Cumulative Cross Research Articles

Watchful waiting to surgery in men with mildly symptomatic or asymptomatic inguinal hernia: an individual participant data meta-analysis of long-term follow-up of randomized controlled trials.

Individual studies on men with mildly symptomatic or asymptomatic inguinal hernia who have opted for watchful waiting (WW) vary considerably. Furthermore, long-term data on such patients who cross over to herniorrhaphy is scarce. PubMed, EMBASE, and Cochrane databases were searched systematically from inception to 3rd April 2024 for long-term follow-up of randomized controlled trials (RCTs) on men with mildly symptomatic or asymptomatic inguinal hernia. Individual participant survival data of cross over rates from WW to herniorrhaphy were extracted, reconstructed and combined. Secondary outcome was reason for cross over to herniorrhaphy. Long-term follow-up of three RCTs with 592 participants was included. A total of 344/592 participants crossed over to herniorrhaphy during a median follow up period that ranged from 3.2 to 12.0 years. The median cumulative cross over rate was 54.2% (95% CI 45.5% - 66.3%). The cumulative 1-year, 5-year, and 10- year cross over rates were 28.7% (95% CI 25.2% - 32.5%), 51.5% (95% CI 47.4% - 55.6%), and 70.6% (95% CI 66.2% - 74.9%) respectively. During follow-up, the most frequent reasons for cross over to herniorrhaphy were increased pain 198/344 (57.6%) and incarceration 15/344 (4.4%). This study provides valuable long-term data for patient counselling, indicating that while WW is a safe strategy for men with mildly symptomatic or asymptomatic inguinal hernia, symptoms would likely progress eventually, necessitating operative repair.

Fission cross-section measurements for the 238U(n,f)97m+gNb, 238U(n,f)133gTe and 238U(n,f)130gSb reactions induced by D-T neutrons

In this study, we conducted measurements of the independent fission cross-sections of 238U(n, f)97m+gNb, 238U(n, f)133gTe reactions and the cumulative cross section of 238U(n, f)130gSb reactions induced by neutron at energies around 14 MeV, i.e., 14.1 ± 0.3, 14.5 ± 0.3 and 14.7 ± 0.3 MeV. The measurement results were obtained by the neutron activation method in combination with off-line γ-ray spectrometry techniques. The neutron flux was monitored on line by the accompanying α-particle from T(d, n)4He reaction, and the neutron energies were determined by the cross-section ratio of 90Zr(n, 2n)8+gZr to 93Nb(n, 2n)92mNb reactions. The independent fission cross-sections of the fission reactions were obtained by subtracting the influence of precursor nuclei or excited states. The obtained results are as follows: for 238U(n, f)97m+gNb, the independent cross sections are 1.0 ± 0.89, 0.98 ± 0.85 and 0.78 ± 0.70 mb at the specified neutron energy points. For 238U(n, f)133gTe, the independent fission cross-sections are 26.8 ± 2.8, 27.7 ± 2.9 and 20.5 ± 2.3 mb, respectively, at the same neutron energy points. As for 238U(n, f)130gSb, the obtained cumulative fission cross-sections are 5.35 ± 0.58, 5.05 ± 0.53 and 4.03 ± 0.44 mb, respectively, at the specified neutron energy points.

Measurement of Cumulative Cross Sections for 232Th Fission Products upon Irradiation with Medium-Energy 3He Nuclei

Measurement of Cumulative Cross Sections for 232Th Fission Products upon Irradiation with Medium-Energy 3He Nuclei

