bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrogéologie de la région de Lachine-St-Jean, Québec (au sud du St-Laurent), partie des cartes 31H/5 et 31H/6, moitié ouest
Authors: Freeze R A
Published: September 2016

Sufficient groundwater or suitable quality exists throughout the Lachine-Saint-Jean area to supply the domestic agricultural and industrial needs of the present population. There is approximately 5 inches of groundwater recharge each year, giving rise to a
basin-wide safe yield of 140 gallons per minute per square mile. Salt, hydrogen sulphide, and excessive iron occur in the water in localized areas, but for the most part water quality is good. Hardness, total dissolved solids, and the nature of the major chemical constituents can be correlated with
the source aquifer. Alluvial, glacio-fluvial and buried valley deposits constitute excellent sand and gravel aquifers, which are too often over looked in the location of high-capacity wells. The bedrock can be divided into three aquifers, which in order of decreasing transmissibility are: (a)
Sandstone, (b) Carbonate, and (c) Shale aquifer. The groundwater occurs under artesian head and is probably part of an unconfined artesian system. Groundwater flow is toward and into the St. Lawrence River and its tributaries.
A varve record of Lake Ojibway glaciolacustrine deposits from Lac Dasserat, northwestern Quebec, Canada
Authors: Brooks G R
Published: September 2016

Cores recovered from six sites within a study area, ~3 km2, at Lac Dasserat, northwestern Quebec, contained varved Lake Ojibway glaciolacustrine deposits. Measurements of the thicknesses of 546 couplets follow a composite sequence of varves through the
recovered deposits. The couplets are interpreted to span varve numbers 1039 to 1637 with respect to the regional Timiskaming varve series. There is a gap of 48 varves in the varve record, representing an apparent erosional unconformity under the submarine landslide deposits of event horizon E. There
are also two short gaps of unmeasured varves between varves 1266-1267 and 1051-1053. The 'Dasserat varve record' represents about 75% of the varve deposits preserved within the Lac Dasserat basin.
Young patient with generalized lymphangiomatosis: Differentiating the differential
Authors: Putta Tharani , Irodi Aparna , Thangakunam Balamugesh , Oliver Ashwin , Gunasingam Rajesh
Published: September 2016

We present the case of a 19-year-old man who was extensively evaluated in multiple centres for long-standing cough, dyspnea, and hemoptysis without a definitive diagnosis. His chest radiograph at presentation showed mediastinal widening, bilateral pleural effusions, and Kerley B lines. Computed tomography of the thorax showed a confluent, fluid-density mediastinal lesion enveloping the mediastinal viscera without any mass effect. There were bilateral pleural effusions, prominent peribronchovascular interstitial thickening, interlobular septal thickening and lobular areas of ground glass density with relative sparing of apices. There were a few dilated retroperitoneal lymphatics and well-defined lytic lesions in the bones. In this case report, we aim to systematically discuss the relevant differentials and arrive at a diagnosis. We also briefly discuss the treatment options and prognosis along with our patient's course in the hospital and final outcome.
Article Commentary: Online Learning Tools as Supplements for Basic and Clinical Science Education
Authors: Ellman Matthew S. , Schwartz Michael L.
Published: September 2016

Undergraduate medical educators are increasingly incorporating online learning tools into basic and clinical science curricula. In this paper, we explore the diversity of online learning tools and consider the range of applications for these tools in classroom and bedside learning. Particular advantages of these tools are highlighted, such as delivering foundational knowledge as part of the “flipped classroom” pedagogy and for depicting unusual physical examination findings and advanced clinical communication skills. With accelerated use of online learning, educators and administrators need to consider pedagogic and practical challenges posed by integrating online learning into individual learning activities, courses, and curricula as a whole. We discuss strategies for faculty development and the role of school-wide resources for supporting and using online learning. Finally, we consider the role of online learning in interprofessional, integrated, and competency-based applications among other contemporary trends in medical education are considered.
Typical symplectic locally constant cocycles over certain shifts of countable type have simple Lyapunov spectra
Authors: Cambrainha Michel , Matheus Carlos
Published: September 2016

We show that the Lyapunov spectrum of almost every symplectic locally constant integrable cocycle over certain shifts of countable type is simple.
The locus of Brill–Noether general graphs is not dense
Authors: Jensen David
Published: September 2016

We provide an example of a trivalent, 3-vertex connected graph

G

such that, for any choice of metric on

G

, the resulting metric graph is Brill-Noether special.
Internal monoids and groups in the category of commutative cancellative medial magmas
Authors: Fatelo Jorge Pereira , Martins-Ferreira Nelson
Published: September 2016

This article considers the category of commutative medial magmas with cancellation, a structure that generalizes midpoint algebras and commutative semigroups with cancellation. In this category each object admits at most one internal monoid structure for any given unit. Conditions for the existence of internal monoids and internal groups, as well as conditions under which an internal reflexive relation is a congruence, are studied.
Influence of the Bermuda High on interannual variability of summertime ozone in the Houston-­Galveston-Brazoria region
Authors: Wang Yuxuan , Jia Beixi , Wang Sing-Chun , Estes Mark , Shen Lu , Xie Yuanyu
Published: September 2016

