bluuebunny/crossref_metadata_2025 huggingface dataset:
A Functional Return-to-Play Progression After Exertional Heat Stroke in a High School Football Player
Authors: Lopez Rebecca M. , Tanner Patrick , Irani Sarah , Mularoni P. Patrick
Published: January 2018

Objective: 

To present a functional return-to-play (RTP) progression after exertional heat stroke (EHS) in a 17-year-old high school football defensive end (height = 185 cm, mass = 145.5 kg).

Background: 

The patient had no pertinent medical history but moved to a warm climate several days before the EHS occurred. After completing an off-season conditioning test (14- × 110-yd [12.6- × 99.0-m] sprints) on a warm afternoon (temperature = approximately 34°C [93°F], relative humidity = 53%), the patient collapsed. An athletic trainer (AT) was called to the field, where he found the patient conscious but exhibiting central nervous system dysfunction. Emergency medical services were summoned and immediately transported the patient to the hospital.

Differential Diagnosis: 

Exertional heat stroke, heat exhaustion, exertional sickling, rhabdomyolysis, and cardiac arrhythmia.

Treatment: 

The patient was immediately transported to a hospital, where his oral temperature was 39.6°C (103.3°F). He was transferred to a children's hospital and treated for rhabdomyolysis, transaminitis, and renal failure. He was hospitalized for 11 days. After a physician's clearance once the laboratory results normalized, an RTP progression was completed. The protocol began with light activity and progressed over 3 weeks to full football practice. During activity, an AT monitored the patient's gastrointestinal temperature, heart rate, rating of perceived exertion, fluid consumption, and sweat losses.

Uniqueness: 

Documentation of RTP guidelines for young athletes is lacking. We used a protocol intended for the football setting to ensure the athlete was heat tolerant, had adequate physical fitness, and could safely RTP. Despite his EHS, he recovered fully, with no lasting effects, and successfully returned to compete in the final 5 games of the season.

Conclusions: 

Using a gradual RTP progression and close monitoring, a high school defensive end successfully returned to football practice and games after EHS. This case demonstrates the feasibility of implementing a safe RTP protocol after EHS and may serve as a guide to ATs working in the high school setting. This case also highlights the need for more research in this area.
Comparison of Compressive Myofascial Release and the Graston Technique for Improving Ankle-Dorsiflexion Range of Motion
Authors: Stanek Justin , Sullivan Taylor , Davis Samantha
Published: January 2018

Context: 

Restricted dorsiflexion (DF) at the ankle joint can cause acute and chronic injuries at the ankle and knee. Myofascial release and instrument-assisted soft tissue mobilization (IASTM) techniques have been used to increase range of motion (ROM); however, evidence directly comparing their effectiveness is limited.

Objective: 

To compare the effects of a single session of compressive myofascial release (CMR) or IASTM using the Graston Technique (GT) on closed chain ankle-DF ROM.

Design: 

Randomized controlled trial.

Setting: 

Laboratory.

Patients or Other Participants: 

Participants were 44 physically active people (53 limbs) with less than 30° of DF.

Intervention(s): 

Limbs were randomly assigned to 1 of 3 groups: control, CMR, or GT. Both treatment groups received one 5-minute treatment that included scanning the area and treating specific restrictions. The control group sat for 5 minutes before measurements were retaken.

Main Outcome Measure(s): 

Standing and kneeling ankle DF were measured before and immediately after treatment. Change scores were calculated for both positions, and two 1-way analyses of variance were conducted.

Results: 

A difference between groups was found in the standing (F2,52 = 13.78, P = .001) and kneeling (F2,52 = 5.85, P = .01) positions. Post hoc testing showed DF improvements in the standing position after CMR compared with the GT and control groups (both P = .001). In the kneeling position, DF improved after CMR compared with the control group (P = .005).

Conclusions

Compressive myofascial release increased ankle DF after a single treatment in participants with DF ROM deficits. Clinicians should consider adding CMR as a treatment intervention for patients with DF deficits.
Linear Acceleration in Direct Head Contact Across Impact Type, Player Position, and Playing Scenario in Collegiate Women's Soccer Players
Authors: Lamond Lindsey C. , Caccese Jaclyn B. , Buckley Thomas A. , Glutting Joseph , Kaminski Thomas W.
Published: January 2018

Context: 

Heading, an integral component of soccer, exposes athletes to a large number of head impacts over a career. The literature has begun to indicate that cumulative exposure may lead to long-term functional and psychological deficits. Quantifying an athlete's exposure over a season is a first step in understanding cumulative exposure.

Objective: 

To measure the frequency and magnitude of direct head impacts in collegiate women's soccer players across impact type, player position, and game or practice scenario.

Design: 

Cross-sectional study.

Setting: 

National Collegiate Athletic Association Division I institution.

Patients or Other Participants: 

Twenty-three collegiate women's soccer athletes.

Main Outcome Measure(s): 

Athletes wore Smart Impact Monitor accelerometers during all games and practices. Impacts were classified during visual, on-field monitoring of athletic events. All direct head impacts that exceeded the 10g threshold were included in the final data analysis. The dependent variable was linear acceleration, and the fixed effects were (1) type of impact: clear, pass, shot, unintentional deflection, or head-to-head contact; (2) field position: goalkeeper, defense, forward, or midfielder; (3) playing scenario: game or practice.

