bluuebunny/crossref_metadata_2025 huggingface dataset:
Family factors mediate discrimination related stress and externalizing symptoms in rural Latino adolescents
Authors: Ponting Carolyn , Lee Steve S. , Escovar Emily L. , Rapp Amy M. , Camacho Alvaro , Calderon Ignacio , Chavira Denise A.
Published: September 2018

Introduction

Externalizing disorders are more prevalent in rural than urban settings and account for disproportionately high mental health service costs for rural adolescents. Although cultural stressors such as discrimination have been associated with externalizing problems in ethnic minority youth broadly, this relationship is understudied in Latinos, particularly those in rural settings. Further, though the associations of family processes such as familism and family conflict have been studied in relation to youth externalizing symptoms, whether these processes change in the face of adolescent discrimination stress remains unknown.

Methods

A moderated multiple mediation model was used to examine the association between perceived discrimination, externalizing symptoms, and the indirect effect of family factors (familism, and family conflict) in a large sample (n = 455) of rural Latino youth. We also evaluated whether indirect and direct effects of discrimination on externalizing symptoms differed in boys versus girls.

Results

Familism and family conflict each independently mediated the relationship between discrimination related stress and externalizing symptoms. However, discrimination had a direct effect on externalizing symptoms for boys only. In girls, this association held only when family factors were accounted for. Post‐hoc analyses reveal that the moderating effect of sex on discrimination is driven by differences in rule‐breaking behavior, as opposed to aggressive behavior.

Conclusion

Findings suggest that discrimination is associated with changes in the family environment which in turn invoke elevated risk for externalizing problems. Further, family‐focused interventions that address externalizing problems may be especially effective for adolescent girls.
Factors that influence the self-reported confidence of pediatric residents as team leaders during cardiopulmonary resuscitation
Authors: AlSohime Fahad , NurHussen Akram , Temsah Mohamad-Hani , Alabdulhafez Majed , Al-Eyadhy Ayman , Hasan Gamal M , Al-Huzaimi Abdullah , AlKanhal Abdulrahman , Almanie Deemah
Published: September 2018

Objective:

The leadership skills of pediatric residents during cardiopulmonary resuscitation (CPR) may have major impacts on their performance. These skills should be addressed during the pediatric residency training program. Therefore, we aimed to identify the perceptions of residents regarding their level of confidence in providing or leading a real pediatric CPR code, and to identify different factors that might influence their self-confidence when assuming the role of a team leader during a real CPR.

Design & setting:

Cross-sectional paper-based and online electronic surveys were conducted in February 2017, which included all Saudi pediatric residency program trainees.

Interventions:

A survey questionnaire was distributed to Saudi pediatric residency trainees throughout the Kingdom. The main aim was to assess their perceived level of confidence when running a real pediatric CPR code either as a team leader or as a team member.

Results:

The survey was distributed and sent by email to 1052 residents, where it was received by 640 and 231 responded (response rate = 36%). Almost one-fifth of the respondents (19.5%) did not have a valid pediatric advanced life support (PALS) certificate. The most frequently reported obstacles to life support training were lack of time (45.8%) and its financial cost (22.7%). The mean self-reported confidence as a CPR team member was reported significantly more frequently than being a CPR team leader (mean standard deviation, SD) = 7.8 (2.1) and 6.7 (2.4) respectively, P < .001). The self-reported confidence as a CPR team leader was reported significantly more frequently in males compared with female respondents (mean ± SD = 6.7 ± 2.4 and 5.9 ± 2.4, respectively; P < .013). There was a significant positive effect of recent attendance at a real CPR event on the perceived self-rated confidence of residents as a CPR team leader (P < .001). Residents who reported that they had often assumed a real CPR leadership role had significantly greater perceived self-confidence compared with those who assumed a member role (P < .05). Furthermore, residents without a valid PALS certificate had significantly less confidence in leading CPR teams than their peers who were recently certified (P< .05).

Conclusions:

The self-reported confidence as team leader during CPR was higher among residents who were certified in life support courses, exposed to CPR during their training, and those who assumed the role of a team leader during CPR. Our findings suggests the need to incorporate life support training courses and simulation-based mock code programs with an emphasis on the leadership in the curriculum of the pediatric residency training program.
Hepatitis C core antigen highly correlated to HCV RNA
Authors: Chang Christine , Hung Chao‐Hung , Wang Jing‐Houng , Lu Sheng‐Nan
Published: September 2018