Abstract. The Bermuda High (BH) quasi-permanent pressure system is the key large-scale circulation pattern influencing summertime weather over the eastern and southern US. Here we developed a multiple linear regression (MLR) model to characterize the effect of the BH on year-to-year changes of monthly-mean maximum daily 8-hour average (MDA8) ozone in the Houston-Galveston-Brazoria (HGB) metropolitan region during June, July and August (JJA). The BH indicators include the longitude of the BH western edge (BH-Lon), and the BH intensity index (BHI) defined as the pressure gradient along its western edge. Both BH-Lon and BHI are selected by MLR as significant predictors (p < 0.05) of the interannual (1990–2015) variability of the HGB-mean ozone throughout JJA, while local-scale meridional wind speed is selected as an additional predictor for August only. Local-scale temperature and zonal wind speed are not identified as important factors for any summer month. The best-fit MLR model can explain 61 %–72 % of the interannual variability of the HGB-mean summertime ozone over 1990–2015 and shows good performance in cross-validation (R2 higher than 0.48). The BH-Lon is the most important factor, which alone explains 38 %–48 % of such variability. The location and strength of the Bermuda High appears to control whether or not low-ozone maritime air from the Gulf of Mexico can enter southeastern Texas and affect air quality. This mechanism also applies to other coastal urban regions along the Gulf Coast (e.g. New Orleans, LA; Mobile, AL; and Pensacola, FL), suggesting that the BH circulation pattern can affect surface ozone variability through a large portion of the Gulf Coast.
High resolution observations of small scale gravity waves and turbulence features in the OH airglow layer
Authors: Sedlak René , Hannawald Patrick , Schmidt Carsten , Wüst Sabine , Bittner Michael
Published: September 2016

Abstract. A new version of the Fast Airglow Imager (FAIM) for the detection of atmospheric waves in the OH airglow layer has been set up at the German Remote Sensing Data Center (DFD) of the German Aerospace Center (DLR) in Oberpfaffenhofen (48.09° N, 11.28° E), Germany. The spatial resolution of the instrument is 16m in zenith direction with a field of view (FOV) of 11.1 km x 9.0 km at the OH layer height of ca. 87 km. Since November 2015, the system has been in operation in two different setups (zenith angles 46° and 0°) with a temporal resolution of 2.5 to 2.8 s. In a first case study we present observations of two small wave-like features that might be attributed to gravity wave instabilities. In order to spectrally analyse harmonic structures even on small spatial scales down to 550 m horizontal wavelength, we made use of the Maximum Entropy Method (MEM) since this method exhibits an excellent wavelength resolution. MEM further allows analysing relatively short data series, which considerably helps to reduce problems such as stationarity of the underlying data series from a statistical point of view. We present an observation of the subsequent decay of well-organized wave fronts into eddies, which we tentatively interpret in terms of an indication for the onset of turbulence. Another remarkable event which demonstrates the technical capabilities of the instrument was observed during the night of 4th to 5th April 2016. It reveals the disintegration of a rather homogenous brightness variation into several filaments moving in different directions and with different speeds. It resembles the formation of a vortex with a horizontal axis of rotation likely related to a vertical wind shear. This case shows a notable similarity to what is expected from theoretical modelling of Kelvin-Helmholtz instabilities (KHIs). The comparatively high spatial resolution of the presented new version of the FAIM airglow imager provides new insights into the structure of atmospheric wave instability and turbulent processes. Infrared imaging of wave dynamics on the sub-kilometre scale in the airglow layer supports the findings of theoretical simulations and modellings.
Using present-day observations to detect when anthropogenic change forces
surface ocean carbonate chemistry outside preindustrial bounds
Authors: Sutton Adrienne J. , Sabine Christopher L. , Feely Richard A. , Cai Wei-Jun , Cronin Meghan F. , McPhaden Michael J. , Morell Julio M. , Newton Jan A. , Noh Jae-Hoon , Ólafsdóttir Sólveig R. , Salisbury Joseph E. , Send Uwe , Vandemark Douglas C. , Weller Robert A.
Published: September 2016

Abstract. One of the major challenges to assessing the impact of ocean acidification on marine life is detecting and interpreting long-term change in the context of natural variability. This study addresses this need through a global synthesis of monthly pH and aragonite saturation state (Ωarag) climatologies for 12 open ocean, coastal, and coral reef locations using 3-hourly moored observations of surface seawater partial pressure of CO2 and pH collected together since as early as 2010. Mooring observations suggest open ocean subtropical and subarctic sites experience present-day surface pH and Ωarag conditions outside the bounds of preindustrial variability throughout most, if not all, of the year. In general, coastal mooring sites experience more natural variability and thus, more overlap with preindustrial conditions; however, present-day Ωarag conditions surpass biologically relevant thresholds associated with ocean acidification impacts on Mytilus californianus (Ωarag < 1.8) and Crassostrea gigas (Ωarag < 2.0) larvae in the California Current Ecosystem (CCE) and Mya arenaria larvae in the Gulf of Maine (Ωarag < 1.6). At the most variable mooring locations in coastal systems of the CCE, subseasonal conditions approached Ωarag =  1. Global and regional models and data syntheses of ship-based observations tended to underestimate seasonal variability compared to mooring observations. Efforts such as this to characterize all patterns of pH and Ωarag variability and change at key locations are fundamental to assessing present-day biological impacts of ocean acidification, further improving experimental design to interrogate organism response under real-world conditions, and improving predictive models and vulnerability assessments seeking to quantify the broader impacts of ocean acidification.
Digital photography for assessing the link between vegetation phenology and
CO2 exchange in two contrasting northern ecosystems
Authors: Linkosalmi Maiju , Aurela Mika , Tuovinen Juha-Pekka , Peltoniemi Mikko , Tanis Cemal M. , Arslan Ali N. , Kolari Pasi , Böttcher Kristin , Aalto Tuula , Rainne Juuso , Hatakka Juha , Laurila Tuomas
Published: September 2016

