bluuebunny/crossref_metadata_2025 huggingface dataset:
Book Review: Developing Librarian Competencies for the Digital Age
Authors: Cooperman Larry
Published: October 2017

Today’s librarians appear to be at a crossroads, offering traditional library services (such as reference) alongside digital library services, with some services overlapping the two areas. Change in the library profession occurs at a rapid pace in the twenty-first century, so how do librarians (particularly academic librarians) embrace this change successfully to serve their users effectively? And what technological changes can academic librarians expect in the next few years?
Book Review: Leading for School Librarians: There Is No Other Option
Authors: Wachsmann Melanie
Published: October 2017

>Funding cuts to school libraries and librarians are the norm in today’s budget climate, and librarians need specific skills to ensure that school libraries survive and thrive. Weisberg’s book is an all-in-one guide for school librarians. It is organized in three parts: (1) “Safe First Steps to Leadership,” (2) “Building Your Leadership Skills,” and (3) “Playing Larger.”
Book Review: The Readers’ Advisory Guide to Graphic Novels, 2nd ed.
Authors: Siewert Karl G.
Published: October 2017

Taking Ranganathan’s five laws as guiding principles, this new edition of a 2010 work addresses issues of how to effectively discuss and recommend materials in the graphic novel format with readers of all types. It addresses head-on the misconception that graphic works are only for teens and poorly socialized adults and presents a holistic view of the format and the particular challenges that it presents for library workers advising readers.
Book Review: The State and Federal Courts: A Complete Guide to History, Powers, and Controversy
Authors: Wiebe Todd J.
Published: October 2017

This volume provides a very matter-of-fact overview of the American judiciary system at both the state and federal level. The first half is comprised of three “regular” book chapters covering the history and structure and fundamental roles, functions, and powers of the courts—not exactly quick reference material, but these considerable reads could actually make for suitable course material for an American Government class (high school or undergraduate level).
Book Review: We Did What?!: Offensive and Inappropriate Behavior in American History
Authors: Ellermann Marissa
Published: October 2017

We Did What?!: Offensive and Inappropriate Behavior in American History is a work that thoroughly covers topics in American history and culture that have at some point been a source of frustration or contention. Although there are only approximately 150 entries that are between 500 and 1,000 words, the entries are organized alphabetically, well researched, and provide balanced coverage of each topic. It is intended for use by a variety of researchers, but would be best suited as introduction for students in history or social sciences.
Estresse e fatores psicossociais no trabalho de enfermeiros intensivistas
Authors: Lima da Silva Jorge Luiz , Teixeira Liliane Reis , Soares Rafael Da Silva , Costa Felipe Dos Santos , Aranha Joélinton Dos Santos , Teixeira Enéas Rangel
Published: October 2017

El estudio tiene por objeto los aspectos psicosociales y agotamiento. Este estudio tuvo como objetivo describir los factores psicosociales de los trabajadores de enfermería de cuidados intensivos, según las variables socio-demográficas y laborales del mercado. Estudio transversal con 134 profesionales, con aplicación de cuestionario autoadministrado que contenía: un resumen de la Escala de Estrés Trabajo - para medir el estrés; Maslach Burnout Inventory - para evaluar el desgaste; y Self Reporting Questionnaire - para evaluar los trastornos mentales comunes. En cuanto a las dimensiones de estrés: 30,8% eran trabajadores de alta exigencia; 24,6% en el trabajo activo; 20,8% trabajos pasivos y el 23,8% en baja exigencia. La prevalencia de burnout fue de 55.3% estando  72.5% en alta exigencia (p = 0,006). La prevalencia de los trastornos mentales comunes fue de 27,7%. La organización del trabajo en unidades de cuidados intensivos favorece al estrés de alta exigencia y, como consecuencia muestra  prevalencia significativa de los trastornos mentales comunes y burnout. La salud mental se muestra como un elemento clave en el entorno de trabajo en el hospital y necesita de mayor atención por parte de los equipos y autoridades.
Instrumentos y herramientas de evaluación sobre conocimientos de tuberculosis
Authors: Antolínez Figueroa Carolina , Bello Velasquez María Camila , Romero Bernal Luis Fernando , Muñoz Sánchez Alba Idaly
Published: October 2017

Introducción: Los insuficientes conocimientos sobre la tuberculosis atentan contra los programas de control de esta enfermedad y provocan comportamientos erróneos en el cuidado de: la propia salud de los pacientes, la atención brindada por los programas de control de la tuberculosis (TB), la familia al paciente y la comunidad.
Objetivo: Describir la producción científica de instrumentos y herramientas de evaluación sobre conocimientos en TB disponible para el personal de salud, el paciente, la comunidad y la familia.
Metodología: Búsqueda integrativa en cuatro bases de datos (Embase, Science Direct, Redalyc y Biblioteca Virtual de la Salud-BVS), con los siguientes criterios de inclusión: artículos full text (en inglés, español o portugués), publicados entre agosto de 2010 y agosto de 2015.
Resultados: Se incluyeron 42 artículos, que se sistematizaron en una base en Excel por cada una de las poblaciones de estudio. La sistematización permitió evidenciar mayor producción científica en Latinoamérica y África e investigaciones dirigidas a la evaluación de conocimientos al personal de salud y la comunidad. De los 42 artículos seleccionados, solo 5 utilizaron instrumentos con algún tipo de validación y fueron sometidos a pruebas de confiabilidad con alfa de Cronbach.
Conclusiones: Los resultados permitieron identificar la necesidad de desarrollar investigaciones que incluyan el diseño y la validación de instrumentos, así como la evaluación de conocimientos de los pacientes y las familias.
Fatores que dificultam a alimentação por via oral do idoso hospitalizado
Authors: Lima Deise Feijó , Pelzer Marlene Teda , Lima Barros Edaiane Joana , Cabral Semedo Deisa Salyse dos Reis , Rosales Rita Arim
Published: October 2017