Role of precursor nuclei in heavy-ion induced reactions at low energies

In heavy-ion induced reactions, generally, a large number of residues are populated through different reaction channels. In some cases the same residue is populated via two different modes viz., (i) directly from a given reaction and (ii) via $\ensuremath{\beta}$ and/or electron capture decay of a nuclide (precursor). Separation of the two is required for a better understanding of reaction dynamics. The procedure existing in the literature for extracting the independent production cross section from the cumulative cross section employs the assumptions of half-life of the daughter being much larger in comparison to the half-life of the precursor $({t}_{1/2}^{p}\ensuremath{\ll}{t}_{1/2}^{d})$ and require the counting to be performed after large cooling times $({t}_{l}\ensuremath{\rightarrow}\ensuremath{\infty})$. A general and more exact expression is obtained in the present work surpassing the assumptions as well as difficulties reported earlier. Analysis of the experimental reaction data sets covering a broader range of possibilities $({t}_{1/2}^{p}>{t}_{1/2}^{d}$; ${t}_{1/2}^{p}\ensuremath{\approx}{t}_{1/2}^{d};$ ${t}_{1/2}^{p}<{t}_{1/2}^{d})$ presented shows the importance of the current formulations. The advantage of the generalized expression even when the assumptions hold true is also discussed. A comparison of results obtained from the traditional method in the context of its assumptions instead of the calculations from the exact expression has been made. The results obtained with the presently derived formulations are found to give justified values of cross sections for all the cases in contrast to the traditional formulation.

Measuring and Modeling Single Event Transients in 12-nm Inverters

In this article, we present a unique method of measuring single-event transient (SET) sensitivity in 12-nm FinFET technology. A test structure is presented that approximately measures the length of SETs using flip-flop shift registers with clock inputs driven by an inverter chain. The test structure was irradiated with ions at linear energy transfers (LETs) of 4.0, 5.6, 10.4, and 17.9 MeV-cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /mg, and the cross sections of SET pulses measured down to 12.7 ps are presented. The experimental results are interpreted using a modeling methodology that combines TCAD and radiation effect simulations to capture the SET physics, and SPICE simulations to model the SETs in a circuit. The modeling shows that only ion strikes on the fin structure of the transistor would result in enough charge collected to produce SETs, while strikes in the subfin and substrate do not result in enough charge collected to produce measurable transients. Comparisons of the cumulative cross sections obtained from the experiment and from the simulations validate the modeling methodology presented.

Cumulative Cross Course Exposure to Evidence-Based Teaching is Related to Increases in STEM Student Buy-in and Intent to Persist

A growing body of evidence had demonstrated that increased student exposure and commitment to evidence-based teaching (EBT) leads to improved academic performance, greater persistence, and higher buy-in to instructional methods. Despite the increasing number of teaching development opportunities available to STEM instructors, which often encourage the use of EBT, implementation is still highly variable across instructors. The frequency with which students are exposed to EBT across multiple courses in a department or university has not been studied in relation to students’ success in a given course or their ultimate persistence in STEM. This study shows that there is a cumulative benefit of exposure to EBT across multiple courses. Students who are frequently exposed to EBT also find these practices to be more valuable and report a higher intention to persist in STEM. If students demonstrate higher commitment after multiple EBT exposures, this may increase the likelihood that faculty will incorporate these teaching practices into their courses. The findings are useful for instructors, faculty, department chairs, and administrators who are attempting to support a more unified, evidence-based approach to teaching in their department or institution.

Production cross section measurements of proton-induced reactions on Nb at energies of 58 to 100 MeV

Production cross sections for the $^{93}\mathrm{Nb}(p,x)^{90}\mathrm{Mo},\phantom{\rule{0.28em}{0ex}}^{92m,90,89m}\mathrm{Nb},\phantom{\rule{0.28em}{0ex}}^{89,88,86}\mathrm{Zr}$, and $^{88,87m,87g}\mathrm{Y}$ reactions were measured using a stacked-foil technique in the proton energy range of 58--100 MeV. The target was arranged in the stack including Nb, Al, Au foils, and Pb plates and was irradiated with 100-MeV protons. After the irradiation, the production yields of the interested radionuclei were measured by a $\ensuremath{\gamma}$-ray spectroscopy system using HPGe detectors. Proton beam intensities were measured using the $^{27}\mathrm{Al}(p,3pn)^{24}\mathrm{Na},\phantom{\rule{0.28em}{0ex}}^{197}\mathrm{Au}(p,p3n)^{194}\mathrm{Au}$, and $^{197}\mathrm{Au}(p,pn)^{196}\mathrm{Au}$ monitor reactions. Some 54 cross section data points were measured, including independent and cumulative cross sections and were compared with other experimental data. The excitation functions of the reactions were also calculated by nuclear models using the talys code with a default mode as well as different nuclear level-density models. The calculated cross sections were compared to the measured data and to the tendl library. It was figured out that the theoretical calculations could reproduce the shape of the measured cross sections well, whereas the magnitude of the cross sections was not reproduced. It was also shown that the preequilibrium mechanism played an important role in the cross section calculations in this paper.

