bluuebunny/crossref_metadata_2025 huggingface dataset:
From Disciplinarity to Postdisciplinarity: Tourism Studies Dedisciplined
Authors: Darbellay Frédéric
Published: July 2016

Inter- and transdisciplinarity are currently experiencing real development within the national and international university landscape. Moreover, they now feature explicitly on the agendas of political and academic organizations that promote and fund scientific research. The increasing focus on interdisciplinarity in the sciences and humanities, in general, and tourism studies, in particular, reflects an awareness of the complexity of research, which is increasingly confronted with social issues that require dialogue between the institutionalized disciplines. Today, the rooted disciplines face a crisis in meeting the ambitions and expectations of many researchers who question both the potential and limits of their own disciplines and the ways in which they can establish new connections with other disciplines. This article aims to explore the implications of a possible postdisciplinary era in which knowledge would be constructed on the ruins of disciplines from a disciplinary or antidisciplinary perspective. I try to define "postdisciplinarity" and its links to inter- and transdisciplinarity and show how they can be similar or, conversely, dissimilar. In a more consensual vein, I show how it is possible to reconcile the desire to end disciplines and the need to take them into account—or even rethink them. Tourism studies are taken here as a prototypical example of the integration between and beyond disciplines with a view to analyzing and understanding the complexity of tourism activities.
Transposable element evolution in the allotetraploid Capsella bursa‐pastoris
Authors: Ågren J. Arvid , Huang Hui‐Run , Wright Stephen I.
Published: July 2016

PREMISE OF THE STUDY:

Shifts in ploidy affect the evolutionary dynamics of genomes in a myriad of ways. Population genetic theory predicts that transposable element (TE) proliferation may follow because the genomewide efficacy of selection should be reduced and the increase in gene copies may mask the deleterious effects of TE insertions. Moreover, in allopolyploids, TEs may further accumulate because of hybrid breakdown of TE silencing. However, to date the evidence of TE proliferation following an increase in ploidy is mixed, and the relative importance of relaxed selection vs. silencing breakdown remains unclear.

METHODS:

We used high‐coverage whole‐genome sequence data to evaluate the abundance, genomic distribution, and population frequencies of TEs in the self‐fertilizing recent allotetraploid Capsella bursa‐pastoris (Brassicaceae). We then compared the C. bursa‐pastoris TE profile with that of its two parental diploid species, outcrossing C. grandiflora and self‐fertilizing C. orientalis.

KEY RESULTS:

We found no evidence that C. bursa‐pastoris has experienced a large genomewide proliferation of TEs relative to its parental species. However, when centromeric regions are excluded, we found evidence of significantly higher abundance of retrotransposons in C. bursa‐pastoris along the gene‐rich chromosome arms compared with C. grandiflora and C. orientalis.

CONCLUSIONS:

The lack of a genomewide effect of allopolyploidy on TE abundance, combined with the increases TE abundance in gene‐rich regions, suggests that relaxed selection rather than hybrid breakdown of host silencing explains the TE accumulation in C. bursa‐pastoris.
A 2.4% DETERMINATION OF THE LOCAL VALUE OF THE HUBBLE CONSTANT*
Authors: Riess Adam G. , Macri Lucas M. , Hoffmann Samantha L. , Scolnic Dan , Casertano Stefano , Filippenko Alexei V. , Tucker Brad E. , Reid Mark J. , Jones David O. , Silverman Jeffrey M. , Chornock Ryan , Challis Peter , Yuan Wenlong , Brown Peter J. , Foley Ryan J.
Published: July 2016

We use the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) to reduce the uncertainty in the local value of the Hubble constant from 3.3% to 2.4%. The bulk of this improvement comes from new near-infrared (NIR) observations of Cepheid variables in 11 host galaxies of recent type Ia supernovae (SNe Ia), more than doubling the sample of reliable SNe Ia having a Cepheid-calibrated distance to a total of 19; these in turn leverage the magnitude-redshift relation based on ∼300 SNe Ia at z < 0.15. All 19 hosts as well as the megamaser system NGC 4258 have been observed with WFC3 in the optical and NIR, thus nullifying cross-instrument zeropoint errors in the relative distance estimates from Cepheids. Other noteworthy improvements include a 33% reduction in the systematic uncertainty in the maser distance to NGC 4258, a larger sample of Cepheids in the Large Magellanic Cloud (LMC), a more robust distance to the LMC based on late-type detached eclipsing binaries (DEBs), HST observations of Cepheids in M31, and new HST-based trigonometric parallaxes for Milky Way (MW) Cepheids. We consider four geometric distance calibrations of Cepheids: (i) megamasers in NGC 4258, (ii) 8 DEBs in the LMC, (iii) 15 MW Cepheids with parallaxes measured with HST/FGS, HST/WFC3 spatial scanning and/or Hipparcos, and (iv) 2 DEBs in M31. The Hubble constant from each is 72.25 ± 2.51, 72.04 ± 2.67, 76.18 ± 2.37, and 74.50 ± 3.27 km s−1 Mpc−1, respectively. Our best estimate of H
0 = 73.24 ± 1.74 km s−1 Mpc−1 combines the anchors NGC 4258, MW, and LMC, yielding a 2.4% determination (all quoted uncertainties include fully propagated statistical and systematic components). This value is 3.4σ higher than 66.93 ± 0.62 km s−1 Mpc−1 predicted by ΛCDM with 3 neutrino flavors having a mass of 0.06 eV and the new Planck data, but the discrepancy reduces to 2.1σ relative to the prediction of 69.3 ± 0.7 km s−1 Mpc−1 based on the comparably precise combination of WMAP+ACT+SPT+BAO observations, suggesting that systematic uncertainties in CMB radiation measurements may play a role in the tension. If we take the conflict between Planck high-redshift measurements and our local determination of H
0 at face value, one plausible explanation could involve an additional source of dark radiation in the early universe in the range of ΔN
eff ≈ 0.4–1. We anticipate further significant improvements in H
0 from upcoming parallax measurements of long-period MW Cepheids.
THE RED AND FEATURELESS OUTER DISKS OF NEARBY SPIRAL GALAXIES
Authors: Watkins Aaron E. , Mihos J. Christopher , Harding Paul
Published: July 2016