Identificar los factores que dificultan la alimentación por vía oral en pacientes ancianos hospitalizados. Es esta una investigación cualitativa, con delineamiento transversal, desarrollada con 111 ancianos hospitalizados en una institución hospitalaria ubicada en el sur del Rio Grande do Sul. Para recolección de datos se ha utilizado un instrumento denominado Escala de Evaluación Alimentaria para el Anciano Hospitalizado. Ha sido realizado un análisis factorial y descriptivo. Los datos cuantitativos generados fueron digitalizados y organizados en el software Statistical Package for the Social Sciences, versión 20.0. Fueron identificados cuatro valores relacionados con la dificultad de alimentación por vía oral por los ancianos hospitalizados: factores ambientales, alimentarios, fisiológicos y los relacionados con el equipo de salud. Los factores ambientales se destacaron como aquellos que más dificultan la alimentación por vía oral de los pacientes ancianos hospitalizados, más fielmente los ítems que contemplan el dolor, la depresión y el uso/ acción de las medicinas.

 
Monitorização da higienização das mãos: observação direta versus taxa autorreportada
Authors: Oliveira Adriana Cristina , Oliveira de Paula Adriana , Sarmento Gama Camila
Published: October 2017

La higiene de las manos es una de las principales medidas de control de las infecciones. Este estudio tuvo como objetivo comparar las tasas de adherencia a la higiene de las manos obtenidos por métodos de observación directa y la tasa autorreportada en una unidad de cuidados intensivos. Estudio transversal realizado en un hospital universitario, entre septiembre y diciembre de 2013. Los datos fueron recolectados a través de la observación directa del personal médico y de enfermería, y la aplicación de un cuestionario estructurado para identificación de las tasas de adhesión autorreportadas. Se realizaron análisis descriptivos y univariantes. El proyecto fue aprobado por el Comité de Ética. Se obtuvo un total de 1935 oportunidades para la higiene de las manos. La tasa de adhesión autorreportada fue de 87,9%, mientras que la tasa observada fue del 19,0% (p <0,001). La higiene de las manos simple fue referido como preferido por 70,2% de los profesionales de la salud, seguido de 12,3% de fricción con solución alcohólica antiséptica y 17,5% por ambos (higiene de las manos simple seguida de fricción con solución alcohólica antiséptica), y dichas tasas fueron similares en la adhesión autorreportadas y la observación directa. Las tasas de adhesión autorreportadas a la higiene de manos fueron sobreestimadas y las tasas obtenidas por observación directa fueron bajas, aunque no distinta de la escena mundial, reafirmando la necesidad de estrategias de implementación continua para la mejora de estas.
Laparotomia exploratória e colecistectomia: análise da frequência respiratória e saturação de oxigênio de pacientes no pós-operatório imediato
Authors: Pereira Santos Francisco Dimitre Rodrigo , Diniz Lima Moraes Hádina , Lopes Nunes Simony Fabíola , Martins Lima Neto Pedro , Maia Pascoal Lívia
Published: October 2017

Objetivo: Evaluar y comparar la tasa respiratoria y saturación de oxígeno de los pacientes en el postoperatorio inmediato de la laparotomía exploratoria y la colecistectomía.

Material y Métodos: Se trata de un estudio transversal, cuantitativo con 63 pacientes tratados entre noviembre 2014 a abril 2015. Los datos fueron recolectados a través de un cuestionario estructurado aplicado a los pacientes ingresados en la Clínica Quirúrgica del Hospital Municipal Imperatriz. Los participantes del estudio eran pacientes de ambos sexos, con edades comprendidas entre 18-59 años en el postoperatorio inmediato de la laparotomía exploratoria (Grupo I) y colecistectomía (Grupo II). Del cuestionario se extrajeron los datos de tasa por frecuencia respiratoria (FR) y saturación de oxígeno. Los datos fueron analizados estadísticamente empleando el programa BioEstat 5.0 y prueba de Shapiro-Wilk para la normalidad entre variables, análisis de Mann-Whitney inferencial y la prueba de Spearman para la correlación entre las variables.

Se comprobó que no hubo significación estadística en cuanto a los cambios clínicamente relevantes a FR (p=0,4) y los cambios clínicos en saturación de oxígeno (p=0,8) en comparación con las muestras de ambos grupos y los procedimientos quirúrgicos realizados. Los casos en los que se alteraron los valores de ambas variables analizadas, que muestran las condiciones de taquipnea o hipopnea e hipoxemia fueron casos aislados, poco significativos estadísticamente.

