Results for “Formal Methods” — Page 96

DOE OSTI2016

WE-H-201-03: Enthusiasm and Generosity of Spirit Necessitate a Volunteering Structure to Make Them More Meaningful

The desperate need for radiotherapy in low and mid-income countries (LMICs) has been well documented. Roughly 60 % of the worldwide incidence of cancer occurs in these resource-limited settings and the international community alongside governmental and non-profit agencies have begun publishing reports and seeking help from qualified volunteers. However, the focus of several reports has been on how dire the situation is and the magnitude of the problem, leaving most to feel overwhelmed and unsure as to how to help and why to get involved. This session will help to explain the specific ways that Medical Physicists can uniquely assist in this grand effort to help bring radiotherapy to grossly-underserved areas. Not only can these experts fulfill an important purpose, they also can benefit professionally, academically, emotionally and socially from the endeavor. By assisting others worldwide with their skillset, Medical Physicists can end up helping themselves. Learning Objectives: Understand the need for radiotherapy in LMICs. Understand which agencies are seeking Medical Physicists for help in LMICs. Understand the potential research funding mechanisms are available to establish academic collaborations with LMIC researchers/physicians. Understand the potential social and emotional benefits for both the physicist and the LMIC partners when collaborations are made. Understand the potential for collaboration with other high-income scientists that can develop as the physicist partners with other large institutions to assist LMICs. Wil Ngwa - A recent United Nations Study reports that in developing countries more people have access to cell phones than toilets. In Africa, only 63% of the population has access to piped water, yet, 93% of Africans have cell phone service. Today, these cell phones, Skype, WhatsApp and other information and communication technologies (ICTs) connect us in unprecedented ways and are increasingly recognized as powerful, indispensable to global health. Thanks to ICTs, there are growing opportunities for Medical Physicists to reach out beyond the bunker and impact the world far beyond, without even having to travel. These growing opportunities in global health for Medical Physicists, powered by ICTs, will be highlighted in this presentation, illustrated by high impact examples/models across the globe that are improving patient safety and healthcare outcomes, saving lives. Learning Objectives: Published definitions of global health and the emerging field of global radiation oncology Learn about the transformative potential of ICTs in global radiation oncology care, research and education with focus on Medical Physics Learn about high impact examples of ICT-powered global radiation oncology and the increasing opportunities for participation by Medical Physicists. Yakov Pipman - The number and scope of volunteer Medical Physics activities in support of low-to-middle income countries has been increasing gradually. This happens through a variety of formal channels and to some extent through less formal but personal initiatives. A good deal of effort is dedicated by many, but many more could be recruited through a structured framework to volunteer. We will look into typical volunteer activities and how they fit with organizations already involved in advancing Medical Physics in LMIC. We will identify the range of these organizational activities and their scope to reveal areas of further need. We will point to a few key features of MPWB ( http://www.mpwb.org ) as a volunteering and collaborating structure and how members can get involved and contribute to these efforts at the grass roots level. The goal is that scarce resources can thus be channeled to complement rather than compete with those already in place. Learning Objectives: Understand the strengths and limitations of various organizations that support Medical Physics efforts in LMIC. Learn about ways to volunteer and contribute to Global Health through a grass roots organization focused on Medical Physics in LMIC. Perry Sprawls - With the growing capability and complexity of medical imaging methods in all countries of the world, the expanding role of medical physicists includes optimizing imaging procedures with respect to image quality, radiation dose, and other conflicting factors. With access to appropriate educational resources local medical physicists in all countries can provide direct clinical support and educational for other medical professionals. This is being supported through the process of Collaborative Teaching that combines the capabilities and experience of medical physicists in countries spanning the spectrum of economic, technological, and clinical development. The supporting resources are on the web at: http://www.sprawls.org/resources . Learning Objectives: Identify the medical physics educational needs to support effective and optimized medical imaging procedures. Use collaborative teaching resources to enhance the role of medical physicists in all countries of the world.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