We present results from deep, wide-field surface photometry of three nearby (D = 4–7 Mpc) spiral galaxies: M94 (NGC 4736), M64 (NGC 4826), and M106 (NGC 4258). Our imaging reaches a limiting surface brightness of

∼ 28–30 mag arcsec−2 and probes colors down to

∼ 27.5 mag arcsec−2. We compare our broadband optical data to available ultraviolet and high column density H i data to better constrain the star-forming history and stellar populations of the outermost parts of each galaxy’s disk. Each galaxy has a well-defined radius beyond which little star formation occurs and the disk light appears both azimuthally smooth and red in color, suggestive of old, well-mixed stellar populations. Given the lack of ongoing star formation or blue stellar populations in these galaxies’ outer disks, the most likely mechanisms for their formation are dynamical processes such as disk heating or radial migration, rather than inside-out growth of the disks. This is also implied by the similarity in outer disk properties despite each galaxy showing distinct levels of environmental influence, from a purely isolated galaxy (M94) to one experiencing weak tidal perturbations from its satellite galaxies (M106) to a galaxy recovering from a recent merger (M64), suggesting that a variety of evolutionary histories can yield similar outer disk structure. While this suggests a common secular mechanism for outer disk formation, the large extent of these smooth, red stellar populations—which reach several disk scale lengths beyond the galaxies’ spiral structure—may challenge models of radial migration given the lack of any nonaxisymmetric forcing at such large radii.
THE HOST GALAXY PROPERTIES OF VARIABILITY SELECTED AGN IN THE PAN-STARRS1 MEDIUM DEEP SURVEY
Authors: Heinis S. , Gezari S. , Kumar S. , Burgett W. S. , Flewelling H. , Huber M. E. , Kaiser N. , Wainscoat R. J. , Waters C.
Published: July 2016

We study the properties of 975 active galactic nuclei (AGNs) selected by variability in the Pan-STARRS1 Medium deep Survey. Using complementary multi-wavelength data from the ultraviolet to the far-infrared, we use spectral energy distribution fitting to determine the AGN and host properties at z < 1 and compare to a well-matched control sample. We confirm the trend previously observed: that the variability amplitude decreases with AGN luminosity, but we also observe that the slope of this relation steepens with wavelength, resulting in a “redder when brighter” trend at low luminosities. Our results show that AGNs are hosted by more massive hosts than control sample galaxies, while the rest frame dust-corrected NUV − r color distribution of AGN hosts is similar to control galaxies. We find a positive correlation between the AGN luminosity and star formation rate (SFR), independent of redshift. AGN hosts populate the entire range of SFRs within and outside of the Main Sequence of star-forming galaxies. Comparing the distribution of AGN hosts and control galaxies, we show that AGN hosts are less likely to be hosted by quiescent galaxies and more likely to be hosted by Main Sequence or starburst galaxies.
The exploitation of sludge from aggregate plants in the manufacture of porous fired clay bricks
Authors: Chamorro-Trenado M. A. , Pareta-Marjanedas M. M. , Berthelsen-Molist B. E. , Janer-Adrian F. X.
Published: July 2016

Aggregates (gravel and sand) are, after water, the Earth’s second most used natural resource, representing about 50% of all consumed mineral resources. Aggregate production generates a large quantity of waste from the aggregate washing process. This waste is made up of suspended solids – sludge – which has a great environmental impact. It is deposited in huge troughs because of the impossibility of discharging it directly into rivers. Many plants have incorporated decanters and filter presses to separate the solid from the liquid fraction. This paper evaluates the possibility of exploiting the solid fraction (i.e. sludge) in the manufacture of fired clay bricks. The added value of these bricks is, on the one hand, the exploitation of sludge as a currently useless waste product, and on the other, the use of this sludge to enhance the physical and mechanical properties of conventional fired clay bricks.
Gamification and Education: Achievements, Cognitive Loads, and Views of Students
Authors: Turan Zeynep , Avinc Zeynep , Kara Kadir , Goktas Yuksel
Published: July 2016