Abstract. Digital repeat photography has become a widely used tool for assessing the annual course of vegetation phenology of different ecosystems. By using the green chromatic coordinate (GCC) as a greenness measure, we examined the feasibility of digital repeat photography for assessing the vegetation phenology in two contrasting high-latitude ecosystems. Ecosystem–atmosphere CO2 fluxes and various meteorological variables were continuously measured at both sites. While the seasonal changes in GCC were more obvious for the ecosystem that is dominated by annual plants (open wetland), clear seasonal patterns were also observed for the evergreen ecosystem (coniferous forest). Daily and seasonal time periods with sufficient solar radiation were determined based on images of a grey reference plate. The variability in cloudiness had only a minor effect on GCC, and GCC did not depend on the sun angle and direction either. The daily GCC of wetland correlated well with the daily photosynthetic capacity estimated from the CO2 flux measurements. At the forest site, the correlation was high in 2015 but there were discernible deviations during the course of the summer of 2014. The year-to-year differences were most likely generated by meteorological conditions, with higher temperatures coinciding with higher GCCs. In addition to depicting the seasonal course of ecosystem functioning, GCC was shown to respond to environmental changes on a timescale of days. Overall, monitoring of phenological variations with digital images provides a powerful tool for linking gross primary production and phenology.
Scaled distribution mapping: a bias correction method that preserves raw climate model projected changes
Authors: Switanek Matthew B. , Troch Peter A. , Castro Christopher L. , Leuprecht Armin , Chang Hsin-I. , Mukherjee Rajarshi , Demaria Eleonora M. C.
Published: September 2016

Abstract. Commonly used bias correction methods such as quantile mapping (QM) assume the function of error correction values between modelled and observed distributions are stationary or time-invariant. This article finds that this function of the error correction values cannot be assumed to be stationary. As a result, QM lacks justification to inflate/deflate various moments of the climate change signal. Previous adaptations of QM, most notably quantile delta mapping (QDM), have been developed that do not rely on this assumption of stationarity. Here, we outline a methodology called scaled distribution mapping (SDM), which is conceptually similar to QDM, but more explicitly accounts for the frequency of rain days and the likelihood of individual events. The SDM method is found to outperform QM, QDM and detrended QM in its ability to better preserve raw climate model projected changes to meteorological variables such as temperature and precipitation.
Have precipitation extremes and annual totals been increasing in the
world's dry regions over the last 60 years?
Authors: Sippel Sebastian , Zscheischler Jakob , Heimann Martin , Lange Holger , Mahecha Miguel D. , Van Oldenborgh Geert Jan , Otto Friederike E. L. , Reichstein Markus
Published: September 2016

Abstract. Daily rainfall extremes and annual totals have increased in large parts of the global land area over the last decades. These observations are consistent with theoretical considerations of a warming climate. However, until recently these global tendencies have not been shown to consistently affect land regions with limited moisture availability. A recent study, published by Donat et al. (2016), now identified rapid increases in globally aggregated dry region daily extreme rainfall and annual rainfall totals. Here, we reassess the respective analysis and find that a) statistical artifacts introduced by the choice of the reference period prior to data standardization lead to an overestimation of the reported trends by up to 40 %, and also that b) the definition of "dry regions of the globe" affect the reported globally aggregated trends in extreme rainfall. Using the same observational dataset, but accounting for the statistical artifacts and using alternative, well-established dryness definitions, we find no significant increases in heavy precipitation in the world's dry regions. Adequate data pre-processing approaches and accounting for uncertainties regarding the definition of dryness are crucial to the quantification of spatially aggregated trends in the world's dry regions. In view of the high relevance of the question to many potentially affected stakeholders, we call for a cautionary consideration of specific data processing methods, including issues related to the definition of dry areas, to guarantee robustness of communicated climate change relevant findings.
Conhecimento e atitude dos profissionais de enfermagem sobre avaliação e tratamento da dor neonatal
Authors: Oliveira Iana Mundim de , Castral Thaíla Corrêa , Cavalcante Marcela Maria Faria Peres , Carvalho Julyana Calatayud , Daré Mariana Firmino , Salge Ana Karina Marques
Published: September 2016