WE-H-201-04: Models for Developing Medical Physics Educators and Education Programs in the Developing Countries and the Potential Role of US Universities and Individual Medical Physicists

The desperate need for radiotherapy in low and mid-income countries (LMICs) has been well documented. Roughly 60 % of the worldwide incidence of cancer occurs in these resource-limited settings and the international community alongside governmental and non-profit agencies have begun publishing reports and seeking help from qualified volunteers. However, the focus of several reports has been on how dire the situation is and the magnitude of the problem, leaving most to feel overwhelmed and unsure as to how to help and why to get involved. This session will help to explain the specific ways that Medical Physicists can uniquely assist in this grand effort to help bring radiotherapy to grossly-underserved areas. Not only can these experts fulfill an important purpose, they also can benefit professionally, academically, emotionally and socially from the endeavor. By assisting others worldwide with their skillset, Medical Physicists can end up helping themselves. Learning Objectives: Understand the need for radiotherapy in LMICs. Understand which agencies are seeking Medical Physicists for help in LMICs. Understand the potential research funding mechanisms are available to establish academic collaborations with LMIC researchers/physicians. Understand the potential social and emotional benefits for both the physicist and the LMIC partners when collaborations are made. Understand the potential for collaboration with other high-income scientists that can develop as the physicist partners with other large institutions to assist LMICs. Wil Ngwa - A recent United Nations Study reports that in developing countries more people have access to cell phones than toilets. In Africa, only 63% of the population has access to piped water, yet, 93% of Africans have cell phone service. Today, these cell phones, Skype, WhatsApp and other information and communication technologies (ICTs) connect us in unprecedented ways and are increasingly recognized as powerful, indispensable to global health. Thanks to ICTs, there are growing opportunities for Medical Physicists to reach out beyond the bunker and impact the world far beyond, without even having to travel. These growing opportunities in global health for Medical Physicists, powered by ICTs, will be highlighted in this presentation, illustrated by high impact examples/models across the globe that are improving patient safety and healthcare outcomes, saving lives. Learning Objectives: Published definitions of global health and the emerging field of global radiation oncology Learn about the transformative potential of ICTs in global radiation oncology care, research and education with focus on Medical Physics Learn about high impact examples of ICT-powered global radiation oncology and the increasing opportunities for participation by Medical Physicists. Yakov Pipman - The number and scope of volunteer Medical Physics activities in support of low-to-middle income countries has been increasing gradually. This happens through a variety of formal channels and to some extent through less formal but personal initiatives. A good deal of effort is dedicated by many, but many more could be recruited through a structured framework to volunteer. We will look into typical volunteer activities and how they fit with organizations already involved in advancing Medical Physics in LMIC. We will identify the range of these organizational activities and their scope to reveal areas of further need. We will point to a few key features of MPWB ( http://www.mpwb.org ) as a volunteering and collaborating structure and how members can get involved and contribute to these efforts at the grass roots level. The goal is that scarce resources can thus be channeled to complement rather than compete with those already in place. Learning Objectives: Understand the strengths and limitations of various organizations that support Medical Physics efforts in LMIC. Learn about ways to volunteer and contribute to Global Health through a grass roots organization focused on Medical Physics in LMIC. Perry Sprawls - With the growing capability and complexity of medical imaging methods in all countries of the world, the expanding role of medical physicists includes optimizing imaging procedures with respect to image quality, radiation dose, and other conflicting factors. With access to appropriate educational resources local medical physicists in all countries can provide direct clinical support and educational for other medical professionals. This is being supported through the process of Collaborative Teaching that combines the capabilities and experience of medical physicists in countries spanning the spectrum of economic, technological, and clinical development. The supporting resources are on the web at: http://www.sprawls.org/resources . Learning Objectives: Identify the medical physics educational needs to support effective and optimized medical imaging procedures. Use collaborative teaching resources to enhance the role of medical physicists in all countries of the world.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2012