Power corrections in a transverse-momentum cut for vector-boson production at NNLO: the qg-initiated real-virtual contribution

We consider the production of a vector boson (Z, W^pm or gamma ^*) at next-to-next-to-leading order in the strong coupling constant alpha _mathrm{S}. We impose a transverse-momentum cutoff, q_{mathrm{T}}^{mathrm{cut}}, on the vector boson produced in the qg-initiated channel. We then compute the power corrections in the cutoff, up to the second power, of the real-virtual interference contribution to the cumulative cross section at order alpha _mathrm{S}^2. Other terms with the same kinematics, originating from the subtraction method applied to the double-real contribution, have been also considered. The knowledge of such power corrections is a required ingredient in order to reduce the dependence on the transverse-momentum cutoff of the QCD cross sections at next-to-next-to-leading order, when the q_{mathrm{T}}-subtraction method is applied. In addition, the study of the dependence of the cross section on q_{mathrm{T}}^{mathrm{cut}} allows as well for an understanding of its behaviour in the small transverse-momentum limit, giving hints on the structure at all orders in alpha _mathrm{S} and on the identification of universal patterns. Our result are presented in an analytic form, using the process-independent procedure described in a previous paper for the calculation of the all-order power corrections in q_{mathrm{T}}^{mathrm{cut}}.

Massive event-shape distributions at N2LL

In a recent paper we have shown how to optimally compute the differential and cumulative cross sections for massive event-shapes at mathcal{O}left({alpha}_sright) in full QCD. In the present article we complete our study by obtaining resummed expressions for non-recoil-sensitive observables to N2LL + mathcal{O}left({alpha}_sright) precision. Our results can be used for thrust, heavy jet mass and C-parameter distributions in any massive scheme, and are easily generalized to angularities and other event shapes. We show that the so-called E- and P-schemes coincide in the collinear limit, and compute the missing pieces to achieve this level of accuracy: the P-scheme massive jet function in Soft-Collinear Effective Theory (SCET) and boosted Heavy Quark Effective Theory (bHQET). The resummed expression is subsequently matched into fixed-order QCD to extend its validity towards the tail and far- tail of the distribution. The computation of the jet function cannot be cast as the dis- continuity of a forward-scattering matrix element, and involves phase space integrals in d = 4 − 2ε dimensions. We show how to analytically solve the renormalization group equation for the P-scheme SCET jet function, which is significantly more complicated than its 2-jettiness counterpart, and derive rapidly-convergent expansions in various kinematic regimes. Finally, we perform a numerical study to pin down when mass effects become more relevant.

The High-Energy Intra-Nuclear Cascade Liège-based Residual (HEIR) nuclear data library