Hepatitis C virus core antigen (HCV‐Ag) immunoassay has been proposed as a more cost and time efficient one‐step alternative to the current two‐step screening and diagnostic process. This study investigates the correlation between the HCV‐Ag immunoassay and the current gold standard of Hepatitis C Virus (HCV) ribonucleic acid (RNA) molecular assay. Stored sera of 221 consecutive treatment‐naive patients tested anti‐HCV positive were selected to undergo both HCV‐Ag immunoassay and HCV RNA molecular assay. Active infection status and HCV genotype were determined using both assays, and correlation was calculated using a logarithmic scale. Among 221 anti‐HCV‐positive sera, 197 were positive for both HCV Ag (≥3 fmol/L) and HCV RNA (>15 IU/mL), 22 were negative for both tests, while 2 were positive to HCV RNA only. The sensitivity and specificity for HCV Ag in predicting HCV RNA were 99% and 100%, respectively. Out of 199 patients (90%) tested positive for HCV viremia, 107 (56%) were of genotype 1, 77 (38.7%) of genotype 2 and 15 of other genotypes. Analysis of 221 anti‐HCV‐positive patient sera found a strong positive correlation between HCV RNA and HCV‐Ag (r = 0.960, p < 0.001). Genotype 1 (log [HCV RNA] = 0.988 x log [HCV‐Ag] + 2.768), with correlation coefficient 0.945, exhibited a stronger correlation than genotype 2 (log [HCV RNA] = 0.859 x log [HCV‐Ag] + 2.859; r = 0.862). Given the strong positive correlation between HCV‐Ag immunoassay and HCV RNA molecular assay in genotyping affected individuals, we propose that HCV‐Ag immunoassay is a more cost and time efficient alternative to the current two‐step diagnostic process.
Ultrasonographic Evaluation of the Femoral Cartilage, Achilles Tendon, and Plantar Fascia in Young Women Wearing High‐Heeled Shoes
Authors: Mezian Kamal , Ata Ayşe M. , Kara Murat , Şahin Onat Şule , Gürçay Eda , Çalışkan Aslı , Simoes Maria I.T. , Akıncı Ayşen , Özçakar Levent , Franchignoni Franco
Published: September 2018

Background

Specific attention on the musculoskeletal impact of wearing high‐heeled shoes (HHS) has mainly focused on knee osteoarthritis and the literature is limited to biomechanical changes. The distal femoral cartilage has not been morphologically studied. Additionally, although heel elevation is coupled with a shear stress at the heel and overloaded calf muscles, Achilles tendon (AT) and plantar fascia (PF) thicknesses have not been assessed either.

Objective

To investigate whether the distal femoral cartilage, AT, and PF were different in women wearing HHS and flat‐heeled shoes (FHS) and specifically, different in terms of AT/PF and distal femoral cartilage thicknesses.

Design

Cross‐sectional observational study.

Setting

Tertiary care center.

Participants

There were 34 women (mean age; 31.1 ± 6.4, body mass index [BMI]; 21.6 ± 2.4 kg/m2) in the HHS group and 54 women (mean age; 29.5 ± 7.2 years, BMI 22.5 ± 2.9 kg/m2) in the FHS group (P = .271, P = .102, respectively). Women wearing shoes with a heel height of >5 cm were enrolled in the HHS group, and those wearing shoes with a heel height of <1.4 cm were included in the FHS group.

Main Outcome Measurements

Distal femoral cartilage from the lateral condyle, intercondylar area and medial condyle (MFC), AT and PF thicknesses, and any abnormalities were evaluated bilaterally by ultrasound.

Results

Within‐group comparisons yielded thicker right MFC (P = .022) and left AT (P = .028) only in the HHS group. Between‐group comparisons yielded thicker left AT in the HHS group (P = .040). PF thicknesses were similar both within and between group comparisons (all P > .05). Right AT thickness was positively correlated with right (r = .469, P = .005) and left (r = .402, P = .018) PF thicknesses only within the HHS group. Only calcaneal irregularity/spur was found to be common in the HHS group (P = .038).

Conclusions

We found thickening of the right MFC and left AT in those wearing HHS, whereas PF thickness was not significantly different between those wearing HHS and those wearing FHS.

Level of Evidence

III
Risk factors associated with acute in-hospital delirium for patients
diagnosed with a hip fracture in the emergency department
Authors: Thompson Cameron , Brienza Vince J.M. , Sandre Aislinn , Caine Sean , Borgundvaag Bjug , McLeod Shelley
Published: September 2018

CLINICIAN’S CAPSULE

What is known about the topic?

Delirium, or acute confusion, occurs in up to 62% of patients who have experienced a
hip fracture.

What did this study ask?

What risk factors are associated with acute in-hospital delirium for ED patients
diagnosed with a hip fracture?

What did this study find?

History of neurodegenerative disease or dementia, age>75 years, and absence of
analgesia in the ED were associated with acute in-hospital delirium.

Why does this study matter to clinicians?

Although many variables associated with delirium may not be easily modified, more
careful attention to ED pain management and the provision of better analgesia are
important.
Activity types and child-directed speech: a comparison between French, Tunisian Arabic and English
Authors: Glas Ludivine , Rossi Caroline , Hamdi-Sultan Rim , Batailler Cédric , Bellemmouche Hacene
Published: September 2018

Quantity and quality of input affect language development, but input features also depend on the context of language emission. Previous research has described mother-child interactions and their impact on language development according to activity types like mealtimes, book reading, and free play. Nevertheless, few studies have sought to quantify activity types in naturalistic datasets including less-studied languages and cultures. Our research questions are the following: we ask whether regularities emerge in the distribution of activity types across languages and recordings, and whether activities have an impact on mothers' linguistic productions. We analyse input for two children per language, at three developmental levels. We distinguish three activity types: solitary, social and maintenance activities, and measure mothers' linguistic productions within each type. Video-recorded activities differ across families and developmental levels. Linguistic features of child-directed speech (CDS) also vary across activities – notably for measures of diversity and complexity – which points to complex interactions between activity and language.
Late to the Party: On the Prolonged Partisan Socialization Process of Second-Generation Americans
Authors: Carlos Roberto F.
Published: September 2018

