bluuebunny/crossref_metadata_2025 huggingface dataset:
Financial Centres Index and GDP Growth
Authors: Esen Sinan , Gokmenoglu Korhan
Published: March 2016

This study investigates the relationship between financial centres index and GDP growth of 20 countries with the world’s largest GDP. In our sample each country is represented by just one financial centre. We tested many models through several panel approaches. Use of a fixed-effects model, fixed-effects (within) regression, random-effects GLS regression, random-effects ML regression, and empirical findings showed that the global financial centres index variable is highly statistically significant, and coefficients obtained from different estimations are very close to each other. Our findings support the idea that financial centres positively affect the GDP growth of countries.
Determinant of the Relationship between Natural Gas Prices and Leading Natural Gas Countries’ Stock Exchange
Authors: Azizi Kouchaksaraei Meysam , Movahedizadeh Hamed , Mohammadalikhani Hoda
Published: March 2016

Over the recent decades, natural sources of energy have become an interesting topic to investigate for researchers. Sources of energy play a crucial role in all industrial segments such as export revenue, exchange rate and stock market. One of the major sources is natural gas which its price affects many countries’ economy. This paper investigates the effect of natural gas price on the three leading natural gas exporting countries’ stock market: Russia, Norway and Qatar. This paper employs monthly data observations including natural gas price and stock exchange market index on Russia, Norway and Qatar from January 2005 to November 2013. This study uses Unrestricted Vector Autoregressive model (VAR) to apply Granger Causality test, Impulse Response functions and Variance Decomposition. Findings show that there are two-way causality relationship between natural gas prices and stock exchanges of Russia and Norway, though natural gas prices affected Russia stock exchange index at 10% significance level and Norway stock exchange index at 5% significance. However, there is not causality relationship between Qatar stock exchange and natural gas prices. Moreover, outcomes of impulse response function present that natural gas price shock does not have significant impact on all three countries’ stock exchange. The variance decomposition test also reinforces the results from impulse response function since Russia, Norway and Qatar’s stock exchange variance are not significantly due to natural gas price.
Impact of Motivation on Productivity of Craftsmen in Construction Firms in Lagos, Nigeria
Authors: Funso Afuye , Sammy Letema , Gerryshom Munala
Published: March 2016

Motivation has been identified as a useful tool for enhancing productivity. This study aims at determining the impact of motivation on productivity of craftsmen in construction firms in Lagos, Nigeria. Sixteen motivating factors were identified through literature review common to Nigeria construction climate which were used to design questionnaire for the study. A total of 295 questionnaires were administered with 150 filled and returned. This constitute response rate of 50.85%. Productivity rating was done by work study. The mean of motivating factors was correlated with percentage productive hour observed in the sixteen sites surveyed. The outcome indicates that there is positive linear relationship between motivation and productivity. Therefore, motivation influences craftsmen performance in Nigeria construction industry. Further analysis also shows that craftsmen are basically motivated by financial incentives. The paper recommends that financial incentive should be considered for craftsmen in the industry. Moreover, alternative method to working overtime should be employed. The paper concluded that motivation strategy that will enhance productivity should be adopted for workers in the industry.
Smart Shoppers’ Purchasing Experiences: Functions of Product Type, Gender, and Generation
Authors: Atkins Kelly Green , Hyun Sae-Young Jessica
Published: March 2016

Today’s consumers want to feel smart while shopping by minimizing the costs associated with shopping trips (e.g., time, effort, or money) and maximizing the benefits (e.g., convenience, ease, or finding the right product). This study examined whether smart purchasing experiences (i.e., effort and time saving, money saving, and making the right purchase) differ by product type, gender, and generation, after adjusting to the same levels of search and planning that were made before purchasing. Using 1474 respondents drawn by an online consumer panel, a series of ANCOVAs along with MANCOVA revealed that members of different genders and generational cohorts, when purchasing different product types, demonstrate distinct smart shopping purchase experiences in terms of saving time/effort, saving money, and making the right purchase. Specific suggestions are made for marketers to target each consumer and product group.
Multi-level Approach to the “Social Marketing” Context for Innovation: Impact on Organizational Relationships
Authors: Szczepanska-Woszczyna Katarzyna , Nadeem Mohammed
Published: March 2016

The aim of the article is to explore the social aspects of innovation at three levels of research: individual, group, and organization. A multi-level approach enhances the understanding of how organizational context shapes and is shaped by the actions and perceptions of individuals. It may provide more precise research findings and more rigorous theory testing by clarifying the level of analysis. A resource-based approach and adaptation theories are used in relation to the organizational level, while at the individual level, psychological theories are applied. We propose a theoretical approach which could link creativity and competencies at the individual level, managerial / leader action and organizational culture with innovation to marketing innovation as a process and outcome of organizational level. The earlier studies used the approach that focused attention on the innovation process and innovation outcomes rather than on developing the ability to take specific innovative action and focused research on the selected level of innovation process management. It is therefore necessary to take into account the complexity of the research subject and include the actual problems resulting from the needs of multi-level innovation management and respect for the diversity of its conditions in the research.
Exploration of Customer Compliant Behavior toward Asain Full-Service Restaurants
Authors: Chan Grace Suk Ha , Hsiao Anna Chun-Hsuan , Lee Ada Lai Yung
Published: March 2016

