bluuebunny/crossref_metadata_2025 huggingface dataset:
Bainite Formation at Low Temperatures in High C-Si Steel and its Mechanical Behavior
Authors: Junior J. A. C. , Pinheiro I. P. , Rodrigues T. F. M. , Viana V. D. C. , Santos D. B.
Published: July 2011

A significant amount of stabilized austenite can be obtained in high carbon steel containing high amounts of manganese and silicon (1.5–2%). At relatively low temperatures the bainite plates formed are extremely thin; as a result the material becomes very strong. In this study, the influence of austempering on the mechanical behavior of a spring steel 0.56C-1.43Si-0.58Mn-0.47Cr (wt.%), with TRIP effect, was investigated. The thermal cycle consisted of heating two groups of hot-rolled steel at the austenite field of 900°C for 300 s, and transferring it to a metallic bath maintained at 220 or 270°C, respectively, for different isothermal treatment times. The samples were then tested in tension, and their microstructures were examined by optical and scanning electron microscopy. According to the results, the samples treated at 220°C showed higher elongation, yield point, and tensile strength than those maintained at 270°C. The high level of strength and ductility is due to a mixture of martensite and very fine bainite formation.
Gold Catalysis: Particle Size or Promoting Oxide Morphology?
Authors: Guczi László , Beck Andrea , Benkó Tímea , Pászti Zoltán
Published: July 2011

Based on results taken from our own experience and the general literature, in the present contribution issues related to the importance of the particle size and morphology in gold catalysis are considered. Although in reactions of small molecules like carbon monoxide nanosized or otherwise nanostructured gold surfaces are the most active catalysts, especially if forming interface with certain oxides, it turns out that in some cases - independently of the interface - the key issue is the available size of extended gold surface dictating the reaction rate. This dilemma is explored in the paper.
Making Stuff at Princeton University
Authors: Steinberg Daniel J. , Greco Shannon
Published: July 2011

The Princeton Center for Complex Materials (PCCM) joined the PBS NOVA/MRS Making Stuff coalition and created a program to inspire middle school students and their teachers about materials science during exciting large programs at Princeton University and multiple pre and post events. As a National Science Foundation funded Materials Research Science and Engineering Center, it is part of PCCM’s mission to inspire and educate school children, teachers and the public about STEM and materials science. Research shows that it is critical to excite students at a young age and maintain that excitement, and without that these, students are two to three times less likely to have any interest in science and engineering and pursue science careers as adults. The Making Stuff TV series offered a great teachable moment in materials science for students and teachers alike. The four episodes, Stronger, Smaller, Smarter and Cleaner aired in January and February, 2011. Our complementary education program helped promote the viewership of the Making Stuff series in the region, and the NOVA episodes helped us by priming the teachers and students to learn more about materials science research conducted at Princeton University. The Making Stuff coalition events we conducted were designed to have the maximum positive impact on students’ attitudes towards science and scientists, in general, and materials scientists and engineers, specifically. Each and every student had an opportunity to interact with dozens of scientists and engineers, in the lab, at table demonstrations and lecture presentations. As an ongoing MRSEC education and outreach program we have developed many successful educational partnerships to increase our impact. Plus, through years of successful education programs and the participation of our materials scientists and engineers, we have cultivated great trust in the schools and local community. The schools eagerly joined as partners in the program to bring their students to the event. Teachers from those partner schools actively participated in associated professional development programs conducted by education staff and PCCM professors before and after the big event. Included were presentations by MRSEC members and the partners from Princeton Institute for the Science and Technology of Materials (PRISM), Princeton University’s chemistry department, DOE funded centers PP-SOC and PPPL, Liberty Science Center, Franklin Institute, our PBS partner NJN and our many school district partners.
Evaluating the Impact of Interaction between Middle School Students and Materials Science and Engineering Researchers
Authors: Greco Shannon L. , Steinberg Daniel J.
Published: July 2011