This article posits that the key to understanding the low levels of political involvement within contemporary immigrant communities, such as Asian and Latino communities, requires a closer examination of the partisan socialization process of the native-born children of immigrants. This article finds that many native-born children of immigrants, otherwise known as second-generation Americans, experience what I call a “prolonged partisan socialization process.” In the absence of parental partisan transmission, many second-generation Americans are left to find their own path to partisan attainment. The consequences of this are that many second-generation Americans eventually come to find their partisan identity outside of the home and much later in life. These findings disrupt the traditional partisan attainment story, which assumes that partisanship is the product of a process of socialization led by parents. Accounting for this prolonged socialization process provides significant insight into why partisan identification, and by extension political participation, among many second-generation Americans, such as Latinos and Asians appears muted. Therefore, while it will likely take some time for many within these contemporary immigrant communities to reach “partisan maturity,” we should not mistake the prolonged socialization process to mean that these individuals are destined to be politically disengaged.
Patterns and predictors of food texture introduction in French children aged 4–36 months
Authors: Demonteil Lauriane , Ksiazek Eléa , Marduel Agnès , Dusoulier Marion , Weenen Hugo , Tournier Carole , Nicklaus Sophie
Published: September 2018

The aims of this study were to describe which and when food textures are offered to children between 4 and 36 months in France and to identify the associated factors. An online cross-sectional survey was designed, including questions about 188 food texture combinations representing three texture levels: purées (T1), soft small pieces (T2) and hard/large pieces and double textures (T3). Mothers indicated which combinations they already offered to their child. A food texture exposure score (TextExp) was calculated for all of the texture levels combined and for each texture level separately. Associations between TextExp and maternal and child characteristics and feeding practices were explored by multiple linear regressions, per age class. Answers from 2999 mothers living in France, mostly educated and primiparous, were analysed. Over the first year, children were mainly exposed to purées. Soft and small pieces were slowly introduced between 6 and 22 months, whereas hard/large pieces were mainly introduced from 13 months onwards. TextExp was positively associated with children’s number of teeth and ability to eat alone with their finger or a fork. For almost all age classes, TextExp was higher in children introduced to complementary feeding earlier, lower for children who were offered only commercial baby foods and higher for those who were offered only home-made/non-specific foods during the second year. Our study shows that until 12 months of age the majority of French children were exposed to pieces to a small extent. It provides new insights to further understand the development of texture acceptance during a key period for the development of eating habits.
Influences on the Number and Gender of Candidates in Canadian Local Elections
Authors: Breux Sandra , Couture Jérôme , Koop Royce
Published: September 2018

We explore influences on the number of candidates, and female candidates in particular, who contest mayoral elections in Canada. We draw on an original cross-national data set of election results from mayoral elections in Canada's 100 largest cities between 2006 and 2017. An average of 4.96 candidates contested mayoral elections in this period, and 16 per cent of all candidates were women. Density and mayoral prestige were related to higher numbers of candidates; in contrast, incumbent candidates and the availability of other elected positions were related to lower numbers. Notably, the presence of a female incumbent was related to higher numbers of women running for the position of mayor; in contrast, higher mayoral salaries were associated with an increase in the number of male but not female candidates. This analysis enhances our understanding of the factors underlying contested local elections, as well as the factors that appear to facilitate women contesting local elections.
Mental health and well-being trends among children and young people in the UK, 1995–2014: analysis of repeated cross-sectional national health surveys
Authors: Pitchforth Jacqueline , Fahy Katie , Ford Tamsin , Wolpert Miranda , Viner Russell M. , Hargreaves Dougal S.
Published: September 2018

Background

There is a growing concern about the mental health of children and young people (CYP) in the UK, with increasing demand for counselling services, admissions for self-harm and referrals to mental health services. We investigated whether there have been similar recent trends in selected mental health outcomes among CYP in national health surveys from England, Scotland and Wales.

Methods

Data were analysed from 140 830 participants (4–24 years, stratified into 4–12, 13–15, 16–24 years) in 36 national surveys in England, Scotland and Wales, 1995–2014. Regression models were used to examine time trends in seven parent/self-reported variables: general health, any long-standing health condition, long-standing mental health condition; Warwick–Edinburgh Mental Wellbeing Score (WEMWBS), above-threshold Strengths and Difficulties Questionnaire Total (SDQT) score, SDQ Emotion (SDQE) score, General Health Questionnaire (GHQ) score.

Results

Across all participants aged 4–24, long-standing mental health conditions increased in England (0.8–4.8% over 19 years), Scotland (2.3–6.0%, 11 years) and Wales (2.6–4.1%, 7 years) (all p < 0.001). Among young children (4–12 years), the proportion reporting high SDQT and SDQE scores decreased significantly among both boys and girls in England [SDQE: odds ratio (OR) 0.97 (0.96–0.98), p < 0.001] and girls in Scotland [SDQE: OR 0.96 (0.93–0.99), p = 0.005]. The proportion with high SDQE scores (13–15 years) decreased in England [OR 0.98 (0.96–0.99), p = 0.006] but increased in Wales [OR 1.07 (1.03–1.10), p < 0.001]. The proportion with high GHQ scores decreased among English women (16–24 years) [OR 0.98 (0.98–0.99), p = 0.002].