The first law of service productivity and quality in restaurants is doing it right the first time. In today’s highly competitive environment, restaurants should acquire feedback from their customers to improve further the products and services they offer. One means to obtain customer feedback is to encourage and facilitate the complaint process. In response to an unhappy service, customers either speak with the management, their friends or do nothing, and they may also expect fair compensation whenever service failure occurs. This study aimed to investigate the complaint behavior of Hong Kong customers toward Asian full-service restaurants. A qualitative approach was adopted with a sample of 30 respondents who often dine in Asian full-service restaurants. Semi-structured questions were asked through an in-depth interview. Based on the results, the reasons for the complaints and complaint behavior of Hong Kong customers were identified, and recommendations were made to provide insights for industrial practitioners.
Teacher-Child Relationships and Child Temperament in Early Achievement
Authors: Collins Ashleigh , O’Connor Erin
Published: March 2016

Teacher-child relationship quality and child temperament have been associated with children’s school adjustment and academic performance. However, few studies explore the influence of both child temperament and teacher-child relationship quality on children’s academic development. This study investigates the role of teacher-child relationships on kindergarten children’s temperament and academic performance. Study participants were comprised of 324 kindergarten students, attending 22 schools in urban, low-income communities. A multivariate regression analysis was used to explore whether teacher-child relationships moderate or mediate the association between child temperament and academic performance. The study reinforces previous findings that conflictual teacher-child relationships inhibit children’s academic performance and close teacher-child relationships promote children’s academic performance. For cautious children, close teacher-child relationships moderate mathematics performance. For high maintenance children, conflictual teacher-child mediate children’s critical thinking. The findings have implications for teacher training, on-going teacher development, and the promotion of early academic development for children at-risk for underachievement.
Aras kerusakan ekonomi (AKE) larva Ostrinia furnacalis (Lepidoptera: Crambidae) pada tiga fase pertumbuhan tanaman jagung
Authors: Subiadi Subiadi , Trisyono Y. Andi , Martono Edhi
Published: March 2016

Penggerek batang jagung Asia, Ostrinia furnacalis (Guenée) merupakan hama penting tanaman jagung dan telah tersebar luas di wilayah Asia-Pasifik termasuk Indonesia sehingga perlu dikendalikan dengan memperhatikan analisis biaya dan manfaat pengendalian. Penelitian ini bertujuan untuk mengetahui hubungan kepadatan populasi larva O. furnacalis terhadap tingkat kehilangan hasil pada tiga fase pertumbuhan tanaman jagung, dan untuk menghitung nilai aras luka ekonomi (ALE) larva O. furnacalis pada tiga fase pertumbuhan tanaman jagung (V10, R1, dan R2). Percobaan ditata berdasarkan rancangan petak terpisah dengan rancangan lingkungan rancangan acak kelompok yang diulang tiga kali. Selisih bobot biji gram per tanaman antara tanaman yang tidak diinfestasi larva (kontrol) dan infestasi enam larva per tanaman untuk fase V10, R1, dan R2, masing-masing adalah 59,81, 58,76, dan 49,20 g/tanaman. Model regresi linier menunjukkan bahwa setiap pertambahan satu larva per tanaman pada fase V10, R1, dan R2 akan menurunkan hasil masing-masing 4,94%, 4,56%, dan 3,76%. Nilai ALE dikalkulasi dengan asumsi pengendalian dengan pestisida akan menurunkan populasi larva O. furnacalis sebesar 67%. Nilai ALE terendah terdapat pada fase V10 sebesar 0,31 larva per tanaman ketika biaya pengendalian Rp.125.000 per ha dan nilai tanaman Rp.12.000.000 per ha. Nilai ALE tertinggi terdapat pada fase R2 sebesar 1,24 larva per tanaman ketika biaya pengendalian Rp.250.000 per ha dan nilai tanaman Rp.8.000.000 per ha.
Interaksi tropik antara hama dan parasitoid pada pertanaman sayuran: faktor pembentuk dan implikasinya terhadap keefektifan parasitoid
Authors: Nugraha Muhamad Nurhuda , Buchori Damayanti , Nurmansyah Ali , Rizali Akhmad
Published: March 2016

Kondisi agroekosistem dapat memengaruhi keanekaragaman serta keefektifan komunitas parasitoid sebagai musuh alami serangga hama. Intensifikasi pertanian berupa budi daya tanaman monokultur dan aplikasi pestisida juga menyebabkan penurunan keanekaragaman dan kinerja parasitoid di lahan pertanian. Penelitian ini bertujuan untuk mempelajari interaksi tropik antara hama dan parasitoid pada berbagai kondisi lahan sayuran dan mempelajari faktor-faktor yang membentuk interaksi tersebut serta implikasinya terhadap keefektifan parasitoid. Penelitian dilaksanakan pada berbagai lahan sayuran di Bogor yang dikelompokkan ke dalam tiga kategori, yaitu berdasarkan pola budi daya, keanekaragaman tanaman sayuran di sekitar lahan dan perbedaan umur tanaman. Di setiap lahan sayuran, pengambilan contoh serangga dilakukan pada transek sepanjang 50 m, yaitu dengan mengoleksi telur, larva dan pupa dari hama yang ditemukan. Sebanyak 15 spesies hama dan 15 spesies parasitoid diperoleh dari delapan spesies tanaman sayuran. Hasil analisis menunjukkan bahwa interaksi tropik antara hama dan parasitoid dipengaruhi oleh sistem budi daya, kondisi lahan (keanekaragaman tanaman disekitarnya) dan umur tanaman. Walaupun tidak signifikan, keefektifan parasitoid, yaitu berdasarkan tingkat parasitisasinya, cenderung lebih tinggi pada interaksi tropik yang terbentuk pada lahan dengan sistem budi daya organik dan kondisi pertanaman yang beranekaragam.
Relevance of Autonomic Arousal in the Stress Response in Psychopathology
Authors: C. Pruneti  , M. Saccò  , C. Cosentino  , D. Sgromo
Published: March 2016