Results: 

Shots (32.94g ± 12.91g, n = 38; P = .02) and clears (31.09g ± 13.43g, n = 101; P = .008) resulted in higher mean linear accelerations than passes (26.11g ± 15.48g, n = 451). Head-to-head impacts (51.26g ± 36.61g, n = 13; P < .001) and unintentional deflections (37.40g ± 34.41g, n = 24; P = .002) resulted in higher mean linear accelerations than purposeful headers (ie, shots, clears, and passes). No differences were seen in linear acceleration across player position or playing scenario.

Conclusions: 

Nonheader impacts, including head-to-head impacts and unintentional deflections, resulted in higher mean linear accelerations than purposeful headers, including shots, clears, and passes, but occurred infrequently on the field. Therefore, these unanticipated impacts may not add substantially to an athlete's cumulative exposure, which is a function of both frequency and magnitude of impact.
A review of visual impairment
Authors: Naipal Shivani , Rampersad Nishanee
Published: January 2018

Visual impairment (VI), a global concern that is likely to escalate with prolonged life expectancies, has gained increasing attention in the realm of eye care. The purpose of this article is to highlight the different aspects of VI, including its definition and characteristics, prevalence, causes and implications. The importance of rehabilitation in individuals with VI is also discussed.
Gender effects on phonological processing and reading development in Northern Sotho children learning to read in English: A case study of Grade 3 learners
Authors: Wilsenach Carien , Makaure Patricia
Published: January 2018

Gender differences in reading development are a global phenomenon, with girls typically performing better than boys. Some studies have reported gender differences favouring girls in reading comprehension in South Africa, but little systematic evidence exists about gender differences in the cognitive-linguistic abilities that underlie reading development. This study investigated the effect of gender on phonological processing and reading development in Northern Sotho–English bilingual children. Grade 3 learners who received their literacy instruction in English were tested on various phonological processing and reading measures. Phonological awareness was assessed using phoneme isolation and elision tasks. Phonological working memory was assessed using memory for digits and non-word repetition tests while rapid automatised naming was tested using rapid letter, rapid digit, rapid object and rapid colour naming tasks. Reading achievement was assessed with various word reading tasks and with a fluent reading task. A multivariate analysis of variance revealed that gender had a significant effect on the phonological processing and reading abilities of Northern Sotho– English bilingual children. Girls performed significantly better than boys on all the reading measures, as well as on some aspects of phonological processing. The findings provide behavioural evidence in support of biological theories of gender differences, in that girls seemed to have developed some of the cognitive-linguistic skills associated with reading before boys. The girls also coped better with tasks that required increased cognitive processing. This study suggests that sex differences in reading development cannot be ignored in South Africa and need to be addressed in future curriculum development.
Risky sexual behaviour and human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS) among healthcare workers
Authors: Khamisa Natasha , Mokgobi Maboe
Published: January 2018

Background: South Africa is known to have one of the highest prevalence rates of human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS) globally, with one in seven healthcare workers being HIV-positive. An HIV-positive healthcare workforce is less equipped to respond to the increasing spread of the epidemic.Objectives: Assessment of the factors contributing to high HIV prevalence rates among healthcare workers is important in planning the development of human resources. This review sought to identify and understand predominant risky sexual behaviours among healthcare workers in HIV and AIDS-affected countries.Methods: This study reviewed articles focusing on sexual behaviour among healthcare workers. Major health science databases (e.g. ProQuest, Cochrane, PubMed and CINAHL) were searched for combinations of keywords including ‘healthcare workers’, ‘risky sexual behaviour’ and ‘HIV and AIDS’. Articles from a range of countries met inclusion and exclusion criteria.Results: Findings of the study revealed three main contributing factors: unprotected sex, multiple sex partners and sexual violence. Sexual violence emerged as the dominant risk factor in the majority of the studies. Most research was conducted in developed countries where the HIV infection rate is much lower than it is in developing countries.Conclusion: More research needs to be conducted in developing countries and appropriate strategies should be implemented to reduce sexual violence among healthcare workers. Appropriate procedures on reporting sexual violence coupled with education on HIV and AIDS as well as influencing attitudes and belief systems could assist in reducing the spread of HIV and AIDS within the healthcare workforce while minimising the effect on patient care.
EL papel de la prosodia en la expresión de la ironía en español
Authors: Pihler Ciglič Barbara
Published: January 2018

Cuando la ironía verbal, fenómeno intrínsecamente polifónico, forma parte de un discurso oral, a menudo va acompañada de una entonación, de un tono y de un acento particulares (Ruiz Gurillo 2009, Becerra Valderrama 2011). Por lo tanto, la prosodia llega a formar parte significativa de la información paralingüística en una conversación real (Poyatos 1994, Couper-Kuhlen 2000), desempeñando no pocas veces el papel decisivo para el reconocimiento y la correcta interpretación de la ironía verbal por parte del interlocutor. En español hay pocos patrones sintácticos que posibiliten el enunciado irónico (p. ej. la anteposición del adjetivo según Haverkate 1985), de ahí que el papel de la entonación, posiblemente el fenómeno lingüístico más influyente en la comunicación oral, merezca más atención, aunque su estudio no se ha considerado siempre prioritario.Este trabajo tiene como objetivo, primero, mostrar la relevancia pragmática de la prosodia en la producción de los enunciados irónicos y, segundo, observar los factores que determinan la entonación irónica en español, examinando su funcionamiento en ejemplos concretos del discurso oral. Para este objetivo se han comparado ejemplos de enunciados irónicos con no irónicos, especialmente grabados para esta ocasión y analizados con ayuda del programa informático Praat. La comparación, cuyo principal objetivo ha sido determinar el papel de la prosodia en el reconocimiento de la intención irónica sin o con el contexto situacional, se ha realizado a través de un experimento con treinta estudiantes de máster del departamento de lengua y literatura españolas de la Facultad de filosofía y letras de la Universidad de Ljubljana.
Investigating trainee translators’ views on the pronunciation of English: a Slovene perspective
Authors: Hirci Nataša
Published: January 2018

