The accurate computation of Hamiltonian ground, excited and thermal states on quantum computers stands to impact many problems in the physical and computer sciences, from quantum simulation to ...machine learning. Given the challenges posed in constructing large-scale quantum computers, these tasks should be carried out in a resource-efficient way. In this regard, existing techniques based on phase estimation or variational algorithms display potential disadvantages; phase estimation requires deep circuits with ancillae, that are hard to execute reliably without error correction, while variational algorithms, while flexible with respect to circuit depth, entail additional high-dimensional classical optimization. Here, we introduce the quantum imaginary time evolution and quantum Lanczos algorithms, which are analogues of classical algorithms for finding ground and excited states. Compared with their classical counterparts, they require exponentially less space and time per iteration, and can be implemented without deep circuits and ancillae, or high-dimensional optimization. We furthermore discuss quantum imaginary time evolution as a subroutine to generate Gibbs averages through an analogue of minimally entangled typical thermal states. Finally, we demonstrate the potential of these algorithms via an implementation using exact classical emulation as well as through prototype circuits on the Rigetti quantum virtual machine and Aspen-1 quantum processing unit.The quantum imaginary time evolution and Lanczos algorithms offer a resource-efficient way to compute ground or excited states of target Hamiltonians on quantum computers. This offers promise for quantum simulation on near-term noisy devices.
Abstract
Recent experimental advances have stimulated interest in the use of large, two-dimensional arrays of Rydberg atoms as a platform for quantum information processing and to study exotic ...many-body quantum states. However, the native long-range interactions between the atoms complicate experimental analysis and precise theoretical understanding of these systems. Here we use new tensor network algorithms capable of including all long-range interactions to study the ground state phase diagram of Rydberg atoms in a geometrically unfrustrated square lattice array. We find a greatly altered phase diagram from earlier numerical and experimental studies, revealed by studying the phases on the bulk lattice and their analogs in experiment-sized finite arrays. We further describe a previously unknown region with a nematic phase stabilized by short-range entanglement and an order from disorder mechanism. Broadly our results yield a conceptual guide for future experiments, while our techniques provide a blueprint for converging numerical studies in other lattices.
A single serum creatinine measurement cannot distinguish acute kidney injury from chronic kidney disease or prerenal azotemia.
To test the sensitivity and specificity of a single measurement of ...urinary neutrophil gelatinase-associated lipocalin (NGAL) and other urinary proteins to detect acute kidney injury in a spectrum of patients.
Prospective cohort study.
Emergency department of Columbia University Medical Center, New York, New York.
635 patients admitted to the hospital with acute kidney injury, prerenal azotemia, chronic kidney disease, or normal kidney function.
Diagnosis of acute kidney injury was based on the RIFLE (risk, injury, failure, loss, and end-stage) criteria and assigned by researchers who were blinded to experimental measurements. Urinary NGAL was measured by immunoblot, N-acetyl-beta-d-glucosaminidase (NAG) by enzyme measurement, alpha1-microglobulin and alpha(1)-acid glycoprotein by immunonephelometry, and serum creatinine by Jaffe kinetic reaction. Experimental measurements were not available to treating physicians.
Patients with acute kidney injury had a significantly elevated mean urinary NGAL level compared with the other kidney function groups (416 microg/g creatinine SD, 387; P = 0.001). At a cutoff value of 130 microg/g creatinine, sensitivity and specificity of NGAL for detecting acute injury were 0.900 (95% CI, 0.73 to 0.98) and 0.995 (CI, 0.990 to 1.00), respectively, and positive and negative likelihood ratios were 181.5 (CI, 58.33 to 564.71) and 0.10 (CI, 0.03 to 0.29); these values were superior to those for NAG, alpha1-microglobulin, alpha1-acid glycoprotein, fractional excretion of sodium, and serum creatinine. In multiple logistic regression, urinary NGAL level was highly predictive of clinical outcomes, including nephrology consultation, dialysis, and admission to the intensive care unit (odds ratio, 24.71 CI, 7.69 to 79.42).
All patients came from a single center. Few kidney biopsies were performed.
A single measurement of urinary NGAL helps to distinguish acute injury from normal function, prerenal azotemia, and chronic kidney disease and predicts poor inpatient outcomes.
