nils-herrmann/clean_scirepeval huggingface dataset:
Forward treatment planning for modulated electron radiotherapy (MERT) employing Monte Carlo methods.

This paper describes the development of a forward planning process for modulated electron radiotherapy (MERT). The approach is based on a previously developed electron beam model used to calculate dose distributions of electron beams shaped by a photon multi leaf collimator (pMLC).



As the electron beam model has already been implemented into the Swiss Monte Carlo Plan environment, the Eclipse treatment planning system (Varian Medical Systems, Palo Alto, CA) can be included in the planning process for MERT. In a first step, CT data are imported into Eclipse and a pMLC shaped electron beam is set up. This initial electron beam is then divided into segments, with the electron energy in each segment chosen according to the distal depth of the planning target volume (PTV) in beam direction. In order to improve the homogeneity of the dose distribution in the PTV, a feathering process (Gaussian edge feathering) is launched, which results in a number of feathered segments. For each of these segments a dose calculation is performed employing the in-house developed electron beam model along with the macro Monte Carlo dose calculation algorithm. Finally, an automated weight optimization of all segments is carried out and the total dose distribution is read back into Eclipse for display and evaluation. One academic and two clinical situations are investigated for possible benefits of MERT treatment compared to standard treatments performed in our clinics and treatment with a bolus electron conformal (BolusECT) method.



The MERT treatment plan of the academic case was superior to the standard single segment electron treatment plan in terms of organs at risk (OAR) sparing. Further, a comparison between an unfeathered and a feathered MERT plan showed better PTV coverage and homogeneity for the feathered plan, with V95% increased from 90% to 96% and V107% decreased from 8% to nearly 0%. For a clinical breast boost irradiation, the MERT plan led to a similar homogeneity in the PTV compared to the standard treatment plan while the mean body dose was lower for the MERT plan. Regarding the second clinical case, a whole breast treatment, MERT resulted in a reduction of the lung volume receiving more than 45% of the prescribed dose when compared to the standard plan. On the other hand, the MERT plan leads to a larger low-dose lung volume and a degraded dose homogeneity in the PTV. For the clinical cases evaluated in this work, treatment plans using the BolusECT technique resulted in a more homogenous PTV and CTV coverage but higher doses to the OARs than the MERT plans.



MERT treatments were successfully planned for phantom and clinical cases, applying a newly developed intuitive and efficient forward planning strategy that employs a MC based electron beam model for pMLC shaped electron beams. It is shown that MERT can lead to a dose reduction in OARs compared to other methods. The process of feathering MERT segments results in an improvement of the dose homogeneity in the PTV.

Field of study: Medicine, Physics
Time delay estimation with unknown spatially correlated Gaussian noise

The problem of estimating the difference in arrival times of a non-Gaussian signal at two spatially separated sensors is considered. The signal is assumed to be corrupted by spatially correlated Gaussian noises of unknown cross-correlation. The author proposes and analyzes two new classes of methods for time delay estimation based on higher order statistics. The proposed methods are conceptually very similar to the traditional cross-correlation-based techniques in that the proposed criteria peak at a lag value equalizing true delay. Since the proposed methods are based upon higher order cumulant statistics of the data, they result in estimators that remain unbiased in the presence of Gaussian noise.

Field of study: Engineering
Temperature-dependent radiation sensitivity and order of 70S ribosome crystals.

All evidence to date indicates that at T = 100 K all protein crystals exhibit comparable sensitivity to X-ray damage when quantified using global metrics such as change in scaling B factor or integrated intensity versus dose. This is consistent with observations in cryo-electron microscopy, and results because nearly all diffusive motions of protein and solvent, including motions induced by radiation damage, are frozen out. But how do the sensitivities of different proteins compare at room temperature, where radiation-induced radicals are free to diffuse and protein and lattice structures are free to relax in response to local damage? It might be expected that a large complex with extensive conformational degrees of freedom would be more radiation sensitive than a small, compact globular protein. As a test case, the radiation sensitivity of 70S ribosome crystals has been examined. At T = 100 and 300 K, the half doses are 64 MGy (at 3 Å resolution) and 150 kGy (at 5 Å resolution), respectively. The maximum tolerable dose in a crystallography experiment depends upon the initial or desired resolution. When differences in initial data-set resolution are accounted for, the former half dose is roughly consistent with that for model proteins, and the 100/300 K half-dose ratio is roughly a factor of ten larger. 70S ribosome crystals exhibit substantially increased resolution at 100 K relative to 300 K owing to cooling-induced ordering and not to reduced radiation sensitivity and slower radiation damage.