The principal goal of this study is to describe the relevance of typical autonomic patterns of response in accordance to a number of psychopathological syndromes for an accurate multi-dimensional assessment.A sample of 89 subjects was subdivided in five pathological groups in accordance with the clinical diagnosis following the diagnostic criteria of DSM V [1]: Generalized Anxiety Disorder (GAD), Panic Attack Disorders (PAD), Major Depressive Episodes (MDE), Obsessive Compulsive Disorders (OCD), Anorexia Nervosa (AN) and a Healthy control group. Obtained data were compared in regard to each physiological parameters by using the mean value of the last minute of the registration at rest, and two activation indexes: “stress response” and “recovery after stress”.Furthermore, for each of the physiological parameters (EMG, SCL/SCR, PT and HR), and diagnostic group, mean values in the three different phases (last minute of rest, first minute of stress, last minute of recovery) were compared to evaluate the four physiological parameters trends.In GAD and PAD patients, the obtained Conductance Response mean values are much higher than MDE and OCD.Furthermore, the HR response is also higher in GAD than in the other three groups. So, OCD and MDE patients seem to be characterized by a flat profile in all the parameters.We confirmed that a condition of autonomic hyper activation is typically connected to a high level of tension and anxiety; vice versa, a low level of autonomic activation and the impossibility to react to the stimuli is typically connected to MDE, OCD and AN.Obtained data suggest that there might be a new tool for differential diagnosis in psychopathology, represented by specific and typical pattern in autonomic response.
Mesolimbic confidence signals guide perceptual learning in the absence of external feedback
Authors: Guggenmos Matthias , Wilbertz Gregor , Hebart Martin N , Sterzer Philipp
Published: March 2016

It is well established that learning can occur without external feedback, yet normative reinforcement learning theories have difficulties explaining such instances of learning. Here, we propose that human observers are capable of generating their own feedback signals by monitoring internal decision variables. We investigated this hypothesis in a visual perceptual learning task using fMRI and confidence reports as a measure for this monitoring process. Employing a novel computational model in which learning is guided by confidence-based reinforcement signals, we found that mesolimbic brain areas encoded both anticipation and prediction error of confidence—in remarkable similarity to previous findings for external reward-based feedback. We demonstrate that the model accounts for choice and confidence reports and show that the mesolimbic confidence prediction error modulation derived through the model predicts individual learning success. These results provide a mechanistic neurobiological explanation for learning without external feedback by augmenting reinforcement models with confidence-based feedback.
Molecular basis for multimerization in the activation of the epidermal growth factor receptor
Authors: Huang Yongjian , Bharill Shashank , Karandur Deepti , Peterson Sean M , Marita Morgan , Shi Xiaojun , Kaliszewski Megan J , Smith Adam W , Isacoff Ehud Y , Kuriyan John
Published: March 2016

The epidermal growth factor receptor (EGFR) is activated by dimerization, but activation also generates higher-order multimers, whose nature and function are poorly understood. We have characterized ligand-induced dimerization and multimerization of EGFR using single-molecule analysis, and show that multimerization can be blocked by mutations in a specific region of Domain IV of the extracellular module. These mutations reduce autophosphorylation of the C-terminal tail of EGFR and attenuate phosphorylation of phosphatidyl inositol 3-kinase, which is recruited by EGFR. The catalytic activity of EGFR is switched on through allosteric activation of one kinase domain by another, and we show that if this is restricted to dimers, then sites in the tail that are proximal to the kinase domain are phosphorylated in only one subunit. We propose a structural model for EGFR multimerization through self-association of ligand-bound dimers, in which the majority of kinase domains are activated cooperatively, thereby boosting tail phosphorylation.
Osteopathic Medical Education and Social Accountability
Authors: Phillips-Madson Robyn , Dharamsi Shafik
Published: March 2016

The public’s trust in physicians continues to decline. As a way to begin regaining this trust, stakeholders, including physicians, medical educators, patient advocacy groups, and community-based organizations, have called for medical education to meet societal health needs, particularly the needs of those members who are most vulnerable, by incorporating social accountability into the medical school curriculum. The unique attributes of the osteopath-ic medical profession provide an enabling and conducive environment for broader social accountability in the health care system. Osteopathic medical schools must actively safeguard the profession’s unequivocal commitment to producing healers that are fiduciaries for their patients, communities, and populations at large.
Advising Needs of Osteopathic Medical Students Preparing for the Match
Authors: Speicher Mark R. , Pradhan Satej R.
Published: March 2016

Context: Concern over the number of residency positions available to graduating osteopathic medical students has led to calls for better advising, but there is little research on the relationship between student advising and successful matching.