While the importance of excellent pronunciation skills for language professionals is indisputable, research attention has focused mainly on the pronunciation skills of teachers. Nevertheless translators, and even more so interpreters, who are constantly engaged in multi-lingual communication with their clients, face a tough competition in the global market and those with poor pronunciation skills are at a considerable disadvantage. Developing good pronunciation skills is thus an aspect that should not be neglected in the training of translators and interpreters, since it may directly affect their prospects of employment. The paper explores the views of Slovene trainee translators on the pronunciation of English. Their self-perception of English pronunciation skills and expectations concerning their pronunciation are examined by using a questionnaire administered to trainee translators at the University of Ljubljana. The questionnaire results provide an insight into the participants’ perceptions of their attained pronunciation proficiency and their attention to pronunciation instruction. The analysis of the replies reveals that trainee translators view pronunciation as an important element of their speaking proficiency, highlighting the issue of intelligibility as an essential component of communicative competence. The findings raise interesting issues important for pronunciation teaching in translator training, underlining the necessity to identify specific learner needs of future translators and interpreters.
Slovenščina v Beneški Sloveniji in vloga dvojezične šole v Špetru pri medgeneracijskem prenosu jezika: stališča staršev
Authors: Mezgec Maja
Published: January 2018

Članek predstavlja prvi izsek raziskovalnega dela pri ciljnem raziskovalnem projektu Priložnosti in možnosti za ohranjanje oziroma revitalizacijo slovenščine med slovensko manjšinsko skupnostjo v sosednjih državah, namenjenem preučevanju stanja slovenskega jezika v Beneški Sloveniji. V kontekstu globalizacijskih procesov, evropskih integracijskih procesov, ugodnejših in trdnejših zakonskih podlag (t. i. zaščitnega zakona) ter predvsem zaradi prisotnosti dvojezične šole lahko oblikujemo hipotezo, da v Beneški Sloveniji obstajajo ugodne okoliščine za jezikovno revitalizacijo in deasimilacijo mlajših generacij, kar vključuje tudi ponovno učenje slovenščine med generacijami, pri katerih je medgeneracijski prenos jezika zastal. Iz zbranih podatkov je mogoče izluščiti, da je v prejšnji generaciji medgeneracijski prenos jezika pogosto zastal z začetkom šolanja oz. vstopom v vrtec, ki je zaznamoval prehod na italijanski jezik. Tudi zato je dvojezično šolanje za Beneško Slovenijo pomemben dosežek, vendar samo po sebi še ni zadosten pogoj za ohranjanje ali oživitev medgeneracijskega prenosa jezika. Potrebni so še drugi ukrepi jezikovnega načrtovanja in jezikovne politike. Ob tem gre poudariti, da se ti procesi razvijajo v okolju, ki je bolj naklonjeno slovenščini in dvojezičnosti, kot je bilo v preteklosti.
Učenje slovenskega jezika ter stališča dijakov in staršev do slovenščine v Varaždinski in Medžimurski županiji na Hrvaškem
Authors: Medvešek Mojca
Published: January 2018

V zadnjih petih letih so se v Varaždinski in Medžimurski županiji uresničile nove možnosti učenja slovenskega jezika v šolah. V prispevku obravnavamo pravne možnosti urejanja položaja slovenščine na Hrvaškem, uresničevanje možnosti učenja slovenščine v Varaždinski in Medžimurski županiji v praksi ter izsledke raziskav, opravljenih med dijaki dveh srednjih šol in njihovimi starši o učenju slovenskega jezika. Izsledki raziskav so med drugim pokazali, da imajo dijaki in starši do učenja slovenskega jezika pozitiven odnos. Znanje slovenščine jim pomeni zlasti večje možnosti za izobraževanje oziroma zaposlitev v Sloveniji. Pokazalo pa se je tudi, da je med učenci slovenskega jezika malo pripadnikov slovenske manjšine.
Stališča staršev v Porabju do slovenskega jezika
Authors: Munda Hirnök Katalin
Published: January 2018

Prispevek je nastal na podlagi analize kvantitativne raziskave z naslovom Stališča staršev v Porabju do slovenskega jezika oziroma dvo- in večjezičnosti ter tudi preteklih raziskav, strokovne literature in terenskih izkušenj. Študija prikazuje stališča porabskih Slovencev (staršev otrok, ki obiskujejo narodnostne vrtce) do slovenskega jezika (in drugih jezikov) in na drugi strani išče odgovore na vprašanje, zakaj je prišlo do prekinitve prenosa slovenske materinščine na anketirane – starše in posledično na najmlajše. Podatki kažejo, da si stališča in raba jezika v družini ter rezultati pri vprašanju, zakaj se vprašanim staršem zdi znanje slovenskega jezika pomembno za otroka, nasprotujejo. Med odgovori na vprašanje, zakaj se starši z otroki doma ne pogovarjajo porabsko/slovensko, izstopa mnenje, da starši in mladi ne znajo jezika in da ni medgeneracijskega prenosa. Pozitivna stališča staršev do slovenskega jezika so lahko dobra podlaga za revitalizacijo porabščine/slovenskega jezika v Porabju.
Teoretska izhodišča in metodološki okvir pri izdelavi uporabnikom prijaznega spletišča: primer platforme SMeJse – Slovenščina kot manjšinski jezik
Authors: Grgič Matejka
Published: January 2018