We, as education outreach providers at a research center, believe research scientists and engineers have much to contribute to science education. Our job is to design programs that allow our faculty and students to share their expertise and their stories to positively impact student learning and attitudes towards STEM fields. Is it possible to show that middle school students’ interaction with scientists and engineers makes a positive difference in only one day? The National Science Foundation funded Princeton Center for Complex Materials (PCCM), in partnership with MRS and NOVA, held a large-scale, one-day event for middle school students on January 27, 2011. This study measures the impact of that engagement on the students’ attitudes, contributing to their general attitude towards science and scientists that will ultimately determine their career choices later in life. Among other methods, focus group interviews and pre- and post-event attitude surveys were conducted and analyzed to evaluate the impact of the program.
Hemorrhage Secondary to Interforaminal Implant Surgery: Anatomical Considerations and Report of a Case
Authors: Sakka Salah , Krenkel Christian
Published: July 2011

Understanding the anatomy of the floor of mouth is very important as severe submandibular hemorrhages are life threatening. This case report illustrates the potential hemorrhage consequences of implant surgery within the interforaminal region. The highly vascularized interforaminal region is susceptible to hemorrhage, which can be induced simply by instruments causing vascular trauma. The risk of intraoperative bleeding can be minimized by painstaking preoperative clinical and radiological examination but cannot be averted as it is inherent in the underlying anatomy of the region.
Using Magnetic Resonance Imaging for Early Assessment of Submucous Cleft Palate: A Case Report
Authors: Perry Jamie L. , Kuehn David P. , Wachtel Jayne M. , Bailey Jonathan S. , Luginbuhl Laura L.
Published: July 2011

Surgical correction for submucous cleft palate is generally indicated in the presence of velopharyngeal inadequacy. Clinical assessment of velopharyngeal inadequacy requires that the child is able to produce a connected speech sample, which can yield a delay in treatment decisions that extends through a critical period of speech and language development. A perceptual speech assessment and intraoral examination are traditionally the most important methods of establishing a diagnosis of submucous cleft palate. The purpose of this case report is to demonstrate the use of magnetic resonance imaging as a diagnostic tool to provide early identification and an indication of surgical treatment for an individual born with a submucous cleft palate. The magnetic resonance images indicated a discontinuous levator veli palatini muscle sling arrangement with attachment of the muscle bundles onto the hard palate. Surgery was performed at 16 months and postsurgical speech evaluations demonstrated normal resonance and age-appropriate speech.
A test of the senses: Fish select novel habitats by responding to multiple cues
Authors: Huijbers Chantal M. , Nagelkerken Ivan , Lössbroek Pauline A. C. , Schulten Ines E. , Siegenthaler Andjin , Holderied Marc W. , Simpson Stephen D.
Published: July 2011

Habitat‐specific cues play an important role in orientation for animals that move through a mosaic of habitats. Environmental cues can be imprinted upon during early life stages to guide later return to adult habitats, yet many species must orient toward suitable habitats without previous experience of the habitat. It is hypothesized that multiple sensory cues may enable animals to differentiate between habitats in a sequential order relevant to the spatial scales over which the different types of information are conveyed, but previous research, especially for marine organisms, has mainly focused on the use of single cues in isolation. In this study, we investigated novel habitat selection through the use of three different sensory modalities (hearing, vision, and olfaction). Our model species, the French grunt, Haemulon flavolineatum, is a mangrove/seagrass‐associated reef fish species that makes several habitat transitions during early life. Using several in situ and ex situ experiments, we tested the response of fish toward auditory, olfactory, and visual cues from four different habitats (seagrass beds, mangroves, rubble, and coral reef). We identified receptivity to multiple sensory cues during the same life phase, and found that different cues induced different reactions toward the same habitat. For example, early‐juvenile fish only responded to sound from coral reefs and to chemical cues from mangroves/seagrass beds, while visual cues of conspecifics overruled olfactory cues from mangrove/seagrass water. Mapping these preferences to the ecology of ontogenetic movements, our results suggest sequential cue use would indeed aid successful orientation to novel key habitats in early life.
College Students’ Electronic Victimization in Friendships and Dating Relationships: Anticipated Distress and Associations With Risky Behaviors
Authors: Bennett Diana C. , Guran Elyse L. , Ramos Michelle C. , Margolin Gayla
Published: July 2011