Objetivo do estudo foi verificar o conhecimento e atitude dos profissionais de enfermagem de uma unidade neonatal quanto à avaliação e tratamento da dor aguda em recém-nascidos. Estudo descritivo exploratório realizado com 26 profissionais de enfermagem de uma unidade neonatal no Centro-Oeste, Brasil. A maioria dos profissionais identificou ao menos uma escala de avaliação da dor neonatal (76,9%). As estratégias para alívio da dor selecionadas pelos profissionais foram diminuição de ruído e luminosidade (84,6%), posição canguru (76,9%) e colo (76,9%). Menos da metade (28,0%) dos profissionais afirmou registrar sempre ou frequentemente o escore de dor no plantão, e 64,0% referiu utilizar estratégias de alívio da dor. A maioria dos profissionais demonstrou conhecimento quanto ao manejo da dor, apesar de existirem lacunas. A aplicação das escalas e medidas de alívio da dor mostrou-se inadequada, seja pelo pouco uso, não utilização da melhor evidência disponível ou falta de registro.
Shifting Values Toward Profit-Making in Edo Japan: Insights from the Book Ugetsu Monogatari
Authors: Sorte Junior Waldemiro Francisco
Published: September 2016

This paper illustrates the changes in social values toward a more positive image of profit-seeking activities during the Edo period in Japan, through the analysis of the tale Hinpuku-ron from the book Ugetsu Monogatari by Ueda Akinari, an influential literary work first published in 1776. Akinari's thoughts and theories presented in Hinpuku-ron, including the reinterpretation of religious and philosophical concepts, were highly influenced by the social changes that took place during this period, particularly the rise of the merchant class. The discourse of the character known as the spirit of gold tries to demonstrate that money and profit should not be associated with the idea of evil. The story also attempts to justify the importance of wealth and capital accumulation for a nation's success. The views regarding the role of wealthy people in society as well as the debates on Buddhism and Confucianism depicted in Hinpuku-ron illustrate the shifting values of Edo people toward the acceptance of profit-making as a legitimate enterprise and of the merchant class as an important segment of society.
Geographic and Discursive Wanderings of San Francisco's “Evil” Octopuses
Authors: Stangl Paul
Published: September 2016

In mid-nineteenth-century San Francisco, octopuses were abruptly reinvented as “devil-fish,” diabolical sea creatures menacing humans who entered their realm. Simultaneously, metaphorical octopuses began appearing in the press, demonizing a range of phenomena. This paper examines the construction, life and decline of the “evil” octopus myth; the interplay of the literal and metaphoric, and exchange between literature, science, and the press. Notably, literary discourse strongly shaped the popular representation of the octopus, and the deployment of the octopus metaphor was largely driven by its suitability for political agitation in urban space, including racist antagonism against the Chinese. In contrast to accepted theory, which posits an evolution from the literal to metaphoric to mythic, this case study reveals an inverted relationship.
Contabilidad Ambiental: enfoque de publicaciones en Colombia (2009-2012)
Authors: Mejía Soto Eutimio , Serna Mendoza Ciro Alfonso
Published: September 2016

La contabilidad tradicional enfocada a los asuntos económicos determinados por el mercado, es insuficiente para rendir cuentas de los impactos de la gestión de la organización sobre la riqueza ambiental y social. El estudio de las publicaciones científicas colombianas (2009-2012) refleja la tendencia de las investigaciones alternativas en contabilidad, por desarrollar modelos contables complementarios del financiero, que amplíe y mejore la información que las entidades presentan como evaluación de la gestión integral de las mismas. Los documentos analizados tienen grandes coincidencias al diagnosticar la crisis que ha generado en los sistemas socio-ambientales el modelo económico de mercado, al igual que señalan la necesidad de reorientar la contabilidad en su componente teórico y aplicarlo hacia nuevas formas de capturar, procesar y presentar información contable en la cual se incluya la variable naturaleza y sociedad. Los documentos analizados anticipan modelos y sistemas contables acordes al propósito planetario de un desarrollo sostenible generalizado, los cuales superarán la valoración monetaria, la partida doble, el reconocimiento únicamente de hechos económicos y la presentación exclusiva de estados financieros, todo ello para dar paso a una contabilidad para la sostenibilidad con amplio espectro de actuación en el cual se incluyen además de la económica, las dimensiones ambiental y social.
Shellable Cactus Graphs
Authors: Mohammadi Fatemeh , Kiani Dariush , Yassemi Siamak
Published: September 2016

In this paper a new class of vertex decomposable graphs are determined. Moreover, all shellable and sequentially Cohen-Macaulay cactus graphs (i.e., connected graphs in which each edge belongs to at most one cycle) are characterized.
Construction of operators with prescribed orbits in Fréchet spaces with a continuous norm
Authors: Albanese Angela A.
Published: September 2016

Let $X$ be a separable, infinite dimensional real or complex Fréchet space admitting a continuous norm. Let $\{v_n:\ n\geq 1\}$ be a dense set of linearly independent vectors of $X$. We show that there exists a continuous linear operator $T$ on $X$ such that the orbit of $v_1$ under $T$ is exactly the set $\{v_n:\ n\geq 1\}$. Thus, we extend a result of Grivaux for Banach spaces to the setting of non-normable Fréchet spaces with a continuous norm. We also provide some consequences of the main result.
The Cone of Functionals on the Cuntz Semigroup
Authors: Robert Leonel
Published: September 2016

