bluuebunny/crossref_metadata_2025 huggingface dataset:
Dermatoglyphics in Patients with Dental Caries: A Study on 1250 Individuals
Authors: Gupta Mohit , Abhilash PR , Divyashree R , Patil Shankar Gouda , Chandrasekar T , Karthikeyan R
Published: July 2012

Aim

This study was undertaken to investigate and analyze the significance of dermatoglyphics in predicting the susceptibility of individuals to develop dental caries.

Materials and methods

This case-control study was conducted on 1250 children in the age group of 5 to 12 years from Chennai Corporation School, Vadapalani, Chennai. Out of 1250 subjects, 625 subjects were in the study group and the remaining 625 subjects were the control group. The study group included children with dental caries in 5 or more teeth based on the DMFT index performed and control group consisted of normal, healthy children without any dental caries.

The finger and palmar prints of both hands were taken using a stamp pad. The fingertip patterns were analyzed according to the classical method and configurational types were classified according to the topological method.

Statistical analysis was performed using nonparametric tests and t-test to compare the dermatoglyphic pattern changes between the study group and the control group and was applied for each variable, to compare the proportions, and p-value.

Results

(1) Dental caries susceptibility of an individual increases with an increase in the incidence of whorl pattern (83% correlation). (2) All the variables show statistically significant value, with a degree of divergence of specific dermatoglyphic patterns among study and control group. (3) The dermatoglyphic patterns are efficient and can predict in assessing the risk of susceptibility to dental caries in study group.

Conclusion

The dental caries susceptibility of an individual increased with incidence of whorl pattern and it decreased with incidence of loop pattern.

Clinical significance

The dermatoglyphic patterns may be utilized effectively to study the genetic basis of dental caries. In a developing country like India, it might prove to be a noninvasive, inexpensive and effective tool for screening.

How to cite this article

Abhilash PR, Divyashree R, Patil SG, Gupta M, Chandrasekar T, Karthikeyan R. Dermatoglyphics in Patients with Dental Caries: A Study on 1250 Individuals. J Contemp Dent Pract 2012;13(3):266-274.
The Interference of the Cleaning Procedure of Root Walls with Two Different Solvents on the Adhesion of Fiberglass Intraradicular Posts
Authors: Gomes Monica Fatima , Botta Sergio Brossi , Matos Adriana Bona , Garone-Netto Narciso
Published: July 2012

Aim

This study was undertaken to examine the effect of root canal (RT) sealers content and the cleaning procedure of RT walls on bond strength (BS) of a fiber reinforced composite (FRC) post cemented with resin-based or zinc phosphate cement.

Materials and methods

Forty bovine roots were divided into 2 groups (n = 20) and obturated with gutta-percha points plus Sealer 26 sealer or gutta-percha points plus N-Rickert sealer. In each group, half (n = 10) of intracanal walls was cleaned with ethanol and the other half with sulfuric ether. In each of these subgroups, half of intracanal posts (n = 5) were cemented with Bistite resin-based cement and half with zinc phosphate cement. Specimens were submitted to pull-out test and tensile force until post dislodgement. The maximum forces required for post removal was expressed in MPa, means were submitted to statistical analysis (Analysis of Variance Test, α = 0.05).

Results

Fiber reinforced composite cemented with zinc phosphate were significantly more retentive than those cemented with Bistite (p < 0.05). Regarding the influence of eugenol-based sealer on post retention, there was a statistically significant difference (p < 0.05) only between groups cemented with Bistite, in which canals filled with N-Rickert + gutta-percha showed lower BS than canals filled with Sealer 26 + gutta-percha.

Conclusion

Despite endodontic cement used, higher pull-out bond strength were obtained when posts were cemented with zinc phosphate.

Clinical significance

The importance of ethanol or sulphuric ether application to properly replace water from intraradicular dentine still requires further investigations, especially to clarify if this technique may reduce the effect of aging and improve the stability of the bond, when used to cement fiber posts into the root canal.

How to cite this article

Gomes MF, Botta SB, Matos AB, Garone- Netto N. The Interference of the Cleaning Procedure of Root Walls with Two Different Solvents on the Adhesion of Fiberglass Intraradicular Posts. J Contemp Dent Pract 2012;13(3):275-279.
Correlation between Surface Roughness and Microhardness of Experimental Composites with Varying Filler Concentration
Authors: Münchow Eliseu Aldrighi , Correa Marcos Brito , Ogliari Fabrício Aulo , Piva Evandro , Zanchi Cesar Henrique
Published: July 2012

Aim

The purpose of this study was to investigate the influence of the surface roughness on the surface microhardness of experimental composites with varying filler concentration.

Materials and methods

Experimental resin composites were formulated by mixing Bis-GMA and TEGDMA in a 50/50% weight ratio and CQ/EDAB were added to make the material photosensitive. Silanized glass particles were incorporated in the resin blend in two concentrations: C50 with 50% and C75 with 75% in weight ratio. The surface roughness and the surface microhardness measurements were determined after every three finishing procedures with #280-, #600- and #1200-grit wet sandpapers, respectively. The data were analyzed statistically by Two Way ANOVA and Tukey's test, and comparisons were conducted using the Spearman's correlation test (p < 0.05).