This study investigated college students’ reports of electronic victimization in friendships and dating relationships. We examined 22 items representing four categories of electronic victimization: hostility, humiliation, exclusion, and intrusiveness. Nearly all participants (92%) reported some electronic victimization in the past year, with males reporting more victimization and females anticipating more distress. Both females and males anticipated more distress from electronic victimization in dating relationships than friendships. More actual experience with electronic victimization related to lower anticipated distress. Electronic victimization was associated with females’ alcohol use, even after controlling for other victimization experiences. Discussion focuses on the contextualized nature of electronic victimization, and on the importance of understanding what makes electronic victimization highly distressing for some individuals.
Posttraumatic Symptoms Following a Campus Shooting: The Role of Psychosocial Resource Loss
Authors: Littleton Heather , Kumpula Mandy , Orcutt Holly
Published: July 2011

Conservation of resources (COR) theory has proven a useful framework for understanding posttrauma adjustment. A key tenet of this theory is the centrality of resource loss in determining adjustment. However, COR theory research has often been limited by retrospective research design, a focus on material loss (e.g., one’s home), and a lack of attention to other adjustment predictors. This study examined whether psychosocial resource loss prospectively predicted PTSD symptomatology both immediately and 8 months following a campus shooting in a sample of college women (n = 691). Results supported that resource loss predicted symptomatology, even after controlling for other predictors, including prior trauma, psychological distress, initial PTSD symptomatology, and shooting exposure. Implications of the results for research and intervention following mass trauma are discussed.
The Relation of Violence Exposure and Ethnicity to Intelligence and Verbal-Performance Discrepancies in Incarcerated Male Adolescents
Authors: Perkins Suzanne C. , Smith-Darden Joanne P. , Graham-Bermann Sandra A.
Published: July 2011

Incarcerated populations have an estimated incidence of intellectual disabilities (IDs) far higher than national norms, ranging as high as 10%. In the present study, the relation between ID and violence exposure in 115 incarcerated adolescents was examined. Interpersonal violence exposure (IPV-E) predicted an average decrease in full scale IQ of 4.5 points, explaining approximately 5% of the difference in IQ. Child maltreatment increased the odds of having a verbal disability by three folds and explained 17% of the variance in verbal disability. Hierarchical regression was used to examine the relative contribution of ethnicity, poverty, and violence exposure to intellectual functioning. The literature on racial bias in incarceration and the implications for the present study are discussed.
Distress From Sexual Thoughts: Do Religiosity, Emotions, and Thought Appraisal Matter?
Authors: Wetterneck Chad T. , Smith Angela H. , Burgess Angela J. , Hart John M.
Published: July 2011

Sexually intrusive thoughts (SITs) are commonly experienced; yet, there is a paucity of research on distress related to them. Given that the content is similar for intrusive thoughts and obsessions, examining factors related to obsessions in obsessive-compulsive disorder (e.g., thought appraisal and relationships to emotions) may help explain distress from SITs in nonclinical populations. Differences in affective experiences and religiosity may also explain variations in distress from SITs. Nonclinical participants (N = 291) completed questionnaires about frequency of, and distress from, SITs, thought appraisal, beliefs about sexual desire, and emotions. Distress from SITs was correlated with thought appraisal and beliefs about sexual desire, but not with religiosity. In regression analyses, beliefs about sexual desire and the frequency of SITs each predicted distress from SITs. Although thought appraisal is often implicated in obsessive-compulsive symptoms, these results indicate that beliefs about emotions may have a greater impact on distress.
Cognitive Defusion Versus Cognitive Restructuring in the Treatment of Negative Self-Referential Thoughts: An Investigation of Process and Outcome
Authors: Deacon Brett J. , Fawzy Tamer I. , Lickel James J. , Wolitzky-Taylor Kate B.
Published: July 2011