The functionals on an ordered semigroup $S$ in the category $\mathbf{Cu}$ - a category to which the Cuntz semigroup of a C*-algebra naturally belongs - are investigated. After appending a new axiom to the category $\mathbf{Cu}$, it is shown that the "realification" $S_{\mathsf{R}}$ of $S$ has the same functionals as $S$ and, moreover, is recovered functorially from the cone of functionals of $S$. Furthermore, if $S$ has a weak Riesz decomposition property, then $S_{\mathsf{R}}$ has refinement and interpolation properties which imply that the cone of functionals on $S$ is a complete distributive lattice. These results apply to the Cuntz semigroup of a C*-algebra. At the level of C*-algebras, the operation of realification is matched by tensoring with a certain stably projectionless C*-algebra.
Unlocking the ‘Eskimo Secret’: Defence Science in the Cold War Canadian Arctic, 1947–1954
Authors: Wiseman Matthew S.
Published: September 2016

Between 1947 and 1954, medical scientists in Canada received support from federal and independent agencies to conduct a series of comparative biochemical studies on Inuit and white “test subjects.” Originally conceived from a racialized intrigue in defining the vascular characteristics of cold tolerance, the Canadian defence establishment absorbed the research with the intent to apply the findings to military service work in the North. Potentially unlocking the “Eskimo” secret to cold-weather acclimatization meant scientists could devise a screening process for selecting male white bodies for Arctic service. The research took place within the edifice of colonial science, but unlike wider postwar perceptions of the Indigenous body, this article presents the concept of biological appropriation to explore the perceived value of Inuit physiology to northern defence. Interpreting experiential research on Inuit as distinct from cultural assimilation provides a broader interpretation of postwar Arctic policy, and helps discern an understudied yet important episode of the Cold War sciences in Canada.
Louis Veuillot au collège classique : un enseignement littéraire et religieux, 1840-1970
Authors: Lecompte-Ducharme Sébastien
Published: September 2016

Louis Veuillot, bien connu des milieux journalistiques ultramontains, a aussi été reconnu pour son oeuvre littéraire. Les étudiants des collèges classiques québécois ont pu lire ses textes dans le cadre de leur cursus, en incluant les activités parascolaires. Cet article propose d’étudier l’intégration des textes du polémiste à l’éducation littéraire et religieuse de ces jeunes durant trois périodes, 1840-1871, 1910-1930 et 1950-1970. Alors que l’écrivain n’est pas inclus au programme au XIXe siècle, le début du XXe siècle est en quelque sorte l’âge d’or de la diffusion de Veuillot au collège classique, notamment lors des célébrations du centenaire de sa naissance en 1913. À cette époque, l’écrivain est érigé en modèle pour les jeunes, mais les années 1950 sonnent le glas de la diffusion de cet auteur dans les collèges. Néanmoins, durant quelques décennies, il a pu faire partie de la culture livresque des collégiens.
Transcriptional rewiring over evolutionary timescales changes quantitative and qualitative properties of gene expression
Authors: Dalal Chiraj K , Zuleta Ignacio A , Mitchell Kaitlin F , Andes David R , El-Samad Hana , Johnson Alexander D
Published: September 2016

Evolutionary changes in transcription networks are an important source of diversity across species, yet the quantitative consequences of network evolution have rarely been studied. Here we consider the transcriptional ‘rewiring’ of the three GAL genes that encode the enzymes needed for cells to convert galactose to glucose. In Saccharomyces cerevisiae, the transcriptional regulator Gal4 binds and activates these genes. In the human pathogen Candida albicans (which last shared a common ancestor with S. cerevisiae some 300 million years ago), we show that different regulators, Rtg1 and Rtg3, activate the three GAL genes. Using single-cell dynamics and RNA-sequencing, we demonstrate that although the overall logic of regulation is the same in both species—the GAL genes are induced by galactose—there are major differences in both the quantitative response of these genes to galactose and in the position of these genes in the overall transcription network structure of the two species.
Tri-halide vapor-phase epitaxy of GaN using GaCl3 on polar, semipolar, and nonpolar substrates
Authors: Iso Kenji , Takekawa Nao , Matsuda Karen , Hikida Kazuhiro , Hayashida Naoto , Murakami Hisashi , Koukitu Akinori
Published: September 2016

Homoepitaxial tri-halide vapor-phase epitaxy (THVPE) growth on polar, semipolar, and nonpolar bulk GaN substrates was demonstrated using GaCl3 as the precursor. The influence of the surface orientation of the substrate on GaN growth by THVPE was compared with that observed for GaN grown by hydride vapor-phase epitaxy. The dependence of the GaN growth on the surface orientation of the substrate was confirmed; GaN could be grown on

,

,

,

, and

but not on

,

,

, or

. This behavior was explained to be due to the changes in adsorption energy, the magnitudes of which were estimated by theoretical calculations.
Integrated optoelectronic model for organic solar cells based on the finite element method including the effect of oblique sunlight incidence and a non-ohmic electrode contact
Authors: Lee Yongjeong , Kang Kyungnam , Lee Sanghwa , Kim Hyeong Pil , Jang Jin , Kim Jungho
Published: September 2016