Conclusión: Se encontró que, independientemente de los procedimientos quirúrgicos realizados, el patrón de respiración se mantuvo de normal a mínimamente alterado, no habiendo en estos individuos interferencia directa de estas cirugías en la función respiratoria que causase de forma significativa alteración clínica de la respiración.
Merenje i upravljanje ekonomskom izloženošću multinacionalne kompanije deviznom riziku
Authors: Pobrić Nermina
Published: October 2017

Na visinu novčanih tokova multinacionalne kompanije mogu uticati kretanja deviznog kursa ako ona izvršava transakcije u stranimvalutama, ostvaruje prihod u stranim valutama ili je izložena uticaju strane konkurencije. Osetljivost novčanih tokova kompanije naneočekivana kretanja deviznog kursa naziva se ekonomskom, operativnom, konkurentskom ili strategijskom izloženošću. U ovom člankuautor je ukazao na moguće načine merenja i upravljanja ekonomskom izloženošću deviznom riziku da bi finansijskim menadžerima umultinacionalnim kompanijama olakšao obavljanje ovih aktivnosti.
Beneishov M-score model u funkciji detekcije računovodstvenih manipulacija
Authors: Rajković Siniša
Published: October 2017

Jedan od najvažnijih zadataka i ciljeva finansijskog izvještavanja svakako je zaštita investitora i povjerilaca. Značaj objavljenih informacijau finansijskim izvještajima je dramatično porastao u posljednjih nekoliko dekada imajući u vidu brojne afere i finansijske skandale koji sunastali kao posljedica računovodstvenih manipulacija i kreativnog računovodstva.Korisnici finansijskih izvještaja očekuju da u finansijskim izvještajima pronađu pouzdane i istinite podatke kako bi mogli realno da sagledajuprinosni i finansijski položaj određenog entiteta. Jedan od načina da investitori provjere da li se datim finansijskim izvještajimamanipulisalo i da li je u njima zastupljeno kreativno računovodstvo, svakako je Beneishov M-score model, koji je predmet ovog rada, i unastavku ćemo objasniti osnovne postulate ovog modela i ilustrovati njegovu primjenu na praktičnom primjeru.
Vrste interne revizije i stručni nadzor internih revizora
Authors: Koletnik Franc
Published: October 2017

Malo je teorijskih rasprava i primjera dobre prakse o vrstama interne revizije koje, po vremenu, sadržaju, namjeni, ciljevima i/ili drugimkarakteristikama, značajno odstupaju od redovnih i opštih revizija. U internoj reviziji stoga postoji više dilema koje ukazuju na potrebu zaispitivanjem tipova internih revizija na način koji neće narušiti temeljne postulate na kojima i počiva savremena interna revizija.U oblasti interne revizije, koja je potporna aktivnost nosiocima poslovnog odlučivanja, srećemo se sa redovnim, vanrednim i sporednim iliposebnim revizijskim procesima, koje treba organizovati, koordinisati i nadzirati u skladu sa pravilima te struke.Stručni nadzor interne revizije ne treba poistovijetiti sa vanrednom ili posebnom internom revizijom, pošto se radi o stručnoj procjenipravilnosti već potpuno obavljene interne revizije, ili samo određenih radnih aktivnosti internog revizora. Takav nadzor može obaviti samostručna osoba – obučen vještak poslova interne revizije, koji nije bio neposredno i/ili posredno uključen u spornu aktivnost interne revizije.
Kretanje doznaka i uticaj na ekonomiju zemlje
Authors: Amidžić Srđan , Kurteš Siniša , Rajčević Perica
Published: October 2017

Bosna i Hercegovina spada u sam vrh zemalja po obimu doznaka i one čine značajan dio kapitalnih tokova zemlje. Doznake u Bosni iHercegovini su uglavnom neproizvodnog karaktera i usmjerene su na ličnu potrošnju, izgradnju kuća i razvoj poljoprivredne proizvodnje.Nadalje, van svake sumnje je da su doznake doprinijele smanjenju siromaštva podizanjem raspoloživog dohotka stanovništva koje ih jeprimalo, a na taj način i u zemlji kao cjelini. Ipak, bez obzira na značajan i stabilan priliv po ovom osnovu, veoma mali dio doznaka jeuložen u razvoj. Za razliku od strane pomoći i privatizacionih prihoda, koji su ograničenog trajanja, i stranih direktnih investicija, čiji seobim menja zavisno od rizika zemlje, doznake su stabilan izvor deviznog priliva. Doznake za zemlje na nižem nivou razvoja čine i osnovnosredstvo pokrića deficita platnog bilansa i najznačajniji kanal kapitalnih priliva. One se mogu posmatrati i kao svojevrsni amortizer kojidoprinosi ublažavanju kriznih simptoma u privredi zemlje primaoca, upravo usljed stalnosti i stabilnosti priliva doznaka bez obzira na rastili pad ekonomske aktivnosti.
Uticaj institucionalne ekonomije na rast i razvoj
Authors: Mikerević Jovica
Published: October 2017

U radu se polazi od opšteprihvaćenog stava da u teoriji privrednog rasta i razvoja kao makroekonomske teorijske discipline, za razlikuod nekih drugih oblasti, još uvijek ne postoji univerzalan teorijski koncept. Svakodnevno se pojavljuju i različite matemetičko-statističkemetode, kao i pokušaji uključivanja brojnih teško mjerljivih faktora u analizi privrednog rasta. Globalna finansijska i ekonomska krizauslovila je potrebu traženja „novog puta“ kao potrebu preispitivanja uloge tržišta i uloge države. U nastojanju da se pronađe nova komplementarnosti pluralizam, institucionalne promjene se smatraju opštim okvirom, odnosno zajedničkim imeniocem i preduslovom svihostalih promjena, pa i onih u ekonomiji.
Održivost i konkurentnost likvidnosti novčanog toka
Authors: Malešević Đoko
Published: October 2017