Within traditional cognitive therapy, cognitive restructuring is often used to challenge the veracity of dysfunctional thoughts. In contrast, acceptance and commitment therapy (ACT) uses “cognitive defusion” techniques to change the function of negative thoughts rather than modify their content. Previous research has shown that a cognitive defusion technique known as the “milk exercise” (rapidly repeating a self-referential, one-word thought such as “fat”) reduces the discomfort and believability associated with negative thoughts. This study sought to replicate and extend these findings by comparing the impact of cognitive defusion with that of cognitive restructuring in a sample of participants distressed by negative thoughts about their body shape. Participants received a detailed rationale and training followed by instructions to practice the assigned technique as homework for 1 week. Results indicated that both cognitive techniques produced substantial improvements that generalized well beyond the specific thoughts targeted for treatment. Clear differences in treatment process and the course of improvement were evident. Findings are discussed in the context of theoretical and practical similarities and differences between these two approaches.
Revealing the Controls of Soil Water Storage at Different Scales in a Hummocky Landscape
Authors: Biswas Asim , Si Bing Cheng
Published: July 2011

Soil water storage is controlled by topography, soil texture, vegetation, water routing processes, and the depth to the water table. Interactions among these factors may give rise to scale‐dependent nonstationary and nonlinear patterns in soil water storage. The objectives of this study were to identify the dominant scales of variation of nonstationary and nonlinear soil water storage and delineate the dominant controls at those scales in a hummocky landscape using the Hilbert–Huang transform (HHT). Soil water storage (up to 140 cm) was measured along a 128‐point transect established at St. Denis National Wildlife Area, Saskatchewan, Canada, using time domain reflectometry and a neutron probe. Empirical mode decomposition was used to decompose the measured soil water storage series into six different intrinsic mode functions (IMFs) according on their characteristic scales. The first IMF represented the variations at small scales, the second IMF might characterize the variations associated with microtopography and the landform elements. The IMF 3 was highly correlated with elevation and had the largest variance contribution toward the total variance among all the IMFs. The fourth IMF was correlated to organic C (OC), showing the long‐term history of water availability, which may be a reflection of topographic setting or the elevation. The fifth and sixth IMFs were associated with elevation, soil texture, and OC but they contributed a small fraction of the total variance. Therefore, decomposition made through HHT was physically meaningful and provided improved prediction of soil water storage from topography, soil texture, and OC.
Carbon and Nitrogen Accumulation in Post‐Agricultural Forest Soils of Western New England
Authors: Clark J. D. , Johnson A.H.
Published: July 2011

The agricultural history of New England is reflected in the species composition, biomass, and productivity of the second‐growth forests of the region. There are also effects of agricultural use on soil morphology, soil organic C (SOC) and N content, erosion status, and C stability, which can be specific to site‐level characteristics or prior agricultural use. We conducted a survey of SOC amounts in chronosequences comprising 25 post‐agricultural second‐growth forests. Time since abandonment was estimated from tree ages, and the chronosequences were bounded by sites currently in agricultural use (n = 6) and minimally disturbed old forest (n = 4). At sites currently used for pasture, hay, or row crops, the median amount of SOC (to a depth of 55 cm) was 6.5 kg C m−2 compared with 10.3 kg C m−2 in the soils of the oldest forest stands. The chronosequences indicated that nearly all of the SOC accumulation occurred in the first century of afforestation. There were significant trends of SOC accumulation in the forest floor, upper mineral horizons (0–10 or 10–20 cm), and B horizons (20–55 cm) of soils that had been used for pasture, hay, or row crops but not for former woodlots. Multivariate analysis showed that years since agricultural abandonment and growing season degree days were the most important variables related to SOC content (68% sum of squares explained). There was a significant trend of N accumulation (1.3 g N m−2 yr−1) in soils (to a depth of 55 cm) formerly used for cultivated crops but not for other former uses. Farms in this region were an important C sink during the last 150 yr; however, the capacity of former agricultural soils to gain SOC in the future is probably limited.
WET Sensor Performance in Organic and Inorganic Media with Heterogeneous Moisture Distribution
Authors: Kargas G. , Kerkides P. , Seyfried M. , Sgoumbopoulou A.
Published: July 2011