Objectives: To determine the satisfaction of graduating osteopathic medical students with their residency match advising, and to compare advising satisfaction with residency match results.

Methods: A 30-item survey was developed for students preparing for the residency match. The survey was e-mailed to fourth-year osteopathic medical students at Midwestern University/Arizona College of Osteopathic Medicine in February 2015, before the National Matching Services match and the National Resident Matching Program match.

Results: Of the 242 surveys sent, 95 were received and 90 (37%) contained sufficient information for analysis. Of the 90 respondents, 41 (45%) agreed with the statement “My advising needs were adequately met,” and 32 (36%) disagreed. Pearson product moment correlations revealed that having one’s advising needs met was correlated to having clear career goals (r=0.44, n=77; P<.001), having a match strategy (r=0.40, n=78; P<.001), having confidence in one’s qualifications for his or her top choice (r=0.40, n=81; P<.001), and matching to the top choice specialty (r=0.37, n=81; P=.001) and program (r=0.27, n=81; P=.016).

Conclusions: A range of advising resources was shown to be effective for most students during the residency match. Further research is needed to determine whether different advising methods for different academically performing groups or different demographic groups will increase students’ ability to successfully match.
Gene expression profiles during short-term heat stress; branchingvs.massive Scleractinian corals of the Red Sea
Authors: Maor-Landaw Keren , Levy Oren
Published: March 2016

It is well-established that there is a hierarchy of susceptibilities amongst coral genera during heat-stress. However, molecular mechanisms governing these differences are still poorly understood. Here we explored if specific corals possessing different morphologies and different susceptibilities to heat stress may manifest varied gene expression patterns. We examined expression patterns of seven genes in the branching coralsStylophora pistillataandAcropora eurystomaand additionally in the massive robust coral,Poritessp. The tested genes are representatives of key cellular processes occurring during heat-stress in Cnidaria: oxidative stress, ER stress, energy metabolism, DNA repair and apoptosis. Varied response to the heat-stress, in terms of visual coral paling, algal maximum quantum yield and host gene expression was evident in the different growth forms. The two branching corals exhibited similar overall responses that differed from that of the massive coral.A. eurystomathat is considered as a susceptible species did not bleach in our experiment, but tissue sloughing was evident at 34 °C. Interestingly, in this species redox regulation genes were up-regulated at the very onset of the thermal challenge. InS. pistillata, bleaching was evident at 34 °C and most of the stress markers were already up-regulated at 32 °C, either remaining highly expressed or decreasing when temperatures reached 34 °C. The massivePoritesspecies displayed severe bleaching at 32 °C but stress marker genes were only significantly elevated at 34 °C. We postulate that by expelling the algal symbionts fromPoritestissues, oxidation damages are reduced and stress genes are activated only at a progressed stage. The differential gene expression responses exhibited here can be correlated with the literature well-documented hierarchy of susceptibilities amongst coral morphologies and genera in Eilat’s coral reef.
Effects of Low‐Intensity Pulsed Ultrasound on Implant Osseointegration in Ovariectomized Rats
Authors: Zhou Hongbo , Hou Yongfu , Zhu Zhimin , Xiao Weixiong , Xu Qian , Li Lei , Li Xin , Chen Wenchuan
Published: March 2016

Objectives

To investigate the effect of low‐intensity pulsed ultrasound (US) on peri‐implant bone healing and osseointegration under osteoporotic conditions.

Methods

Seventy‐two 12‐week‐old female Sprague Dawley rats received bilateral ovariectomies. Twelve weeks later, titanium implants were bilaterally placed in the proximal tibial metaphysis. The right tibia was exposed to low‐intensity pulsed US (40 mW/cm2, spatial and temporal average) for 20 min/d starting the 2nd day after implantation, and the left tibia served as a control without stimulation. The rats were randomly assigned to 6 groups of 12 each according to the US duration (group 1: weeks 0–2, 280 minutes; group 2: weeks 0–4, 560 minutes; group 3: weeks 0–6, 840 minutes; group 4: weeks 0–8, 1120 minutes; group 5: weeks 0–10, 1400 minutes; group 6: weeks 0–12, 1680 minutes). At the end of the 2nd, 4th, 6th, 8th, 10th, and 12th weeks, the rats were euthanized, and bilateral tibias were harvested. Peri‐implant bone volume and bone‐implant contact were assessed by micro–computed tomography; the implant‐bone interface was assessed histologically; and implant fixation strength was determined by a removal torque test.

Results

Low‐intensity pulsed US increased bone‐implant contact at the 4th, 6th, 8th, 10th, and 12th weeks (P = .019, .017, <.001, <.001, and <.001, respectively) and peri‐implant bone volume at all times (P = <.001, .002, .012, .007, .005, and .010). Removal torque on the US side was improved at the 6th, 8th, 10th, and 12th weeks (P= .012, <.001, .006, and .009). Ultrasound evoked a favorable bone response in the histologic study.