Motiv i cilj ove rasprave je da se skrene pažnja na značaj analize održivosti i konkurentnosti likvidnosti novčanog toka. Malo je studijao analizi novčanog toka, za razliku od analize profitabilnosti odnosno rentabilnosti, iako se slobodan novčani tok klasifikuje glavnomdeterminantom finansijske fleksibilnosti i pravcem razvoja kompanije. Veza između novčanog toka i održivosti je jaka i, stoga, jak stalannovčani tok je bitna strategijska snaga u pozicioniranju kompanije na tržištu.Za celishodnu analizu izloženi su određeni koncepti likvidnosti i novčanog toka. Shodno njihovom određenju i razumevanju prikazanisu instrumenti i metode (metode i alati) za racionalnu analizu likvidnosti i novčanog toka. Pri tome se ima u vidu da analiza likvidnostii novčanog toka, u smislu održivosti, ne može, sama po sebi, biti dovoljna za potpuno razumevanje konkurentske pozicije kompanije.Međutim, značajno može tome doprineti i podići značaj i ulogu opšte poslovne analize na viši nivo.
Američki model Zeta skor ocene boniteta preduzeća
Authors: Rodić Jovan
Published: October 2017

Prikazan je model Zeta skor ocene boniteta preduzeća čijim se HOV trguje na berzi, proizvodnog preduzeća čijim se HOV ne trguje naberzi i neproizvodnog preduzeća.Model je testiran na sedam preduzeća (četiri proizvodna i tri neproizvodna). Na osnovu testa utvrđeno je da se dobija realniji Zeta skorkada se X1 kvantifikuje obrtni kapital/ zalihe nego kada se kvantifikuje obrtni kapital/ poslovna imovina. Razlog tome je što su zaliheuvek niže od poslovne imovine. Kvantifikacija X1 obrtni kapital/ zalihe indirektno uvažava finansijsku stabilnost, koja je bitna i za bonitet(platežnu sposobnost) preduzeća i za dugoročni opstanak preduzeća, zbog čega potpisani kvantifikuje X1 obrtni kapital/ zalihe.
Pravila oporezivanja vaučera u EU
Authors: Antić Dinka
Published: October 2017

Pojam „vaučer“ obuhvata različite vrste vrijednosnih kupona, prepaid kartica mobilne telefonije, poklon-kartica, šoping-kartica za diskontkupovine i sličnih kartica kojima se omogućava kupovina dobara ili usluga, direktno ili putem elektronske trgovine. Do sada su članicena različit način oporezivale vaučere, neke odmah po izdavanju, a druge u momentu realizacije vaučera kada se vrši promet dobrimaili uslugama. U prekograničnim transakcijama unutar EU, različit poreski tretman vaučera dovodi do pojave dvostrukog oporezivanja ilidvostrukog neoporezivanja, sa negativnim posljedicama po prihode članica i tržište EU u cjelini. EU je u junu 2016. usvojila izmjene PDVdirektive u vezi sa oporezivanjem vaučera, koje imaju za cilj eliminiranje divergentnih nacionalnih poreskih pravila.
Frequency-dependent mobilization of heterogeneous pools of synaptic vesicles shapes presynaptic plasticity
Authors: Doussau Frédéric , Schmidt Hartmut , Dorgans Kevin , Valera Antoine M , Poulain Bernard , Isope Philippe
Published: October 2017

The segregation of the readily releasable pool of synaptic vesicles (RRP) in sub-pools that are differentially poised for exocytosis shapes short-term plasticity. However, the frequency-dependent mobilization of these sub-pools is poorly understood. Using slice recordings and modeling of synaptic activity at cerebellar granule cell to Purkinje cell synapses of mice, we describe two sub-pools in the RRP that can be differentially recruited upon ultrafast changes in the stimulation frequency. We show that at low-frequency stimulations, a first sub-pool is gradually silenced, leading to full blockage of synaptic transmission. Conversely, a second pool of synaptic vesicles that cannot be released by a single stimulus is recruited within milliseconds by high-frequency stimulation and support an ultrafast recovery of neurotransmitter release after low-frequency depression. This frequency-dependent mobilization or silencing of sub-pools in the RRP in terminals of granule cells may play a role in the filtering of sensorimotor information in the cerebellum.
IRAK2 directs stimulus-dependent nuclear export of inflammatory mRNAs
Authors: Zhou Hao , Bulek Katarzyna , Li Xiao , Herjan Tomasz , Yu Minjia , Qian Wen , Wang Han , Zhou Gao , Chen Xing , Yang Hui , Hong Lingzi , Zhao Junjie , Qin Luke , Fukuda Koichi , Flotho Annette , Gao Ji , Dongre Ashok , Carman Julie A , Kang Zizhen , Su Bing , Kern Timothy S , Smith Jonathan D , Hamilton Thomas A , Melchior Frauke , Fox Paul L , Li Xiaoxia
Published: October 2017

Expression of inflammatory genes is determined in part by post-transcriptional regulation of mRNA metabolism but how stimulus- and transcript-dependent nuclear export influence is poorly understood. Here, we report a novel pathway in which LPS/TLR4 engagement promotes nuclear localization of IRAK2 to facilitate nuclear export of a specific subset of inflammation-related mRNAs for translation in murine macrophages. IRAK2 kinase activity is required for LPS-induced RanBP2-mediated IRAK2 sumoylation and subsequent nuclear translocation. Array analysis showed that an SRSF1-binding motif is enriched in mRNAs dependent on IRAK2 for nuclear export. Nuclear IRAK2 phosphorylates SRSF1 to reduce its binding to target mRNAs, which promotes the RNA binding of the nuclear export adaptor ALYREF and nuclear export receptor Nxf1 loading for the export of the mRNAs. In summary, LPS activates a nuclear function of IRAK2 that facilitates the assembly of nuclear export machinery to export selected inflammatory mRNAs to the cytoplasm for translation.
Histamine-2 receptor antagonist famotidine modulates cardiac stem cell characteristics in hypertensive heart disease
Authors: Saheera Sherin , Potnuri Ajay G. , Nair Renuka
Published: October 2017

Background

Cardiac stem cells (CSCs) play a vital role in cardiac homeostasis. A decrease in the efficiency of cardiac stem cells is speculated in various cardiac abnormalities. The maintenance of a healthy stem cell population is essential for the prevention of adverse cardiac remodeling leading to cardiac failure. Famotidine, a histamine-2 receptor antagonist, is currently used to treat ulcers of the stomach and intestines. In repurposing the use of the drug, reduction of cardiac hypertrophy and improvement in cardiac function of spontaneously hypertensive rats (SHR) was reported by our group. Given that stem cells are affected in cardiac pathologies, the effect of histamine-2 receptor antagonism on CSC characteristics was investigated.

