM, Steyerberg, Ewout W, Demchuk, Andrew M, Muir, Keith W, Dávalos, Antoni, Mitchell, Peter J, Bracard, Serge, Berkhemer, Olvert A, Lycklama à Nijeholt, Geert J, van Oostenbrugge, Robert J, Roos, Yvo BWEM, van Zwam, Wim H, van der Lugt, Aad, Hill, Michael D, White, Philip, Campbell, Bruce CV, Guillemin, Francis, Saver, Jeffrey L, Jovin, Tudor G, Goyal, Mayank, Dippel, Diederik WJ, Lingsma, Hester F, der Lugt, Aad van, Boiten, Jelis, Vos, Jan Albert, Jansen, Ivo GH, Goldhoorn, Robert-Jan B, Compagne, Kars CJ, Kappelhof, Manon, Brouwer, Josje, den Hartog, Sanne J, Hinsenveld, Wouter H, van Es, Adriaan CGM, Emmer, Bart J, Coutinho, Jonathan M, Schonewille, Wouter J, Wermer, Marieke JH, van Walderveen, Marianne AA, Staals, Julie, Hofmeijer, Jeannette, Martens, Jasper M, de Bruijn, Sebastiaan F, van Dijk, Lukas C, van der Worp, H Bart, Lo, Rob H, van Dijk, Ewoud J, Boogaarts, Hieronymus D, Vries, J de, de Kort, Paul LM, van Tuijl, Julia, Peluso, Jo P, Fransen, Puck, van den Berg, Jan SP, van Hasselt, Boudewijn AAM, Aerden, Leo AM, Dallinga, René J, Uyttenboogaart, Maarten, Eschgi, Omid, Bokkers, Reinoud PH, Schreuder, Tobien HCML, Heijboer, Roel JJ, Keizer, Koos, Yo, Lonneke SF, den Hertog, Heleen M, Bulut, Tomas, Brouwers, Paul JAM, Sprengers, Marieke ES, Jenniskens, Sjoerd FM, van den Berg, René, Yoo, Albert J, Beenen, Ludo FM, Postma, Alida A, Roosendaal, Stefan D, van der Kallen, Bas FW, van den Wijngaard, Ido R, Bot, Joost, van Doormaal, Pieter-Jan, Meijer, Anton, Ghariq, Elyas, van Proosdij, Marc P, Krietemeijer, G Menno, Lo, Rob, Gerrits, Dick, Dinkelaar, Wouter, and Appelman, Auke PA

Subjects
Clinical Trials and Supportive Activities, Clinical Research, Stroke, Brain Disorders, Neurosciences, Aged, Aged, 80 and over, Brain Ischemia, Endovascular Procedures, Humans, Ischemic Stroke, Male, Middle Aged, Registries, Thrombectomy, Treatment Outcome, ischemic stroke, registry, reperfusion, thrombectomy, uncertainty, HERMES collaborators and MR CLEAN Registry Investigators*, Cardiorespiratory Medicine and Haematology, Clinical Sciences, Neurology & Neurosurgery
Abstract

Background and purposeBenefit of early endovascular treatment (EVT) for ischemic stroke varies considerably among patients. The MR PREDICTS decision tool, derived from MR CLEAN (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands), predicts outcome and treatment benefit based on baseline characteristics. Our aim was to externally validate and update MR PREDICTS with data from international trials and daily clinical practice.MethodsWe used individual patient data from 6 randomized controlled trials within the HERMES (Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke Trials) collaboration to validate the original model. Then, we updated the model and performed a second validation with data from the observational MR CLEAN Registry. Primary outcome was functional independence (defined as modified Rankin Scale score 0–2) 3 months after stroke. Treatment benefit was defined as the difference between the probability of functional independence with and without EVT. Discriminative performance was evaluated using a concordance (C) statistic.ResultsWe included 1242 patients from HERMES (633 assigned to EVT, 609 assigned to control) and 3156 patients from the MR CLEAN Registry (all of whom underwent EVT within 6.5 hours). The C-statistic for functional independence was 0.74 (95% CI, 0.72–0.77) in HERMES and, after model updating, 0.80 (0.78–0.82) in the Registry. Median predicted treatment benefit of routinely treated patients (Registry) was 10.3% (interquartile range, 5.8%–14.4%). Patients with low (