Field of study: Chemistry
Image recognition by spectral intensity filtering

A description is given of a coherent-optical filtering method which makes it possible to obtain output signals unaffected by shifts in the input plane. The method is based on intensity filtering of the Fourier spectra and integrated measurements of the intensity of light transmitted by a filter. At each processing stage, a pair of binary filter masks makes it possible to assign the image to one of the two classes of a general set of patterns. The method is illustrated by an example.

Field of study: Engineering, Physics
Elites, poder local y regimen colonial: El cabildo y los regidores de Santiago de Guatemala, 1700-1787 (review)

1848, ended quickly with the return of Carrera the following year. Taracena narrates these events vigorously and provides a careful analysis of the rise of regionalism in Guatemala in the context of the federalist-centralist conflict. The analysis ends, following Carrera’s death in 1865, with the successful 1871 Liberal revolt against the Conservative regime of his successor, Vicente Cerna. With strong backing from Los Altos that ultimately resulted in the establishment of hegemony under Justo Rufino Barrios, the creole-ladino elite of Los Altos triumphed. This victory for the regional interests of Los Altos finally resulted in a strong centralist state in Guatemala, but it failed to end the continuing regional and ethnic conflicts within that country. Taracena also demonstrates how the creole-ladino elite of Los Altos maintained a constant and repressive control over the indigenous majority in the region, a situation that only deepened following their conquest of the national government. Oppressive rule over the Mayan majority continued, and serious attention to indigenous grievances would not begin until the midto late twentieth century. Taracena, with his splendid account of a critical period in the formation of this oppressive region, has made a major contribution to the historiography of Los Altos and to regional studies in Latin America.

Field of study: History
Hippocampal lesions impair retention of discriminative responding based on energy state cues.

The present research investigated the hypothesis that the hippocampus is involved with the control of appetitive behavior by interoceptive "hunger" and "satiety" signals. Rats were trained to solve a food deprivation intensity discrimination problem in which stimuli produced by 0-hr and 24-hr food deprivation served as discriminative cues for the delivery of sucrose pellets. For Group 0+, sucrose pellets were delivered at the conclusion of each 4-min session that took place under 0-hr food deprivation, whereas no pellets were delivered during sessions that took place when the rats had been food deprived for 24 hr. Group 24+ received the reverse discriminative contingency (i.e., they received sucrose pellets under 24-hr but not under 0-hr food deprivation). When asymptotic discrimination performance was achieved (indexed by greater incidence of food magazine approach behavior on reinforced compared with nonreinforced sessions), half of the rats in each group received hippocampal lesions, and the remaining rats in each group were designated as sham- or nonlesioned controls. Following recovery from surgery, food deprivation discrimination performance was compared for lesioned and control rats in both Groups 0+ and 24+. Discriminative responding was impaired for rats with hippocampal lesions relative to their controls. This impairment was based largely on elevated responding to nonreinforced food deprivation cues. In addition, hippocampal damage was associated with increased body weight under conditions of ad libitum feeding. The results suggest that the inhibition of appetitive behavior by energy state signals may depend, in part, on the hippocampus.