In this mixed method research study, the effect of gamification strategies on students’ cognitive load levels and achievements was examined along with student opinions about gamification. The topic of spreadsheets was covered for six weeks in a sixth grade information technologies and software course. The sample consisted of a control group of 48 students who were trained via traditional procedures and an experimental group of 46 students who were trained using gamification strategies. Independent sample t-test, Mann-Whitney U test and descriptive analysis were applied to the data. A significant difference was found between the two groups that indicated higher achievement in the experimental group. When comparing cognitive load levels, the experimental group also scored higher than the control group. Interviews indicated that the students had positive views about gamification strategies.
Visualizations of Online Course Interactions for Social Network Learning Analytics
Authors: Hernández-García Ángel , González-González Inés , Jiménez-Zarco Ana Isabel , Chaparro-Peláez Julián
Published: July 2016

Social network learning analytics aims to extract useful information to improve the learning process, but the variety of learning management systems makes this task burdensome and difficult to manage. This study shows how Gephi, a general-purpose, open-source social network analysis application, can be used by instructors and institutions to extract and visualize relevant information that is commonly hidden or difficult to observe for course coordinators and teachers. The empirical case study uses data from one cross-curricular course with 656 students at the Open University of Catalonia (UOC) and showcases the use of Gephi as a social network learning analytics tool. The study further discusses the potential of social network learning analytics to improve online instruction by visualization of educational data.
Technology Standards for Chinese Language Teacher Education
Authors: Wang Wenxia , Feng Liying
Published: July 2016

Guided by the TPACK theory (Mishra & Koehler, 2006), this chapter reviews and compares the technology standards related to and designed for teachers of Chinese as a Foreign Language (CFL) from the entry level to the accomplished level in the United States and China. It has found that the technology standards are often included in the comprehensive standards for teachers and parallel the standards about other aspects of teaching. The technology standards related to CFL in the two countries share some similarities but also differ in important ways. Several important and critical understandings are identified, including the needs for CFL technology standards, the theoretical foundations for CFL technology standards, and a more solid and comprehensive infrastructure for CFL education. Recommendations are made to address the needs, and research is called for to study the development and implementation of CFL technology standards.
Teaching Foreign Languages in the Twenty-First Century
Authors: Gretter Sarah , Gondra Ager
Published: July 2016

This chapter explores the case of a hybrid Spanish program where technology, standards, and teacher expertise in foreign language education are merged to bolster students' learning. The chapter identifies the instructional elements relevant to 21st century foreign language education, and depicts the transactional relationship between technology, standards and teacher experience in a Spanish hybrid teaching environment. Finally, we provide a set of recommendations for current and future Spanish educators, as well as foreign language educators in general based on the experiences shared by students, educators, and administrator in the program.
Mentoring Preservice EFL Teachers for Technology Integration
Authors: Liu Mei-Hui
Published: July 2016

This chapter proposes an integrated mentoring model in the context of established and emerging Information and Communications Technology (ICT) tools to be applied into teacher professional development. Twenty preservice English as a Foreign Language (EFL) preservice teachers participating in a Cloud-based internship project were involved in a series of training activities, including virtual technology training workshops, in-class methods instruction, design and implementation of teaching projects on a Cloud platform, and subsequent face-to-face and online discussions on teaching practices. Multiple qualitative data collected offers evidence to examine the potential of employing this mentoring mechanism to make amends for what has been rarely exploited in the extant technology teacher training models in the foreign language education field. Based on the research findings, a revised mentoring model is suggested for further investigation.
Social Media and Foreign Language Teacher Education
Authors: Li Jiahang
Published: July 2016

This chapter will focus on examining how instructors who are preparing foreign language teachers, both pre-service and in-service, integrate social media in their teaching practices to gain more insights on what beliefs these instructors hold and what differences and similarities between their beliefs and actual teaching practices about social media integration in foreign language teacher education. The chapter will first provide a literature review about the general beliefs that instructors held on the integration of social media and foreign language teacher education. Next, promising examples of the integration of social media in foreign language teacher education will be provided. Last but not least, affordances and challenges of the integration of social media and foreign language teacher education will be discussed, followed by implications and future directions.
The Interaction between Collaboration, Organisational Capacity and E-Business Diffusion and their Effect on Business Performance
Authors: Lu Wu , Al-Hakim Latif
Published: July 2016

This study empirically tests the joint impact of trust, e-commerce diffusion and organisational capacity and collaboration and investigates the effect of the interaction among them on business performance. Basing on the literature review and seven pilot case studies, this research conducted hypotheses and mediation tests for collaboration and e-collaboration in interactive with two facilitating roles from trust and organisational capacity on business performance. Data analysis is based on a usable dataset of 395 responses (valid response rate of 79%) collected from the perspectives of CEOs and senior managers in Wenzhou China manufacturing electrical industry cluster. This research is supported by Department of Education of Zhejiang Province Foundation (Y201328223) and Priority Academic Program Development of Zhejiang Higher Education Institutions -Business Administration. Results indicate that collaboration plays a full mediator between the trust and business performance, as well as between organisational capacities and business performance; and e-business diffusion not significantly affect the output of collaboration. This result may be rationalized by the inability of these organisations to nurture an e-business diffusion culture and organisational process effectiveness in making collaboration with their trading partners and the organisations do not give attention to the with partners. The empirical evidence from this research implied that, e-business facilitated business interactions require sound organisational capacities and trusted relationship in managing wide value-chain wide interorganisational collaboration.
Lack of IL-1 Receptor–Associated Kinase-4 Leads to Defective Th1 Cell Responses and Renders Mice Susceptible to Mycobacterial Infection
Authors: Marinho Fábio V. , Fahel Júlia S. , Scanga Charles A. , Gomes Marco Tulio R. , Guimarães Gabriela , Carvalho Gabrielle R. M. , Morales Stefanny V. , Báfica André , Oliveira Sergio Costa
Published: July 2016