We present an integrated optoelectronic model for organic solar cells (OSCs) based on the finite element method, which can numerically simulate the optical and electrical properties in the same calculation domain. In the optical model, the spatial distribution of optical absorption is calculated with respect to the incidence angle and light polarization. A glass factor is introduced to include the incoherent light interaction inside the thick glass substrate. In the electrical model, the current density–voltage (J–V) characteristics can be calculated by self-consistently solving the combined equations based on the Onsager–Braun charge-transfer exciton dissociation, drift-diffusion carrier transport, and non-ohmic contact models. The calculation results of the carrier density, the electric potential, and the electric field in the active layer are compared between the ohmic and non-ohmic contact models at the electrode–organic interface. We numerically calculate the angular and polarization dependences of the short-circuit current density, the open-circuit voltage, and the output electric power density at the spectral irradiance of the AM 1.5 spectrum. The calculation results are well matched with the experimental results at various incidence angles and light polarizations. The application of the proposed integrated optoelectronic model to OSCs will not be restricted to one-dimensional planar structures and can be extended to nonplanar or surface-textured structures.
Analytic modeling of potential and threshold voltage for short-channel thin-body fully depleted silicon-on-insulator MOSFETs with a vertical Gaussian doping profile
Authors: Wei Sufen , Zhang Guohe , Shao Zhibiao , Huang Huixiang , Geng Li
Published: September 2016

We verify that one-dimensional (1D) Gaussian expression is an appropriate approximation of the vertical doping profile, which is obtained by combining perpendicular ion implantation and rapid thermal annealing (RTA), for short-channel thin-body (20–30 nm) fully depleted (FD) silicon-on-insulator (SOI) MOSFETs. The two-dimensional (2D) potential distribution of the silicon film is derived by adopting the evanescent mode analysis method, in which the potential function is broken into 1D long-channel and 2D short-channel potentials. The threshold voltage model is represented by the minimum front- and back-surface potentials of the silicon film. The application of the threshold voltage model can be extended to a 12 nm channel length. The results obtained using the models match well with the 2D numerical simulation results obtained using the Synopsys Sentaurus Device™. They provide a feasible way of developing new 2D models for nonuniform nanoscale thin-body FD-SOI devices.
Advances in global sensitivity analyses of demographic-based species distribution models to address uncertainties in dynamic landscapes
Authors: Naujokaitis-Lewis Ilona , Curtis Janelle M.R.
Published: September 2016

Developing a rigorous understanding of multiple global threats to species persistence requires the use of integrated modeling methods that capture processes which influence species distributions. Species distribution models (SDMs) coupled with population dynamics models can incorporate relationships between changing environments and demographics and are increasingly used to quantify relative extinction risks associated with climate and land-use changes. Despite their appeal, uncertainties associated with complex models can undermine their usefulness for advancing predictive ecology and informing conservation management decisions. We developed a computationally-efficient and freely available tool (GRIP 2.0) that implements and automates a global sensitivity analysis of coupled SDM-population dynamics models for comparing the relative influence of demographic parameters and habitat attributes on predicted extinction risk. Advances over previous global sensitivity analyses include the ability to vary habitat suitability across gradients, as well as habitat amount and configuration of spatially-explicit suitability maps of real and simulated landscapes. Using GRIP 2.0, we carried out a multi-model global sensitivity analysis of a coupled SDM-population dynamics model of whitebark pine (Pinus albicaulis) in Mount Rainier National Park as a case study and quantified the relative influence of input parameters and their interactions on model predictions. Our results differed from the one-at-time analyses used in the original study, and we found that the most influential parameters included the total amount of suitable habitat within the landscape, survival rates, and effects of a prevalent disease, white pine blister rust. Strong interactions between habitat amount and survival rates of older trees suggests the importance of habitat in mediating the negative influences of white pine blister rust. Our results underscore the importance of considering habitat attributes along with demographic parameters in sensitivity routines. GRIP 2.0 is an important decision-support tool that can be used to prioritize research, identify habitat-based thresholds and management intervention points to improve probability of species persistence, and evaluate trade-offs of alternative management options.
Love the one you’re with: replicate viral adaptations converge on the same phenotypic change
Authors: Miller Craig R. , Nagel Anna C. , Scott LuAnn , Settles Matt , Joyce Paul , Wichman Holly A.
Published: September 2016

Parallelism is important because it reveals how inherently stochastic adaptation is. Even as we come to better understand evolutionary forces, stochasticity limits how well we can predict evolutionary outcomes. Here we sought to quantify parallelism and some of its underlying causes by adapting a bacteriophage (ID11) with nine different first-step mutations, each with eight-fold replication, for 100 passages. This was followed by whole-genome sequencing five isolates from each endpoint. A large amount of variation arose—281 mutational events occurred representing 112 unique mutations. At least 41% of the mutations and 77% of the events were adaptive. Within wells, populations generally experienced complex interference dynamics. The genome locations and counts of mutations were highly uneven: mutations were concentrated in two regulatory elements and three genes and, while 103 of the 112 (92%) of the mutations were observed in ≤4 wells, a few mutations arose many times. 91% of the wells and 81% of the isolates had a mutation in the D-promoter. Parallelism was moderate compared to previous experiments with this system. On average, wells shared 27% of their mutations at the DNA level and 38% when the definition of parallel change is expanded to include the same regulatory feature or residue. About half of the parallelism came from D-promoter mutations. Background had a small but significant effect on parallelism. Similarly, an analyses of epistasis between mutations and their ancestral background was significant, but the result was mostly driven by four individual mutations. A second analysis of epistasis focused on de novo mutations revealed that no isolate ever had more than one D-promoter mutation and that 56 of the 65 isolates lacking a D-promoter mutation had a mutation in genes D and/or E. We assayed time to lysis in four of these mutually exclusive mutations (the two most frequent D-promoter and two in gene D) across four genetic backgrounds. In all cases lysis was delayed. We postulate that because host cells were generally rare (i.e., high multiplicity of infection conditions developed), selection favored phage that delayed lysis to better exploit their current host (i.e., ‘love the one you’re with’). Thus, the vast majority of wells (at least 64 of 68, or 94%) arrived at the same phenotypic solution, but through a variety of genetic changes. We conclude that answering questions about the range of possible adaptive trajectories, parallelism, and the predictability of evolution requires attention to the many biological levels where the process of adaptation plays out.
Lowland tapir distribution and habitat loss in South America
Authors: Cordeiro Jose Luis Passos , Fragoso José M.V. , Crawshaw Danielle , Oliveira Luiz Flamarion B.
Published: September 2016