Nuclear shape transitions in neutron-rich medium-mass nuclei

We study the isotopic evolution of the ground-state nuclear shapes in neutron-rich Kr, Rb, Sr, Y, Zr, Nb, and Mo isotopic chains. Both even-even and odd-A nuclei are included in the analysis. For the latter we also study the systematics of their one-quasiparticle low-lying configurations. The theoretical approach is based on a selfconsistent Hartree-Fock-Bogoliubov formalism with finite range Gogny energy density functionals. Neutron separation energies, charge radii, and the spin-parity of the ground states are calculated and compared with available data. Shape-transition signatures are identified around N= 60 isotones as discontinuities in both charge radii isotopic shifts and spin-parities of the ground states. The nuclear deformation including triaxiality is shown to play a relevant role in the understanding of the bulk and spectroscopic features of the ground and low-lying one-quasiparticle states.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2020

Development of the finite slab geometry in the NORA code

In this work we develop the complete linearization formalism for the radiation transfer equation in slab geometry. This development was motivated by an observed convergence instability arising from the NORA code’s inner boundary while modeling a suite of simple test problems in slab geometry presented at the Line Transfer Workshop held in LLNL in May of 2019. The convergence issue was seen to emerge early on in Newton-Raphson iterations. These test problems required parameters in the former NORA inner boundary to achieve the asymptotic limit of zero incoming intensity. In this work we derive the limiting case directly to gain insight into the former algorithm’s pathology.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2019

Gauge structures: From stabilizer codes to continuum models

Stabilizer codes are a powerful method for implementing fault-tolerant quantum memory and in the case of topological codes, they form useful models for topological phases of matter. In this paper, we discuss the theory of stabilizer codes as a discrete version of a linear gauge structure, a concept we introduce here. A linear gauge structure captures all the familiar ingredients of U(1) gauge theory including a generalization of charge conservation, Maxwell equations and topological terms. Using this connection, we prove some important results for stabilizer codes which can be used to characterize their error-correction properties. However, this perspective does not depend on any particular Hamiltonian or Lagrangian, which as a consequence is agnostic to the source of the gauge redundancy. Based upon the connection to stabilizer codes, we view the source of the gauge redundancy as an ambiguity in the tensor product structure of the Hilbert space. That is, the gauge provides a set of equivalent but arbitrary ways to factorize the Hilbert space. We apply this formalism to the d=2 and 3 toric code as well as the paradigm fracton models, X-Cube and Haah’s cubic code. From this perspective, we are able to map all these models to some continuum version which captures all or some of the fractonic and topological features of their parent discrete models.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2024

Planning for Material Control and Accountancy at Liquid Fueled Molten Salt Reactors

The purpose of this report is to provide molten salt reactor (MSR) developers and future US Nuclear Regulatory Commission (NRC) license applicants with recommendations for developing an effective and practical material control and accounting (MC&A) plan, focused primarily on MSR designs that use circulating liquid fuel. Because of the breadth of MSR designs, there is no single, generic, detailed MC&A plan that will work for every design. The wide variation of fresh fuel salts, the method and frequency of loading fresh fuel, the reactor system design components (e.g., tanks, filtration systems, chemical processing streams), and waste streams will determine the specific measurement locations and instrumentation that can best meet MC&A objectives throughout an MSR facility. Additionally, MSR designs are rapidly evolving, and new design features and deployment scenarios that will affect MC&A are being explored and pursued. This report defines a generic MC&A approach that was developed for terrestrial (as opposed to maritime) deployments to meet the intent of NRC domestic safeguards and MC&A. MSR license applicants should consider nuclear safeguards (both domestic and international) and security throughout the design, as early as the preconceptual design phase. MC&A of special nuclear material (SNM) is an aspect of the NRC’s domestic safeguards program, alongside physical protection. Because liquid-fueled MSRs are reactors with SNM in nondiscrete (or item) form, it is likely that the NRC may require liquid-fueled MSR license applicants to submit a formal MC&A plan as a part of their license application. Currently, the NRC licensing protocol presents a challenge because the NRC MC&A regulations have not been updated to accommodate advanced reactors, including types of MSRs. Because no liquid-fueled MSR has been licensed for operation at the time of this report, no template or precedence for a successfully licensed MSR MC&A plan exists. However, the MSR license applicant can take advantage of the NRC’s published commitments to performance-based regulations. The authors recommend that the license applicant, or MSR designers, develop an MC&A plan throughout the design lifecycle and plan to submit a detailed MC&A program description, or MC&A plan, to the NRC as a part of a license application. No MC&A plan template or guidance exists that is specific to liquid-fueled MSRs. The authors recommend that license applicants discuss the topic of MC&A during preapplication engagement. Because of the uniqueness of MC&A for liquid fueled MSRs, the authors recommend that liquid fueled MSR developers engage with the NRC on the topic of MC&A in the early phases of its design development and follow up any time there are significant modifications in design plans that would affect MC&A. For example, topics like modifications in fuel handling processes, changes in uranium enrichment, or additional chemical processing streams added to the design could be discussed with the NRC specifically on the topic of MC&A.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2023