It is standard practice for nuclear data files to include tabulated data for distinct reaction channels for incident energies up to 20-30 MeV. Above these energies, the assumptions implicit in the definition of individual channels break down and event generators are typically used within codes that simulate nuclear observables in applications. These offer robust simulation of the physics but increase the computational burden. So-called ‘high-energy’ nuclear data files have been produced, but the well-known libraries are more than a decade old and rely upon models developed many years before their release. This presentation describes a modern library with a high level of production automation that offers regular updates as the models it is based upon are improved. The most recent versions of the intra-nuclear cascade and de-excitation models available within Geant4 were used to generate tabulated data of residual nuclide production. For the first released library, the INCL++5.3 and ABLA version within Geant4 v10.3 were used to calculate over 1012 incident protons over 2095 target isotopes with incident energies up to 1 GeV. These were collated into tabulated data in the international-standard ENDF-6 format. The resulting files were provided as group-wise files and were distributed as HEIR-0.1 with the FISPACT-II version 4.0 release. A second library, HEIR-0.2, has been generated using the new INCL++6.0 and C++ translation of the ABLA07 model available within Geant4 v10.4. Simulations were performed using incident protons, neutrons, deuterons and π±. An improved agreement is observed in the comparison to experimental data not only between the two versions, but against the other well-known high-energy nuclear data files and models available within Geant4. This benchmark includes mass and isotopic distributions, as well as incident-energy dependent cumulative and independent cross sections from the EXFOR database.

Spallation reactions induced by 4.4 GeV deuterons on lead isotopes

Independent and cumulative production cross sections for radioactive nuclear fragments from the deuteron-irradiation of isotopically enriched lead (204Pb, 206Pb, 207Pb, and 208Pb) targets were obtained for the first time. The experiment has been performed with a 4.4 GeV deuteron beam from the Nuclotron of the Laboratory of High Energy Physics (LHE), Joint Institute for Nuclear Research (JINR) at Dubna. The production cross sections of target fragments were determined by off-line γ-ray spectroscopy. Charge dispersion and mass-yield distributions were deduced from these data. The results are discussed in terms of the relative importance of different reaction mechanisms (evaporation–spallation, fission and multifragmentation). Comparison of our results with the data from the reaction induced by protons of about the same kinetic energy per nucleon, has been performed. The coexistence of the different decay modes in the formation of the reaction residues, such as spallation, fission and multifragmentation is suggested.

Measurement of spallation cross sections for the production of terbium radioisotopes for medical applications from tantalum targets

We present new measurements of cumulative cross sections for the production of 139Ce and 149Tb by proton-induced spallation of tantalum foil targets at different proton energies between 300 and 1700 MeV, using the COSY synchrotron at FZ Jülich. Those measurements are presented in the context of the production of medically-relevant radioisotopes for medical applications.

Electron and Positron Impact Ionization Cross Sections of O and Hg Atoms

Total ionization crosssections for O and Hg atoms have been calculated for electron and positron impact scattering. A quantum mechanical formulation originating from complex atomic spherical potential is adapted in the scattering calculations on two targets. Then we obtain total ionization cross sections and cumulative total excitation cross sections by applying variant CSP-ic method. Our calculated results are presented for impact energy starting from the first threshold of ionization and going up to about 2000 electron volts (eV). For positron-atom scattering, our total inelastic cross sections include positronium formation together with ionization and excitation channels. Because of Ps formation channel it is difficult to separate our ionization cross sections from the total inelastic cross sections. An approximate method has been applied in this regard. Electron impact studies on Hg atom are scarce in literature. Similarly positron impact ionization in relation to electronic ionization discussed presently has not been highlighted much.

Foliar morphology and spatial distribution in five-year-old plantations of Betula alnoides

Foliage spatial distribution and morphological variation within crowns reflect the adjustment of a tree to acclimatise to different microenvironments within crowns and stands. They play important roles in the light use efficiency, carbon assimilation and photosynthesis capacity of the whole tree. In this study, leaf quantity and size at the tree and crown layer levels, and leaf morphology across crown layers, sectors and zones, from 18 trees were investigated in five-year-old Betula alnoides plantations with six planting densities. The results showed that the vertical distributions of leaf number, leaf area index, cumulative branch cross sectional area and leaf area and their ratios were skewed towards the upper crown layers, especially for high planting densities. There was a tendency for leaf size (leaf length, width, perimeter and area) and leaf dry mass to increase from lower to upper crown layer and also from the inner to outer crown zones. The leaf shape factor was larger, and the ratio of leaf length to width and specific leaf area were much smaller, for leaves in the outer and upper crown positions. Leaves in the southern and eastern sectors were smaller than those in the northern and western sectors, but leaf length to width ratio, leaf shape factor and specific leaf area did not differ significantly among four crown sectors. In addition, planting density had no significant effect on leaf related traits at the individual tree and crown layer levels, and leaf morphology also did not vary regularly with planting density, but the specific leaf area was significantly negatively correlated with planting density. However, the interactions between planting density and crown layer, crown sector and crown zone, and among planting density, crown layer and crown zone, were significant. The findings confirmed the acclimation of leaf distribution and morphology to different microenvironments, and provided baseline information for plantation management of B. alnoides and other valuable hardwood species in southern China and other regions with similar climate conditions.