Methods

To examine whether famotidine has a positive effect on CSCs, spontaneously hypertensive rats (SHR) treated with the drug were sacrificed; and CSCs isolated from atrial appendages was evaluated. Six-month-old male SHRs were treated with famotidine (30 mg/kg/day) for two months. The effect of famotidine treatment on migration, proliferation and survival of CSCs was compared with untreated SHRs and normotensive Wistar rats.

Results

Functional efficiency of CSCs from SHR was compromised relative to that in Wistar rat. Famotidine increased the migration and proliferation potential, along with retention of stemness of CSCs in treated SHRs. Cellular senescence and oxidative stress were also reduced. The expression of H2R was unaffected by the treatment.

Discussion

As anticipated, CSCs from SHRs were functionally impaired. Stem cell attributes of famotidine-treated SHRs was comparable to that of Wistar rats. Therefore, in addition to being cardioprotective, the histamine 2 receptor antagonist modulated cardiac stem cells characteristics. Restoration of stem cell efficiency by famotidine is possibly mediated by reduction of oxidative stress as the expression of H2R was unaffected by the treatment. Maintenance of healthy stem cell population is suggested as a possible mechanism underlying the cardioprotective effect of famotidine.
Design of Remediation Actions for Nutrient Mitigation in the Hyporheic Zone
Authors: Morén I. , Wörman A. , Riml J.
Published: October 2017

Although hyporheic exchange has been shown to be of great importance for the overall water quality of streams, it is rarely considered quantitatively in stream remediation projects. A main driver of hyporheic exchange is the hydraulic head fluctuation along the streambed, which can be enhanced by modifications of the streambed topography. Here we present an analytical 2‐D spectral subsurface flow model to estimate the hyporheic exchange associated with streambed topographies over a wide range of spatial scales; a model that was validated using tracer‐test‐results and measurements of hydraulic conductivity. Specifically, engineered steps in the stream were shown to induce a larger hyporheic exchange velocity and shorter hyporheic residence times compared to the observed topography in Tullstorps Brook, Sweden. Hyporheic properties were used to parameterize a longitudinal transport model that accounted for reactions in terms of first‐order decay and instantaneous adsorption. Theoretical analyses of the mitigation effect for nitrate due to denitrification in the hyporheic zone show that there is a Damköhler number of the hyporheic zone, associated with several different stream geomorphologies, that optimizes nitrate mass removal on stream reach scale. This optimum can be limited by the available hydraulic head gradient given by the slope of the stream and the geological constraints of the streambed. The model illustrates the complex interactions between design strategies for nutrient mitigation, hyporheic flow patterns, and stream biogeochemistry and highlights the importance to diagnose a stream prior remediation, specifically to evaluate if remediation targets are transport or reaction controlled.
Evaluating the Effects of Tracer Choice and End‐Member Definitions on Hydrograph Separation Results Across Nested, Seasonally Cold Watersheds
Authors: Bansah Samuel , Ali Genevieve
Published: October 2017

Isotope‐based hydrograph separation (IHS) is a widely used method in studies of runoff generation and streamflow partitioning. Challenges in choosing and characterizing appropriate tracers and end‐members have, however led to presumably highly uncertain IHS results. Here we tested the effects of end‐member definitions and tracer choices on IHS results in nested Prairie watersheds of varying size and landscape characteristics. Specifically, the consideration of eight potential “new” water end‐members, eight potential “old” water end‐members, and two stable water isotope tracers led to 80 potential IHS results for each stream water sample. IHS‐related uncertainty was evaluated using a Gaussian error propagation method. Results show that choosing an appropriate “new” water end‐member is most challenging during the freshet: highly variable “old” water fractions associated with high uncertainties were attributed to changing conditions from melting snow only to rain‐on‐snow. In summer and fall, it was rather the choice of an appropriate “old” water end‐member that was most problematic. IHS results obtained using δ18O versus δ2H as a tracer were significantly different except in the flattest and most wind‐sheltered watersheds examined. Overall, δ2H‐based IHS results were more uncertain than their δ18O‐based counterparts. Recommendations are therefore made toward careful selection of a tracer and a sampling strategy aimed at characterizing the most appropriate end‐members for IHS, especially when dealing with seasonally cold watersheds.
Phase Relations in the System MgSiO3‐Al2O3 up to 2300 K at Lower Mantle Pressures
Authors: Liu Zhaodong , Nishi Masayuki , Ishii Takayuki , Fei Hongzhan , Miyajima Nobuyoshi , Ballaran Tiziana Boffa , Ohfuji Hiroaki , Sakai Takeshi , Wang Lin , Shcheka Svyatoslav , Arimoto Takeshi , Tange Yoshinori , Higo Yuji , Irifune Tetsuo , Katsura Tomoo
Published: October 2017