•Mechanisms by which landscape stucture directly affects insect pests are proposed.•Diverse landscapes can cause dispersal mortality and decreased fitness for insect pests.•Insect life history and ...landscape structure interact to affect insect pest density.
The ‘resource concentration hypothesis’ proposes mechanisms by which polycultures (local plant diversity) can directly reduce densities of insect pests in agriculture. It predicts that herbivore loads are directly reduced because host plant cues are disrupted and herbivore residency times are shorter in polycultures than in monocultures. The hypothesis has been similarly applied to landscape-scale investigations; however, the mechanisms by which diverse landscapes can directly suppress herbivores are likely different than those operating at the polyculture scale and have not been clearly articulated. Here, we discuss how landscape-scale habitat diversity may directly reduce agricultural pest loads by requiring more dispersal activity, which, in turn, can increase mortality and decrease fitness. We also lay out a research agenda and argue that a better understanding of the mechanisms by which landscape-scale habitat diversity affect insect pest populations can lead to better predictions of pest control as an ecosystem service provided by diverse agricultural landscapes.
An investigation into the mechanism of Cu-catalyzed aryl boronic acid halodeboronation using electrophilic halogen reagents is reported. Evidence is provided to show that this takes place via a ...boronate-driven ipso-substitution pathway and that Cu is not required for these processes to operate: general Lewis base catalysis is operational. This in turn allows the rational development of a general, simple, and effective base-catalyzed halodeboronation that is amenable to the preparation of 125I-labeled products for SPECT applications.
We propose an algorithm to convert a projected entangled pair state (PEPS) into a canonical form, analogous to the well-known canonical form of a matrix product state. Our approach is based on a ...variational gauging ansatz for the QR tensor decomposition of PEPS columns into a matrix product operator and a finite depth circuit of unitaries and isometries. We describe a practical initialization scheme that leads to rapid convergence in the QR optimization. We explore the performance and stability of the variational gauging algorithm in norm calculations for the transverse-field Ising and Heisenberg models on a square lattice. We also demonstrate energy optimization within the PEPS canonical form for the transverse-field Ising and Heisenberg models. We expect this canonical form to open up improved analytical and numerical approaches for PEPS.
We evaluated the efficacy of gemcitabine versus gemcitabine and carboplatin in patients with advanced non-small-cell lung cancer (NSCLC) and a performance status (PS) of 2 and assessed if tumoral ...RRM1 and ERCC1 protein levels are predictive of response to therapy.
A randomized phase III trial was conducted in community-based oncology practices. Tumor specimens were collected a priori and shipped to a single laboratory for blinded determination of in situ RRM1 and ERCC1 protein expression levels by an automated quantitative immunofluorescent-based technology.
One hundred seventy patients were randomly assigned. Overall median survival was 5.1 months for gemcitabine and 6.7 months for gemcitabine and carboplatin (P = .24). RRM1 (range, 5.3 to 105.6; median, 34.1) and ERCC1 (range, 5.2 to 131.3; median, 34.7) values were significantly and inversely correlated with disease response (r = -0.41; P = .001 for RRM1; r = -0.39; P = .003 for ERCC1; ie, response was better for patients with low levels of expression). A model for response prediction that included RRM1, ERCC1, and treatment arm, was highly predictive of the treatment response observed (P = .0005). We did not find statistically significant associations between survival and RRM1 or ERCC1 levels.
Single-agent chemotherapy remains the standard of care for patients with advanced NSCLC and poor PS. Quantitative analysis of RRM1 and ERCC1 protein expression in routinely collected tumor specimens in community oncology practices is predictive of response to gemcitabine and gemcitabine and carboplatin therapy. Oncologists should consider including in situ expression analysis for these proteins into their therapeutic decisions.