Conclusions

Low‐intensity pulsed US might enhance new bone formation, especially at an early stage, and improve osseointegration in osteoporotic bone as an auxiliary method. However, further studies are needed to elucidate the mechanisms underlying its action.
First‐Trimester Echocardiographic Features and Perinatal Outcomes in Fetuses With Congenital Absence of the Aortic Valve
Authors: Yu Rong , Li Sheng-li , Luo Guo-yang , Wen Hua-xuan , Ouyang Shu-yuan , Chen Cong-ying , Yuan Ying
Published: March 2016

Objectives

The purpose of this study was to describe the echocardiographic features and perinatal outcomes of congenital absence of the aortic valve diagnosed by first‐trimester echocardiography.

Methods

This retrospective study assessed the feasibility of first‐trimester echocardiography in detecting absence of the aortic valve. All cases of absence of the aortic valve diagnosed by first‐trimester fetal echocardiography from January 2010 to December 2014 were identified at a single referral center using an established perinatal database. Demographic information, echocardiograms, perinatal outcomes, and autopsy reports were reviewed. Echocardiographic features were described.

Results

A total of 50,822 fetuses underwent first‐trimester echocardiography during the study period. Ten cases of congenital absence of the aortic valve were diagnosed, for an overall incidence rate of 0.019%. The earliest gestational age at diagnosis was 11 weeks 6 days. The mean crown‐lump length was 61.9 mm; mean gestational age was 12 weeks; and mean maternal body mass index ± SD was 21.2 ± 3.9 kg/m2. Nine fetuses had increased nuchal translucency ranging from 2.4 to 12.4 mm (mean ± SD, 6.4 ± 3.6 mm). Color Doppler flow imaging revealed biphasic bidirectional flow in the ascending aorta and aortic arch and reversed flow in the ductus venosus during atrial systole in all cases. Reversed diastolic flow was present in the umbilical arteries and thoracic aorta. All cases had complex cardiac malformations as well as extracardiac abnormalities.

Conclusions

Our study confirms that absence of the aortic valve is a rare cardiac defect that can be diagnosed by first‐trimester fetal echocardiography. A “to‐and‐fro” flow pattern or biphasic bidirectional flow in the great arteries is a key echocardiographic feature in fetuses with absence of the aortic valve.
Three‐Dimensional Sonography of Biliary Tract Disorders
Authors: Frank Susan J. , Kurian Jessica
Published: March 2016

In this pictorial essay, we review the 3‐dimensional sonographic appearance of the normal gallbladder and biliary tree, as well as the appearance of congenital and acquired biliary tract disorders. Using examples, we demonstrate the advantage of 3‐dimensional scanning compared with 2‐dimensional sonography and, even in certain cases, magnetic resonance cholangiopancreatography.
Nonobliteration of the Processus Vaginalis
Authors: Rafailidis Vasileios , Varelas Sotirios , Apostolopoulou Foteini , Rafailidis Dimitrios
Published: March 2016

The objective of this pictorial essay is to systematically classify processus vaginalis–related disorders in the light of embryology and present illustrative sonograms with corresponding diagrams. Failure of the processus vaginalis to obliterate during gestation results in a wide spectrum of anomalies, including communicating and noncommunicating hydroceles and inguinal and inguinoscrotal hernias, along with other related disorders of the genital system. There are varying classifications in the literature regarding the aforementioned entities. Proper and timely diagnosis of these entities is essential, given the differences in treatment. Although physical examination can narrow the differential diagnosis, sonography plays an essential role in establishing the diagnosis.
Prediction of High‐grade Vesicoureteral Reflux in Children Younger Than 2 Years Using Renal Sonography
Authors: You Sun Kyoung , Kim Jong Chun , Park Won Hong , Lee So Mi , Cho Hyun-Hae
Published: March 2016

Objectives

To investigate the predictive value of renal sonography for vesicoureteral reflux (VUR) and the efficacy of renal sonography, technetium Tc 99m–labeled dimercaptosuccinic acid (DMSA) scanning, and a combination of the two for VUR screening in children younger than 2 years with a first episode of febrile urinary tract infection.

Methods

Thirty‐eight patients younger than 2 years with a first febrile urinary tract infection were included in our study, which was conducted from April through October 2014. Each kidney was considered a separate renal unit. A retrospective review of clinical information and images (renal sonography, DMSA scanning, and voiding cystourethrography) was performed.

Results

Of the 14 renal units (18.4%) with VUR, 4 (28.5%) had high‐grade VUR. Among single findings, dilatation of the renal collecting system, wall thickening of the renal collecting system, and DMSA scans significantly predicted VUR (P= .038, .027, and .01, respectively). Dilatation was the most common single finding (46 of 76 renal units). The sensitivity values for dilatation, wall thickening, and DMSA scans were 85.7%, 64.2%, and 50.0%, and the negative predictive values were 93.3%, 89.7%, and 87.9%.

Conclusions

The negative predictive values indicate that normal renal sonographic and DMSA findings can predict the absence of high‐grade VUR. We propose that renal sonographic findings of wall thickening as well as dilatation of the renal collecting system should be considered predictive of high‐grade VUR.
Quantitative Evaluation for Differentiating Malignant and Benign Thyroid Nodules Using Histogram Analysis of Grayscale Sonograms
Authors: Nam Se Jin , Yoo Jaeheung , Lee Hye Sun , Kim Eun-Kyung , Moon Hee Jung , Yoon Jung Hyun , Kwak Jin Young
Published: March 2016

Objectives

To evaluate the diagnostic value of histogram analysis using grayscale sonograms for differentiation of malignant and benign thyroid nodules.