V prispevku predstavljam teoretska in metodološka izhodišča za izdelavo portala SMeJse (Slovenščina kot manjšinski jezik), ob tem pa se obsežneje zaustavljam ob analizi položaja, stanja in statusa slovenskega jezika v Italiji, nekaterih specifičnih jezikovnih pojavih, metodoloških izzivih in socioloških okvirih.Pojmi, kot so zvrstnost jezika, norma, prvi/materni oz. tuji jezik, manjšina, diglosija in številni drugi izgubljajo namreč pomen, ki so ga imeli v epistemologijah 20. stoletja, in pridobivajo nove konotacije. Do teh ključnih premikov pri obravnavi jezikovnih pojavov in načrtovanju jezikovnih politik prihaja zaradi novih družbenih kontekstov ob prehodu iz 20. v 21. stoletje. Na percepcije in reprezentacije jezika, ki močno pogojujejo njegovo usvajanje, rabo in tudi uradni položaj – pa tudi znanstveno obravnavo – namreč vplivajo nekateri »zunanji« dejavniki. Med temi gre izpostaviti razvoj in dostopnost novih tehnologij, evropsko politiko na področju manjšinskih jezikov in večjezičnosti nasploh, ekonomsko krizo in njene posledice ter migracijske tokove. Pojmovanje »manjšine« in »manjšinskosti« je tudi na področju jezika in jezikoslovja dobilo nove in drugačne razsežnosti.Na podlagi teh ugotovitev sta Slovenski raziskovalni inštitut (SLORI) in Dijaški dom S. Kosovela v Trstu izdelala spletno platformo SMeJse (www.smejse.it) kot zbirališče novih in že obstoječih orodij, gradiv in informacij za razvoj jezikovnih veščin in spretnosti v slovenskem jeziku. Namen platforme je spodbujanje različnih rab živega slovenskega jezika na območju italijansko-slovenskega jezikovnega stikanja, predvsem v Italiji – s ciljem, da se zagotovi visoka sporazumevalna zmožnost v vseh zvrsteh in različicah slovenskega jezika, uravnotežena dvojezičnost in razvoj tudi lokalnih idiomov, a znotraj slovenskega jezikovnega kontinuuma.
A detailed characterization of the Saharan dust collected during the Fennec campaign in 2011: in situ ground-based and laboratory measurements
Authors: Rocha-Lima Adriana , Martins J. Vanderlei , Remer Lorraine A. , Todd Martin , Marsham John H. , Engelstaedter Sebastian , Ryder Claire L. , Cavazos-Guerra Carolina , Artaxo Paulo , Colarco Peter , Washington Richard
Published: January 2018

Abstract. Millions of tons of mineral dust are lifted by the wind from
arid surfaces and transported around the globe every year. The physical and
chemical properties of the mineral dust are needed to better constrain remote
sensing observations and are of fundamental importance for the understanding
of dust atmospheric processes. Ground-based in situ measurements and in situ
filter collection of Saharan dust were obtained during the Fennec campaign in
the central Sahara in 2011. This paper presents results of the absorption and
scattering coefficients, and hence single scattering albedo (SSA), of the
Saharan dust measured in real time during the last period of the campaign
and subsequent laboratory analysis of the dust samples collected in two
supersites, SS1 and SS2, in Algeria and in Mauritania, respectively. The
samples were taken to the laboratory, where their size and aspect ratio
distributions, mean chemical composition, spectral mass absorption
efficiency,
and spectral imaginary refractive index were obtained from the
ultraviolet (UV) to the near-infrared (NIR) wavelengths. At SS1 in Algeria,
the time series of the scattering coefficients during the period of the
campaign show dust events exceeding 3500 Mm−1, and a relatively high
mean SSA of 0.995 at 670 nm was observed at this site. The laboratory
results show for the fine particle size distributions (particles
diameter < 5µm and mode diameter at 2–3 µm) in both
sites a spectral dependence of the imaginary part of the refractive index
Im(m) with a bow-like shape, with increased absorption in UV as well as in the shortwave infrared. The same signature was not observed, however,
in the mixed particle size distribution (particle
diameter < 10 µm and mode diameter at 4 µm) in
Algeria. Im(m) was found to range from 0.011 to 0.001i for dust collected in
Algeria and 0.008 to 0.002i for dust collected in Mauritania over the
wavelength range of 350–2500 nm. Differences in the mean elemental
composition of the dust collected in the supersites in Algeria and in
Mauritania and between fine and mixed particle size distributions were
observed from EDXRF measurements, although those differences cannot be used
to explain the optical properties variability between the samples. Finally,
particles with low-density typically larger than 10 µm in diameter
were found in some of the samples collected at the supersite in Mauritania,
but these low-density particles were not observed in Algeria.
Impact of aerosols on ice crystal size
Authors: Zhao Bin , Liou Kuo-Nan , Gu Yu , Jiang Jonathan H. , Li Qinbin , Fu Rong , Huang Lei , Liu Xiaohong , Shi Xiangjun , Su Hui , He Cenlin
Published: January 2018