Conclusions

Despite a striking increase in the reported prevalence of long-standing mental health conditions among UK CYP, there was relatively little change in questionnaire scores reflecting psychological distress and emotional well-being.
A facilitatory effect of rich stem allomorphy but not inflectional productivity on single-word recognition
Authors: NIKOLAEV ALEXANDRE , LEHTONEN MINNA , HIGBY EVE , HYUN JUNGMOON , ASHAIE SAMEER
Published: September 2018

The aim of the present study was to investigate whether the recognition speed of Finnish nominal base forms varies as a function of their paradigmatic complexity (stem allomorphy) or productivity status. Nikolaev et al. (2014) showed that words with greater stem allomorphy from an unproductive inflectional class are recognized faster than words with lower stem allomorphy from a productive inflectional class. Productivity of an inflectional paradigm correlates with the number of stem allomorphs in languages like Finnish in that unproductive inflectional classes tend to have higher stem allomorphy. We wanted to distinguish which of these two characteristics provides the benefit to speed of recognition found by Nikolaev et al. (2014). The current study involved a lexical decision task comparing three categories of words: unproductive with three or more stem allomorphs, unproductive with two stem allomorphs, and productive with two stem allomorphs. We observed a facilitation effect for word recognition only for unproductive words with three or more stem allomorphs, but not for unproductive words with two allomorphs. This effect was observed particularly in words of low to moderate familiarity. The findings suggest that high stem allomorphy, rather than productivity of the inflectional class, is driving the facilitation effect in word recognition.
Screening of more than 2000 Hungarian healthcare workers’ anti-measles antibody level: results and possible population-level consequences
Authors: Lengyel G. , Marossy A. , Ánosi N. , Farkas S. L. , Kele B. , Nemes-Nikodém É. , Szentgyörgyi V. , Kopcsó I. , Mátyus M.
Published: September 2018

Due to the European measles epidemic and the increased number of imported cases, it can be theorised that the risk of exposure among Hungarian healthcare workers (HCWs) has increased. In 2017, the increased measles circulation in the region led to the emergence of smaller local and hospital epidemics. Therefore, our objective was to determine the herd immunity in the high-risk group of HCWs. A hospital-based study of detecting anti-measles IgG activity was performed in 2017 and included 2167 employees of the Military Medical Centre (Hungary). The screening of HCWs presented a good general seropositivity (90.6%). The highest seroprevalence value (99.1%) was found in the age group of 60 years or older. The lowest number of seropositive individuals was seen in the 41–45 years (86.2%) age group, indicating a significant herd immunity gap between groups. Regarding the Hungarian data, there might be gaps in the seroprevalence of the analysed HCWs, implying that susceptible HCWs may generate healthcare-associated infections. This study suggests that despite the extensive vaccination and high vaccine coverage, it is still important to monitor the level of protective antibodies in HCWs, or in a representative group of the whole population of Hungary, and possibly in other countries as well.
Assessing surface phonological specification through simulation and classification of phonetic trajectories
Authors: Shaw Jason A. , Kawahara Shigeto
Published: September 2018

Many previous studies have argued that phonology may leave some phonetic dimensions unspecified in surface representations. We introduce computational tools for assessing this possibility though simulation and classification of phonetic trajectories. The empirical material used to demonstrate the approach comes from electromagnetic articulography recordings of high-vowel devoicing in Japanese. Using Discrete Cosine Transform, tongue-dorsum movement trajectories are decomposed into a small number of frequency components (cosines differing in frequency and amplitude) that correspond to linguistically meaningful signal modulations, i.e. articulatory gestures. Stochastic generators of competing phonological hypotheses operate in this frequency space. Distributions over frequency components are used to simulate (i) the vowel-present trajectories and (ii) the vowel-absent trajectories. A Bayesian classifier trained on simulations assigns posterior probabilities to unseen data. Results indicate that /u/ is optionally produced without a vowel-height specification in Tokyo Japanese and that the frequency of such targetlessness varies systematically across phonological environments.
Taxonomic definitions in social science, with firms, markets and institutions as case studies
Authors: HODGSON GEOFFREY M.
Published: September 2018

Definitions are crucial for institutional analysis. This article explains the nature of taxonomic definitions, with particular attention to their use in economics and other social sciences. Taxonomic definitions demarcate one species of entity from another. They are vital for the communication of meaning between scientists, who must share some basic conception of what types of entity they are investigating, to establish a division of labour over subsequent theoretical analysis and empirical investigation of the type of entity defined. Generally, taxonomic definitions build on past usage and are parsimonious: they are not meant to be explanations or descriptions. By contrast, overloaded taxonomic definitions can create square-one disagreement about what is being investigated. As illustrative examples, the paper considers different degrees of progress with attempts to definefirms,marketsandinstitutions.
Do the adiponectin and leptin levels in preterm and term breast milk samples relate to infants’ short-term growth?
Authors: Kocaadam Betul , Koksal Eda , Ozcan Kudret Ebru , Turkyilmaz Canan
Published: September 2018