Methods

From July 2013 through October 2013, 579 nodules in 563 patients who had undergone ultrasound‐guided fine‐needle aspiration were included. For the grayscale histogram analysis, pixel echogenicity values in regions of interest were measured as 0 to 255 (0, black; 255, white) with in‐house software. Five parameters (mean, skewness, kurtosis, standard deviation, and entropy) were obtained for each thyroid nodule. With principal component analysis, an index was derived. Diagnostic performance rates for the 5 histogram parameters and the principal component analysis index were calculated.

Results

A total of 563 patients were included in the study (mean age ± SD, 50.3 ± 12.3 years;range, 15–79 years). Of the 579 nodules, 431 were benign, and 148 were malignant. Among the 5 parameters and the principal component analysis index, the standard deviation (75.546 ± 14.153 versus 62.761 ± 16.01; P < .001), kurtosis (3.898 ± 2.652 versus 6.251 ± 9.102; P < .001), entropy (0.16 ± 0.135 versus 0.239 ± 0.185; P < .001), and principal component analysis index (–0.386±0.774 versus 0.134 ± 0.889; P < .001) were significantly different between the malignant and benign nodules. With the calculated cutoff values, the areas under the curve were 0.681 (95% confidence interval, 0.643–0.721) for standard deviation, 0.661 (0.620–0.703) for principal component analysis index, 0.651 (0.607–0.691) for kurtosis, 0.638 (0.596–0.681) for entropy, and 0.606 (0.563–0.647) for skewness. The subjective analysis of grayscale sonograms by radiologists alone showed an area under the curve of 0.861 (0.833–0.888).

Conclusions

Grayscale histogram analysis was feasible for differentiating malignant and benign thyroid nodules but did not show better diagnostic performance than subjective analysis performed by radiologists. Further technical advances will be needed to objectify interpretations of thyroid grayscale sonograms.
Upper D region chemical kinetic modeling of LORE relaxation times
Authors: Gordillo‐Vázquez F. J. , Luque A. , Haldoupis C.
Published: March 2016

The recovery times of upper D region electron density elevations, caused by lightning‐induced electromagnetic pulses (EMP), are modeled. The work was motivated from the need to understand a recently identified narrowband VLF perturbation named LOREs, an acronym for LOng Recovery Early VLF events. LOREs associate with long‐living electron density perturbations in the upper D region ionosphere; they are generated by strong EMP radiated from large peak current intensities of ±CG (cloud to ground) lightning discharges, known also to be capable of producing elves. Relaxation model scenarios are considered first for a weak enhancement in electron density and then for a much stronger one caused by an intense lightning EMP acting as an impulsive ionization source. The full nonequilibrium kinetic modeling of the perturbed mesosphere in the 76 to 92 km range during LORE‐occurring conditions predicts that the electron density relaxation time is controlled by electron attachment at lower altitudes, whereas above 79 km attachment is balanced totally by associative electron detachment so that electron loss at these higher altitudes is controlled mainly by electron recombination with hydrated positive clusters H+(H2O)n and secondarily by dissociative recombination with NO+ ions, a process which gradually dominates at altitudes >88 km. The calculated recovery times agree fairly well with LORE observations. In addition, a simplified (quasi‐analytic) model build for the key charged species and chemical reactions is applied, which arrives at similar results with those of the full kinetic model. Finally, the modeled recovery estimates for lower altitudes, that is <79 km, are in good agreement with the observed short recovery times of typical early VLF events, which are known to be associated with sprites.
Dynamic effects of restoring footpoint symmetry on closed magnetic field lines
Authors: Reistad J. P. , Østgaard N. , Tenfjord P. , Laundal K. M. , Snekvik K. , Haaland S. , Milan S. E. , Oksavik K. , Frey H. U. , Grocott A.
Published: March 2016

Here we present an event where simultaneous global imaging of the aurora from both hemispheres reveals a large longitudinal shift of the nightside aurora of about 3 h, being the largest relative shift reported on from conjugate auroral imaging. This is interpreted as evidence of closed field lines having very asymmetric footpoints associated with the persistent positive y component of the interplanetary magnetic field before and during the event. At the same time, the Super Dual Auroral Radar Network observes the ionospheric nightside convection throat region in both hemispheres. The radar data indicate faster convection toward the dayside in the dusk cell in the Southern Hemisphere compared to its conjugate region. We interpret this as a signature of a process acting to restore symmetry of the displaced closed magnetic field lines resulting in flux tubes moving faster along the banana cell than the conjugate orange cell. The event is analyzed with emphasis on Birkeland currents (BC) associated with this restoring process, as recently described by Tenfjord et al. (2015). Using data from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) during the same conditions as the presented event, the large‐scale BC pattern associated with the event is presented. It shows the expected influence of the process of restoring symmetry on BCs. We therefore suggest that these observations should be recognized as being a result of the dynamic effects of restoring footpoint symmetry on closed field lines in the nightside.
Characteristics of the near‐surface atmosphere over the Ross Ice Shelf, Antarctica
Authors: Cassano John J. , Nigro Melissa A. , Lazzara Matthew A.
Published: March 2016