Results

The surface roughness and surface microhardness were negatively associated (r = – 0.68) and the finishing procedures of both composites resulted in harder and smoother surfaces than the initial ones. Additionally, in a smooth circumstance, the higher content of fillers has not resulted in a composite with better microhardness and smoothness.

Conclusion

Finishing procedures decreased the surface roughness and consequently improved the surface microhardness of the composites evaluated.

Clinical significance

Finishing and polishing procedures are effectives in reducing the surface roughness amplitude of composite materials and in improving their surface microhardness. Thus a microhardness test and any hardness evaluation must be conducted only after a properly finished and polished surface is achieved.

How to cite this article

Münchow EA, Correa MB, Ogliari FA, Piva E, Zanchi CH. Correlation between Surface Roughness and Microhardness of Experimental Composites with Varying Filler Concentration. J Contemp Dent Pract 2012;13(3):299-304.
Antimicrobial Effect of Conventional Root Canal Medicaments vs Propolis against Enterococcus faecalis, Staphylococcus aureus and Candida albicans
Authors: Mattigatti Sudha , Jain Deepak , Ratnakar P , Moturi Shridhar , Varma Sarath , Rairam Surabhi
Published: July 2012

Aim

To evaluate and compare antimicrobial effect of various root canal medicaments against Enterococcus faecalis, Staphylococcus aureus and Candida albicans.

Materials and methods

Six root canal medicaments: 2% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX) Calcium hydroxide (Ca(OH)2), EDTA, MTAD and propolis and three microorganisms: Staphylococcus aureus, Enterococcus faecalis and Candida albicans were used. These strains were inoculated in brain heart infusion (BHI) and incubated at 37 degrees C for 24 hours. For the agar diffusion test (ADT), petri plates with 20 ml of BHI agar were inoculated with 0.1 ml of the microbial suspensions, using sterile swabs that were spread on the medium, obtaining growth injunction. Paper disks were immersed in the experimental solutions for 1 minute. Subsequently, four papers disks containing one of the substances were placed on the BHI agar surface in each agar plate. The plates were incubated at 37°C for 48 hours. The diameter of microbial inhibition was measured around the papers disks containing the substances. One way ANOVA followed by Tukey's post-hoc test were used. p-value <0.05 was considered statistically significant.

Results

Propolis and other irrigants were found to be effective on C. albicans, S. aureus and E. faecalis. CHX and MTAD were found to be most effective amongst all the materials tested followed by propolis.

Conclusion

Propolis showed antimicrobial activity against E. faecalis, S. aureus, C. albicans. It appears that propolis is an effective intracanal irrigant in eradicating E. faecalis and C. albicans.

Clinical significance

Propolis is an effective intracanal irrigant in eradicating E. faecalis and C. albicans. It could be used as an alternative intracanal medicament.

How to cite this article

Mattigatti S, Jain D, Ratnakar P, Moturi S, Varma S, Rairam S. Antimicrobial Effect of Conventional Root Canal Medicaments vs Propolis Against Enterococcus faecalis, Staphylococcus aureus and Candida albicans. J Contemp Dent Pract 2012;13(3):305-309.
To Determine the Prevalence Rate of Malocclusion among 12 to 14-Year-Old Schoolchildren of Urban Indian Population (Bagalkot)
Authors: Mattigatti Sudha , Kallur Ravi , Vaz Anna , Gajapurada Jagadeesha , LNU Sugaraddy
Published: July 2012

Aim

To determine the prevalence rates of different occlusal characteristics of permanent dentition in 12 to 14 years old children in Bagalkot city and to determine the differences in occlusal characteristics in the same children by age and sex.

Materials and methods

A total of 1000 school going children between the age group of 12 to 14 years were selected in the study from Bagalkot city of India. All the occlusal parameters, such as molar relation, canine relation, overjet, overbite and crowding and spacing were recorded in a record sheet. The gender and sex difference was evaluated using Chi-square test.

Results

According to the classification of Angle, the prevalence of class I, II and III malocclusions was 17.8, 30.1 and 1.6%, respectively. Ideal occlusion was 3.2% where as normal occlusion was 46.8%. An overjet of at least 4 mm or more was present in 15.2 and 7.2% had a reverse overjet. A total of 9.2 had an increased overbite and 10.6% had open bite.

Conclusion

Highly significant (p < 0.001) age differences were found for overjet, overbite and highly significant (p < 0.001) gender differences were found for crowding and spacing.

Clinical significance

The study gives the prevalence of malocclusion amongst 12 to 14 years old in urban Indian population. The data can be used for may research projects and gives us a better understanding of malocclusion in urban Indian population.

How to cite this article

Phaphe S, Kallur R, Vaz A, Gajapurada J, Sugaraddy, Mattigatti S. To Determine the Prevalence Rate of Malocclusion among 12 to 14-Year-Old Schoolchildren of Urban Indian Population (Bagalkot). J Contemp Dent Pract 2012;13(3):316-321.
The Quality of Thermafil Obturations with Different Final Apical Tapers: A Three-dimensional Microcomputed Tomographic Comparative Study
Authors: Naaman Alfred , Zogheib Carla , Medioni Etienne , Bourbouze Gaël , Arbab-Chirani Reza
Published: July 2012

Aim

The aim of this study is to evaluate the influence of final canal taper on the sealing ability of Thermafil by using microcomputed tomography (micro-CT).