Adiponectin and leptin are involved in appetite control and body weight regulation. We aimed to evaluate the relationship between breast milk adipokine levels and short-term growth of preterm and term infants. Thirty-one preterm (median=35.3 weeks) and 34 term (median=38.7 weeks) infants were enrolled. Enzyme-linked immunosorbent assay was used to detect adipokines in mature milk. Infant growth was followed during the first 3 months. Although weight gain in the first month was insufficient, positive linear growth was observed in the following months for preterm infants, while term infants had positive steady linear growth. The median level of adipokines was found to be higher in preterm infants (P>0.05). Adiponectin showed significant negative correlations with some anthropometric measurements of term infants. However, in preterm infants, adiponectin was negatively correlated with length increment and positively correlated with body mass index (BMI) increment in the second–third month. In addition, leptin was negatively associated with the head circumference at birth in preterm infants and the triceps skinfold thickness increment in the first–second month term infants (P<0.05). In linear regression models, while gestational age, adiponectin and leptin were not related, maternal age and pre-pregnancy BMI had effects on body weight increment in 0–1 months (P<0.05). In conclusion, adiponectin may affect short-term growth, while leptin has no important effect. It would be beneficial to carry out longitudinal studies to evaluate the effects of these adipokines on the growth of infants.
Police Powers, Indirect Expropriation in International Investment Law, and Article 31(3)(c) of the VCLT: A Critique of Philip Morris v. Uruguay
Authors: RANJAN Prabhash
Published: September 2018

Given the global contestation against BITs and ISDS, the outcome of thePhilip Morrisv.Uruguaycase upholding Uruguay’s right to regulate for public health is important for the international investment law community. However, it is not just the outcome of a case but also the quality of legal reasoning that is significant in building the legitimacy of the ISDS system. This paper focuses on the reasoning adopted by the tribunal in deciding whether Uruguay’s regulatory measures resulted in the expropriation of Philip Morris’s investment. The paper critiques the tribunal’s use of Article 31(3)(c) of the Vienna Convention on the Law of Treaties to invoke the police powers rule in interpreting the expropriation provision of the Switzerland-Uruguay BIT. The tribunal’s reasoning was internally inconsistent and based on abuse of arbitral precedents. Clarity in legal reasoning by ISDS tribunals is imperative to boost the legitimacy of the ISDS system for all stakeholders.
Are the Variants of the Circle of Willis Determined by Genetic or Environmental Factors? Results of a Twin Study and Review of the Literature
Authors: Forgo Bianka , Tarnoki Adam Domonkos , Tarnoki David Laszlo , Kovacs Daniel Tamas , Szalontai Laszlo , Persely Aliz , Hernyes Anita , Szily Marcell , Littvay Levente , Medda Emanuela , Szabo Adam , Kozak Lajos Rudolf , Rudas Gabor , Sas Attila , Sepsi Marianna , Kostyal Laszlo , Olah Csaba
Published: September 2018

Background: Anatomic variants of the circle of Willis (CW) are commonly observed in healthy subjects. Genetic and environmental factors influencing these variants remain unclear. Our aim was to assess the genetic and environmental background affecting variant CW phenotypes. Methods: A total of 122 adult healthy twins from the Hungarian Twin Registry (39 monozygotic (MZ) and 22 dizygotic (DZ) pairs, average age 49.7 ± 13.4 years) underwent Time-of-Flight magnetic resonance angiography and transcranial Doppler sonography. We investigated the anterior and posterior CW according to morphological categories. Prevalence and concordance rates of CW variants were calculated. MZ twins discordant for CW variants were analyzed for cardiovascular risk factors and altered blood flow. Results: Complete CW (45.0%) and bilaterally absent posterior communicating artery (PCoA) (22.5%) were the most prevalent variants in the anterior and posterior CW, respectively. There was no significant difference regarding the prevalence of variants across zygosity except for bilaterally hypoplastic PCoA (p = .02). DZ concordance was higher compared to MZ twins regarding morphological categories of the CW. Cardiovascular risk factors were not significantly associated with variant CW in MZ twins discordant to CW morphology. Flow parameters did not differ significantly among MZ twins discordant to CW variants. Conclusion: CW variants may not be determined by substantial genetic effects and are not influenced by altered blood flow in healthy individuals. Further investigations are needed to identify potential environmental factors affecting these variants.
Annual Bluegrass (Poa annua) Biotypes Exhibit Differential Levels of Susceptibility and Biochemical Responses to Protoporphyrinogen Oxidase Inhibitors
Authors: Yu Jialin , McCullough Patrick E. , Czarnota Mark A.
Published: September 2018