pyGWBSE: a high throughput workflow package for GW-BSE calculations

Abstract We develop an open-source python workflow package, py GWBSE to perform automated first-principles calculations within the GW-BSE (Bethe-Salpeter) framework. GW-BSE is a many body perturbation theory based approach to explore the quasiparticle (QP) and excitonic properties of materials. GW approximation accurately predicts bandgaps of materials by overcoming the bandgap underestimation issue of the more widely used density functional theory (DFT). BSE formalism produces absorption spectra directly comparable with experimental observations. py GWBSE package achieves complete automation of the entire multi-step GW-BSE computation, including the convergence tests of several parameters that are crucial for the accuracy of these calculations. py GWBSE is integrated with Wannier90 , to generate QP bandstructures, interpolated using the maximally-localized wannier functions. py GWBSE also enables the automated creation of databases of metadata and data, including QP and excitonic properties, which can be extremely useful for future material discovery studies in the field of ultra-wide bandgap semiconductors, electronics, photovoltaics, and photocatalysis.

36 MATERIALS SCIENCE↗

DOE OSTI2011

Modelling charge transfer reactions with the frozen density embedding formalism

The frozen density embedding (FDE) subsystem formulation of density-functional theory is a useful tool for studying charge transfer reactions. In this work charge-localized, diabatic states are generated directly with FDE and used to calculate electronic couplings of hole transfer reactions in two {pi}-stacked nucleobase dimers of B-DNA: 5{sup '}-GG-3{sup '} and 5{sup '}-GT-3{sup '}. The calculations rely on two assumptions: the two-state model, and a small differential overlap between donor and acceptor subsystem densities. The resulting electronic couplings agree well with benchmark values for those exchange-correlation functionals that contain a high percentage of exact exchange. Instead, when semilocal GGA functionals are used the electronic couplings are grossly overestimated.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2011

Elementary excitations in homogeneous superfluid neutron star matter: Role of the proton component

The thermal evolution of neutron stars depends on the elementary excitations affecting the stellar matter. In particular, the low-energy excitations, whose energy is proportional to the transferred momentum, can play a major role in the emission and propagation of neutrinos. In this paper, we focus on the density modes associated with the proton component in the homogeneous matter of the outer core of neutron stars (at density between one and three times the nuclear saturation density, where the baryonic constituents are expected to be neutrons and protons). In this region, it is predicted that the protons are superconducting. We study the respective roles of the proton pairing and Coulomb interaction in determining the properties of the modes associated with the proton component. This study is performed in the framework of the random phase approximation, generalized in order to describe the response of a superfluid system. The formalism we use ensures that the generalized Ward's identities are satisfied. An important conclusion of this work is the presence of a pseudo-Goldstone mode associated with the superconducting protons in neutron-star matter. Indeed, the Goldstone mode, which characterizes a pure superfluid, is suppressed in usual superconductors because of the long-range Coulomb interaction, which allows a plasmon mode. However, for the proton component of stellar matter, the Coulomb field is screened by the electrons and a pseudo-Goldstone mode occurs, with a velocity increased by the Coulomb interaction.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2014