The Toll-like and IL-1 family receptors play critical roles in innate and adaptive immunity against intracellular pathogens. Although previous data demonstrated the importance of TLRs and IL-1R signaling events for the establishment of an effective immune response to mycobacteria, the possible function of the adaptor molecule IL-1R–associated kinase (IRAK)-4 against this pathogen has not been addressed. In this study, we determined the role of IRAK-4 in signaling pathways responsible for controlling mycobacterial infections. This kinase is important for the production of IL-12 and TNF-α by macrophages and dendritic cells exposed to mycobacteria. Moreover, Mycobacterium bovis–infected IRAK-4–knockout macrophages displayed impaired MAPK and NF-κB activation. IL-1β secretion and caspase-1 activation were also dependent on IRAK-4 signaling. Mice lacking IRAK-4 showed increased M. bovis burden in spleen, liver, and lungs and smaller liver granulomas during 60 d of infection compared with wild-type mice. Furthermore, 80% of IRAK-4−/− mice succumbed to virulent M. tuberculosis within 100 d following low-dose infection. This increased susceptibility to mycobacteria correlated with reduced IFN-γ/TNF-α recall responses by splenocytes, as well as fewer IL-12p70–producing APCs. Additionally, we observed that IRAK-4 is also important for the production of IFN-γ by CD4+ T cells from infected mice. Finally, THP-1 cells treated with an IRAK-4 inhibitor and exposed to M. bovis showed reduced TNF-α and IL-12, suggesting that the results found in mice can be extended to humans. In summary, these data demonstrate that IRAK-4 is essential for innate and adaptive immunity and necessary for efficient control of mycobacterial infections.
Privacidad: cómo se entiende y se gestiona en Facebook. Estudio de caso de jóvenes chilenos
Authors: Moreno-Becerra Tabita , Gajardo-León Constanza , Parra-Ortiz Elizabeth
Published: July 2016

os usuarios de Facebook comparten continuamente variada información, incluyendo datos personales hasta su localización física. Dichas prácticas alteran el concepto de privacidad, pues los datos permanecen disponibles para los contactos pero son también muchas veces de acceso público.Metodología. Este artículo analiza el modo en que adultos jóvenes (25-34 años), en Chile, concilian la difusión de información personal a través de Facebook con el cuidado de su privacidad. Mediante un estudio de caso se entrevistó en profundidad a 20 jóvenes de Concepción. Resultados y conclusiones. Los resultados muestran que los jóvenes seleccionan con cuidado la información que podrán consultar sus contactos y adoptan diferentes estrategias para proteger su información personal y definir quiénes accederán a contenido específico. En concordancia y dado ese sentido de control que consideran tener sobre la información que comparten, estos jóvenes no perciben una amenaza a su privacidad social (vigilancia social), pero desconfían y sienten amenazada su privacidad institucional (vigilancia institucional).
Do Current Lattice Boltzmann Methods for Diffusion and Advection-Diffusion Equations Respect Maximum Principle and the Non-Negative Constraint?
Authors: Karimi S. , Nakshatrala K. B.
Published: July 2016

The Lattice Boltzmann Method (LBM) has established itself as a popular numerical method in computational fluid dynamics. Several advancements have been recently made in LBM, which include multiple-relaxation-time LBM to simulate anisotropic advection-diffusion processes. Because of the importance of LBM simulations for transport problems in subsurface and reactive flows, one needs to study the accuracy and structure preserving properties of numerical solutions under the LBM. The solutions to advective-diffusive systems are known to satisfy maximum principles, comparison principles, the non-negative constraint, and the decay property. In this paper, using several numerical experiments, it will be shown that current single- and multiple-relaxation-time lattice Boltzmann methodsfailto preserve these mathematical properties for transient diffusion-type equations. We will also show that these violations may not be removed by simply refining the discretization parameters. More importantly, it will be shown that meeting stability conditions alone does not guarantee the preservation of the aforementioned mathematical principles and physical constraints in the discrete setting. A discussion on the source of these violations and possible approaches to avoid them is included. A condition to guarantee the non-negativity of concentration under LBM in the case of isotropic diffusion is also derived. The impact of this research is twofold.First, the study poses several outstanding research problems, which should guide researchers to develop LBM-based formulations for transport problems that respect important mathematical properties and physical constraints in the discrete setting. This paper can also serve as a good source of benchmark problems for such future research endeavors.Second, this study cautions the practitioners of the LBM for transport problems with the associated numerical deficiencies of the LBM, and provides guidelines for performing predictive simulations of advective-diffusive processes using the LBM.
Analysis of the Effect of Spatial Uncertainties on the Dynamic Behavior of Electrostatic Microactuators
Authors: Alwan Aravind , Aluru Narayana R.
Published: July 2016