Field of study: Biology, Psychology
Dense molecular gas in the nearby low-metallicity dwarf starburst galaxy IC 10

Dense molecular gas and star formation are correlated in galaxies. The effect of low metallicity on this relationship is crucial for interpreting observations of high redshift galaxies, which have lower metallicities than galaxies today. However, it remains relatively unexplored because dense molecular gas tracers like HCN and HCO+ are faint in low metallicity systems. We present Green Bank Telescope observations of HCN(1-0) and HCO+(1-0) on giant molecular cloud (34pc) scales in the nearby low metallicity ($12+\log({\rm O/H})=8.2$) starburst IC 10 and compare them to those in other galaxies. We detect HCN and HCO+ in one and three of five pointings, respectively. The $I_{\rm HCN}/I_{\rm HCO+}$ values are within the range seen in other galaxies, but are most similar to those seen in other low metallicity sources and in starbursts. The detections follow the fiducial $L_{\rm IR}$-$L_{\rm HCN}$ and $L_{\rm IR}$-$L_{\rm HCO+}$ relationships. These trends suggest that HCN and HCO+ can be used to trace dense molecular gas at metallicities of 1/4 $Z_\odot$, to first order. The dense gas fraction is similar to that in spiral galaxies, but lower than that in U/LIRGs. The dense molecular gas star formation efficiency, however, is on the upper end of those in normal galaxies and consistent with those in U/LIRGs. These results suggest that the CO and HCN/HCO+ emission occupy the same relative volumes as at higher metallicity, but that the entire emitting structure is reduced in size. Dense gas mass estimates for high redshift galaxies may need to be corrected for this effect.

Field of study: Physics
Fine-tuning the calibration of the early to middle Eocene geomagnetic polarity time scale: Paleomagnetism of radioisotopically dated tuffs from Laramide foreland basins

Age calibration of the early to middle Eocene geomagnetic polarity time scale remains highly uncertain due to conflicting magnetostratigraphic, radioisotopic, and astrochronologic results. In this study, new paleomagnetic polarity determinations of 29 ash-fall tuffs preserved in strata of five Laramide foreland basins were used in conjunction with previously published 40 Ar/ 39 Ar ages from the same tuffs to evaluate eight different calibration models for the early to middle Eocene part of the geomagnetic polarity time scale. Reliable paleomagnetic information was recovered from 23 tuffs, of which 17 showed normal polarity and six showed reversed polarity. After comparison of the models with the paleomagnetic and radioisotopic data from the tuffs and an array of independent chronostratigraphic observations, the new Willwood model is herein selected as the best alternative to the current geomagnetic polarity time scale calibration for the early to middle Eocene. Three important implications are apparent in our proposed model. First, the early Eocene is shortened by 0.6 m.y., and the middle Eocene is lengthened by 0.8 m.y. compared with the 2004 geomagnetic polarity time scale. Also, the early Eocene climatic optimum is estimated to have lasted from 52.9 to 50.7 Ma, ∼1 m.y. longer than previously suggested, and overlapping in time with the inferred age of the Wasatchian-Bridgerian faunal transition. Our new model agrees with a previous astronomical model when it is tied to the oldest proposed age for the Paleocene-Eocene Thermal Maximum at 56.33 Ma.

Field of study: Geology
Scatter from tilted-columnar birefringent thin films: observation and measurement of anisotropic scatter distributions.

We show that the angular distribution of scattered light (haze) from tilted-columnar birefringent thin films is highly anisotropic. When a narrow laser beam is incident normally upon a substrate coated with a tilted-columnar film, such as titania deposited at 60° to a thickness of ≈2 µm, the distribution of light scattered into the surrounding transmission and reflection air spaces has the form of one or more arcs. Scatter of light into the substrate is also highly anisotropic, and secondary scatter from the trapped substrate flux produces characteristic bright patterns that appear superposed on the coating.When viewed in transmission the bright pattern typically consists of two strong lobes and in reflection four weaker lobes that make a cross. The various anisotropic distributions are shown to be consistent with interference of light from scattering centers that are correlated along the column direction and hence can be described as reflections from the tilted-columnar thin-film microstructure.