Abstract. The interactions between aerosols and ice clouds represent one of the largest
uncertainties in global radiative forcing from pre-industrial time to the
present. In particular, the impact of aerosols on ice crystal effective
radius (Rei), which is a key parameter determining ice clouds'
net radiative effect, is highly uncertain due to limited and conflicting
observational evidence. Here we investigate the effects of aerosols on
Rei under different meteorological conditions using 9-year
satellite observations. We find that the responses of Rei to
aerosol loadings are modulated by water vapor amount in conjunction with
several other meteorological parameters. While there is a significant
negative correlation between Rei and aerosol loading in moist
conditions, consistent with the “Twomey effect” for liquid clouds, a strong
positive correlation between the two occurs in dry conditions. Simulations
based on a cloud parcel model suggest that water vapor modulates the relative
importance of different ice nucleation modes, leading to the opposite aerosol
impacts between moist and dry conditions. When ice clouds are decomposed into
those generated from deep convection and formed in situ, the water vapor
modulation remains in effect for both ice cloud types, although the
sensitivities of Rei to aerosols differ noticeably between them
due to distinct formation mechanisms. The water vapor modulation can largely
explain the difference in the responses of Rei to aerosol
loadings in various seasons. A proper representation of the water vapor
modulation is essential for an accurate estimate of aerosol–cloud radiative
forcing produced by ice clouds.
Climate impact of idealized winter polar mesospheric and stratospheric ozone losses as caused by energetic particle precipitation
Authors: Meraner Katharina , Schmidt Hauke
Published: January 2018

Abstract. Energetic particles enter the polar atmosphere and
enhance the production of nitrogen oxides and hydrogen oxides in the winter
stratosphere and mesosphere. Both components are powerful ozone destroyers.
Recently, it has been inferred from observations that the direct effect of
energetic particle precipitation (EPP) causes significant long-term
mesospheric ozone variability. Satellites observe a decrease in mesospheric
ozone up to 34 % between EPP maximum and EPP minimum. Stratospheric ozone
decreases due to the indirect effect of EPP by about 10–15 % observed by
satellite instruments. Here, we analyze the climate impact of winter boreal
idealized polar mesospheric and polar stratospheric ozone losses as caused by
EPP in the coupled Max
Planck Institute Earth System Model (MPI-ESM). Using radiative transfer
modeling, we find that the radiative forcing of mesospheric ozone loss during
polar night is small. Hence, climate effects of mesospheric ozone loss due to
energetic particles seem unlikely. Stratospheric ozone loss due to energetic
particles warms the winter polar stratosphere and subsequently weakens the
polar vortex. However, those changes are small, and few statistically
significant changes in surface climate are found.
A 3-D evaluation of the MACC reanalysis dust product over Europe, Northern Africa and Middle East using CALIOP/CALIPSO dust satellite observations
Authors: Georgoulias Aristeidis K. , Tsikerdekis Athanasios , Amiridis Vassilis , Marinou Eleni , Benedetti Angela , Zanis Prodromos , Alexandri Georgia , Kourtidis Konstantinos A. , Lelieveld Jos
Published: January 2018

Abstract. The MACC reanalysis dust product is evaluated over Europe, Northern Africa and Middle East using the EARLINET-optimized CALIOP/CALIPSO pure dust satellite-based product LIVAS (2007–2012). MACC dust optical depth at 550 nm (DOD550) data are compared against LIVAS DOD532 observations. As only natural aerosol (dust and sea salt) profiles are available in MACC, here we focus on layers above 1 km a.s.l. to diminish the influence of sea salt particles that typically reside at low heights. So, MACC natural aerosol extinction coefficient profiles at 550 nm are compared against dust extinction coefficient profiles at 532 nm from LIVAS assuming that the MACC natural aerosol profile data can be similar to the dust profile data, especially over pure continental regions. It is shown that the reanalysis data are capable of capturing the major dust hot spots in the area as the MACC DOD550 patterns are close to the LIVAS DOD532 patterns throughout the year. MACC overestimates DOD for regions with low dust loadings and underestimates DOD for regions with high dust loadings where DOD exceeds ~ 0.3. The mean bias between the MACC and LIVAS DOD is 0.025 (~ 25 %) over the whole domain. Both MACC and LIVAS capture the summer and spring high dust loadings, especially over Northern Africa and Middle East, and exhibit similar monthly structures despite the biases. In this study, dust extinction coefficient patterns are reported at four layers (layer 1: 1200–3000 m a.s.l., layer 2: 3000–4800 m a.s.l., layer 3: 4800–6600 m a.s.l. and layer 4: 6600–8400 m a.s.l.). The MACC and LIVAS extinction coefficient patterns are similar over areas characterized by high dust loadings for the first 3 layers. Within layer 4, MACC overestimates extinction coefficients consistently throughout the year over the whole domain. MACC overestimates extinction coefficients compared to LIVAS over regions away from the major dust sources while over regions close to the dust sources (Sahara and Middle East) underestimates strongly only for heights below ~ 3–5 km a.s.l. depending on the period of the year. In general, it is shown that dust loadings appear over remote regions and at heights up to 9 km a.s.l. in MACC contrary to LIVAS. This could be due to the model performance and parameterizations of emissions and other processes, due to the assimilation of satellite aerosol measurements over dark surfaces only or due to a possible enhancement of aerosols by the MACC assimilation system.
Amplification of light absorption of black carbon associated with air pollution
Authors: Zhang Yuxuan , Zhang Qiang , Cheng Yafang , Su Hang , Li Haiyan , Li Meng , Zhang Xin , Ding Aijun , He Kebin
Published: January 2018