Phase relations in the system MgSiO3‐Al2O3 were investigated at pressures of 27–45 GPa and temperatures of 1700, 2000, and 2300 K using sintered diamond and tungsten carbide anvils in a multianvil apparatus. The bulk compositions in the MgSiO3‐Al2O3 binary system crystallize a phase assemblage of pyrope and corundum at pressures below 27 GPa and an assemblage of bridgmanite and corundum at pressures above 27 GPa regardless of temperatures. The solubility of Al2O3 in bridgmanite and that of MgSiO3 in corundum increases significantly with increasing temperature. The solubility of Al2O3 in bridgmanite increases from 6.7 mol % at 1700 K to 21.8 mol % at 2500 K under a constant pressure of 27 GPa. Bridgmanite becomes more aluminous with increasing pressure from 27 to 45 GPa at a given temperature. The MgSiO3 content in corundum increases with increasing pressure at pressure lower than 27 GPa, while it decreases at pressure higher than 27 GPa. Our results suggest that bridgmanite can incorporate a considerably higher Al2O3 content than that of the pyrope composition (25 mol % Al2O3). The present study further suggests that the entire Al2O3 component is accommodated into bridgmanite in the pyrolite lower mantle. However, Al2O3 cannot be fully accommodated into bridgmanite in the coldest parts of subducted slabs in the shallow part of the lower mantle, and therefore, additional phases such as MgAl2O4 with calcium ferrite‐type structure are necessary to host the excess Al2O3.
Spatiotemporal Variation of Stress Drop During the 2008 Mogul, Nevada, Earthquake Swarm
Authors: Ruhl C. J. , Abercrombie R. E. , Smith K. D.
Published: October 2017

We estimate stress drops for 148 shallow (<6 km) earthquakes in the complex 2008 Mogul, Nevada, swarm using empirical Green's function‐derived spectral ratios. Near‐source, temporary broadband seismometers deployed before theMw4.9 main shock provide high‐quality records of many foreshocks and aftershocks, and an ideal opportunity to investigate uncertainties in corner frequency measurement as well as stress drop (Δσ) variation related to space, time, depth, mechanism, and magnitude. We explore uncertainties related to source model, measurement approach, cross‐correlation limit, and frequency bandwidth.P(S) wave Δσresults range from 0.2 ± 0.15 (0.3 ± 0.15) to 36±20 (58±7) MPa, a variation greater than the error range of each individual estimate. Although this variation is not explained simply by any one parameter, spatiotemporal variation along the main shock fault plane is distinct: coherent clusters of high and low Δσearthquakes are seen, and high‐Δσforeshocks correlate with an area of reduced aftershock productivity. These observations are best explained by a difference in rheology along the fault plane. Average Δσs of 3.9±1.1 (4.0±1.1) MPa usingP(S) are similar to those found for earthquakes in a variety of settings, implying that these shallow, potentially fluid‐driven earthquakes do not have systematically lower Δσthan average tectonic earthquakes (~4 MPa) and, therefore, have similar (or higher, due to proximity to the surface) expected ground motions compared to typical earthquakes. The unprecedented detail achieved for these shallow, small‐magnitude earthquakes confirms that Δσ, when measured precisely, is a valuable observation of physically meaningful fault zone properties and earthquake behavior.
Modeling Forced Imbibition Processes and the Associated Seismic Attenuation in Heterogeneous Porous Rocks
Authors: Solazzi Santiago G. , Guarracino Luis , Rubino J. Germán , Müller Tobias M. , Holliger Klaus
Published: October 2017

Quantifying seismic attenuation during laboratory imbibition experiments can provide useful information toward the use of seismic waves for monitoring injection and extraction of fluids in the Earth's crust. However, a deeper understanding of the physical causes producing the observed attenuation is needed for this purpose. In this work, we analyze seismic attenuation due to mesoscopic wave‐induced fluid flow (WIFF) produced by realistic fluid distributions representative of imbibition experiments. To do so, we first perform two‐phase flow simulations in a heterogeneous rock sample to emulate a forced imbibition experiment. We then select a subsample of the considered rock containing the resulting time‐dependent saturation fields and apply a numerical upscaling procedure to compute the associated seismic attenuation. By exploring both saturation distributions and seismic attenuation, we observe that two manifestations of WIFF arise during imbibition experiments: the first one is produced by the compressibility contrast associated with the saturation front, whereas the second one is due to the presence of patches containing very high amounts of water that are located behind the saturation front. We demonstrate that while the former process is expected to play a significant role in the case of high injection rates, which are associated with viscous‐dominated imbibition processes, the latter becomes predominant during capillary‐dominated processes, that is, for relatively low injection rates. We conclude that this kind of joint numerical analysis constitutes a useful tool for improving our understanding of the physical mechanisms producing seismic attenuation during laboratory imbibition experiments.
Reservoir Structure and Wastewater‐Induced Seismicity at the Val d'Agri Oilfield (Italy) Shown by Three‐Dimensional Vp and Vp/Vs Local Earthquake Tomography
Authors: Improta L. , Bagh S. , De Gori P. , Valoroso L. , Pastori M. , Piccinini D. , Chiarabba C. , Anselmi M. , Buttinelli M.
Published: October 2017