Materials and methods

Fifty-four single-rooted teeth were instrumented to apical size 40 taper 4, 6 and 8%. Teeth were divided into three groups. All teeth were filled with Thermafil (Dentsply, Tulsa Dental Products). Using micro-CT, roots were scanned and volume measurements of voids at 1, 3 and 5 mm from the apex were calculated using specialized CT software. Measurements were analyzed statistically with ANOVA followed by Bonferroni multiple comparison correction.

Results

Data analysis showed that 0.08 preparations provided better results than 0.06 and 0.04% tapered samples especially at 1 mm from the apex. Mean percentage of voids were significantly higher with Thermafil taper 0.06% (p = 0.05). None of the root canals filled teeth were gap free. Root canal preparations with bigger taper exhibited less voids than smaller tapered preparations.

Clinical significance

In our daily practice, enlarging the apical third (last 3 mm) of root canals to an 8% taper gives a better sealing ability and thus long-term success for our root canal obturations.

How to cite this article

Zogheib C, Naaman A, Medioni E, Bourbouze G, Arbab-Chirani R. The Quality of Thermafil Obturations with Different Final Apical Tapers: A Threedimensional Microcomputed Tomographic Comparative Study. J Contemp Dent Pract 2012;13(3):322-326.
A Comparative Evaluation of the Vertical Root Fracture Resistance of Endodontically Treated Teeth using Different Root Canal Sealers: An in vitro Study
Authors: Prashanth MB , Tavane Pradeep N , Annapoorna BM , Prashanth NT , Deepak BS , Nagpal Ajay , Singla Munish , Singh Ashmita
Published: July 2012

Objective

The objective of this study is to evaluate the vertical root fracture resistance of endodontically treated teeth obturated with – Tubli-Seal EWT/Gutta-percha, AH Plus/Gutta-percha, Epiphany SE sealer/Epiphany point.

Study design

Sixty-five single rooted premolars were decoronated and root length was 14 mm for each specimen. Fifty five teeth were enlarged up to ISO size 40 master apical file with stainless steel K-files using standardized preparation and remaining ten teeth were served as negative control. Then teeth were randomly assigned into different groups depending on sealer used for obturation as follows:

Group 1

Negative control—no instrumentation was performed.

Group 2

Positive control—gutta-percha with out the use of any sealer.

Group 3

Experimental group—gutta-percha and Tubli-Seal EWT root canal sealer.

Group 4

Experimental group—gutta-percha and AH Plus.

Group 5

Experimental group—epiphany SE sealer and epiphany points.

After 72 hours, the specimens were embedded in autopolymerizing resin leaving 7 mm of each root exposed and were subjected to fracture testing under universal testing machine at a crosshead speed of 1.0 mm per minute until the root fractured. Results were statistically analyzed using one-way ANOVA and independent t-test.

Results

Showed that Epiphany SE sealer/Epiphany points showed highest mean fracture resistance and Tubli-Seal EWT group showed the least fracture resistance of all the materials tested. There was no statistically significant difference among experimental groups.

Conclusion

Epiphany SE sealer/Epiphany points demonstrated highest fracture resistance values than the other materials tested and intact tooth had highest resistance against vertical root fracture.

Clinical significance

Epiphany SE sealer/Epiphany points may be one of the materials of choice in the endodontic treatment of teeth.

How to cite this article

Nagpal A, Annapoorna BM, Prashanth MB, Prashanth NT, Singla M, Deepak BS, Singh A, Tavane PN. A Comparative Evaluation of the Vertical Root Fracture Resistance of Endodontically Treated Teeth using Different Root Canal Sealers: An in vitro Study. J Contemp Dent Pract 2012;13(3):351-355.
Knowledge, Attitude and use of Fluorides among Dentists in Texas
Authors: Bansal Ritu , Bolin Kenneth A , Abdellatif Hoda M , Shulman Jay D
Published: July 2012

Aim

The centers for disease control and prevention (CDC) recommendations on fluoride use were published in 2001. This study examines how this information has diffused to practicing dentists and the level of fluoride knowledge and use among Texas dentists.

Materials and methods

A questionnaire was sent to dentists who self-identified as being in pediatric (343), dental public health (72), and general practices (980); a 12% sample of registered dentists in Texas.

Results

Response rate was 42.9%. About 90% of surveyed dentists reported using fluorides routinely. Only 18.8% reported fluoride varnish as the topical fluoride most often used. About 57% incorrectly identified primary effect of fluoride. ‘Makes enamel stronger while tooth is developing prior to eruption’ was the most commonly cited wrong answer (44%). Only 5% identified that posteruptive effect exceeds any preeruptive effect.

Conclusion

Despite the evidence for fluoride varnish preventing and controlling dental caries being Grade I, its use is still uncommon. Dentists are expected to be knowledgeable about products they use, but this study reflects lack of understanding about fluoride's predominant mode of action. More accurate understanding enables dentists to make informed and appropriate judgment on treatment options and effective use of fluoride based on risk assessment of dental caries.

Clinical significance

Lack of knowledge of, or failure of adherence to evidence based guidelines in caries prevention by use of appropriate fluoride regimens may adversely affect caries incidence in the population.