Interest in electronic monitoring of soil water has grown as increased demand for water creates a greater need for effective water management. Relatively inexpensive commercial soil water sensors that use measured soil dielectric properties to calculate soil water content have been developed to address this need but have received little independent testing of critical calibration procedures and parameters. The WET sensor (Delta‐T Devices, Cambridge, UK) is one such sensor. The two primary objectives in this study were to: (i) determine appropriate calibration parameters for a variety of inorganic soils and organic media; and (ii) determine how WET sensor readings are affected in media with strongly contrasting water contents. We found that the two‐point calibrations suggested by the manufacturer yielded parameters that were not significantly different (α = 0.05) from those suggested by the manufacturer and yielded values consistent with well‐established oven‐dry values. For the organic media, we found that accurate, media‐specific calibration could be obtained for all media tested and that the general form of the calibration equation used for soils applies to organic media. Experiments in a variety of layered media showed that, in contrast to time domain reflectometry results, the WET‐measured dielectric value is the arithmetic average of the two contrasting layers. In soils, the linear correlation between measured and arithmetic average dielectric constants was very high (R2 > 0.99) for all four soils tested. This indicates that the upward infiltration calibration technique is generally inappropriate for the WET sensor.
Two‐Dimensional Porosity of Crusted Silty Soils: Indicators of Soil Quality in Semiarid Rangelands?
Authors: Miralles-Mellado I. , Cantón Y. , Solé-Benet A.
Published: July 2011

Little is known about the morphological characteristics of pores in soil crusts. The objective was to characterize the two‐dimensional (2D) porosity (amount, shape, size, and area of pores) of soil crusts to ascertain their potential as indicators of soil quality for natural crusted soils. The 2D‐porosity was described in thin sections and measured by image analysis of polished resin‐impregnated soil blocks. Physical soil crust and incipient biological soil crusts appear to be the lowest‐quality soils in terms of number of pores (average of 131–133 cm−1) and area occupied by pores or meso‐macroporosity (3.5–4.2%). Their most abundant pore types were small unconnected rounded pores. Soil crust infiltration coefficients (65–72% annual) were among the lowest and their high erosion rates (81–204 g m−2 yr−1) were not only due to their lower total porosity, but also to their pore shapes and sizes. Biological soil crusts appear on higher‐quality soil, where the higher the organic C content, the more evolved the soil crust is (with lichens and cyanobacteria). Such soil crusts have better developed pore‐systems with specific meso‐ and macropore morphologies, for example, large, interconnected elongated and irregular pores. Biological soil crusts (BSCs) dominated by lichens have the largest meso‐macroporosity (up to 23.65%) due to the predominance of elongated pores. In many cases, infiltration is low (46–57%) because the biological crusts are somewhat detached from the soil underneath, but the armouring effect decreases erosion rates (7–23 g m−2 yr−1). Soil crust pore numbers, size, and shape were useful indicators of soil quality.
Recycled Materials as Substitutes for Virgin Aggregates in Road Construction: II. Inorganic Contaminant Leaching
Authors: Kang Dong-Hee , Gupta Satish C. , Bloom P. R. , Ranaivoson Andry Z. , Roberson Ruth , Siekmeier John
Published: July 2011

Construction and maintenance of roads requires large volume of aggregates for use in base or subbase layers. Because of the expense of buying virgin aggregates, federal and state agencies are encouraging the recycling of waste materials in road construction. A study was under taken to evaluate the suitability of fly ash (FA), reclaimed asphalt pavement (RAP), recycled cement material (RCM), and foundry sand (FS) mixed in with virgin aggregates as base and subbase materials. In this paper we report the results on inorganic contaminants leaching from six mixtures of FA–RAP aggregates under batch and flow through conditions. The concentrations of most inorganic chemicals in both batch and flow through modes from all six mixtures were either below the detection limit of the instrument or less than the EPA drinking water standard. The exceptions were Al and Cr. Aluminum concentrations were higher than the EPA secondary drinking water standard in both batch and flow‐through tests whereas Cr concentration exceeded the primary EPA drinking water standard in the flow through tests only. Aluminum concentrations in the leachate increased with a decrease in the proportion of FA whereas Cr concentration in the leachate increased with an increase in the proportion of FA in the mixtures. The mixtures had lower pH compared to 100% FA, due to dilution of Ca(HO)2 in the FA, which resulted in higher Al concentrations. Addition of up to 5% FA and 75% RAP to virgin aggregates does not lead to any substantial leaching of various inorganic chemicals. At 15% FA, there is a slight risk for transport of some dissolved inorganic chemicals at a concentration higher than the EPA primary drinking water standards.
Soil Water Repellency within a Burned Piñon–Juniper Woodland: Spatial Distribution, Severity, and Ecohydrologic Implications
Authors: Madsen M. D. , Zvirzdin D. L. , Petersen S. L. , Hopkins B. G. , Roundy B. A. , Chandler D. G.
Published: July 2011