Atom trap trace analysis of krypton in xenon for the XENON Dark Matter Project

We report on the first atom trap trace analysis (ATTA) measurements of Kr in Xe samples with Kr/Xe concentrations of \U0001d4aa(10 ppt) and \U0001d4aa(100 ppt). The ATTA results were independently confirmed by measurements of the same samples with a rare gas mass spectrometer. Measurements of samples with Kr/Xe concentrations below these levels were inhibited by a residual Kr background in the ATTA apparatus, attributed to a cumulative cross sample contamination due to the radio frequency plasma discharge source region from tests with Kr-rich gas samples.

Mass transfer study of water deoxygenation in a rotor–stator reactor based on principal component regression method

This study investigated mass transfer characteristics in a rotor–stator reactor (RSR) in terms of the overall volumetric mass-transfer coefficient (Kxa) using nitrogen stripping (N2–H2O–O2) and nitrogen stripping coupled with vacuum degassing (vacuum–N2–H2O–O2) processes. Principal component regression (PCR) method was used to establish a mass transfer model, and the number of principal components (PCs) was examined by three different techniques including cumulative percent variance (CPV), average eigenvalue (AE), and cross validation (CV). The prediction performance of the PCR model was compared to that of the multiple linear regression (MLR) model. Results reveal that the number of PCs determined by CV based on the predicted residual error sum of squares can be used to determine the optimal number of PCs to express the relationship between various modeling variables and Kxa. The values of Kxa predicted by the PCR and MLR models in the N2–H2O–O2 system were in agreement with the experimental values with deviations within 15% while those in the vacuum–N2–H2O–O2 system generally agreed with the experimental values with deviations within 15% and 30%, respectively. These results indicate that the PCR method is best suited for mass transfer modeling in an RSR.

Quantification of architectural variability and controls in an Upper Oligocene to Lower Miocene carbonate ramp, Browse Basin, Australia

Integration of seismic geomorphology and trajectory analysis of the Oligocene through Lower Miocene distally-steepened carbonate ramp system in the subsurface Browse Basin of the Northwest Shelf of Australia introduces a new way to parameterize carbonate slope channel systems and their stability, and sheds light on how basinward sediment transport is influenced by allogenic and autogenic controls. Seismic geomorphologic analysis identified large-scale prograding clinoforms with an extensive slope channel system and slope angles of up to 12°. Clinoforms have an average slope angle of 8°, a height of ∼500 m, and prograded 9 km during the Upper Oligocene through the Lower Miocene. Relative sea level changes overprinted the effect of intermediate-scale and small-scale antecedent topography, and determined progradation, aggradation and slope angles of the system. We introduce cumulative channel cross sectional area (CCCSA) as the product of number of slope channels, slope channel depth, and slope channel width. CCCSA quantifies the capability of the slope channel system to transport sediment basinward and highlights phases of autogenic slope system re-organization in response to changes in relative sea level. Abruptly increasing values of CCCSA correlate with slope sediment bypass through the incision of new slope channels during system re-organization phases at slope angles of 10°. Thus, we propose that CCCSA can be used as a proxy for slope system stability. Incision of new slope channels into the ramp margin created strike-parallel variability of the ramp margin trajectory. Our seismically-derived relative sea level curve and subsidence rates of 9–30 m/Myr indicate a good preservation of the subsidence and sea level signal in the data.