Abstract. The impacts of black carbon (BC) aerosols on air quality, boundary layer dynamic and climate depend not only on the BC mass concentration but also on the light absorption capability of BC. It well known that the light absorption capability of BC depends on the amount of coating materials (namely other species on BC by condensation and coagulation). However, the difference of light absorption capability of ambient BC-containing particles under different air pollution conditions (e.g., the air clean and polluted conditions) remains unclear due to the complex aging process of BC in the atmosphere. In this work, we investigated the evolution of light absorption capability for BC-containing particles with changing pollution levels in urban Beijing, China. During the campaign period (17 to 30 November 2014), with the growth of PM1 concentration from ~ 10 μg m−3 to ~ 230 μg m−3, we found that the aging degree and light absorption capability of BC-containing particles with refractory BC cores of ~ 75–200 nm increased by 26–73 % and 13–44 % respectively, indicating stronger light absorption capability of BC-containing particles under more polluted conditions due to more coating materials on the BC surface. By using effective emission intensity (EEI) model, we further found that aging during the regional transport plays an important role in the difference among the light absorption capability of BC-containing particles under different air pollution levels. During the pollution episode, ~ 63 % of the BC over Beijing originated from regional sources outside of Beijing. These regionally sourced BC-containing particles were characterized by more coating materials on BC surface due to accelerated aging process within more polluted air, which contributed ~ 78 % of the increase in light absorption capability of BC observed in Beijing during the polluted period (PM1 of ~ 230 μg m−3) comparing to that in the clean period (PM1 of ~ 10 μg m−3). Due to the increase of light absorption capability of BC associated with air pollution, the direct radiative forcing of BC was estimated to be increased by ~ 20 % based on a simple radiation transfer model. Our work identified an amplification of light absorption and direct radiative forcing under more air polluted environment due to more coating pollutants on BC. The air pollution control measures may, on the other hand, break the amplification effect by reducing both emissions of BC and the coating materials and achieve co-benefits of both air quality and climate.
LISA: a lightweight stratospheric air sampler
Authors: Hooghiem Joram J. D. , de Vries Marcel , Been Henk A. , Heikkinen Pauli , Kivi Rigel , Chen Huilin
Published: January 2018

Abstract. We developed a new LIghtweight Stratospheric Air sampler (LISA). The LISA sampler is designed to collect four bag samples in the stratosphere during a balloon flight for CO2, CH4 and CO mole fraction measurements. It consists of 4 Multi-Layer Foil (MLF) sampling bags, a custom-made manifold, and a diaphragm pump, with a total weight of ~ 2.5 kg. A series of laboratory storage tests were performed to assess the stability of CO2, CH4, CO and H2O mole fractions in both MLF and Tedlar bags. The MLF bag was chosen due to its better overall performance than the Tedlar bag for the four species CO2, CH4, CO and H2O. Furthermore, we evaluated the performance of the pump under low-pressure conditions to optimise a trade-off between the vertical resolution and the sample size. The LISA sampler was flown on the same balloon flight with an AirCore in Sodankylä, Finland (67.368° N, 26.633° E, 179 m a.s.l.) on 26 April and 4–7 September, 2017. A total of 15 stratospheric air samples were obtained during the ascent of four flights. The sample size ranges between 800 to 180 mL for the altitude between 12 and 25 km, with the corresponding vertical resolution ranging from 0.5 to 1.5 km. The collected air samples were analysed for CO2, CH4 and CO mole fractions, and evaluated against AirCore retrieved profiles, showing mean differences of 0.84 ppm for CO2, 1.8 ppb for CH4 and 6.3 ppb for CO, respectively. High-accuracy stratospheric measurements of greenhouse gas mole fractions are useful to validate remote sensing measurements from ground and from space, which has been primarily performed by comparison with collocated aircraft measurements (0.15–13 km), and more recently with AirCore observations (0–30 km). While AirCore is capable of achieving high-accuracy greenhouse gas mole fraction measurements, it is challenging to obtain accurate altitude registration for AirCore measurements. The LISA sampler provides a viable low-cost tool for retrieving stratospheric air samples for greenhouse gas measurements that is complementary to AirCore. Furthermore, The LISA sampler is advantageous in both the vertical resolution and the sample size to perform routine stratospheric measurements of isotopic compositions of trace gases.
Holocene climate aridification trend and human impact interrupted by millennial- and centennial-scale climate fluctuations from a new sedimentary record from Padul (Sierra Nevada, southern Iberian Peninsula)
Authors: Ramos-Román María J. , Jiménez-Moreno Gonzalo , Camuera Jon , García-Alix Antonio , Anderson R. Scott , Jiménez-Espejo Francisco J. , Carrión José S.
Published: January 2018