An annual bluegrass (Poa annuaL.) biotype with limited susceptibility to POST flumioxazin applications was identified in Georgia. The objectives of this research were to quantify tolerance levels of this biotype (R-biotype) to protoporphyrinogen oxidase (PPO) inhibitors and characterize physiological responses to flumioxazin. In dose–response experiments on 3- to 5-tiller plants, flumioxazin and sulfentrazone rates required to reduce dry-shoot biomass 50% from the nontreated were >14.5 and 10.4 times greater for the R-biotype, as compared with a susceptible (S)-biotype, respectively. Establishment of the R-biotype from seed was completely controlled by PRE applications of flumioxazin and oxadiazon, similar to the S-biotype. Tank mixtures of chlorpyrifos with flumioxazin did not enhance biomass reductions of the R-biotype, suggesting that tolerance levels may not be related to cytochrome P450–associated metabolism. In laboratory experiments, the R-biotype averaged 27% less electrolyte leakage, as compared with the S-biotype, after flumioxazin treatments. Lipid peroxidation in the R-biotype, as measured by malondialdehyde levels, averaged 25% less than the S-biotype at 72 h after broadcast flumioxazin treatments at 280 and 560 g ha−1. The tolerance to POST applications of PPO inhibitors in thisP. annuabiotype is associated with less lipid peroxidation and electrolyte leakage as compared with the S-biotype. These biochemical differences in biotypes may contribute to erratic levels of POST control from flumioxazin and could contribute to PPO-inhibitor resistance.
Divergence in Life-History and Developmental Traits in Silvery-Thread Moss (Bryum argenteumHedw.) Genotypes between Golf Course Putting Greens and Native Habitats
Authors: Raudenbush Zane , Greenwood Joshua L. , McLetchie D. Nicholas , Eppley Sarah M. , Keeley Steven J. , Castetter Richard C. , Stark Lloyd R.
Published: September 2018

Silvery-Thread Moss (Bryum argenteumHedw.) is an undesirable invader of golf course putting greens across North America, establishing colonies and proliferating despite practices to suppress it. The goal was to grow genotypes ofgreen(growing in putting greens) andnative(growing in habitats outside of putting greens)B. argenteumin a common garden experiment, allowing an experimental test of life-history traits between genotypes from these two habitats. Seventeen collections ofgreenand 17 collections ofnative B. argenteumwere cloned to single genotypes and raised through a minimum of two asexual generations in the lab. A culture of each genotype was initiated using a single detached shoot apex and was allowed to grow for 6 mo under conditions of inorganic nutrients present and absent. Compared with genotypes from native habitats, genotypes ofB. argenteumfrom putting greens exhibited earlier shoot regeneration and shoot induction, faster protonemal extension, longer (higher) shoots, lower production of gemmae and bulbils, and greater aerial rhizoid cover, and showed similar tendencies of chlorophyll fluorescence properties and chlorophyll content. Cultures receiving no inorganic nutrients produced less chlorophyll content, greatly reduced growth, and bleaching of shoots. Mosses from putting greens establish more quickly, grow faster, produce more abundant rhizoids, and yet do not produce as many specialized asexual propagules compared with mosses of the same species from native habitats. The highly managed putting green environment has either selected for a suite of traits that allow the moss to effectively compete with grasses, or genotypic diversity is very high in this species, allowing a set of specialized genotypes to colonize the putting green from native habitats. Successful golf course weeds have been able to adapt to this highly competitive environment by selection acting on traits or genotypes to produce plants more successful in competing with golf course grasses.
Prevalence and Mechanism of Atrazine Resistance in Waterhemp (Amaranthus tuberculatus) from Nebraska
Authors: Vennapusa Amaranatha Reddy , Faleco Felipe , Vieira Bruno , Samuelson Spencer , Kruger Greg R. , Werle Rodrigo , Jugulam Mithila
Published: September 2018

Resistance to atrazine (a photosystem II [PSII] inhibitor) is prevalent in waterhemp [Amaranthus tuberculatus(Moq.) J. D. Sauer] across the U.S. Midwest. Previous research suggests that target-site mutation or rapid metabolism of atrazine mediated by glutathioneS-transferase (GST) conjugation confers resistance inA. tuberculatusfrom Illinois. The distribution and mechanism of resistance to atrazine inA. tuberculatuspopulations from Nebraska (NE) are unknown. In this research we (1) evaluated the response and frequency of resistance in NEA. tuberculatusto soil-applied PSII (metribuzin and atrazine) and protoporphyrinogen oxidase (sulfentrazone) inhibitors, as well as POST-applied atrazine; and (2) determined the mechanism of atrazine resistance in NEA. tuberculatus. The chloroplasticpsbAgene, coding for a D1 protein (the target site of atrazine) was sequenced in 85 plants representing 27 populations ofA. tuberculatus. Furthermore, 24 plants selected randomly from four atrazine-resistant (AR) populations were used to determine the metabolism of atrazine via GST conjugation. Results from the soil-applied herbicide evaluation suggest that metribuzin (0.56 kg ai ha−1) and sulfentrazone (0.28 kg ai ha−1) were effective onA. tuberculatusmanagement. PRE and POST screenings against atrazine in the greenhouse indicate that atrazine (1.345 kg ai ha−1) was not effective on 39% and 73% of theA. tuberculatuspopulations evaluated (total of 109 and 85 populations, respectively), suggesting the prevalence of atrazine resistance inA. tuberculatusin NE. Sequence analysis of thepsbAgene found no known point mutations conferring atrazine resistance. However, the AR plants conjugated atrazine via GST activity faster than the known atrazine-susceptibleA. tuberculatus. Overall, the outcome of this study demonstrates the predominance of metabolism-based resistance to atrazine inA. tuberculatusfrom NE, which may predispose this species to evolve resistance to other herbicides. The use of integrated management strategies forA. tuberculatusis crucial for the control of this troublesome species.
Weed Seedbank and Weed Biomass Dynamics in a Long-Term Organic Vegetable Cropping Systems Experiment
Authors: Mohler Charles L. , Caldwell Brian A. , Marschner Caroline A. , Cordeau Stephane , Maqsood Qaiser , Ryan Matthew R. , DiTommaso Antonio
Published: September 2018