Influence of spectral particle properties on radiative heat transfer in optically thin and thick media of fluidized bed combustors

In this study, influence of spectral particle properties on radiative heat transfer in the freeboard/dilute zone of fluidized bed combustors (FBCs) is investigated. The aim is to identify how important it is to involve spectral particle properties and to determine the predictive accuracy of gray Mie and gray Geometric Optics (GOA) approximations in optically thin and thick media by benchmarking their predictions against spectral solutions. For that purpose, input data required for modelling radiative heat transfer and validating its predictions are provided from three combustion tests carried out in lignite-fired 300 kWt Atmospheric Bubbling Fluidized Bed Combustor (ABFBC) and 150 kWt Circulating Fluidized Bed Combustor (CFBC) test rigs. The results show that gray particle assumption leads to accurate radiative heat flux predictions with one order of magnitude less CPU time for both optically thin and thick media while it gives acceptable accuracy in source term predictions for only optically thin medium and the error becomes significant as the optical thickness increases. Assessment of GOA in FBCs, on the other hand, reveals that applicability limit of GOA should be based on cumulative cross sectional area distribution rather than surface mean diameter or cumulative weight distribution of particles. If the majority of cumulative cross sectional area is constituted by large particles which fall into geometric optics limit, gray GOA yields satisfactory results compared to spectral solution even if the medium is optically thick without going through cumbersome spectral calculations.

Activation cross sections of longer-lived radionuclides produced in germanium by alpha particle irradiation

The cross sections of alpha particles induced nuclear reactions on natural germanium were investigated by using the standard stacked foil target technique, the activation method and high resolution gamma spectrometry. Targets with thickness of about 1μm were prepared from natural Ge by vacuum evaporation onto 25μm thick polyimide (Kapton) backing foils. Stacks were composed of Kapton-Ge-Ge-Kapton sandwich target foils and additional titanium monitor foils with nominal thickness of 11μm to monitor the beam parameters using the natTi(α,x)51Cr reaction. The irradiations were done with Eα=20.7 and Eα=51.25MeV, Iα=50nA alpha particle beams for about 1h. Direct or cumulative activation cross sections were determined for production of the 72,73,75Se, 71,72,74,76,78As, and 69Ge radionuclides. The obtained experimental cross sections were compared to the results of theoretical calculations taken from the TENDL data library based on the TALYS computer code. A comparison was made with available experimental data measured earlier. Thick target yields were deduced from the experimental cross sections and compared with the data published before.

Dynamical formation and scattering of hierarchical triples: cross-sections, Kozai–Lidov oscillations, and collisions

Dynamical scattering of binaries and triple systems of stars, planets, and compact objects may produce highly inclined triple systems subject to Kozai-Lidov (KL) oscillations, potentially leading to collisions, mergers, Type Ia supernovae, and other phenomena. We present the results of more than 400 million gravitational scattering experiments of binary-binary, triple-single, and triple-binary scattering. We compute the cross sections for all possible outcomes and explore their dependencies on incoming velocity, mass, semi-major axis, and eccentricity, including analytic fits and discussion of the velocity dependence. For the production of new triple systems by scattering we find that compact triples are preferred, with ratios of outer to inner semi-major axes of ~few--100, flat or quasi-thermal eccentricity distributions, and flat distributions in cosine of the mutual inclination. Dynamically formed triples are thus subject to strong KL oscillations, the "eccentric Kozai mechanism," and non-secular effects. For single and binary flyby encounters with triple systems, we compute the cumulative cross section for changes to the mutual inclination, eccentricity, and semi-major axis ratio. We apply these results to scattering events in the field, open clusters, and globular clusters, and explore the implications for Type Ia supernovae via collisions and mergers, stellar collisions, and the lifetime and dynamical isolation of triple systems undergoing KL oscillations. An Appendix provides an analysis of the velocity dependence of the collision cross section in binary-single scattering.