This paper examines the effect of spatial roughness on the dynamical behaviour of electrostatic microactuators. We develop a comprehensive physical model that comprises a nonlinear electrostatic actuation force aswell as a squeeze-film damping term to accurately simulate the dynamical behavior of a cantilever beam actuator. Spatial roughness is modeled as a nonstationary stochastic process whose parameters can be estimated from profilometric measurements. We propagate the stochastic model through the physical system and examine the resulting uncertainty in the dynamical behavior that manifests as a variation in the quality factor of the device. We identify two distinct, yet coupled, modes of uncertainty propagation in the system, that result from the roughness causing variation in the electrostatic actuation force and the damping pressure, respectively. By artificially turning off each of these modes of propagation in sequence, we demonstrate that the variation in the damping pressure has a greater effect on the damping ratio than that arising from the electrostatic force. Comparison with similar simulations performed using a simplified mass-spring-damper model show that the coupling between these two mechanisms can be captured only when the physical model includes the primary nonlinear interactions along with a proper treatment of spatial variations. We also highlight the difference between nonstationary and stationary covariance formulations by showing that the stationary model is unable to properly capture the full range of variation as compared to its nonstationary counterpart.
Glass-ionomer Cements in Restorative Dentistry: A Critical Appraisal
Authors: Almuhaiza Mohammed
Published: July 2016

Glass-ionomer cements (GICs) are mainstream restorative materials that are bioactive and have a wide range of uses, such as lining, bonding, sealing, luting or restoring a tooth. Although the major characteristics of GICs for the wider applications in dentistry are adhesion to tooth structure, fluoride releasing capacity and tooth-colored restorations, the sensitivity to moisture, inherent opacity, long-term wear and strength are not as adequate as desired. They have undergone remarkable changes in their composition, such as the addition of metallic ions or resin components to their composition, which contributed to improve their physical properties and diversified their use as a restorative material of great clinical applicability. The lightcured polymer reinforced materials appear to have substantial benefits, while retaining the advantages of fluoride release and adhesion. Further research should be directed towards improving the properties, such as strength and esthetics without altering its inherent qualities, such as adhesion and fluoride releasing capabilities.

How to cite this article

Almuhaiza M. Glass-ionomer Cements in Restorative Dentistry: A Critical Appraisal. J Contemp Dent Pract 2016;17(4):331-336.
The Removable Mandibular Retractor vs the Boneanchored Intermaxillary Traction in the Correction of Skeletal Class III Malocclusion in Children: A Randomized Controlled Trial
Authors: Hajeer Mohammad Y , Majanni Abdulmalek MR
Published: July 2016

Background

No randomized controlled trial has tried to compare early class III treatment outcomes between the removable mandibular retractor (RMR) and the bone-anchored intermaxillary traction (BAIMT). The objective of this study was to evaluate skeletal, dental, and soft-tissue changes following early class III treatment with these two treatment modalities.

Materials and methods

A parallel group randomized controlled trial was conducted on patients with class III malocclusion, treated at the University of Al-Baath Dental School in Hamah, Syria. Ninetythree children with skeletal class III malocclusion were evaluated and 41 children fulfilled the inclusion criteria. Randomization was performed using computer-generated tables; allocation was concealed using sequentially numbered opaque and sealed envelopes. Thirty-eight participants were analyzed (mean age 11.46 ± 1.28 years). They were randomly distributed into two groups receiving either the RMR or the BAIMT technique with 19 children in each (1:1 allocation ratio). The primary outcome measure was the horizontal movement of points A, B, and Pogonion.

Results

Point A showed greater anterior movement in the BAIMT group (x̄ = 1.69 mm) than in the RMR group (x̄ = 1.05 mm; p < 0.001). Points B and Pog showed posterior movement in the BAIMT group (x̄ = −3.01 and −2.51 mm respectively) and anterior movements in the RMR group (x̄ = 0.22 and 0.78 mm respectively).

Conclusion

The BAIMT appeared to be more effective than the RMR in the correction of mild to moderate class III malocclusion in growing patients.

Clinical significance

Bone-anchored intermaxillary elastics appears to be a promising solution for class III growing patients with mild to moderate degrees of skeletal discrepancy.

How to cite this article

Majanni AMR, Hajeer MY. The Removable Mandibular Retractor vs the Bone-anchored Intermaxillary Traction in the Correction of Skeletal Class III Malocclusion in Children: A Randomized Controlled Trial. J Contemp Dent Pract 2016;17(5):361-371.
Hydrolytic and Color Stability of Resin Infiltration: A Preliminary in vitro Trial
Authors: Ritwik Priyanshi , Jones Christopher M , Fan Yuwei , Sarkar Nikhil K
Published: July 2016

Aims

Resin infiltration is an emerging technique for management of noncavitated lesions. This study evaluated the in vitro hydrolytic and color stability of the ICON® resin infiltration system (IC) in 42 extracted human teeth.