Dielectric relaxations and alternating current conductivity in manganese substituted cobalt ferrite

Manganese (Mn) substituted cobalt ferrites (CoFe{sub 2-x}Mn{sub x}O{sub 4}, referred to CFMO) have been synthesized by the solid state reaction method and their dielectric properties and ac conductivity have been evaluated as a function of applied frequency and temperature. X-ray diffraction measurements indicate that CFMO crystallize in the inverse cubic spinel phase with a lattice constant ∼8.38 Å. Frequency dependent dielectric measurements at room temperature obey the modified Debye model with relaxation time of 10{sup −4} s and spreading factor of 0.35(±0.05). The frequency (20 Hz–1 MHz) and temperature (T = 300–900 K) dependent dielectric constant analyses indicate that CFMO exhibit two dielectric relaxations at lower frequencies (1–10 kHz), while completely single dielectric relaxation for higher frequencies (100 kHz–1 MHz). The dielectric constant of CFMO is T-independent up to ∼400 K, at which point increasing trend prevails. The dielectric constant increase with T > 400 K is explained through impedance spectroscopy assuming a two-layer model, where low-resistive grains separated from each other by high-resistive grain boundaries. Following this model, the two electrical responses in impedance formalism are attributed to the grain and grain-boundary effects, respectively, which also satisfactorily accounts for the two dielectric relaxations. The capacitance of the bulk of the grain determined from impedance analyses is ∼10 pF, which remains constant with T, while the grain-boundary capacitance increases up to ∼3.5 nF with increasing T. The tan δ (loss tangent)-T also reveals the typical behavior of relaxation losses in CFMO.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2018

(U) Boundary Conditions for Ejecta Source Models with Stationary Velocity Distributions

We show that certain apparently universal features of the piezoelectric voltage traces measured in HE-driven tin coupon experiments [1, 2] constrain the functional form of any ejecta source model with a stationary velocity distribution. Building on an analytic formalism that has been extensively documented elsewhere [3, 4, 5, 6, 7], we derive simple expressions for V(t 0 a ), V'(t 0 a ), and the discontinuity in V(t break ) where t 0 a is the time of first ejecta arrival at the sensor and t break is the “depletion” time for the fastest particles arriving at the sensor. These three quantities appear to be zero, or nearly so, in the Vo- gan voltage data [1] (modulo noise and any smoothing effects created by the circuit); however, the predicted voltages for this general class of source models do not automatically achieve these conditions unless special boundary conditions are met. Source models which violate these boundary conditions will produce voltage predictions at odds with the measurements. The RMI+SSVD ejecta source model in its current formulation satisfies none of these boundary conditions, and therefore predictions from a stationary-velocity-distribution approximation to the RMI+SSVD source model deviate significantly from the voltage data. This analysis suggests straightforward methods for potentially improving the predictions of the RMI+SSVD ejecta source model. We test this with a simple adjustment to the SSVD and find, as anticipated, the adjustment corrects three properties of the voltage prediction. Furthermore, the adjusted model’s prediction for ejecta mass accumulation at the sensor exhibits a smoother and more gradual rise from the baseline than that produced by the original source model, thereby improving overall model/data agreement.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2014

Hamiltonian and action formalisms for two-dimensional gyroviscous magnetohydrodynamics

A general procedure for constructing action principles for continuum models via a generalization of Hamilton's principle of mechanics is described. Through the procedure, an action principle for a gyroviscous magnetohydrodynamics model is constructed. The model is shown to agree with a reduced version of Braginskii's fluid equations. The construction reveals the origin of the gyromap, a device used to derive previous gyrofluid models. Also, a systematic reduction procedure is presented for obtaining the Hamiltonian structure in terms of the noncanonical Poisson bracket. The construction procedure yields a class of Casimir invariants, which are then used to construct variational principles for equilibrium equations with flow and gyroviscosity. The procedure for obtaining reduced fluid models with gyroviscosity is also described.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