Soil water repellency is commonly found in piñon (Pinus spp.)–juniper (Juniperus spp.) (P‐J) woodlands and may limit site recovery after a fire. Understanding the extent of this problem and the impact it has on vegetation recovery will help guide land managers in conducting their restoration efforts. In this study, we (i) examined the spatial distribution and severity of post‐fire soil water repellency in a burned P‐J woodland, (ii) related ecohydrologic properties to pre‐fire tree canopy cover and post‐fire vegetation establishment, and (iii) demonstrated a geographic information system (GIS)‐based approach to extrapolate observed patterns to the fire boundary scale. During a 2‐yr period, several soil and vegetative measurements were performed along radial line transects extending from the trunk of burned Utah juniper [Juniperus osteosperma (Torr.) Little] trees to twice the canopy radius. Results indicate that water repellency patterns are highly correlated with pre‐fire tree canopy cover. Critical water repellency extended from the base of the tree to just beyond the canopy edge, while subcritical water repellency extended half a canopy radius past the edge of the critical water repellency zone. At sites where critical water repellency was present, infiltration rates, soil moisture, and vegetation cover and density were significantly less than non‐water‐repellent sites. These variables were also reduced in soils with subcritical water repellency (albeit to a lesser extent). Results were exported into a GIS‐based model and used in conjunction with remotely sensed imagery to estimate the spatial distribution of soil water repellency at the landscape scale.
Phosphorus Sorption Dynamics of Anion Exchange Resin Membranes in Tropical Rain Forest Soils
Authors: Vandecar Karen L. , Lawrence Deborah , Clark Deborah
Published: July 2011

Bioavailable P is recognized as a major constraint on productivity in many tropical rain forests. Nevertheless, insufficient knowledge about short‐term temporal patterns in soil labile P limits our understanding of the mechanisms controlling soil P supply in tropical forest soils. The use of field‐deployed anion exchange resin membranes (AEMs) to determine soil nutrient supply rates is increasingly common, however, the lack of information regarding their behavior over time in tropical wet forest soils interferes with interpretation of results. This study quantifies in situ labile P as measured by AEMs over various incubation periods (4, 8, 12, 14, 20, and 24 d) in the surface soil of two neighboring Costa Rican tropical rain forest Oxisols of differing P content (0.46 vs. 1.18 Mg ha−1, 0–10 cm). Using a nested design, we evaluated the importance of incubation length, environmental conditions (i.e., rainfall, temperature, and solar radiation), vegetation characteristics (i.e., basal area, stem density, and species composition), and total P status in driving spatial and temporal variability in AEM P. Spatially averaged AEM P in the site with higher P content ranged from 0.26 to 1.38 μg membrane−1 across all incubation periods; approximately two fold higher than AEM P in the more P‐deficient site (0.11–0.77 μg membrane−1). Temporal variability in AEM P was best explained by rainfall. Despite consistently high volumetric soil moisture (50–66%), increasing rainfall was associated with greater P availability in both sites. Mean P availability increased with plant basal area and basal area of legumes.
Multiscale Characterization of Vadose Zone Macroporosity in Relation to Hydraulic Conductivity and Subsurface Drainage
Authors: Frey Steven K. , Rudolph David L.
Published: July 2011