Published
2021

36. Improving Piecewise Linear Snow Density Models through Hierarchical Spatial and Orthogonal Functional Smoothing

Author

White, Philip, Keeler, Durban, Sheanshang, Daniel, and Rupper, Summer

Subjects
Statistics - Methodology, Statistics - Applications
Abstract

Snow density estimates as a function of depth are used for understanding climate processes, evaluating water accumulation trends in polar regions, and estimating glacier mass balances. The common and interpretable physically-derived differential equation models for snow density are piecewise linear as a function of depth (on a transformed scale); thus, they can fail to capture important data features. Moreover, the differential equation parameters show strong spatial autocorrelation. To address these issues, we allow the parameters of the physical model, including random change points over depth, to vary spatially. We also develop a framework for functionally smoothing the physically-motivated model. To preserve inference on the interpretable physical model, we project the smoothing function into the physical model's spatially varying null space. The proposed spatially and functionally smoothed snow density model better fits the data while preserving inference on physical parameters. Using this model, we find significant spatial variation in the parameters that govern snow densification.

Published
2020

37. Hierarchical Integrated Spatial Process Modeling of Monotone West Antarctic Snow Density Curves

Author

White, Philip A., Keeler, Durban G., and Rupper, Summer

Subjects
Statistics - Applications, Statistics - Methodology
Abstract

Snow density estimates below the surface, used with airplane-acquired ice-penetrating radar measurements, give a site-specific history of snow water accumulation. Because it is infeasible to drill snow cores across all of Antarctica to measure snow density and because it is critical to understand how climatic changes are affecting the world's largest freshwater reservoir, we develop methods that enable snow density estimation with uncertainty in regions where snow cores have not been drilled. In inland West Antarctica, snow density increases monotonically as a function of depth, except for possible micro-scale variability or measurement error, and it cannot exceed the density of ice. We present a novel class of integrated spatial process models that allow interpolation of monotone snow density curves. For computational feasibility, we construct the space-depth process through kernel convolutions of log-Gaussian spatial processes. We discuss model comparison, model fitting, and prediction. Using this model, we extend estimates of snow density beyond the depth of the original core and estimate snow density curves where snow cores have not been drilled. Along flight lines with ice-penetrating radar, we use interpolated snow density curves to estimate recent water accumulation and find predominantly decreasing water accumulation over recent decades.

Published
2020
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39. Effects of oral anticoagulation in people with atrial fibrillation after spontaneous intracranial haemorrhage (COCROACH): prospective, individual participant data meta-analysis of randomised trials

Author

Klug, Didier, Casolla, Barbara, Puy, Laurent, Coffee, Morgane, Kuchcinski, Grégory, Labreuche, Julien, van Nieuwenhuizen, Koen M., Algra, Ale, van Gelder, Isabelle C., Kappelle, L. Jaap, Rinkel, Gabriel J.E., Schutgens, Roger E.G., Khatri, Pooja, Conwit, Robin, Falcone, Guido, Elm, Jordan, Anderson, Craig S., Song, Lili, Pandian, Jeyaraj, Hart, Robert G., Sharma, Mukul, Aref, Hany, Tarhuni, Wadea, Fabregas, Joan Marti, Diener, Hans-Christoph, Endres, Matthias, Lemmens, Robin, Kwon, Sun U., Lee, Byung-Chul, Ameriso, Sebastian, Milling, Truman J., Kasner, Scott E., Mikulik, Robert, Xavier, Denis, Beer, Ronny, Toni, Danilo, Eckstein, Jens, Seiffge, David, Ferro, Jose M., Tsivgoulis, Georgios, Sharma, Sanjib K., Wei-Liou, Chia, Hohnloser, Stefan H., Katsanos, Aristeidis, Bosch, Jackie, Healey, Jeff, Eikelboom, John, Khaw, Alexander, Gladstone, David, Pikula, Aleksandra, Coutts, Shelagh, Smith, Eric E., Butcher, Ken, Field, Thalia, Gioia, Laura, Stapf, Christian, Halse, Omid, Ringleb, Peter, Enzinger, Christian, Sibon, Igor, Montaner, Joan, Caso, Valeria, Heuschmann, Peter, Lip, Gregory Y.H., Haefeli, Walter, Debette, Stefanie, Dennis, Martin S., Wyller, Torgeir Bruun, Rønning, Ole M., Eilertsen, Helle, Ihle-Hansen, Hege, Sandset, Else Charlotte, Pennlert, Johanna, Glader, Eva-Lotta, Kruuse, Christina, Wester, Per, Carlsson, Maria, Forfang, Elisabeth, Al-Shahi Salman, Rustam, Stephen, Jacqueline, Tierney, Jayne F, Lewis, Steff C, Newby, David E, Parry-Jones, Adrian R, White, Philip M, Connolly, Stuart J, Benavente, Oscar R, Dowlatshahi, Dar, Cordonnier, Charlotte, Viscoli, Catherine M, Sheth, Kevin N, Kamel, Hooman, Veltkamp, Roland, Larsen, Kristin T, Hofmeijer, Jeannette, Kerkhoff, Henk, Schreuder, Floris H B M, Shoamanesh, Ashkan, Klijn, Catharina J M, and van der Worp, H Bart