Wastewater injection into a high‐rate well in the Val d'Agri oilfield, the largest in onshore Europe, has induced swarm microseismicity since the initiation of disposal in 2006. To investigate the reservoir structure and to track seismicity, we performed a high‐spatial resolution local earthquake tomography using 1,281 natural and induced earthquakes recorded by local networks. The properties of the carbonate reservoir (rock fracturing, pore fluid pressure) and inherited faults control the occurrence and spatiotemporal distribution of seismicity. A low‐Vp, high‐Vp/Vs region under the well represents a fluid saturated fault zone ruptured by induced seismicity. High‐Vp, high‐Vp/Vs bumps match reservoir culminations indicating saturated liquid‐bearing zones, whereas a very low Vp, low Vp/Vs anomaly might represent a strongly fractured and depleted zone of the hydrocarbon reservoir characterized by significant fluid withdrawal. The comprehensive picture of the injection‐linked seismicity obtained by integrating reservoir‐scale tomography, high‐precision earthquake locations, and geophysical and injection data suggests that the driving mechanism is the channeling of pore pressure perturbations through a high permeable fault damage zone within the reservoir. The damage zone surrounds a Pliocene reverse fault optimally oriented in the current extensional stress field. The ruptured damage zone measures 2 km along strike and 3 km along dip and is confined between low permeability ductile formations. Injection pressure is the primary parameter controlling seismicity rate. Our study underlines that local earthquake tomography also using wastewater‐induced seismicity can give useful insights into the physical mechanism leading to these earthquakes.
Comprehensive Analysis of Traveltime Data Collected Through GPS‐Acoustic Observation of Seafloor Crustal Movements
Authors: Honsho Chie , Kido Motoyuki
Published: October 2017

We have developed a comprehensive inversion scheme to analyze traveltime data collected through GPS‐acoustic observations on a campaign basis. Our method uses a quantity called the “nadir total delay” (NTD), which is analogous to the zenith total delay in Global Navigation Satellite Systems analyses, to represent the time variation of the sound speed. The observation equation using the NTD is an approximated formulation. We examine its applicable scope using numerical experiments and demonstrate that the approximation holds well enough in practice. Traveltime data from all our observation campaigns were utilized together for inversion calculation to determine the following: (1) the positions of individual precision acoustic transponders at the time of a particular reference campaign, (2) the displacement from these positions of a rigid array at the time of each campaign, and (3) the time variation of the NTD during each campaign. We applied this method to actual data to fix the array geometry more precisely. Also, we have made a first step in detecting vertical motions as well as horizontal motions, though further enhancement of the accuracy will be required. In performing linear regression of array displacements obtained from the inversion, their error covariance has a significant effect on the resulting velocities. When the covariance is taken into account, nearly the same velocities are obtained no matter what campaign is taken as reference in the inversion.
Impact of In‐Cloud Aqueous Processes on the Chemistry and Transport of Biogenic Volatile Organic Compounds
Authors: Li Yang , Barth Mary C. , Patton Edward G. , Steiner Allison L.
Published: October 2017

We investigate the impacts of cloud aqueous processes on the chemistry and transport of biogenic volatile organic compounds (BVOC) using the National Center for Atmospheric Research's large‐eddy simulation code with an updated chemical mechanism that includes both gas‐ and aqueous‐phase reactions. We simulate transport and chemistry for a meteorological case with a diurnal pattern of nonprecipitating cumulus clouds from the Baltimore‐Washington area DISCOVER‐AQ campaign. We evaluate two scenarios with and without aqueous‐phase chemical reactions. In the cloud layer (2–3 km), the addition of aqueous phase reactions decreases HCHO by 18% over the domain due to its solubility and the fast depletion from aqueous reactions, resulting in a corresponding decrease in radical oxidants (e.g., 18% decrease in OH). The decrease of OH increases the mixing ratios of isoprene and methacrolein (MACR) (100% and 15%, respectively) in the cloud layer because the reaction rate is lower. Aqueous‐phase reactions can modify the segregation between OH and BVOC by changing the sign of the segregation intensity, causing up to 55% reduction in the isoprene‐OH reaction rate and 40% reduction for the MACR‐OH reaction when clouds are present. Analysis of the isoprene‐OH covariance budget shows the chemistry term is the primary driver of the strong segregation in clouds, triggered by the decrease in OH. All organic acids except acetic acid are formed only through aqueous‐phase reactions. For acids formed in the aqueous phase, turbulence mixes these compounds on short time scales, with the near‐surface mixing ratios of these acids reaching 20% of the mixing ratios in the cloud layer within 1 h of cloud formation.
Does Strong Tropospheric Forcing Cause Large‐Amplitude Mesospheric Gravity Waves? A DEEPWAVE Case Study
Authors: Bramberger Martina , Dörnbrack Andreas , Bossert Katrina , Ehard Benedikt , Fritts David C. , Kaifler Bernd , Mallaun Christian , Orr Andrew , Pautet P.‐Dominique , Rapp Markus , Taylor Michael J. , Vosper Simon , Williams Bifford P. , Witschas Benjamin
Published: October 2017

On 4 July 2014, during the Deep Propagating Gravity Wave Experiment (DEEPWAVE), strong low‐level horizontal winds of up to 35 m s−1 over the Southern Alps, New Zealand, caused the excitation of gravity waves having the largest vertical energy fluxes of the whole campaign (38 W m−2). At the same time, large‐amplitude mesospheric gravity waves were detected by the Temperature Lidar for Middle Atmospheric Research (TELMA) located at Lauder (45.0°S, 169.7°E), New Zealand. The coincidence of these two events leads to the question of whether the mesospheric gravity waves were generated by the strong tropospheric forcing. To answer this, an extensive data set is analyzed, comprising TELMA, in situ aircraft measurements, radiosondes, wind lidar measurements aboard the DLR Falcon as well as Rayleigh lidar and advanced mesospheric temperature mapper measurements aboard the National Science Foundation/National Center for Atmospheric Research Gulfstream V. These measurements are further complemented by limited area simulations using a numerical weather prediction model. This unique data set confirms that strong tropospheric forcing can cause large‐amplitude gravity waves in the mesosphere, and that three essential ingredients are required to achieve this: first, nearly linear propagation across the tropopause; second, leakage through the stratospheric wind minimum; and third, amplification in the polar night jet. Stationary gravity waves were detected in all atmospheric layers up to the mesosphere with horizontal wavelengths between 20 and 100 km. The complete coverage of our data set from troposphere to mesosphere proved to be valuable to identify the processes involved in deep gravity wave propagation.
Verification of Space Weather Forecasts Issued by the Met Office Space Weather Operations Centre
Authors: Sharpe M. A. , Murray S. A.
Published: October 2017