Microsampling of patient blood promises several benefits over conventional phlebotomy practices to facilitate precision medicine studies. These include at-home patient blood collection, supporting ...telehealth monitoring, minimal postcollection processing, and compatibility with nonrefrigerated transport and storage. However, for proteomic biomarker studies, mass spectrometry of whole blood has generally been avoided in favor of using plasma or serum obtained from venepuncture. We evaluated the use of a volumetric absorptive microsampling (VAMS) device as a sample preparation matrix to enable LC-MS proteomic analyses of dried whole blood. We demonstrated the detection and robust quantitation of up to 1600 proteins from single-shot shotgun-LC-MS analysis of dried whole blood, greatly enhancing proteome depth compared with conventional single-shot LC-MS analyses of undepleted plasma. Some proteins not previously reported in blood were detected using this approach. Various washing reagents were used to demonstrate that proteins can be preferentially removed from VAMS devices prior to downstream analyses. We provide a demonstration that archival frozen blood cell pellets housed under long-term storage (exceeding 5 years) are compatible with VAMS to enable quantitation of potential biomarker proteins from biobank repositories. These demonstrations are important steps in establishing viable analysis workflows to underpin large-scale precision medicine studies. Data are available via ProteomeXchange with the identifier PXD028605.
IntroductionThe first clinical interaction most patients have in the emergency department occurs during triage. An unstructured narrative is generated during triage and is the first source of ...in-hospital documentation. These narratives capture the patient’s reported reason for the visit and the initial assessment and offer significantly more nuanced descriptions of the patient’s complaints than fixed field data. Previous research demonstrated these data are useful for predicting important clinical outcomes. Previous reviews examined these narratives in combination or isolation with other free-text sources, but used restricted searches and are becoming outdated. Furthermore, there are no reviews focused solely on nurses’ (the primary collectors of these data) narratives.Methods and analysisUsing the Arksey and O’Malley scoping review framework and PRISMA-ScR reporting guidelines, we will perform structured searches of CINAHL, Ovid MEDLINE, ProQuest Central, Ovid Embase and Cochrane Library (via Wiley). Additionally, we will forward citation searches of all included studies. No geographical or study design exclusion criteria will be used. Studies examining disaster triage, published before 1990, and non-English language literature will be excluded. Data will be managed using online management tools; extracted data will be independently confirmed by a separate reviewer using prepiloted extraction forms. Cohen’s kappa will be used to examine inter-rater agreement on pilot and final screening. Quantitative data will be expressed using measures of range and central tendency, counts, proportions and percentages, as appropriate. Qualitative data will be narrative summaries of the authors’ primary findings.Patient and public involvementNo patients involved.Ethics and disseminationNo ethics approval is required. Findings will be submitted to peer-reviewed conferences and journals. Results will be disseminated using individual and institutional social media platforms.
IntroductionRapid population ageing is a demographic trend being experienced and documented worldwide. While increased health screening and assessment may help mitigate the burden of illness in older ...people, issues such as misdiagnosis may affect access to interventions. This study aims to elicit the values and preferences of evidence-informed older people living in the community on early screening for common health conditions (cardiovascular disease, diabetes, dementia and frailty). The study will proceed in three Phases: (1) generating recommendations of older people through a series of Citizens’ Juries; (2) obtaining feedback from a diverse range of stakeholder groups on the jury findings; and (3) co-designing a set of Knowledge Translation resources to facilitate implementation into research, policy and practice. Conditions were chosen to reflect common health conditions characterised by increasing prevalence with age, but which have been underexamined through a Citizens’ Jury methodology.Methods and analysisThis study will be conducted in three Phases—(1) Citizens’ Juries, (2) Policy Roundtables and (3) Production of Knowledge Translation resources. First, older people aged 50+ (n=80), including those from traditionally hard-to-reach and diverse groups, will be purposively recruited to four Citizen Juries. Second, representatives from a range of key stakeholder groups, including consumers and carers, health and aged care policymakers, general practitioners, practice nurses, geriatricians, allied health practitioners, pharmaceutical companies, private health insurers and community and aged care providers (n=40) will be purposively recruited for two Policy Roundtables. Finally, two researchers and six purposively recruited consumers will co-design Knowledge Translation resources. Thematic analysis will be performed on documentation and transcripts.Ethics and disseminationEthical approval has been obtained through the Torrens University Human Research Ethics Committee. Participants will give written informed consent. Findings will be disseminated through development of a policy brief and lay summary, peer-reviewed publications, conference presentations and seminars.
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