Published
2023
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42. Generalized Evolutionary Point Processes: Model Specifications and Model Comparison

Author

White, Philip A. and Gelfand, Alan E.

Subjects
Statistics - Methodology, Statistics - Applications, Statistics - Computation
Abstract

Generalized evolutionary point processes offer a class of point process models that allows for either excitation or inhibition based upon the history of the process. In this regard, we propose modeling which comprises generalization of the nonlinear Hawkes process. Working within a Bayesian framework, model fitting is implemented through Markov chain Monte Carlo. This entails discussion of computation of the likelihood for such point patterns. Furthermore, for this class of models, we discuss strategies for model comparison. Using simulation, we illustrate how well we can distinguish these models from point pattern specifications with conditionally independent event times, e.g., Poisson processes. Specifically, we demonstrate that these models can correctly identify true relationships (i.e., excitation or inhibition/control). Then, we consider a novel extension of the log Gaussian Cox process that incorporates evolutionary behavior and illustrate that our model comparison approach prefers the evolutionary log Gaussian Cox process compared to simpler models. We also examine a real dataset consisting of violent crime events from the 11th police district in Chicago from the year 2018. This data exhibits strong daily seasonality and changes across the year. After we account for these data attributes, we find significant but mild self-excitation, implying that event occurrence increases the intensity of future events.

Published
2019
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43. Multivariate Functional Data Modeling with Time-varying Clustering

Author

White, Philip A. and Gelfand, Alan E.

Subjects
Statistics - Methodology
Abstract

We consider the situation where multivariate functional data has been collected over time at each of a set of sites. Our illustrative setting is bivariate, monitoring ozone and PM$_{10}$ levels as a function of time over the course of a year at a set of monitoring sites. The data we work with is from 24 monitoring sites in Mexico City which record hourly ozone and PM$_{10}$ levels. We use the data for the year 2017. Hence, we have 48 functions to work with. Our objective is to implement model-based clustering of the functions across the sites. Using our example, such clustering can be considered for ozone and PM$_{10}$ individually or jointly. It may occur differentially for the two pollutants. More importantly for us, we allow that such clustering can vary with time. We model the multivariate functions across sites using a multivariate Gaussian process. With many sites and several functions at each site, we use dimension reduction to provide a stochastic process specification for the distribution of the collection of multivariate functions over the say $n$ sites. Furthermore, to cluster the functions, either individually by component or jointly with all components, we use the Dirichlet process which enables shared labeling of the functions across the sites. Specifically, we cluster functions based on their response to exogenous variables. Though the functions arise in continuous time, clustering in continuous time is extremely computationally demanding and not of practical interest. Therefore, we employ a partitioning of the time scale to capture time-varying clustering.