The Met Office Space Weather Operations Centre was founded in 2014 and part of its remit is a daily Space Weather Technical Forecast to help the UK build resilience to space weather impacts; guidance includes 4 day geomagnetic storm forecasts (GMSF) and X‐ray flare forecasts (XRFF). It is crucial for forecasters, users, modelers, and stakeholders to understand the strengths and weaknesses of these forecasts; therefore, it is important to verify against the most reliable truth data source available. The present study contains verification results for XRFFs using Geo‐Orbiting Earth Satellite 15 satellite data and GMSF using planetary K‐index (Kp) values from the GFZ Helmholtz Centre. To assess the value of the verification results, it is helpful to compare them against a reference forecast and the frequency of occurrence during a rolling prediction period is used for this purpose. An analysis of the rolling 12 month performance over a 19 month period suggests that both the XRFF and GMSF struggle to provide a better prediction than the reference. However, a relative operating characteristic and reliability analysis of the full 19 month period reveals that although the GMSF and XRFF possess discriminatory skill, events tend to be overforecast.
Refractive‐Light‐Transmission Technique Applied to Density‐Driven Convective Mixing in Porous Media With Implications for Geological CO2 Storage
Authors: Rasmusson M. , Fagerlund F. , Rasmusson K. , Tsang Y. , Niemi A.
Published: October 2017

Density‐driven convection has been identified to accelerate the rate of CO2 solubility trapping during geological CO2 storage in deep saline aquifers. In this paper, we present an experimental method using the refractive properties of fluids (their impact on light transmission), and an analogous system design, which enables the study of transport mechanisms in saturated porous media. The method is used to investigate solutally induced density‐driven convective mixing under conditions relevant to geological CO2 storage. The analogous system design allows us by choice of initial solute concentration and bead size to duplicate a wide range of conditions (
‐values), making it possible to study the convective process in general, and as a laboratory analogue for systems found in the field. We show that the method accurately determines the solute concentration in the system with high spatial and temporal resolution. The onset time of convection (
), mass flux (
), and flow dynamics are quantified and compared with experimental and numerical findings in the literature. Our data yield a scaling law for
which gives new insight into its dependence on
, indicating
to be more sensitive to large
than previously thought. Furthermore, our data show and explain why
is described equally well by a
‐dependent or a
‐independent scaling law. These findings improve the understanding of the physical process of convective mixing in saturated porous media in general and help to assess the CO2 solubility trapping rate under certain field conditions.
Evaporation From Soil Containers With Irregular Shapes
Authors: Assouline Shmuel , Narkis Kfir
Published: October 2017

Evaporation from bare soils under laboratory conditions is generally studied using containers of regular shapes where the vertical edges are parallel to the flow lines in the drying domain. The main objective of this study was to investigate the impact of irregular container shapes, for which the flow lines either converge or diverge toward the surface. Evaporation from initially saturated sand and sandy loam soils packed in cones and inverted cones was compared to evaporation from corresponding cylindrical columns. The initial evaporation rate was higher in the cones, and close to potential evaporation. At the end of the experiment, the cumulative evaporation depth in the sand cone was equal to that in the column but higher than in the inverted cone, while in the sandy loam, the order was cone > column > inverted cone. By comparison to the column, stage 1 evaporation was longer in the cones, and practically similar in the inverted cones. Stage 2 evaporation rate decreased with the increase of the evaporating surface area. These results were more pronounced in the sandy loam. For the sand column, the transition between stage 1 and stage 2 evaporation occurred when the depth of the saturation front was approximately equal to the characteristic length of the soil. However, for the cone and the inverted cone, it occurred for a shallower depth of the saturation front. It seems therefore that the concept of the characteristic length derived from the soil hydraulic properties is related to drying systems of regular shapes.
Statistical Formulation of Generalized Tracer Retention in Fractured Rock
Authors: Cvetkovic Vladimir
Published: October 2017

We study tracer retention in fractured rock by combing Lagrangian and time domain random walk frameworks, as well as a statistical representation of the retention process. Mass transfer is quantified by the retention time distribution that follows from a Lagrangian coupling between advective transport and mass exchange processes, applicable for advection‐dominated transport. A unifying parametrization is presented for generalized diffusion using two rates denoted byk1andk2wherek1is a forward rate andk2a reverse rate, plus an exponent as an additional parameter. For the Fickian diffusion model,k1andk2are related to measurable retention properties of the fracture‐matrix by the method of moments, whereas for the non‐Fickian case dimensional analysis is used. The derived retention time distributions are exemplified for interpreting tracer tests as well as for predictive modeling of expected tracer breakthrough. We show that non‐Fickian effects can be notable when transport is upscaled based on a non‐Fickian interpretation of a tracer test for which deviations from Fickianity are relatively small. The statistical representation of retention clearly shows the significance of the forward ratek1which depends on the active specific surface area and is the most difficult parameter to characterize in the field.