Abstract. Holocene centennial-scale paleoenvironmental variability has been described in a multiproxy analysis (i.e., lithology, geochemistry, macrofossil, and microfossil analyses) of a paleoecological record from the Padul Basin in Sierra Nevada, southern Iberian Peninsula. This sequence covers a relevant time interval hitherto unreported in the studies of the Padul sedimentary sequence. The  ∼  4700-year record has preserved proxies of climate variability, with vegetation, lake levels, and sedimentological change during the Holocene in one of the most unique and southernmost wetlands in Europe. The progressive middle and late Holocene trend toward arid conditions identified by numerous authors in the western Mediterranean region, mostly related to a decrease in summer insolation, is also documented in this record; here it is also superimposed by centennial-scale variability in humidity. In turn, this record shows centennial-scale climate oscillations in temperature that correlate with well-known climatic events during the late Holocene in the western Mediterranean region, synchronous with variability in solar and atmospheric dynamics. The multiproxy Padul record first shows a transition from a relatively humid middle Holocene in the western Mediterranean region to more aridity from  ∼  4700 to  ∼  2800 cal yr BP. A relatively warm and humid period occurred between  ∼  2600 and  ∼  1600 cal yr BP, coinciding with persistent negative North Atlantic Oscillation (NAO) conditions and the historic Iberian–Roman Humid Period. Enhanced arid conditions, co-occurring with overall positive NAO conditions and increasing solar activity, are observed between  ∼  1550 and  ∼  450 cal yr BP (∼  400 to  ∼  1400 CE) and colder and warmer conditions occurred during the Dark Ages and Medieval Climate Anomaly (MCA), respectively. Slightly wetter conditions took place during the end of the MCA and the first part of the Little Ice Age, which could be related to a change towards negative NAO conditions and minima in solar activity. Time series analysis performed from local (Botryococcus and total organic carbon) and regional (Mediterranean forest) signals helped us determining the relationship between southern Iberian climate evolution, atmospheric and oceanic dynamics, and solar activity. Our multiproxy record shows little evidence of human impact in the area until  ∼  1550 cal yr BP, when evidence of agriculture and livestock grazing occurs. Therefore, climate is the main forcing mechanism controlling environmental change in the area until relatively recently.
Global CO2 emissions from cement production
Authors: Andrew Robbie M.
Published: January 2018

Abstract. The global production of cement has grown very rapidly in recent years, and after fossil fuels and land-use change, it is the third-largest source of anthropogenic emissions of carbon dioxide. The required data for estimating emissions from global cement production are poor, and it has been recognised that some global estimates are significantly inflated. Here we assemble a large variety of available datasets and prioritise official data and emission factors, including estimates submitted to the UNFCCC plus new estimates for China and India, to present a new analysis of global process emissions from cement production. We show that global process emissions in 2016 were 1.45±0.20 Gt CO2, equivalent to about 4 % of emissions from fossil fuels. Cumulative emissions from 1928 to 2016 were 39.3±2.4 Gt CO2, 66 % of which have occurred since 1990. Emissions in 2015 were 30 % lower than those recently reported by the Global Carbon Project. The data associated with this article can be found at https://doi.org/10.5281/zenodo.831455.
Climate-driven disturbances in the San Juan River sub-basin of the Colorado River
Authors: Bennett Katrina E. , Bohn Theodore J. , Solander Kurt , McDowell Nathan G. , Xu Chonggang , Vivoni Enrique , Middleton Richard S.
Published: January 2018

Abstract. Accelerated climate change and associated forest disturbances in the
southwestern USA are anticipated to have substantial impacts on regional
water resources. Few studies have quantified the impact of both climate
change and land cover disturbances on water balances on the basin scale, and
none on the regional scale. In this work, we evaluate the impacts of forest
disturbances and climate change on a headwater basin to the Colorado River,
the San Juan River watershed, using a robustly calibrated (Nash–Sutcliffe efficiency
0.76) hydrologic model run with updated formulations that improve estimates
of evapotranspiration for semi-arid regions. Our results show that future
disturbances will have a substantial impact on streamflow with implications
for water resource management. Our findings are in contradiction with
conventional thinking that forest disturbances reduce evapotranspiration and increase
streamflow. In this study, annual average regional streamflow under the
coupled climate–disturbance scenarios is at least 6–11 % lower than
those scenarios accounting for climate change alone; for forested zones
of the San Juan River basin, streamflow is 15–21 % lower. The monthly
signals of altered streamflow point to an emergent streamflow pattern related
to changes in forests of the disturbed systems. Exacerbated reductions of
mean and low flows under disturbance scenarios indicate a high risk of low
water availability for forested headwater systems of the Colorado River
basin. These findings also indicate that explicit representation of land
cover disturbances is required in modeling efforts that consider the impact
of climate change on water resources.
Censored rainfall modelling for estimation of fine-scale extremes
Authors: Cross David , Onof Christian , Winter Hugo , Bernardara Pietro
Published: January 2018

Abstract. Reliable estimation of rainfall extremes is essential for drainage system design, flood mitigation, and risk quantification. However, traditional techniques lack physical realism and extrapolation can be highly uncertain. In this study, we improve the physical basis for short-duration extreme rainfall estimation by simulating the heavy portion of the rainfall record mechanistically using the Bartlett–Lewis rectangular pulse (BLRP) model. Mechanistic rainfall models have had a tendency to underestimate rainfall extremes at fine temporal scales. Despite this, the simple process representation of rectangular pulse models is appealing in the context of extreme rainfall estimation because it emulates the known phenomenology of rainfall generation. A censored approach to Bartlett–Lewis model calibration is proposed and performed for single-site rainfall from two gauges in the UK and Germany. Extreme rainfall estimation is performed for each gauge at the 5, 15, and 60 min resolutions, and considerations for censor selection discussed.
Passive acoustic measurement of bedload grain size distribution using self-generated noise
Authors: Petrut Teodor , Geay Thomas , Gervaise Cédric , Belleudy Philippe , Zanker Sebastien
Published: January 2018