Most previous research on changes in weed abundance and community composition in cropping systems has focused on field crops. The study presented here examined changes in the weed seedbank and aboveground biomass in four organic vegetable cropping systems over a 10-yr period. The systems included an Intensive system with six crops per 4-yr rotation, an Intermediate system with one cash crop per year, a Bio-extensive system with alternating cash crop and tilled fallow years plus prevention of seed rain, and a Ridge-tillage system with one cash crop per year. Systems also differed in the types and number of cover crops between cash crops. During the course of the experiment, the weed community shifted from one dominated by summer annual broadleaf species that reproduce at the end of their lives to a community dominated by summer and winter annuals that mature rapidly. This shift in community composition can be attributed to the change in land use from conventionally managed corn (Zea maysL.) and alfalfa (Medicago sativaL.) to organic vegetable production. In particular, crop rotations with diverse preplantings and postharvest tillage dates interrupted the life cycle of common lambsquarters (Chenopodium albumL.) and pigweed species (Amaranthusspp.: mostly Powell amaranth [Amaranthus powelliiS. Watson], with small numbers of redroot pigweed [Amaranthus retroflexusL.] and smooth pigweed [Amaranthus hybridusL.]), while favoring a diverse assemblage of quickly maturing species. The study thus demonstrates that an appropriate crop rotation can control the seedbank of weeds likeC. albumthat potentially persist well in the soil. The Ridge-tillage system greatly reduced the frequency and depth of tillage relative to other systems while effectively suppressing perennial weeds. The early-reproducing annuals, however, became more abundant in the Ridge-tillage system than in the other systems, primarily due to escapes along the edge of the scraped ridges. The tilled fallow periods coupled with prevention of seed rain in the Bio-extensive system substantially reduced weed abundance through time and relative to the other systems.
Effect of Air‐Sea Environmental Conditions and Interfacial Processes on Extremely Intense Typhoon Haiyan (2013)
Authors: Wada Akiyoshi , Kanada Sachie , Yamada Hiroyuki
Published: September 2018

Typhoon Haiyan (2013) intensified rapidly and reached a central pressure of 895 hPa over the warm northwestern Pacific. To clarify why Haiyan became such an extraordinarily intense tropical cyclone (TC), we investigated the impacts of atmospheric and oceanic conditions and air‐sea interfacial processes on Haiyan's intensity. We performed ensemble experiments with many different initial oceanic conditions and a 7‐km‐mesh atmosphere‐wave‐ocean coupled model. We also performed sensitivity experiments to examine the impacts of sea spray and use of a 2‐km‐mesh horizontal resolution. Also, analogous experiments were performed with Typhoon Mike (1990), which followed a similar track but was less intense than Haiyan. For both TCs, ocean coupling helped alleviate uncertainty in the simulated intensities caused by different preexisting oceanic conditions. Increases in air‐sea latent heat fluxes helped increase the intensity of both TCs although the effect of sea spray depended on whitecap coverage. Preexisting oceanic conditions and air‐sea interfacial processes directly affected the secondary circulation via changes in latent heat fluxes and near‐surface moisture influxes. However, the 2‐km‐mesh resolution improved only Haiyan's simulation; the mean latent heat flux over the strength area was insufficient to simulate the intensity. It was easterly winds and specific humidity at 850 hPa that determined the small size, rapid translation, less sea surface cooling, and small decreases in latent heat fluxes beneath the frictional convergence area of simulated Haiyan. Understanding of the effect of preexisting oceanic conditions and air‐sea interfacial processes on simulated TCs will serve as a guideline for improvement of the atmosphere‐wave‐ocean coupled model.
The Earth's Hum Variations From a Global Model and Seismic Recordings Around the Indian Ocean
Authors: Deen M. , Stutzmann E. , Ardhuin F.
Published: September 2018

The Earth's hum is the continuous oscillations of the Earth at frequencies between 2 and 20 mHz in the absence of earthquakes. The hum strongest signal consists mainly of surface waves. These seismic waves can be generated by infragravity waves propagating over a sloping ocean bottom close to the coast. So far, this theory has only been tested quantitatively using European seismic stations. We use seismic data recorded all around the Indian Ocean together with an ocean wave model that provides time‐frequency varying hum sources. We show that seasonal variations of the hum sources are smaller in the southern hemisphere than the northern hemisphere. Using these sources, we model Rayleigh wave root‐mean‐square amplitudes in the frequency band 3.5–20 mHz, and the good agreement with seismic data on the vertical component confirms the theory of hum generation. Because the Indian Ocean is uniquely connected to the southern hemisphere oceans but lies partly in northern hemisphere latitudes, the seasonal pattern of the hum recorded there is particular and shows no significant seasonal variations. At ~10 mHz the hum is strongly influenced by local events, such as the passage of a cyclone close to a seismic station.
Assessment of Northeastern Japan Tree‐Ring Oxygen Isotopes for Reconstructing Early Summer Hydroclimate and Spring Arctic Oscillation
Authors: Sakashita Wataru , Yokoyama Yusuke , Miyahara Hiroko , Aze Takahiro , Obrochta Stephen P. , Ohyama Motonari , Yonenobu Hitoshi
Published: September 2018