The development of species distribution models (SDMs) can help conservation efforts by generating potential distributions and identifying areas of high environmental suitability for protection. Our study presents a distribution and habitat map for lowland tapir in South America. We also describe the potential habitat suitability of various geographical regions and habitat loss, inside and outside of protected areas network. Two different SDM approaches, MAXENT and ENFA, produced relative different Habitat Suitability Maps for the lowland tapir. While MAXENT was efficient at identifying areas as suitable or unsuitable, it was less efficient (when compared to the results by ENFA) at identifying the gradient of habitat suitability. MAXENT is a more multifaceted technique that establishes more complex relationships between dependent and independent variables. Our results demonstrate that for at least one species, the lowland tapir, the use of a simple consensual approach (average of ENFA and MAXENT models outputs) better reflected its current distribution patterns. The Brazilian ecoregions have the highest habitat loss for the tapir. Cerrado and Atlantic Forest account for nearly half (48.19%) of the total area lost. The Amazon region contains the largest area under protection, and the most extensive remaining habitat for the tapir, but also showed high levels of habitat loss outside protected areas, which increases the importance of support for proper management.
Desire to Quit Smoking, Opt-Out Tobacco Treatment, and Cessation
Authors: Gajewski Byron , Faseru Babalola , Richter Kimber P.
Published: September 2024

This secondary analysis of a randomized clinical trial examines whether an individual’s desire to quit interacts with the association between opt-out tobacco treatment and 1-month quit rates.
Automated confidence estimation in deep learning auto‐segmentation for brain organs at risk on MRI for radiotherapy
Authors: Alzahrani Nouf M. , Henry Ann M. , Al‐Qaisieh Bashar M. , Murray Louise J. , Nix Michael G.
Published: September 2024

Purpose

We have built a novel AI‐driven QA method called AutoConfidence (ACo), to estimate segmentation confidence on a per‐voxel basis without gold standard segmentations, enabling robust, efficient review of automated segmentation (AS). We have demonstrated this method in brain OAR AS on MRI, using internal and external (third‐party) AS models.

Methods

Thirty‐two retrospectives, MRI planned, glioma cases were randomly selected from a local clinical cohort for ACo training. A generator was trained adversarialy to produce internal autosegmentations (IAS) with a discriminator to estimate voxel‐wise IAS uncertainty, given the input MRI. Confidence maps for each proposed segmentation were produced for operator use in AS editing and were compared with “difference to gold‐standard” error maps. Nine cases were used for testing ACo performance on IAS and validation with two external deep learning segmentation model predictions [external model with low‐quality AS (EM‐LQ) and external model with high‐quality AS (EM‐HQ)]. Matthew's correlation coefficient (MCC), false‐positive rate (FPR), false‐negative rate (FNR), and visual assessment were used for evaluation. Edge removal and geometric distance corrections were applied to achieve more useful and clinically relevant confidence maps and performance metrics.

Results

ACo showed generally excellent performance on both internal and external segmentations, across all OARs (except lenses). MCC was higher on IAS and low‐quality external segmentations (EM‐LQ) than high‐quality ones (EM‐HQ). On IAS and EM‐LQ, average MCC (excluding lenses) varied from 0.6 to 0.9, while average FPR and FNR were ≤0.13 and ≤0.21, respectively. For EM‐HQ, average MCC varied from 0.4 to 0.8, while average FPR and FNR were ≤0.37 and ≤0.22, respectively.

Conclusion

ACo was a reliable predictor of uncertainty and errors on AS generated both internally and externally, demonstrating its potential as an independent, reference‐free QA tool, which could help operators deliver robust, efficient autosegmentation in the radiotherapy clinic.
Evaluation of a Metal Artifact Reduction Algorithm for Image Reconstruction on a Novel CBCT Platform
Authors: Yashayaeva Abby , MacDonald Robert Lee , Robar James , Cherpak Amanda
Published: September 2024

Purpose

The presence of metal implants can produce artifacts and distort Hounsfield units (HU) in patient computed tomography (CT) images. The purpose of this work was to characterize a novel metal artifact reduction (MAR) algorithm for reconstruction of CBCT images obtained by the HyperSight imaging system.