Abstract. Monitoring sediment transport processes in rivers is of particular interest
to engineers and scientists to assess the stability of rivers and hydraulic
structures. Various methods for sediment transport process description were
proposed using conventional or surrogate measurement techniques. This paper
addresses the topic of the passive acoustic monitoring of bedload transport
in rivers and especially the estimation of the bedload grain size
distribution from self-generated noise. It discusses the feasibility of
linking the acoustic signal spectrum shape to bedload grain sizes involved in
elastic impacts with the river bed treated as a massive slab. Bedload grain
size distribution is estimated by a regularized algebraic inversion scheme
fed with the power spectrum density of river noise estimated from one
hydrophone. The inversion methodology relies upon a physical model that
predicts the acoustic field generated by the collision between rigid bodies.
Here we proposed an analytic model of the acoustic energy spectrum generated
by the impacts between a sphere and a slab. The proposed model computes the
power spectral density of bedload noise using a linear system of analytic
energy spectra weighted by the grain size distribution. The algebraic system
of equations is then solved by least square optimization and solution
regularization methods. The result of inversion leads directly to the
estimation of the bedload grain size distribution. The inversion method was
applied to real acoustic data from passive acoustics experiments realized on
the Isère River, in France. The inversion of in situ measured spectra
reveals good estimations of grain size distribution, fairly close to what was
estimated by physical sampling instruments. These results illustrate the
potential of the hydrophone technique to be used as a standalone method that
could ensure high spatial and temporal resolution measurements for sediment
transport in rivers.
A Study of Earthquake Recurrence based on a One-body Spring-slider Model in the Presence of Thermal-pressurized Slip-weakening Friction and Viscosity
Authors: Wang Jeen-Hwa
Published: January 2018

Abstract. Earthquake recurrence is studied from the temporal variation in slip through numerical simulations based on the normalized equation of motion of a one-body spring-slider model in the presence of thermal-pressurized slip-weakening friction and viscosity. The major model parameters are the normalized characteristic displacement, Uc, of the friction law and the normalized damping coefficient (to represent viscosity), η. Simulation results exhibit that both friction and viscosity remarkably affect slip of the slider. The recurrence time, TR, increases with η or with decreasing Uc. The final slip, D, and the duration time of slip, τD, of an event decrease with increasing η; while τD increases with Uc. The time-predictable and slip-predictable models can describe the temporal variation in cumulative slip. Considering the effect caused by wear process, the thickness of slip zone, h, depends on the cumulated slip, S(t) = ∑D(t): h(t) = CS(t) where C is a dimensionless constant. Uc is a function of h and thus influenced by C. In the computational time period, when C 0.0001 the wear process influences the slip recurrence and its effect increases with C. Neither the time-predictable model nor the slip-predictable model can describe the temporal variation in cumulative slip when the wear process with high C works.
Effect of Using PC Tablets on Perceived Learning Outcomes of Generation Z Trainees
Authors: Khan Iftikhar Ahmed , Bansal Vikram
Published: January 2018

This study aims at analyzing the effects of using PC Tabs on perceived learning outcomes of Generation Z trainees in a vocational training institute. Generation Z is the name given to youth born around mid 90s. Having born in and grown up in an era of internet and worldwide web, this generation has become accustomed to e-technology. Their learning preferences have also been conditioned by the e-environment. Resultantly, learning and development experts are focusing on designs and tools matching their learning preferences; adoption of e-learning using PC Tabs for teaching and training is one such step in this direction. This is a correlational study, adopting a mixed method approach, conducted in a Vocational Training Institute in UAE. Sampling frame comprised 100 trainees and their 20 instructors. Purposive sampling technique was used to select 50% instructors (N=10) who had experience of delivering training using PC Tabs. Random sampling technique was used to select 60% of the trainees (N=60). Data was gathered using informal discussions and a questionnaire. Cronbac’s Alpha for the questionnaire was 0.834. Data was analyzed using SPSS 16. A moderate positive correlation (Pearson’s r= 0.565; p < 0.01) was found between use of PC Tabs and better understanding of lecture. Regression analysis indicated that 30.8% of the variance in better understanding of lecture can be explained by use of PC Tabs by trainees. A moderate positive correlation (Pearson’s r= 0.515; p < 0.01), was found between use of PC Tabs and trainees’ perceived learning. Regression analysis indicated that 25.3% of the variance in trainees’ perceived learning can be explained by use of PC Tabs by trainees. This study concludes that use of PC Tabs have moderate positive effects on better understanding of lecture and trainees’ perceived learning outcomes, however, the Generation Z trainees are tilted more towards interactive learning rather than non-interactive content on PC Tabs. The study recommends that the curriculum must be tailored into an interactive format otherwise it may not accrue desired results in enhancing learning outcomes. This study contributes to the body of practical applied knowledge and has significance for training industry, in general, and vocational training, in specific, which are dealing with Generation Z trainees.