How to cite this article

Bansal R, Bolin KA, Abdellatif HM, Shulman JD. Knowledge, Attitude and use of Fluorides among Dentists in Texas. J Contemp Dent Pract 2012;13(3):371-375.
Comparison of Metal Ion Release from Different Bracket Archwire Combinations: An in vitro Study
Authors: Manjith CM , Karnam Srinivas Kumar , Reddy A Naveen
Published: July 2012

Aim

The metal ion released from the orthodontic appliance may cause allergic reactions particularly nickel and chromium ions. Hence, this study was undertaken to determine the amount of nickel, chromium, copper, cobalt and iron ions released from simulated orthodontic appliance made of new archwires and brackets.

Materials and methods

Sixty sets of new archwire, band material, brackets and ligature wires were prepared simulating fixed orthodontic appliance. These sets were divided into four groups of fifteen samples each.Group 1: Stainless steel rectangular archwires.Group 2: Rectangular NiTi archwires.Group 3: Rectangular copper NiTi archwires.Group 4: Rectangular elgiloy archwires. These appliances were immersed in 50 ml of artificial saliva solution and stored in polypropylene bottles in the incubator to simulate oral conditions. After 90 days the solution were tested for nickel, chromium, copper, cobalt and iron ions using atomic absorption spectrophotometer.

Results

Results showed that high levels of nickel ions were released from all four groups, compared to all other ions, followed by release of iron ion levels. There is no significant difference in the levels of all metal ions released in the different groups.

Conclusion

The study confirms that the use of newer brackets and newer archwires confirms the negligible release of metal ions from the orthodontic appliance.

Clinical significance

The measurable amount of metals, released from orthodontic appliances in artificial saliva, was significantly below the average dietary intake and did not reach toxic concentrations.

How to cite this article

Karnam SK, Reddy AN, Manjith CM. Comparison of Metal Ion Release from Different Bracket Archwire Combinations: An in vitro Study. J Contemp Dent Pract 2012;13(3):376-381.
The Use of Fragments of Thin Veneers as a Restorative Therapy for Anterior Teeth Disharmony: A Case Report with 3 Years of Follow-up
Authors: Goiato Marcelo Coelho , Santos Daniela Micheline dos , Baräo Valentim Adelino Ricardo , Okida Ricardo Coelho , Filho Aljomar José Vechiato
Published: July 2012

Aim

The present case report described the use of contact lens of thin porcelain veneers as a restorative therapy to solve anterior teeth disharmony.

Background

Fragments of thin veneers are minimally invasive restorations with little or no dental preparation and present thickness ranging from 0.2 to 0.5 mm. They are used in case of diastema closure, small changes of teeth, color and restoration of teeth with small fractures.

Case report

A 25-year-old man was admitted at a dental clinic complaining about the diastema presence on the upper anterior teeth. Patient was referred to an orthodontic treatment in order to provide better distribution of the diastemas and harmonious proportion of the teeth. Afterwards, contact lens of thin porcelain veneers were fabricated on the six upper anterior teeth.

Conclusion

Based on the outcomes of this clinical report, we considered the use of fragments of thin veneers as a successful treatment option after 3 years of follow-up.

Clinical significance

The fragments of thin veneers have been established to be an interesting alternative to esthetically restore the anterior teeth with minimal invasiveness. However, since it is a new treatment modality, longitudinal studies are necessary to understand the material's behavior.

How to cite this article

Okida RC, Filho AJV, Barão VAR, dos Santos DM, Goiato MC. The Use of Fragments of Thin Veneers as a Restorative Therapy for Anterior Teeth Disharmony: A Case Report with 3 Years of Follow-up. J Contemp Dent Pract 2012;13(3):416-420.
The effect of photochemical ageing and initial precursor concentration on the composition and hygroscopic properties of β-caryophyllene secondary organic aerosol
Authors: Alfarra M. R. , Hamilton J. F. , Wyche K. P. , Good N. , Ward M. W. , Carr T. , Barley M. H. , Monks P. S. , Jenkin M. E. , Lewis A. C. , McFiggans G. B.
Published: July 2012

Abstract. The effect of photochemical ageing and initial precursor concentration on the composition and hygroscopic properties of secondary organic aerosol (SOA) formed during the chamber photo-oxidation of β-caryophyllene/NOx mixtures were investigated. Nucleation of β-caryophyllene SOA particles occurred almost immediately after oxidation was initiated and led to the formation of fresh SOA with a relatively simpler composition than has been reported for monoterpenes. The SOA yield values ranged from 9.5–26.7% and 30.4–44.5% using a differential mobility particle sizer (DMPS) and an aerosol mass spectrometer (AMS) mass based measurements, respectively. A total of 20 compounds were identified in the SOA by LC-MS/MS, with the most abundant compounds identified as β-caryophyllonic acid and β-caryophyllinic acid/β-nocaryophyllonic acid. The O:C and H:C elemental ratios of products identified in the condensed phase ranged from 0.20 to 1.00 and 1.00 to 2.00, with average values of 0.39 and 1.58, respectively. The increase in the O:C ratio was associated with a decrease in the saturation concentration of the identified compounds. The compounds identified in the lower initial concentration experiments were more oxidised compared to those that were found to be more abundant in the higher initial concentration experiments with average O:C ratios of 0.51 and 0.27, respectively. Photochemical ageing led to a more complex SOA composition with a larger contribution coming from lower molar mass, higher generation products, where both double bonds had been oxidised. This effect was more evident in the experiments conducted using the lower initial precursor concentration; a finding confirmed by the temporal behaviour of key organic mass fragment measured by an Aerosol Mass Spectrometer. Although the composition changed with both initial precursor concentration and ageing, this had no significant measurable effect on the hygroscopic properties of the SOA formed. The latter finding might have been influenced by the difference in pre-treatment of the semivolatile-containing particles prior to their measurements.
Role of sediment denitrification in water column oxygen dynamics: comparison of the North American East and West Coasts
Authors: Bianucci L. , Fennel K. , Denman K. L.
Published: July 2012