Published
2019
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46. LA100 Equity Strategies

Author

Anderson, Kate, primary, Day, Megan, additional, Romero Lankao, Patricia, additional, Berdahl, Sonja, additional, Rauser, Casandra, additional, Bowen, Thomas, additional, Fournier, Eric, additional, Heath, Garvin, additional, Hinojosa, Raul, additional, Ong, Paul, additional, Palmintier, Bryan, additional, Pierce, Gregory, additional, Pincetl, Stephanie, additional, Prasanna, Ashreeta, additional, Ravi, Vikram, additional, Reyna, Janet, additional, Lee, Dong-Yeon, additional, Rosner, Nicole, additional, Sandoval, Noah, additional, Sekar, Ashok, additional, Sheinberg, Rachel, additional, Simeone, Christina, additional, Stenger, Katelyn, additional, Sun, Bingrong, additional, Valenzuela, Abel, additional, Wilson, Alana, additional, Zhu, Yifang, additional, Abraham, Sherin Ann, additional, Blanco, Lis, additional, Bolla, Greg, additional, Bustamante, Leticia, additional, Coffee, Daniel, additional, Craer, Jennifer, additional, Das, Paritosh, additional, Denholm, Paul, additional, Duwadi, Kapil, additional, Fontanini, Anthony, additional, Gonzalez, Silvia, additional, Gu, Yu, additional, He, Yueshuai, additional, Hernandez, Ariana, additional, Horsey, Ry, additional, Katz, Sophie, additional, Krishnamoorthy, Gayathri, additional, Li, Yun, additional, Lin, Yun, additional, Liu, Lixi, additional, Lockshin, Jane, additional, Ma, Jiaqi, additional, Maguire, Jeff, additional, Marroquin, Isaias, additional, Mooney, Meghan, additional, Panda, Kinshuk, additional, Pleitez, Marcelo, additional, Robertson, Joe, additional, Rodriguez, Ruth, additional, Ruddick-Schulman, Saul, additional, Sanchez-Hall, Magali, additional, Sedzro, Kwami Senam, additional, Velasquez, Leslie, additional, Walzberg, Julien, additional, White, Philip, additional, Yu, Qiao, additional, and Zimny-Schmitt, Daniel, additional

Published
2023
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48. LA100 Equity Strategies. Executive Summary

Author

Anderson, Kate, primary, Day, Megan, additional, Romero-Lankao, Patricia, additional, Berdahl, Sonja, additional, Rauser, Casandra, additional, Bowen, Thomas, additional, Fournier, Eric Daniel, additional, Heath, Garvin, additional, Hinojosa, Raul, additional, Ong, Paul, additional, Palmintier, Bryan, additional, Pierce, Gregory, additional, Pincetl, Stephanie, additional, Prasanna, Ashreeta, additional, Ravi, Vikram, additional, Reyna, Janet, additional, Lee, Dong-Yeon, additional, Rosner, Nicole, additional, Sandoval, Noah, additional, Sekar, Ashok, additional, Sheinberg, Rachel, additional, Simeone, Christina, additional, Stenger, Katelyn, additional, Sun, Bingrong, additional, Valenzuela, Abel, additional, Wilson, Alana, additional, Zhu, Yifang, additional, Abraham, Sherin Ann, additional, Blanco, Lis, additional, Bolla, Greg, additional, Bustamante, Leticia, additional, Coffee, Daniel, additional, Craer, Jennifer, additional, Das, Paritosh, additional, Denholm, Paul, additional, Duwadi, Kapil, additional, Fontanini, Anthony, additional, Gonzalez, Silvia, additional, Gu, Yu, additional, He, Yueshuai, additional, Hernandez, Ariana, additional, Horsey, Ry, additional, Krishnamoorthy, Gayathri, additional, Katz, Sophie, additional, Li, Yun, additional, Lin, Yun, additional, Liu, Lixi, additional, Lockshin, Jane, additional, Ma, Jiaqi, additional, Maguire, Jeff, additional, Marroquin, Isaias, additional, Mooney, Meghan, additional, Panda, Kinshuk, additional, Pleitez, Marcelo, additional, Robertson, Joe, additional, Rodriguez, Ruth, additional, Ruddick-Schulman, Saul, additional, Sanchez-Hall, Magali, additional, Sedzro, Kwami Senam, additional, Velasquez, Leslie, additional, Walzberg, Julien, additional, White, Philip, additional, Yu, Qiao, additional, and Zimny-Schmitt, Daniel, additional

Published
2023
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50. Functions of macronutrients

Author

Hawkesford, Malcolm J., primary, Cakmak, Ismail, additional, Coskun, Devrim, additional, De Kok, Luit J., additional, Lambers, Hans, additional, Schjoerring, Jan K., additional, and White, Philip J., additional

Published
2023
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