The spring Arctic Oscillation (AO) significantly affects the subsequent summer rainfall in the East Asian summer monsoon (EASM) region, and analysis of meteorological data indicates this teleconnection strength varied on interdecadal timescales during the late 20th century. Tree‐ring records may be able to extend the relatively short observational record, but the extent to which these proxy reconstructions correspond to AO variability has yet to be explored in this region. Therefore, we present new tree‐ring cellulose oxygen isotope (δ18O) records from northeastern Japan (Akita, northern limit of EASM), spanning a.d. 1950 to 2003 which overlaps with the instrumental record. Tree‐ring δ18O is used for reconstructing the past hydroclimate variability and allows us to consider whether tree‐ring δ18O has the potential to clarify the longer‐term interdecadal changes in the spring AO‐EASM relationship. Measurements and analyses show that our tree‐ring δ18O data sets have a significant negative correlation with May‐June‐July relative humidity, and the tree‐ring δ18O in northeastern Japan also significantly correlates with the summer EASM index. Temporal comparisons between our record and observed monthly AO index indicate that reconstructed following early summer relative humidity significantly correlates to the previous March‐April‐May AO. This linkage changes on interdecadal timescales, and the linkage is relatively strong during early 1970s through early 1990s. Similar results are also obtained using a separate tree‐ring δ18O record from a separate location about 200 km to the southeast, suggesting that tree‐ring cellulose δ18O in northeastern Japan is indeed useful for better understanding the long‐term teleconnection between the spring AO and EASM.
The Sources and Transformations of Dissolved Organic Matter in the Pearl River Estuary, China, as Revealed by Stable Isotopes
Authors: Ye Feng , Guo Wei , Wei Gangjian , Jia Guodong
Published: September 2018

To investigate the sources and transformation processes of bulk marine dissolved organic matter (DOM), seasonally collected water samples from the Pearl River Estuary (PRE), south China, were analyzed for concentration and stable isotopic ratios (δ13C and δ15N) of DOM. The δ13C values clearly indicated a shift of dissolved organic carbon (DOC) sources from terrigenous material in the river to predominantly plankton in the lower estuary. The distribution of δ13C during the estuarine mixing, in combination with the notable deviation of DOC concentration, provided strong evidence for a substantial DOC removal in the salinity range of 5 to 22. In contrast to δ13C, the δ15N of DOM exhibits a strong seasonality, implying a clear decoupling of estuarine DOC and dissolved organic nitrogen (DON) dynamics. During dry periods with low river discharge, sewage‐derived DON contributed significantly to the riverine loading. While freshwater‐saltwater mixing is important in regulating the distribution of DON, the distribution of δ15N along the salinity gradient provided strong evidence for active sediment‐water interaction and adsorption/desorption processes at the middle to high salinities. During wet periods, severe soil loss and erosion, and/or in situ biological production, adsorption onto suspended particles dominate the riverine DON fluxes, whereas the DON dynamics might be governed by different biogeochemical processes between spring and summer, as reflected by distinct δ15DON patterns in the estuarine zone. In spring, highly degraded DON originating from soil experienced little further biological alternation during estuarine mixing, whereas there was a tight coupling of DON production and consumption in summer.
Validating the Integrated Multisatellite Retrievals for Global Precipitation Measurement in Terms of Diurnal Variability With Hourly Gauge Observations Collected at 50,000 Stations in China
Authors: Li Runze , Wang Kaicun , Qi Dan
Published: September 2018

The diurnal cycle of precipitation is a key feature in the Earth system and related to multiscale physical processes. The Integrated Multi‐satellitE Retrievals for Global Precipitation Measurement (IMERG) data are expected to improve its presentation of diurnal cycle, but how it really performs remains poorly known. This study compares the diurnal characteristics of the half‐hourly IMERG V05 Final Run product with the hourly rain gauge data collected at approximately 50,000 automatic weather stations in China during a 3‐year period (2014–2016). Our results show that IMERG performs well in terms of the diurnal cycle of precipitation amount but less well in terms of frequency and even worse in terms of intensity. Ground observations show that the frequency and intensity are rather stable for the diurnal cycle; however, IMERG shows strong fluctuations. Significant inverse correlation is found between the diurnal cycles of IMERG precipitation frequency and intensity; thus, the biases of these two variables offset and result in a better estimate of amount. A low probability of detection (POD≈50%) and a high false alarm ratio (FAR≈50%) are the major reasons for the inaccurate diurnal cycles of precipitation intensity and frequency. In particular, IMERG presents a false peak of frequency at approximately 23:00–01:00 (Beijing Time) because a large proportion of the data sources at this time contain the indirect estimates from thermal infrared observations. The significant underestimation of the frequency and overestimation of the intensity at approximately 09:00–11:00 and 20:00–22:00 is because the estimates primarily come from less accurate cross‐track microwave sensors.