Abstract. Low oxygen concentrations, either natural or anthropogenically driven, can severely affect coastal marine ecosystems. A deeper understanding of oxygen dynamics is required in order to improve numerical models, eventually to predict the timing and severity of hypoxia. In this study we investigate the effect of sediment denitrification on oxygen concentrations in bottom waters over the continental shelf. We used two coupled physical-biological models based on the Regional Ocean Modelling System (ROMS) to compare summer simulations with and without denitrification within the sediments for two North American shelves: the Middle Atlantic Bight (MAB) and the Vancouver Island Shelf (VIS). These regions belong to western and eastern boundary current systems, respectively, and are characterized by different physical and biological dynamics. Both models assume coupled nitrification-denitrification within the sediments. Denitrification represents a loss of bioavailable nitrogen through the production of dinitrogen gas, with the potential to affect biogeochemical cycles. In our MAB model, this loss of regenerated nutrients through denitrification within the sediments significantly affects primary production, since recycled nitrogen supports most of the primary production in that region. The diminished primary production and consequent decrease of organic matter flux to the seafloor leads to less sediment oxygen consumption and higher oxygen concentrations in bottom waters. However, changes in regenerated nitrogen on the VIS barely affect primary production due to the efficient supply of new nutrients through wind-driven upwelling during summer and the nutrient-rich coastal current. We recommend that modelling experiments focusing on oxygen dynamics (as well as oxygen budget calculations) should include sediment denitrification in coastal regions where regenerated primary production dominates productivity.
Emissions of BVOC from Lodgepole Pine in response to Mountain Pine Beetle attack in high and low mortality forest stands
Authors: Duhl T. R. , Gochis D. , Guenther A. , Ferrenberg S. , Pendall E.
Published: July 2012

Abstract. In this screening study biogenic volatile organic compound (BVOC) emissions from intact branches of lodgepole pine (Pinus contorta) trees were measured from trees at two forested sites that have been impacted differently by the mountain pine beetle (MPB) with one having higher mortality and the other with lower mortality. Differences in the amounts and chemical diversity of BVOC between the two sites and from apparently healthy trees versus trees in different stages of MPB attack are presented, as well as (for one site) observed seasonal variability in emissions. A brief site comparison is made of the hydrological characteristics and prior disturbances (both natural and man-made) at the sites. Trees sampled at the site experiencing high MPB-related tree mortality had lower chemodiversity in terms of monoterpene (MT) emission profiles, while profiles were more diverse at the lower-mortality site. Also at the higher-mortality site, MPB-infested trees in various stages of decline had lower emissions of sesquiterpenes (SQT) compared to healthy trees, while at the site with lower mortality, MPB-survivors had significantly higher SQT emissions during part of the growing season when compared to both uninfested and newly-infested trees. SQT profiles differed between the two sites, and, like monoterpene and oxygenated VOC profiles, varied through the season For the low-mortality site in which repeated measurements were made over the course the early summer-late fall, higher chemical diversity was observed in early- compared to late-season measurements for all compound classes investigated (MT, oxygenated VOC, and SQT), with the amount of change appearing to correlate to the MPB status of the trees studied. Emissions of methyl-3-buten-2-ol had a distinct seasonal signal but were not much different between healthy or infested trees, except in trees with dead needles, from which emissions of this compound were negligible, and in late-season MPB survivors, in which they were higher than in newly-infested or uninfested trees. Emissions of SQT were significantly higher in the MPB survivors during both mid- and late-season sampling at the low-mortality site. The changes in emissions could have implications for regional air quality and climate through changes in ozone and aerosol distributions, although this study was designed as a preliminary screening effort and not enough individuals were sampled for all of the observed differences to be statistically demonstrated. Despite this, the compelling differences in emissions observed between the sites and individual trees with differing MPB-infestation statuses and the potential impacts these have on regional atmospheric chemistry argue for further research in this topic.
Sediment-water column fluxes of carbon, oxygen and nutrients in Bedford Basin, Nova Scotia, inferred from 224Ra measurements
Authors: Burt W. J. , Thomas H. , Fennel K. , Horne E.
Published: July 2012