Materials and methods

ICON® resin infiltration system was compared with dental adhesive (DA) and dental sealant (DS). The products were applied according to manufacturer's instructions. The baseline weight and color of the samples were recorded. Color was recorded by spectoral colorimeter. The samples were subjected to four experimental conditions: (1) group 1: Stored in lactic acid solution (pH 4.9) for 24 hours; (2) group 2: Thermocycled for 100 cycles (temperatures: 5°C, 55°C, and dwell time of 15 seconds); (3) group 3: Stored in 0.1 N sodium hydroxide solution (pH 12.48) for 14 days at 60°C; (4) group 4: Stored in phosphate-buffered saline solution (pH 7.2) at 37°C for 4 months. The weight and color were recorded again after removal of the samples from the experimental conditions. Two-factor analysis of variance models and Tukey's Honestly Significant Difference were performed to assess statistical differences among the groups. Scanning electron microscopy imaging was performed for samples from groups 1, 3, and 4.

Results

All the samples showed loss of material and change in color. In the demineralizing solution, IC showed significantly greater weight loss (p = 0.032) and color change (p = 0.038) compared with DA. Dental Sealant showed significantly greater weight loss than IC (p = 0.027) after thermocycling. Teeth in group 3 exhibited the greatest weight loss (p < 0.001). Teeth in group 2 exhibited the greatest color change (p < 0.001).

Conclusion

All tested materials showed loss of retention and color change in the experimental conditions. Infiltration system exhibited greatest weight loss and color change in demineralizing solution. Dental sealant exhibited greatest weight loss upon thermocycling.

Clinical significance

Clinicians should be cautious about the limitations of retention and color stability when considering resin infiltration for incipient lesions.

How to cite this article

Ritwik P, Jones CM, Fan Y, Sarkar NK. Hydrolytic and Color Stability of Resin Infiltration: A Preliminary in vitro Trial. J Contemp Dent Pract 2016;17(5):377-381.
Assessment of Various Nutritional Parameters in Geriatric Patients Who underwent Different Prosthodontic Treatments
Authors: Aneja Sarita , Jeergal Vasanti A , Patel Alpesh , Bhardwaj Atul , Patel Nikunj
Published: July 2016

Background

Some relation exists between oral and general health with progressive aging. Certain risk factors are common between oral and systemic diseases. Absence of teeth also affects the oral health by altering the quality of life. Hence, the nutritional changes occurring in elderly patients following prosthodontic rehabilitation are evaluated.

Materials and methods

A total of 250 patients who underwent prosthodontic treatment for missing teeth were included for the study. Twice measurement of nutritional parameters was done: Initially at the time of diagnosis and then 5 months following commencement of the prosthodontic treatment. Dental analysis, evaluation of the diet, anthropometric assessment, and analysis of serum biochemical values were done in all the patients and tabulated records were maintained. Independent Student's t test and Tukey's test were done to assess the level of significance.

Results

A total of 250 patients were included for the study. The complete denture (CD) group showed the highest alteration in the mean values of the nutritional parameters followed by the removable partial denture group. A significant change was seen in the body mass index, protein, carbohydrate, and iron levels among the different patients who were grouped based on the mode of treatment modality. The CD group showed significantly higher mean change in carbohydrates value compared with mean change in patients receiving fixed treatment.

Conclusion

Both nutrition and diet form an integral part of the prosthodontic treatment to maintain the health of elderly population.

Clinical significance

With the advancement in the level of edentulism, rehabilitation by prosthetic treatment has become progressively important to restore and improve dietary parameters.

How to cite this article

Aneja S, Jeergal VA, Patel A, Bhardwaj A, Patel N, Shah V. Assessment of Various Nutritional Parameters in Geriatric Patients Who underwent Different Prosthodontic Treatments. J Contemp Dent Pract 2016;17(5):408-413.
Why do GCMs overestimate the aerosol cloud lifetime effect? A comparison of CAM5 and a CRM
Authors: Zhou Cheng , Penner Joyce E.
Published: July 2016

Abstract. Observation-based studies have shown that the aerosol cloud lifetime effect or the increase of cloud liquid water (LWP) with increased aerosol loading may have been overestimated in climate models. Here, we simulate shallow warm clouds on 05/27/2011 at the Southern Great Plains (SGP) measurement site established by Department of Energy's Atmospheric Radiation Measurement (ARM) Program using a single column version of a global climate model (CAM5.3) and a cloud resolving model (CRM). The LWP simulated by CAM increases substantially with aerosol loading while that in the CRM does not. The increase of LWP in CAM is caused by a large decrease of the autoconversion rate when cloud droplet number increases. In the CRM, the autoconversion rate is also reduced, but this is offset or even outweighed by the increased evaporation of cloud droplets near cloud top, resulting in an overall decrease in LWP. Our results suggest that climate models need to include the dependence of cloud top growth and the evaporation/condensation process on cloud droplet number concentrations.
Drivers of atmospheric methane uptake by montane forest soils in the
southern Peruvian Andes
Authors: Jones Sam P. , Diem Torsten , Huaraca Quispe Lidia P. , Cahuana Adan J. , Reay Dave S. , Meir Patrick , Teh Yit Arn
Published: July 2016