DOE OSTI2018

A pedagogical intrinsic approach to relative entropies as potential functions of quantum metrics: The q–z family

The so-called q-z-Rényi Relative Entropies provide a huge two parameter family of relative entropies which include almost all well-known examples of quantum relative entropies for suitable values of the parameters. In this paper we consider a log-regularized version of this family and use it as a family of potential functions to generate covariant (0,2) symmetric tensors on the space of invertible quantum states in finite dimensions. The geometric formalism developed here allows us to obtain the explicit expressions of such tensor fields in terms of a basis of globally defined differential forms on a suitable unfolding space without the need to introduce a specific set of coordinates. To make the reader acquainted with the intrinsic formalism introduced, we first perform the computation for the qubit case, and then, we extend the computation of the metric-like tensors to a generic n-level system. By suitably varying the parameters q and z, we are able to recover well-known examples of quantum metric tensors that, in our treatment, appear written in terms of globally defined geometrical objects that do not depend on the coordinates system used. In particular, we obtain a coordinate-free expression for the von Neumann–Umegaki metric, for the Bures metric and for the Wigner–Yanase metric in the arbitrary n-level case.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2014

Performance analysis of boron nitride embedded armchair graphene nanoribbon metal–oxide–semiconductor field effect transistor with Stone Wales defects

We study the performance of a hybrid Graphene-Boron Nitride armchair nanoribbon (a-GNR-BN) n-MOSFET at its ballistic transport limit. We consider three geometric configurations 3p, 3p + 1, and 3p + 2 of a-GNR-BN with BN atoms embedded on either side (2, 4, and 6 BN) on the GNR. Material properties like band gap, effective mass, and density of states of these H-passivated structures are evaluated using the Density Functional Theory. Using these material parameters, self-consistent Poisson-Schrodinger simulations are carried out under the Non Equilibrium Green's Function formalism to calculate the ballistic n-MOSFET device characteristics. For a hybrid nanoribbon of width ∼5 nm, the simulated ON current is found to be in the range of 265 μA–280 μA with an ON/OFF ratio 7.1 × 10{sup 6}–7.4 × 10{sup 6} for a V{sub DD} = 0.68 V corresponding to 10 nm technology node. We further study the impact of randomly distributed Stone Wales (SW) defects in these hybrid structures and only 2.5% degradation of ON current is observed for SW defect density of 3.18%.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2011

PHOTOIONIZATIONAL PLASMAS. I. THEORY

In this paper, an attempt is made to define the subject of photoionizational plasmas through rigorous mathematical formalism. The central results of this paper are the following. (1) A set of recursive equations is introduced for the computation of the charge state distributions in photoionizational plasmas. (2) Quantitative validity limits are given for both the collisional and the photoionizational domains. (3) A parameter that determines the charge state distribution in the photoionizational regime is introduced. (4) We provide detailed discussion about the most important components of the emission spectrum in the different equilibrium domains of the emitting plasma. Some of these components have not been reported so far as included in the analysis of such plasmas.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2021

Theory of Plasmonic Hot-Carrier Generation and Relaxation

Hot-carrier (HC) generation from (localized) surface plasmon decay has recently attracted much attention due to its promising applications in physical, chemical, materials, and energy science. However, the detailed mechanisms of plasmonic HC generation, relaxation, and trapping are less studied. In this work, we developed and applied a quantum-mechanical model and coupled master equation method to study the generation of HCs from plasmon decay and their following relaxation processes with different mechanisms treated on equal footing. First, a quantum-mechanical model for HC generation is developed. Its connection to existing semiclassical models and time-dependent density functional theory (TDDFT) is discussed. Second, the relaxation and lifetimes of HCs are investigated in the presence of electron–electron and electron–phonon interactions. A GW-like approximation is introduced to account for the electron–electron scattering. The numerical simulations on the Jellium nanoparticles with a size up to 1.6 nm demonstrate the electron–electron scattering and electron–phonon scattering dominate different time scale in the relaxation dynamics. We also generalize the model to study the extraction of HCs to attached molecules. The quantum yield of extracting HCs for other applications is found to be size-dependent. In general, the smaller size of NP improves the quantum yield, which is in agreement with recent experimental measurements. Even though we demonstrate this newly developed theoretical formalism with Jellium model, the theory applies to any other atomistic models.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2014