Abstract. Exchanges between sediment pore waters and the overlying water column play a significant role in the chemical budgets of many important chemical constituents. Quantification of such benthic fluxes requires explicit knowledge of the sediment properties and biogeochemistry. Alternatively, changes in water column properties near the sediment-water column interface can be exploited to gain insight into the sediment biogeochemistry and benthic fluxes. Here, we apply a 1-D diffusive mixing model to near-bottom water column profiles of 224Ra activity in order to yield vertical eddy diffusivities (KZ), based upon which we assess the diffusive exchange of inorganic carbon (DIC), nutrients and oxygen (O2), across the sediment-water interface in a coastal inlet, Bedford Basin, Nova Scotia, Canada. Near-bottom observations of DIC, O2 and nutrients provide flux ratios similar to Redfield values, suggesting that benthic respiration of primarily marine organic matter is the dominant driver. Furthermore, we did not observe any significant release of alkalinity (AT) from the sediments to the overlying water column, providing further insight into the dominant reactions taking place within sediments: the respiration of organic matter occurs largely under aerobic conditions or products of anaerobic processes are reoxidized quickly in oxygenated layers of the sediments. Finally, comparison with other carbon sources reveal the observed benthic DIC release as a significant contributor to the Bedford Basin carbon system.
Interannual hydroclimatic variability and its influence on winter nutrient loadings over the Southeast United States
Authors: Oh J. , Sankarasubramanian A.
Published: July 2012

Abstract. It is well established in the hydroclimatic literature that the interannual variability in seasonal streamflow could be partially explained using climatic precursors such as tropical sea surface temperature (SST) conditions. Similarly, it is widely known that streamflow is the most important predictor in estimating nutrient loadings and the associated concentration. The intent of this study is to bridge these two findings so that nutrient loadings could be predicted using season-ahead climate forecasts forced with forecasted SSTs. By selecting 18 relatively undeveloped basins in the Southeast US (SEUS), we relate winter (January-February-March, JFM) precipitation forecasts that influence the JFM streamflow over the basin to develop winter forecasts of nutrient loadings. For this purpose, we consider two different types of low-dimensional statistical models to predict 3-month ahead nutrient loadings based on retrospective climate forecasts. Split sample validation of the predictive models shows that 18–45% of interannual variability in observed winter nutrient loadings could be predicted even before the beginning of the season for at least 8 stations. Stations that have very high coefficient of determination (> 0.8) in predicting the observed water quality network (WQN) loadings during JFM exhibit significant skill in predicting seasonal total nitrogen (TN) loadings using climate forecasts. Incorporating antecedent flow conditions (December flow) as an additional predictor did not increase the explained variance in these stations, but substantially reduced the root-mean-square error (RMSE) in the predicted loadings. Relating the dominant mode of winter nutrient loadings over 18 stations clearly illustrates the association with El Niño Southern Oscillation (ENSO) conditions. Potential utility of these season-ahead nutrient predictions in developing proactive and adaptive nutrient management strategies is also discussed.
A critical discussion of the electromagnetic radiation (EMR) method to determine stress orientations within the crust
Authors: Krumbholz M. , Bock M. , Burchardt S. , Kelka U. , Vollbrecht A.
Published: July 2012

Abstract. In recent years, the ElectroMagnetic Radiation (EMR) method has been used to detect faults and to determine main horizontal stress directions from variations in intensities and directional properties of electromagnetic emissions, which are assumed to be generated during micro-cracking. Based on a large data set taken from an area of about 250 000 km2 in Northern Germany, Denmark, and Southern Sweden with repeated measurements at one location during a time span of about 1.5 yr, the method was systematically tested. Reproducible observations of temporary changes in the signal patterns, as well as a strongly concentric spatial pattern of the main directions of the magnetic component of the EMR point to VLF transmitters as the main source and hence raise serious concerns about the applicability of the method to determine recent crustal stresses. We conclude that the EMR method, at its current stage of development, does not allow determination of the main horizontal stress directions.
A simple approach to providing a more consistent Arctic sea ice extent timeseries from the 1950s to present
Authors: Meier W. N. , Stroeve J. , Barrett A. , Fetterer F.
Published: July 2012

Abstract. Observations for passive microwave satellite sensors have provided a continuous and consistent record of sea ice extent since late 1978. Earlier records, compiled from ice charts and other sources exist, but are not consistent with the satellite record. Here, a method is presented to adjust a compilation of pre-satellite sources to remove discontinuities between the two periods and create a more consistent combined 59-yr timeseries spanning 1953–2011. This adjusted combined timeseries shows more realistic behavior across the transition between the two individual timeseries and thus provides higher confidence in trend estimates from 1953 through 2011. The long-term timeseries is used to calculate linear trend estimates and compare them with trend estimates from the satellite period. The results indicate that trends through the 1960s were largely positive (though not statistically significant) and then turned negative by the mid-1970s and have been consistently negative since, reaching statistical significance (at the 95% confidence level) by the late 1980s. The trend for September (when Arctic extent reaches its seasonal minimum) for the satellite period, 1979–2011 is –12.9% decade–1, nearly double the 1953–2011 trend of –6.8% decade–1 (relative to the 1981–2010 mean). The recent decade (2002–2011) stands out as a period of persistent decline in ice extent. The combined 59-yr timeseries puts the strong observed decline in the Arctic sea ice cover during 1979–2011 in a longer-term context and provides a useful resource for comparisons with historical model estimates.
Snow accumulation variability in Adelie Land (East Antarctica) derived from radar and firn core data. A 600 km transect from Dome C
Authors: Verfaillie D. , Fily M. , Le Meur E. , Magand O. , Jourdain B. , Arnaud L. , Favier V.
Published: July 2012