Methods

Three tissue‐equivalent phantoms were fitted with materials commonly used in medical applications. The first consisted of a variety of metal samples centered within a solid water block, the second was an Advanced Electron Density phantom with metal rods, and the third consisted of hip prostheses positioned within a water tank. CBCT images of all phantoms were acquired and reconstructed using the MAR and iCBCT Acuros algorithms on the HyperSight system. The signal‐to‐noise ratio (SNR), artifact index (AI), structural similarity index measure (SSIM), peak signal‐to‐noise ratio (PSNR), and mean‐square error (MSE) were computed to assess the image quality in comparison to artifact‐free reference images. The mean HU at various VOI positions around the cavity was calculated to evaluate the artifact dependence on distance and angle from the center of the cavity. The artifact volume of the phantom (excluding the cavity) was estimated by summing the volume of all voxels with HU values outside the 5th and 95th percentiles of the phantom CBCT with no artifact.

Results

The SNR, AI, SSIM, PSNR, and MSE metrics demonstrated significantly higher similarity to baseline when using MAR compared to iCBCT Acuros for all high‐density materials, except for aluminum. Mean HU returned to expected solid water background at a shorter distance from metal sample in the MAR images, and the standard deviation remained lower for the MAR images at all distances from the insert. The artifact volume decreased using the novel MAR algorithm for all metal samples excluding aluminum (p < 0.001) and all hip prostheses (p < 0.05).

Conclusion

Varian's HyperSight MAR reconstruction algorithm shows a reduction in metal artifact metrics, motivating the use of MAR reconstruction for patients with metal implants.
Evaluation of deep learning based dose prediction in head and neck cancer patients using two different types of input contours
Authors: Saito Masahide , Kadoya Noriyuki , Kimura Yuto , Nemoto Hikaru , Tozuka Ryota , Jingu Keiichi , Onishi Hiroshi
Published: September 2024

Purpose

This study evaluates deep learning (DL) based dose prediction methods in head and neck cancer (HNC) patients using two types of input contours.

Materials and methods

Seventy‐five HNC patients undergoing two‐step volumetric‐modulated arc therapy were included. Dose prediction was performed using the AIVOT prototype (AiRato.Inc, Sendai, Japan), a commercial software with an HD U‐net‐based dose distribution prediction system. Models were developed for the initial plan (46 Gy/23Fr) and boost plan (24 Gy/12Fr), trained with 65 cases and tested with 10 cases. The 8‐channel model used one target (PTV) and seven organs at risk (OARs), while the 10‐channel model added two dummy contours (PTV ring and spinal cord PRV). Predicted and deliverable doses, obtained through dose mimicking on another radiation treatment planning system, were evaluated using dose‐volume indices for PTV and OARs.

Results

For the initial plan, both models achieved approximately 2% prediction accuracy for the target dose and maintained accuracy within 3.2 Gy for OARs. The 10‐channel model outperformed the 8‐channel model for certain dose indices. For the boost plan, both models exhibited prediction accuracies of approximately 2% for the target dose and 1 Gy for OARs. The 10‐channel model showed significantly closer predictions to the ground truth for D50% and Dmean. Deliverable plans based on prediction doses showed little significant difference compared to the ground truth, especially for the boost plan.

Conclusion

DL‐based dose prediction using the AIVOT prototype software in HNC patients yielded promising results. While additional contours may enhance prediction accuracy, their impact on dose mimicking is relatively small.
Comparative assessment and QA measurement array validation of Monte Carlo and Collapsed Cone dose algorithms for small fields and clinical treatment plans
Authors: Spenkelink Guus B. , Huijskens Sophie C. , Zindler Jaap D. , de Goede Marc , van der Star Wilhelmus J. , van Egmond Jaap , Petoukhova Anna L.
Published: September 2024

Purpose

Many studies have demonstrated superior performance of Monte Carlo (MC) over type B algorithms in heterogeneous structures. However, even in homogeneous media, MC dose simulations should outperform type B algorithms in situations of electronic disequilibrium, such as small and highly modulated fields.

Our study compares MC and Collapsed Cone (CC) dose algorithms in RayStation 12A. Under consideration are 6 MV and 6 MV flattening filter‐free (FFF) photon beams, relevant for VMAT plans such as head‐and‐neck and stereotactic lung treatments with heterogeneities, as well as plans for multiple brain metastases in one isocenter, involving highly modulated small fields. We aim to investigate collimator angle dependence of small fields and performance differences between different combinations of ArcCHECK configuration and dose algorithm.

Methods

Several verification tests were performed, ranging from simple rectangular fields to highly modulated clinical plans. To evaluate and compare the performance of the models, the agreements between calculation and measurement are compared between MC and CC. Measurements include water tank measurements for test fields, ArcCHECK measurements for test fields and VMAT plans, and film dosimetry for small fields.

Results and conclusions

In very small or narrow fields, our measurements reveal a strong dependency of dose output to collimator angle for VersaHD with Agility MLC, reproduced by both dose algorithms.

ArcCHECK results highlight a suboptimal agreement between measurements and MC calculations for simple rectangular fields when using inhomogeneous ArcCHECK images. Therefore, we advocate for the use of homogeneous phantom images, particularly for static fields, in ArcCHECK verification with MC.

MC might offer performance benefits for more modulated treatment fields. In ArcCHECK results for clinical plans, MC performed comparable to CC for 6 MV. For 6 MV FFF and the preferred homogeneous phantom image, MC resulted in consistently better results (13%–64% lower mean gamma index) compared to CC.