Protein and microRNA biomarkers from lavage, urine, and serum in military personnel evaluated for dyspnea

Background: We have identified candidate protein and microRNA (miRNA) biomarkers for dyspnea by studying serum, lavage fluid, and urine from military personnel who reported serious respiratory symptoms after they were deployed to Iraq or Afghanistan. Methods: Forty-seven soldiers with the complaint of dyspnea who enrolled in the STudy of Active Duty Military Personnel for Environmental Dust Exposure (STAMPEDE) underwent comprehensive pulmonary evaluations at the San Antonio Military Medical Center. The evaluation included fiber-optic bronchoscopy with bronchoalveolar lavage. The clinical findings from the STAMPEDE subjects pointed to seven general underlying diagnoses or findings including airway hyperreactivity, asthma, low diffusivity of carbon monoxide, and abnormal cell counts. The largest category was undiagnosed. As an exploratory study, not a classification study, we profiled proteins or miRNAs in lavage fluid, serum, or urine in this group to look for any underlying molecular patterns that might lead to biomarkers. Proteins in lavage fluid and urine were identified by accurate mass tag (database-driven) proteomics methods while miRNAs were profiled by a hybridization assay applied to serum, urine, and lavage fluid. Results: Over seventy differentially expressed proteins were reliably identified both from lavage and from urine in forty-eight dyspnea subjects compared to fifteen controls with no known lung disorder. Six of these proteins were detected both in urine and lavage. One group of subjects was distinguished from controls by expressing a characteristic group of proteins. A related group of dyspnea subjects expressed a unique group of miRNAs that included one miRNA that was differentially overexpressed in all three fluids studied. The levels of several miRNAs also showed modest but direct associations with several standard clinical measures of lung health such as forced vital capacity or gas exchange efficiency. Conclusions: Candidate proteins and miRNAs associated with the general diagnosis of dyspnea have been identified in subjects with differing medical diagnoses. Since these markers can be measured in readily obtained clinical samples, further studies are possible that test the value of these findings in more formal classification or case–control studies in much larger cohorts of subjects with specific lung diseases such as asthma, emphysema, or some other well-defined lung disease.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

DOE OSTI2026

Re-evaluating probable maximum precipitation estimates: sensitivity to transposition domains and storm rotation using modern datasets

This study examines the sensitivity of Probable Maximum Precipitation (PMP) estimates to key methodological decisions embedded in the legacy approach adopted in the U.S. National Weather Service Hydrometeorological Reports No. 51 and No. 52. Although widely used for infrastructure design and risk regulation, fundamental aspects of PMP estimation—such as storm sample size, transposition domain, maximization procedures, and storm rotation—remain poorly constrained and lack formal guidance. Using the Red Rock watershed in Iowa as a case study, and leveraging the 2002–2023 NOAA Analysis of Record for Calibration (AORC) precipitation dataset, we systematically evaluate how each methodological choice, individually and in combination, influences PMP estimates. Our findings demonstrate that PMP is not a fixed physical upper bound but rather a modeling construct shaped heavily by user-defined assumptions. Notably, PMP values derived from modern gridded rainfall datasets can be substantially higher than the legacy estimate used in the original spillway design for Red Rock Dam. Decisions regarding storm sample size, domain extent, climatological window, and particularly storm rotation all contributed to higher PMP estimates. Storm rotation alone—a loosely constrained element in the current PMP practice—can amplify PMP by more than 25%. These results reveal the lack of standardized bounds in current PMP workflows and the need for systematic sensitivity and uncertainty analysis. As PMP estimation shifts toward probabilistic approaches, incorporating physically meaningful storm attributes will be key to developing more transparent, defensible methods for dam safety and climate-resilient infrastructure.

Probable maximum precipitation↗