Abstract. The soils of tropical montane forests can act as sources or sinks of atmospheric methane (CH4). Understanding this activity is important in regional atmospheric CH4 budgets given that these ecosystems account for substantial portions of the landscape in mountainous areas like the Andes. We investigated the drivers of net CH4 fluxes from premontane, lower and upper montane forests, experiencing a seasonal climate, in south-eastern Peru. Between February 2011 and June 2013, these soils all functioned as net sinks for atmospheric CH4. Mean (standard error) net CH4 fluxes for the dry and wet season were −1.6 (0.1) and −1.1 (0.1) mg CH4-C m−2 d−1 in the upper montane forest, −1.1 (0.1) and −1.0 (0.1) mg CH4-C m−2 d−1 in the lower montane forest, and −0.2 (0.1) and −0.1 (0.1) mg CH4-C m−2 d−1 in the premontane forest. Seasonality in CH4 exchange varied among forest types with increased dry season CH4 uptake only apparent in the upper montane forest. Variation across these forests was best explained by available nitrate and water-filled pore space indicating that nitrate inhibition of oxidation or diffusional constraints imposed by changes in water-filled pore space on methanotrophic communities may represent important controls on soil–atmosphere CH4 exchange. Net CH4 flux was inversely related to elevation; a pattern that differs to that observed in Ecuador, the only other extant study site of soil–atmosphere CH4 exchange in the tropical Andes. This may result from differences in rainfall patterns between the regions, suggesting that attention should be paid to the role of rainfall and soil moisture dynamics in modulating CH4 uptake by the organic-rich soils typical of high-elevation tropical forests.
Influence of topography and human activity on erosion in Yunnan,
SW China
Authors: Schmidt Amanda H. , Neilson Thomas B. , Bierman Paul R. , Rood Dylan H. , Ouimet William B. , Sosa Gonzalez Veronica
Published: July 2016

Abstract. In order to understand better if and where long-term erosion rates calculated using in situ 10Be are affected by contemporary changes in land use and attendant deep regolith erosion, we calculated erosion rates using measurements of in situ 10Be in quartz from 52 samples of river sediment collected from three tributaries of the Mekong River (median basin area = 46.5 km2). Erosion rates range from 12–209 mm/kyr with an area-weighted mean of 117 ± 49 mm/kyr (1 standard deviation) and median of 74 mm/kyr. We observed a decrease in the relative influence of human activity from our steepest and least altered watershed in the north to the most heavily altered landscapes in the south. In the areas of the landscape least disturbed by humans, erosion rates correlate best with measures of topographic steepness. In the most heavily altered landscapes, measures of modern land use correlate with 10Be-estimated erosions rates but topographic steepness parameters cease to correlate with erosion rates. We conclude that in some small watersheds we sampled, those with high rates and intensity of agricultural land use, that tillage and resultant erosion has excavated deeply enough into the regolith to deliver subsurface sediment to streams and thus raise apparent in situ 10Be-derived erosion rates by as much as 2.5 times over background rates had the watersheds not been disturbed.
A post-wildfire response in cave dripwater chemistry
Authors: Nagra Gurinder , Treble Pauline C. , Andersen Martin S. , Fairchild Ian J. , Coleborn Katie , Baker Andy
Published: July 2016

Abstract. Surface disturbances above a cave have the potential to impact cave dripwater discharge, isotopic composition and solute concentrations, which may subsequently be recorded in the stalagmites forming from these dripwaters. One such disturbance is wildfire; however, the effects of wildfire on cave chemistry and hydrology remains poorly understood. Using dripwater data monitored at two sites in a shallow cave, beneath a forest, in southwest Australia, we provide one of the first cave monitoring studies conducted in a post-fire regime, which seeks to identify the effects of wildfire and post-fire vegetation dynamics on dripwater δ18O composition and solute concentrations. We compare our post-wildfire δ18O data with predicted dripwater δ18O using a forward model based on measured hydro-climatic influences alone. This helps to delineate hydro-climatic and fire-related influences on δ18O. Further we also compare our data with both data from Golgotha Cave – which is in a similar environment but was not influenced by this particular fire – as well as regional groundwater chemistry, in an attempt to determine the extent to which wildfire affects dripwater chemistry. We find in our forested shallow cave that δ18O is higher after the fire relative to modelled δ18O. We attribute this to increased evaporation due to reduced albedo and canopy cover. The solute response post-fire varied between the two drip sites: at Site 1a, which had a large tree above it that was lost in the fire, we see a response reflecting both a reduction in tree water use and a removal of nutrients (Cl, Mg, Sr, and Ca) from the surface and subsurface. Solutes such as SO4 and K maintain high concentrations, due to the abundance of above-ground ash. At Site 2a, which was covered by lower–middle storey vegetation, we see a solute response reflecting evaporative concentration of all studied ions (Cl, Ca, Mg, Sr, SO4, and K) similar to the trend in δ18O for this drip site. We open a new avenue for speleothem science in fire-prone regions, focusing on the geochemical records of speleothems as potential palaeo-fire archives.
Morphological dynamics of an englacial channel
Authors: Vatne Geir , Irvine-Fynn Tristram D. L.
Published: July 2016