Abstract. Polar ice sheets mass balance is a timely topic intensively studied in the context of global change and sea-level rise. However, obtaining mass balance estimates in Antarctica in particular, remains difficult due to various logistical problems. In the framework of the TASTE-IDEA program, labeled as an International Polar Year project, continuous Ground Penetrating Radar (GPR) measurements were carried out during a traverse realised in Adelie Land (East Antarctica) during the 2008–2009 austral summer between the Italo-French Dome C (DC) polar plateau site and French Dumont D'Urville (DdU) coastal station. The aim of this study was to process and interpret GPR data in terms of snow accumulation, to analyse its spatial and temporal variability along the DC-DdU traverse and compare it with historical data and modeling. The emphasis has been put on the last 300 yr, from the pre-industrial to recent time period. Beta-radioactivity counting and gamma spectrometry were studied in cores at LGGE laboratory, providing a depth-age calibration for radar measurements. Over the 600 km of usable GPR data, depth and snow accumulation were determined with the help of three distinct layers visible on the radargrams (≈1730, 1799 and 1941 AD). Preliminary results reveal a gradual accumulation increase towards the coast and the occurrence of previously undocumented undulating structures between 300 and 600 km from DC. Results agree fairly well with data from previous studies and modeling. Concluding on temporal variations is difficult because of the margin of error introduced by density estimation. This study should have various applications such as for model validation.
Choroid Thickness Measurement with RTVue Optical Coherence Tomography in Emmetropic Eyes, Mildly Myopic Eyes, and Highly Myopic Eyes
Authors: Coscas Gabriel , Zhou Qienyuan , Coscas Florence , Zucchiatti Ilaria , Rispoli Marco , Uzzan Joel , De Benedetto Umberto , Savastano Maria C. , Soules Kelly , Goldenberg Dafna , Loewenstein Anat , Lumbroso Bruno
Published: July 2012

Purpose.

To evaluate choroid thickness (CT) with RTVue spectral domain optical coherence tomography (SD-OCT) and the effect of age and myopia in eyes without posterior complications.

Methods.

In this multicenter cross-sectional study, all enrolled patients were over age 18 and divided them in 3 groups based on refraction: emmetropia (+1 D to −1 D), mild myopia (–1 D to −6 D), and high myopia (–6 D to −20 D) groups. Horizontal scans through the fovea were acquired with RTVue OCT (Optovue Inc., Fremont, California, USA). Choroid thickness was measured at 500 µm intervals up to 1,500 µm temporal and nasal to the fovea by 2 graders. Mean CT was calculated based on the average of the 7 locations. Statistical analysis was performed to evaluate CT at each location, the effects of age and myopia, and grader agreement.

Results.

A total 85 eyes of 85 subjects (30 emmetropic, 24 myopic, and 31 high myopic) were enrolled. Excellent grader agreement was observed with an intraclass correlation coefficient (ICC) >0.97. The mean CT was 248.2±78.5 (µm) for emmetropia (age = 58±18), 247.0±85.4 (µm) for myopia (age = 45±20), and 131.5±70.9 (µm) for high myopia (age = 54±13). The mean CT was not significantly different between emmetropia and myopia groups, which were significantly thicker than high myopia group. The overall slope of age-related change for the mean CT was −1.95 µm/y and the effect of age differed among the groups.

Conclusions.

Choroid thickness can be measured from RTVue OCT images with good reproducibility. Age and high myopia appear to negatively affect CT. The age effect may vary with refraction groups.
Local and landscape-scale biotic correlates of mistletoe distribution in Mediterranean pine forests
Authors: Roura-Pascual N. , Brotons L. , García D. , Zamora R. , De Càceres M.
Published: July 2012

The study of the spatial patterns of species allows the examination of hypotheses on the most plausible ecological processes and factors determining their distribution. To investigate the determinants of parasite species on Mediterranean forests at regional scales, occurrence data of the European Misletoe (Viscum album) in Catalonia (NE Iberian Peninsula) were extracted from forest inventory data and combined with different types of explanatory variables by means of generalized linear mixed models. The presence of mistletoes in stands of Pinus halepensis seems to be determined by multiple factors (climatic conditions, and characteristics of the host tree and landscape structure) operating at different spatial scales, with the availability of orchards of Olea europaea in the surroundings playing a relevant role. These results suggest that host quality and landscape structure are important mediators of plant-plant and plant-animal interactions and, therefore, management of mistletoe populations should be conducted at both local (i.e. clearing of infected host trees) and landscape scales (e.g. controlling the availability of nutrient-rich food sources that attract bird dispersers). Research and management at landscape-scales are necessary to anticipate the negative consequence of land-use changes in Mediterranean forests.
Climate change and forest diseases: using today’s knowledge to address future challenges
Authors: Sturrock R.
Published: July 2012