Two years of data from a 30 m instrumented tower are used to characterize the near‐surface atmospheric state over the Ross Ice Shelf, Antarctica. Stable stratification dominates the surface layer at this site, occurring 83% of the time. The strongest inversions occur for wind speeds less than 4 m s−1 and the inversion strength decreases rapidly as wind speed increases above 4 m s−1. In summer unstable stratification occurs 50% of the time and unstable conditions are observed in every season. A novel aspect of this work is the use of an artificial neural network pattern identification technique, known as self‐organizing maps, to objectively identify characteristic potential temperature profiles that span the range of profiles present in the 2 year study period. The self‐organizing map clustering technique allows the more than 100,000 observed potential temperature profiles to be represented by just 30 patterns. The pattern‐averaged winds show distinct and physically consistent relationships with the potential temperature profiles. The strongest winds occur for the nearly well mixed but slightly stable patterns and the weakest winds occur for the strongest inversion patterns. The weakest wind shear over the depth of the tower occurs for slightly unstable profiles and the largest wind shear occurs for moderately strong inversions. Pattern‐averaged log wind profiles are consistent with theoretical expectations. The log wind profiles exhibit a kinked profile for the strongest inversion cases indicative of decoupling of the winds between the bottom and top of the tower.
Predictability of the stratospheric polar vortex breakdown: An ensemble reforecast experiment for the splitting event in January 2009
Authors: Noguchi Shunsuke , Mukougawa Hitoshi , Kuroda Yuhji , Mizuta Ryo , Yabu Shoukichi , Yoshimura Hiromasa
Published: March 2016

A series of ensemble reforecast experiments is conducted to investigate the predictability and the occurrence mechanism of a stratospheric sudden warming occurred in late January 2009, which is a typical polar vortex splitting event. To fully examine the rapid vortex splitting evolution and predictability variation, ensemble forecasts are carried out every day during January 2009. The vortex splitting event is reliably predicted by forecasts initialized after 6 days prior to the vortex breakup. It is also found that the propagating property of planetary waves within the stratosphere is a key to the successful prediction for the vortex splitting event. Planetary waves incoming from the troposphere are reflected back into the troposphere for failed forecasts, whereas they are absorbed within the stratosphere for succeeded forecasts. Composite analysis reveals the following reflection process of planetary waves for the failed forecast: Upward propagation of planetary wave activity from a tropospheric blocking over Alaska is weaker during initial prediction periods; then, the deceleration of the zonal wind in the upper stratosphere becomes weaker over Europe, which produces a preferable condition for the wave reflection; hence, subsequently incoming wave activity from the troposphere over Europe is reflected back over the Siberia inducing the eastward phase tilt of planetary waves, which shuts down the further upward propagation of planetary waves leading to the vortex splitting. Thus, this study shows that the stratospheric condition would be another important control factor for the occurrence of the vortex splitting event, besides anomalous tropospheric circulations enforcing upward propagation of planetary waves.
The signatures of large‐scale patterns of atmospheric variability in Antarctic surface temperatures
Authors: Marshall Gareth J. , Thompson David W. J.
Published: March 2016

We investigate the impact that the four principal large‐scale patterns of Southern Hemisphere (SH) atmospheric circulation variability have on Antarctic surface air temperature (SAT): (1) the southern baroclinic annular mode (BAM), which is associated with variations in extratropical storm amplitude; (2) the Southern Annular Mode (SAM), associated with latitudinal shifts in the midlatitude jet; and (3) the two Pacific‐South American patterns (PSA1 and PSA2), which are characterized by wave trains originating in the tropical Pacific that extend across the SH extratropics. A key aspect is the use of 35 years of daily observations and reanalysis data, which affords a sufficiently large sample size to assess the signatures of the circulation patterns in both the mean and variability of daily mean SAT anomalies. The BAM exerts the weakest influence on Antarctic SAT, albeit it is still important over select regions. Consistent with previous studies, the SAM is shown to influence SAT across most of the continent throughout the year. The PSA1 also affects SAT across almost all of Antarctica. Regionally, both PSA patterns can exert a greater impact on SAT than the SAM but also have a significantly weaker influence during summer, reflecting the seasonality of the SH response to El Niño–Southern Oscillation. The SAM and PSA patterns have distinct signatures in daily SAT variance that are physically consistent with their signatures in extratropical dynamic variability. The broad‐scale climate linkages identified here provide benchmarks for interpreting the Antarctic climate response to future changes in tropical sea surface temperatures, ozone recovery, and greenhouse gas increases.
P and S wave responses of bacterial biopolymer formation in unconsolidated porous media
Authors: Noh Dong‐Hwa , Ajo‐Franklin Jonathan B. , Kwon Tae‐Hyuk , Muhunthan Balasingam
Published: March 2016