The purpose of this study was to quantify macroporosity distribution in relation to tile drains, and to determine any correlation between macroporosity and hydraulic conductivity (K). Macropore−tile drain relations were investigated at three plots within a single field. Macropores on 149 0.25‐m2 horizontal surfaces, located at depths of 0.02 to 1 m, and distances of 0 to 3.5 m from the tile drains, were counted and classified into 0.5 to 5, 5 to 8, 8 to 10, and 10 to 12 mm equivalent circular diameter categories. Results show no significant (P < 0.1) difference in macropore area fraction (MAF) (defined as macropore area/total soil area) distribution relative to tile drain position; however, MAF did vary significantly between plots. The coefficient of variation for plot‐specific, depth‐averaged, total MAF ranged from 10 to 48%. Macropores in the 0.5‐ to 5‐mm and 5‐ to 12‐mm size ranges were most abundant near the surface and the shallow B horizon, respectively. When present, macropores at tile depth were mostly 0.5 to 5mm in size. Maximum depth‐averaged total MAF ranged from 0.0036 to 0.0087 within the plots, whereas the minimum depth averaged MAF was less than 0.001 and located at tile depth. Strong correlation was observed between field surface K and MAF below 0.45 m depth (r = 0.79), and B horizon K and MAF below 0.02 m depth (r ≥ 0.83). Dye staining patterns revealed that >20‐yr‐old tile installation scars were channeling infiltrate to tile drains at two plots.
A Comparison of Soil Sulfur Extraction Methods
Authors: Ketterings Quirine , Miyamoto Chie , Mathur Renuka Rao , Dietzel Kevin , Gami Sanjay
Published: July 2011

There are currently no field calibration data for interpretation of soil S tests in the U.S. Northeast and limited data elsewhere. Given the reduction in the S deposition rate during the past decade in the Northeast, it is important to evaluate the potential for soil testing as a tool for S management in the region. An incubation study was conducted to compare: (i) the accuracy and effectiveness of six S extraction methods to identify an increase in available S; and (ii) S detection in solution using inductively coupled plasma atomic emission spectroscopy (ICP–AES) at 182 nm with turbidimetric determination of S using BaCl2×2H2O and a spectrophotometer at 420 nm. The six extraction solutions were 1.0 mol L−1 NH4OAc, 0.016 mol L−1 KH2PO4, 0.01 mol L−1 Ca(H2PO4)2, 0.01 mol L−1 CaCl2, Morgan, and the Mehlich‐3 solution. Four New York soils were treated with six S rates (0, 28, 56, 84, 112, 168 kg ha−1) applied as gypsum and incubated for 4 wk (in the dark, at room temperature, 75% of field capacity, four replications). Sulfur test results correlated with S fertilizer application for all extraction and detection methods; however, the 0.01 mol L−1 CaCl2 extraction with ICP–AES detection of S in solution was best correlated with S added (highest r2, smallest RMSE across all four soils), the regression equation had the largest slope, and this method showed the greatest consistency between the two detection methods. We conclude 0.01 mol L−1 CaCl2 extraction with ICP–AES detection of S is most promising and should be evaluated in field trials.
Spatial Variations in Soil Chemistry and Organic Matter Content across aVochysia divergensInvasion Front in the Brazilian Pantanal
Authors: Vourlitis George L. , de Almeida Lobo Francisco , Biudes Marcelo Sacardi , Rodríguez Ortíz Carmen Eugenia , de Souza Nogueira Jose
Published: July 2011