Field of study: Physics
Queues Subject to Service Interruption

A treatment is given of the M/G/1 queue with interruptions of Poisson incidence occasioned either by server breakdown or the arrival of customers with higher priority. Interruption times and priority service times have arbitrary distribution. After pre-emptive interruption, ordinary service is either repeated or resumed. The time dependent behavior of the system is discussed in a complete state space and the joint density in all system variables of this space is constructed systematically from the densities associated with a set of simpler first-passage problems. Equilibrium distributions are available as limiting forms and server busy period distributions obtained.

Field of study: Mathematics
PRE- INTRODUCTORY ANALYSIS OF THE SELECTED LEAN MANAGEMENT TOOLS IMPLEMENTATION EFFECTIVNESS USING SIMULATION ANALYSIS—CASE STUDY

The aim of the article was the lean tools implementation effectiveness analysis with simulation technologies based on a project in a selected manufacturing company. Production process analysis was based on qualitative and simulation analysis methods. The evaluation was supported with tools and techniques as the Value Stream Mapping, Fishbone diagram and 5 Whys. Simulation analysis was made on 3D models created within FlexSim simulation software. With the above elements, the evaluation of the Lean tools implementation effectiveness was done. Additionally, one prepared a collation of lean tools in the dimension of their capabilities to be simulated.

Field of study: Engineering
New applications of palladium in organic syntheses

The palladium catalyzed vinylic substitution reaction with organic halides is a new and useful method for producing carbon-carbon bonds. The reaction is useful with aryl, heterocyclic, benzylic, and vinylic bromides and iodides. The most useful reactions are with bromides in which cases a triarylphosphine is required with the palladium catalyst. The best phosphine to employ for a specific synthesis can now be predicted based upon knowledge of how the phosphines influence vinylic substitution rates and side reactions forming phosphonium salts and palladium metal. Essentially all common functional groups can be tolerated by the reaction under the same conditions with the exception of α,β-unsaturated ketones and aldehydes. These react normally in the form of their acetals or ketals, however. Reactions proceed well with conjugated or isolated double bonds with mono-, di- and often tri-substituted olefins, generally in a stereospecific manner. A syn addition of the organopalladium compound to the olefin followed by a syn elimination of the palladium hydride is observed. The direction of addition of the organopalladium complex to the olefin depends upon the substituents present. Both steric and electronic influences have been observed. The direction of addition is dominated by steric effects; the organic group always adds, at least mainly, to the least substituted carbon of the double bond. Electron withdrawing substituents on the double bond generally cause exclusive addition of the organic group to the olefinic carbon not having the substituent. With electron donating groups, some addition to the carbon carrying the substituent is usually observed.

Field of study: Chemistry
Diversity of bryophyte vegetation in some forest types in Estonia: a comparison of old unmanaged and managed forests

The bryophyte vegetation of 3 pairs of unmanaged and managed forest stands, representing Oxalis drained peatland, Aegopodium and Oxalis forest site type, were compared. The total number of bryophyte species in unmanaged stands was 74 and that in managed stands 54. Out of the 20 species occurring only in unmanaged forests, 9 grow on decaying wood, and 3 on trunks or bases of big trees; 13 of them were hepatics. In unmanaged forests 11 hemerophobic species were recorded altogether. Although the difference in substrate and species diversity between unmanaged and managed stands is not statistically significant, in unmanaged forests more substrates characteristic for an old-growth stand are available, and the percentage of species preferring dryer habitats or prolonged humidity is a bit higher than in managed forests; the percentage of species associated with better illuminated habitats is higher in managed forests. Analysis of classification structure of the bryophyte layer synusia shows that the number of societies is also higher in unmanaged forests. This is associated with more numerous microhabitats; the average light and humidity indices calculated for every society, confirm this conclusion. The large discrepancy in bryophyte layer classification structure in old-growth and managed forests of the same forest site type is manifested not so much by species content in synusia as by their abundance proportions. The larger diversity of classification units in unmanaged forests is also seen at the synusia facies level; four of nine facies are confined exclusively to unmanaged stands. This is a strong argument for the informativeness of bryophyte layer classification structure for purposes of indication and monitoring as well.