This study investigated the P and S wave responses and permeability reduction during bacterial biopolymer formation in unconsolidated porous media. Column experiments with fine sands, where the model bacteria Leuconostoc mesenteroides were stimulated to produce insoluble biopolymer, were conducted while monitoring changes in permeability and P and S wave responses. The bacterial biopolymer reduced the permeability by more than 1 order of magnitude, occupying ~10% pore volume after 38 days of growth. This substantial reduction was attributed to the bacterial biopolymer with complex internal structures accumulated at pore throats. S wave velocity (VS) increased by more than ~50% during biopolymer accumulation; this indicated that the bacterial biopolymer caused a certain level of stiffening effect on shear modulus of the unconsolidated sediment matrix at low confining stress conditions. Whereas replacing pore water by insoluble biopolymer was observed to cause minimal changes in P wave velocity (VP) due to the low elastic moduli of insoluble biopolymer. The spectral ratio analyses revealed that the biopolymer formation caused a ~50–80% increase in P wave attenuation (1/QP) at the both ultrasonic and subultrasonic frequency ranges, at hundreds of kHz and tens of kHz, respectively, and a ~50–60% increase in S wave attenuation (1/QS) in the frequency band of several kHz. Our results reveal that in situ biopolymer formation and the resulting permeability reduction can be effectively monitored by using P and S wave attenuation in the ultrasonic and subultrasonic frequency ranges. This suggests that field monitoring using seismic logging techniques, including time‐lapse dipole sonic logging, may be possible.
Extracting ocean‐generated tidal magnetic signals from Swarm data through satellite gradiometry
Authors: Sabaka Terence J. , Tyler Robert H. , Olsen Nils
Published: March 2016

Ocean‐generated magnetic field models of the Principal Lunar, M2, and the Larger Lunar elliptic, N2, semidiurnal tidal constituents were estimated through a “Comprehensive Inversion” of the first 20.5 months of magnetic measurements from European Space Agency's (ESA) Swarm satellite constellation mission. While the constellation provides important north‐south along‐track gradiometry information, it is the unique low‐spacecraft pair that allows for east‐west cross‐track gradiometry. This latter type is crucial in delivering an M2 estimate of similar quality with that derived from over 10 years of CHAMP satellite data but over a shorter interval, at higher altitude, and during more magnetically disturbed conditions. Recovered N2 contains nonoceanic signal but is highly correlated with theoretical models in regions of maximum oceanic amplitude. Thus, satellite magnetic gradiometry may eventually enable the monitoring of ocean electrodynamic properties at temporal resolutions of 1 to 2 years, which may have important implications for the inference of ocean temperature and salinity.
Ocean waves across the Arctic: Attenuation due to dissipation dominates over scattering for periods longer than 19 s
Authors: Ardhuin Fabrice , Sutherland Peter , Doble Martin , Wadhams Peter
Published: March 2016

The poorly understood attenuation of surface waves in sea ice is generally attributed to the combination of scattering and dissipation. Scattering and dissipation have very different effects on the directional and temporal distribution of wave energy, making it possible to better understand their relative importance by analysis of swell directional spreading and arrival times. Here we compare results of a spectral wave model—using adjustable scattering and dissipation attenuation formulations—with wave measurements far inside the ice pack. In this case, scattering plays a negligible role in the attenuation of long swells. Specifically, scattering‐dominated attenuation would produce directional wave spectra much broader than the ones recorded, and swell events arriving later and lasting much longer than observed. Details of the dissipation process remain uncertain. Average dissipation rates are consistent with creep effects but are 12 times those expected for a laminar boundary layer under a smooth solid ice plate.
Simultaneous observations of atmospheric tides from combined in situ and remote observations at Mars from the MAVEN spacecraft
Authors: England Scott L. , Liu Guiping , Withers Paul , Yiğit Erdal , Lo Daniel , Jain Sonal , Schneider Nicholas M. , Deighan Justin , McClintock William E. , Mahaffy Paul R. , Elrod Meredith , Benna Mehdi , Jakosky Bruce M.
Published: March 2016

We report the observations of longitudinal variations in the Martian thermosphere associated with nonmigrating tides. Using the Neutral Gas Ion Mass Spectrometer (NGIMS) and the Imaging Ultraviolet Spectrograph (IUVS) on NASA's Mars Atmosphere and Volatile EvolutioN Mission (MAVEN) spacecraft, this study presents the first combined analysis of in situ and remote observations of atmospheric tides at Mars for overlapping volumes, local times, and overlapping date ranges. From the IUVS observations, we determine the altitude and latitudinal variation of the amplitude of the nonmigrating tidal signatures, which is combined with the NGIMS, providing information on the compositional impact of these waves. Both the observations of airglow from IUVS and the CO2 density observations from NGIMS reveal a strong wave number 2 signature in a fixed local time frame. The IUVS observations reveal a strong latitudinal dependence in the amplitude of the wave number 2 signature. Combining this with the accurate CO2 density observations from NGIMS, this would suggest that the CO2 density variation is as high as 27% at 0–10° latitude. The IUVS observations reveal little altitudinal dependence in the amplitude of the wave number 2 signature, varying by only 20% from 160 to 200 km. Observations of five different species with NGIMS show that the amplitude of the wave number 2 signature varies in proportion to the inverse of the species scale height, giving rise to variation in composition as a function of longitude. The analysis and discussion here provide a roadmap for further analysis as additional coincident data from these two instruments become available.