The health of the earth’s forests and urban green spaces is increasingly challenged by the outcomes of human activities, including global climate change. As climate changes, the role and impact of diseases on trees in both forest ecosystems and in urban settings will also change. Knowledge of relationships between climate variables and diseases affecting forest and urban trees is reviewed, with specific emphasis on those affecting foliage, shoots, and stems. Evidence that forest diseases are already responding to the earth’s changing climate is examined (e.g., Dothistroma needle blight in northern British Columbia) as are predicted scenarios for future changes in impact on forests by other tree diseases. Outbreaks of tree diseases caused by native and alien pathogens are predicted to become more frequent and intense – this and other general predictions about the effects of climate change on forest and tree diseases are discussed. Despite the uncertainty that accompanies such predictions it is imperative that researchers, forest and urban tree managers, and policy makers work together to develop and implement management strategies that enhance the resilience of the worlds’ forests and urbanized trees. Strategies discussed include monitoring, forecasting, planning, and mitigation.
Effects of Seedbed Density on Seedling Morphological Characteristics of four Broadleaved Species
Authors: Yucedag C. , Gailing O.
Published: July 2012

The aim of this study was to investigate the effects of seedling spacing on morphological characteristics of one year-old Amygdalus communis L., Prunus avium L., Pyrus elaeagnifolia Pall. and Eriolobus trilobatus (Poiret) Roemer seedlings under nursery conditions. Seedlings were grown in completely randomized blocks with four replications. Seedbeds were 1.2 m wide with 5 rows each 20 cm apart. Within-row spacings were chosen as 4, 8 and 12 cm to analyze the effect of seedlings density on growth performance. Seedling spacing significantly affected root collar diameter, shoot height, tap root length and number of fine roots in A. communis and P. avium, but not in P. elaeagnifolia and E. tribolatus. Additionally wider seedling spacings resulted in larger seedlings in A. communis and P. avium. In conclusion, it would be beneficial to use wider seedling spacing in order to obtain better seedling growth in A. communis and P. avium. Larger seedlings could also provide significant advantages because of reduced cultural activities and an expected higher growth and survival rate.
Sustaining forest landscape connectivity under different land cover change scenarios
Authors: Rubio L. , Rodríguez-Freire M. , Mateo-Sánchez M.C. , Estreguil C. , Saura S.
Published: July 2012

Managing forest landscapes to sustain functional connectivity is considered one of the key strategies to counteract the negative effects of climate and human-induced changes in forest species pools. With this objective, we evaluated whether a robust network of forest connecting elements can be identified so that it remains efficient when facing different types of potential land cover changes that may affect forest habitat networks and ecological fluxes. For this purpose we considered changes both in the forested areas and in the non-forest intervening landscape matrix. We combined some of the most recent developments in graph theory with models of land cover permeability and least-cost analysis through the forest landscape. We focused on a case of study covering the habitat of a forestdwelling bird (nuthatch, Sitta europaea) in the region of Galicia (NW Spain). Seven land-use change scenarios were analysed for their effects on connecting forest elements (patches and links): one was the simplest case in which the landscape is represented as a binary forest/non-forest pattern (and where matrix heterogeneity is disregarded), four scenarios in which forest lands were converted to other cover types (to scrubland due to wildfires, to extensive and intensive agriculture, and to urban areas), and two scenarios that only involved changes in the non-forested matrix (renaturalization and intensification). Our results show that while the network of connecting elements for the species was very robust to the conversion of the forest habitat patches to different cover types, the different change scenarios in the landscape matrix could more significantly weaken its long-term validity and effectiveness. This is particularly the case when most of the key connectivity providers for the nuthatch are located outside the protected areas or public forests in Galicia, where biodiversity-friendly measures might be more easily implemented. We discuss how the methodology can be applied to a wide range of forest landscape management situations, where both the conservation of the forest critical areas and an adequate management of the landscape matrix between them are of concern to achieve the sustainability of the ecological flows and ecosystem services at the wider forest landscape scale.
Litterfall and litter decomposition in chestnut high forest stands in northern Portugal
Authors: Patricio M.S. , Nunes L.F. , Pereira E.L.
Published: July 2012

This research aimed to: estimate the inputs of litterfall; model the decomposition process and assess the rates of litter decay and turnover; study the litter decomposition process and dynamics of nutrients in old chestnut high forests. This study aimed to fill a gap in the knowledge of chestnut decomposition process as this type of ecosystems have never been modeled and studied from this point of view in Portugal. The study sites are located in the mountains of Marão, Padrela and Bornes in a west-to-east transect, across northern Portugal, from a more-Atlantic-to-lessmaritime influence. This research was developed on old chestnut high forests for quality timber production submitted to a silviculture management close-to-nature. We collected litterfall using littertraps and studied decomposition of leaf and bur litter by the nylon net bag technique. Simple and double exponential models were used to describe the decomposition of chestnut litterfall incubated in situ during 559 days. The results of the decomposition are discussed in relation to the initial litter quality (C, N, P, K, Ca, Mg) and the decomposition rates. Annually, the mature chestnut high-forest stands (density 360-1,260 tree ha–1, age 55-73 years old) restore 4.9 Mg DM ha–1 of litter and 2.6 Mg ha–1 yr–1 of carbon to the soil. The two-component litter decay model proved to be more biologically realistic, providing a decay rate for the fast initial stage (46-58 yr–1for the leaves and 38-42 yr–1for the burs) and a decay rate related to the recalcitrant pool (0.45-0.60 yr–1for the leaves and 0.22-0.36 yr–1for the burs). This study pointed to some decay patterns and release of bioelements by the litterfall which can be useful for calibrating existing models and indicators of sustainability to improve both silvicultural and environmental approaches for the management of chestnut forests.