Abstract. Despite an interest in the hydraulic functioning of supraglacial and englacial channels over the last 4 decades, the processes and forms of such ice-bounded streams have remained poorly documented. Recent glaciological research has demonstrated the potential significance of so-called "cut-and-closure" streams, where englacial or subglacial flow paths are created from the long-term incision of supraglacial channels. These flow paths are reported to exhibit step-pool morphology, comprising knickpoints and/or knickzones, exaggerated in dimensions in comparison to supraglacial channels. However, little is known of the development of such channels' morphology. Here, we examine the spatial organisation of step pools and the upstream migration of steps, many of which form knickzones, with repeated surveys over a 10-year period in an englacial conduit in cold-based Austre Brøggerbreen, Svalbard. The observations show upstream step recession to be the dominant process for channel evolution. This is paralleled by an increase in average step height and conduit gradient over time. Characteristic channel-reach types and step-riser forms are consistently observed in each of the morphological surveys reported. We suggest that the formation of steps has a hydrodynamic origin, where step-pool geometry is more efficient for energy dissipation than meanders. The englacial channel system is one in rapid transition towards a quasi-equilibrium form within a decadal timescale. The evolution and recession of knickzones reported here result in the formation of a 37 m deep moulin shaft, suggesting that over time an incising supraglacial channel may evolve towards an englacial channel form exhibiting a stable end-point characterised by a singular vertical descent, which potentially can reach the glacier bed. This challenges the prevailing notions that crevasses or hydrofractures are needed to form deep moulins. Our observations highlight the need to further examine the adjustment processes in cut-and-closure channels to better understand their coupling to supraglacial meltwater sources and potential significance in cold-based glacier hydrology and ice dynamics.
Sediment concentration rating curves for a monsoonal climate: upper Blue
Nile
Authors: Moges Mamaru A. , Zemale Fasikaw A. , Alemu Muluken L. , Ayele Getaneh K. , Dagnew Dessalegn C. , Tilahun Seifu A. , Steenhuis Tammo S.
Published: July 2016

Abstract. Information on sediment concentration in rivers is important for design of reservoirs and for environmental applications. Because of the scarcity of continuous sediment data, methods have been developed to predict sediment loads based on few discontinuous measurements. Traditionally, loads are being predicted using rating curves that relate sediment load to discharge. The relationship assumes inherently a unique relationship between concentration and discharge and therefore although performing satisfactorily in predicting loads, it may be less suitable for predicting concentration. This is especially true in the Blue Nile Basin of Ethiopia where concentrations decrease for a given discharge with the progression of the rainy monsoon phase. The objective of this paper is to improve the sediment concentration predictions throughout the monsoon period for the Ethiopian highlands with a modified rating type equation. To capture the observed sediment concentration pattern, we assume that the sediment concentration was at the transport limit early in the rainy season and then decreases linearly with effective rainfall towards source-limited concentration. The modified concentration rating curve was calibrated for the four main rivers in the Lake Tana basin where sediment concentrations affect fish production and tourism. Then the scalability of the rating type equation was checked in three 100 ha watersheds for which historic data were available. The results show that for predicting sediment concentrations, the (modified) concentration rating curve was more accurate than the (standard) load rating curve as expected. In addition loads were predicted more accurately for three of the four rivers. We expect that after more extensive testing over a wider geographical area, the proposed concentration rating curve will offer improved predictions of sediment concentrations in monsoonal climates.
Circumpolar polynya regions and ice production in the Arctic: Results from MODIS thermal infrared imagery for 2002/2003 to 2014/2015 with a regional focus on the Laptev Sea
Authors: Preußer Andreas , Heinemann Günther , Willmes Sascha , Paul Stephan
Published: July 2016

Abstract. High-resolution MODIS thermal infrared satellite data are used to infer spatial and temporal characteristics of 16 prominent coastal polynya regions over the entire Arctic basin. Thin-ice thickness distributions (≤ 20 cm) are calculated from MODIS ice-surface temperatures, combined with ECMWF ERA-Interim atmospheric reanalysis data in an energy balance model for 13 winter-seasons (2002/2003 to 2014/2015; November to March). From all available swath-data, (quasi-) daily thin-ice thickness composites are computed in order to derive quantities such as polynya area and total thermodynamic (i.e. potential) ice production. A gap-filling approach is applied to account for cloud and data gaps in the MODIS composites. All polynya regions combined cover an average thin-ice area (POLA) of 184.3 ± 35.6 × 103 km2 in winter. This allows for an average total wintertime accumulated ice production of about 1444 ± 258 km3, whereby the Kara Sea region and the North Water polynya (both 19 %) as well as scattered smaller polynyas in the Canadian Arctic Archipelago (all combined 15 %) are the main contributors. Other well-known sites of polynya formation (Laptev Sea, Chukchi Sea) show smaller contributions and range between 2 and 7 %. Compared to an earlier study on pan-Arctic polynya characteristics that utilized lower resolution passive microwave remote sensing data, our estimates are about 22 % larger on average. This partly originates from the use of high-resolution MODIS data, which increases the capability to resolve small scale (> 2 km) thin-ice features such as large leads. Despite the short record of 13 winter-seasons, positive trends in ice production are detected for several regions of the eastern Arctic (most significant in the Laptev Sea region with an increase of 6.8 km3/yr) and the North Water polynya, while other polynyas in the western Arctic show a more pronounced variability with varying trends. We emphasize the role of the Laptev Sea polynyas as being a major influence on Transpolar Drift characteristics through a distinct relation between increasing ice production and ice area export. Overall, our study contains the most accurate characterization of circumpolar polynya dynamics and ice production to date which should be valuable for future modeling efforts on atmosphere–sea ice–ocean interactions in the Arctic.