Field of study: Environmental science
Indole derivatives

Abstract3-Aminoindole was obtained by the action of alkali on its hydrochloride in a reductive medium. Acylation of 3-aminoindole with acetic anhydride gave its mono-, di-, and triacetyl derivatives, whereas reaction with p-substituted benzenesulfonyl chlorides gave the corresponding N-3-indolylsulfonamides. The reaction of 3-aminoindole with aromatic aldehydes gives Schiff bases.

Field of study: Chemistry
Projection of images on a holographic screen

A calculation is given of the distribution of illumination in selective vision zones formed by a holographic screen. It is shown that the actual distribution of illumination in the zones is governed by the initial distribution and by the distribution of illumination in the projected image. It is demonstrated that images whose dimensions are governed by the acuity of the human eye can be projected on such a screen. The results are in agreement with the experimental data obtained by projection on a small part of a screen.

Field of study: Engineering, Physics
DYNAMIC INVESTIGATION OF MOLDING PROCESS AND MECHANICAL STRENGTH OF Fe-Cr WGSR CATALYST

A dynamic method for investigating the molding process and the mechanical strength of solid catalyst was presented.By means of two sets of equipment(catalyst molding process analyzer CMPA and catalyst mechanical properties tester CMPT) designed and fabricated by the authors in laboratory, the dynamic study for Fe-Cr WGSR catalyst pellets was carried out based on the orthogonal experimental design,the effects of some factors in the molding process of Fe-Cr WGSR solid catalyst on the mechanical strength of catalyst pellets were systematically examined,and the molding conditions were optimized. The results showed that there existed the relationship between catalyst pellet density and compact pressure,and the concept of macroscopic elastic modulus was introduced.Furthermore,the remarkable factors (such as predensification process and calcination temperature) affectng Y 0 factors,macroscopic elastic modulus E ′,rate of densification and side crushing strength were also investigated.

Field of study: Chemistry, Environmental science
Examining a model of life satisfaction among unemployed adults.

The present study examined a model of life satisfaction among a diverse sample of 184 adults who had been unemployed for an average of 10.60 months. Using the Lent (2004) model of life satisfaction as a framework, a model was tested with 5 hypothesized predictor variables: optimism, job search self-efficacy, job search support, job search behaviors, and work volition. After adding a path in the model from optimism to work volition, the hypothesized model was found to be a good fit for the data and a better fit than a more parsimonious, alternative model. In the hypothesized model, optimism, work volition, job search self-efficacy, and job search support were each found to significantly relate to life satisfaction, accounting for 35% of the variance. Additionally, using 50,000 bootstrapped samples, optimism was found to have a significant indirect effect on life satisfaction as mediated by job search self-efficacy, job search support, and work volition. Implications for research and practice are discussed.

Field of study: Psychology
Role of hydrogen in III–N–V compound semiconductors

The role of hydrogen in altering the electronic properties of the InxGa1?xAs1?yNy/GaAs system has been investigated by photoluminescence (PL) spectroscopy. Several heterostructures whose nitrogen concentration, y, spans from the dilute (0.0001 ? y ? 0.001) to the alloy (0.01 ? y ? 0.052) limit have been studied. The most remarkable effects observed are a quenching of the PL lines related to exciton recombination in N complexes in the dilute limit, and a bandgap blueshift of the N-containing material towards that of the N-free reference samples in the alloy limit. Differences and similarities found between In-free and x = 0.25?0.41 samples are highlighted. In all cases, the system fully recovers by thermal annealing the optical properties it had before hydrogenation. These behaviours can be accounted for by the formation of N?H bonds, which leads to an effective electronic passivation of the N atoms in the lattice. An analysis of the annealing experiments provides some clues on the geometry of the N complexes in the dilute limit as well as an estimate of the N?H bond strength in both dilute and alloy limits. All these results show that the charge distribution around the N atoms maintains in the alloy limit the strongly localized character it has in the impurity limit.

Field of study: Materials science