The Pantanal is a large and diverse wetland that spans three South American countries including parts of Brazil, Paraguay, and Bolivia. An invasive tree,Vochysia divergensPohl (commonly known as Cambara), has been expanding throughout the Pantanal for more than four decades forming monospecific stands. Given the rapid and extensive spread of Cambara, and the potential for woody plant invasion to alter soil organic matter and nutrient stocks, we hypothesized that Cambara invasion would significantly increase soil organic matter and nutrient content. To test this hypothesis we sampled the soil, litter, and vegetation of a monospecific Cambara stand, a grassland (campo) stand in the process of Cambara invasion (transitional), and a campo stand free of Cambara during the dry season in July and August of 2009 and 2010 when stands were free from seasonal flooding. Surface (0–10 cm) soil in sites dominated by Cambara had significantly higher soil organic matter (SOM), P, and cation content, and higher cation exchange capacity (CEC), but soil pH and K+concentration were less coincident with Cambara presence. The variation of soil characteristics was also significantly higher in the transitional site, indicating that the transition from a grassland‐ to a Cambara‐dominated system significantly increased the spatial variability of soil chemistry. These results indicate that Cambara invasion fundamentally alters the C and nutrient storage of Panatanal soils. Future research will investigate if these results are general for Cambara invasion and address mechanisms of how Cambara invasion affects the nutrient cycling and storage of Pantanal soils.
Addition of Cover Crops Enhances No‐Till Potential for Improving Soil Physical Properties
Authors: Blanco-Canqui Humberto , Mikha Maysoon M. , Presley DeAnn R. , Claassen Mark M.
Published: July 2011

Inclusion of cover crops (CCs) may be a potential strategy to boost no‐till performance by improving soil physical properties. To assess this potential, we utilized a winter wheat (Triticum aestivum L.)–grain sorghum [Sorghum bicolor (L.) Moench] rotation, four N rates, and a hairy vetch (HV; Vicia villosa Roth) CC after wheat during the first rotation cycles, which was replaced in subsequent cycles with sunn hemp (SH; Crotalaria juncea L.) and late‐maturing soybean [LMS; Glycine max (L.) Merr.] CCs in no‐till on a silt loam. At the end of 15 yr, we studied the cumulative impacts of CCs on soil physical properties and assessed relationships between soil properties and soil organic C (SOC) concentration. Across N rates, SH reduced near‐surface bulk density (ρb) by 4% and increased cumulative infiltration by three times relative to no‐CC plots. Without N application, SH and LMS reduced Proctor maximum ρb, a parameter of soil compactibility, by 5%, indicating that soils under CCs may be less susceptible to compaction. Cover crops also increased mean weight diameter of aggregates (MWDA) by 80% in the 0‐ to 7.5‐cm depth. The SOC concentration was 30% greater for SH and 20% greater for LMS than for no‐CC plots in the 0‐ to 7.5‐cm depth. The CC‐induced increase in SOC concentration was negatively correlated with Proctor maximum ρb and positively with MWDA and cumulative infiltration. Overall, addition of CCs to no‐till systems improved soil physical properties, and the CC‐induced change in SOC concentration was correlated with soil physical properties.
Sorption, Volatilization, and Efficacy of the Fumigant 1,3‐Dichloropropene in a Biochar‐Amended Soil
Authors: Graber E. R. , Tsechansky L. , Khanukov J. , Oka Y.
Published: July 2011

Sorption of the soil fumigant, 1,3‐dichloropropene (DCP), on cornstraw biochar (fast pyrolysis at 500°C; specific surface area [SSA] of 3.0 m2 g−1) was strongly nonlinear and significantly greater on a soil–1% biochar mixture (26 Mg biochar ha−1) than on soil alone. This resulted in substantial reductions in DCP concentrations in the vapor phase. However, concentration of the fumigant in the aqueous phase of the soil, where it is active against soil nematodes, was also significantly reduced due to strong sorption to the biochar. In the studied system, adequate nematode control was achieved at 13 and 26 Mg biochar ha−1and DCP of 94 and 187 L ha−1, respectively, where the fumigant manufacturers suggested dose range of DCP is 84 to 514 L ha−1. Biochars produced at relatively high temperatures (>600°C) with a high SSA have been shown to absorb organic chemicals more strongly by one or more orders of magnitude than those, like the biochar used herein, produced at lower temperatures with a low SSA. Calculations show that adequate nematode control would not have been obtained had the biochar absorbed only five times more DCP per given solution concentration. Thus it is evident that while nematode control was adequate in the specific studied system, soil amendment with biochar could adversely impact pest control, depending on the sorption strength of the particular biochar. This issue should be considered when determining desirable biochar physical and chemical characteristics for use in agronomic systems.
Distribution and Properties of Vesicular Horizons in the Western United States
Authors: Turk Judith K. , Graham Robert C.
Published: July 2011

Vesicular horizons are thin (usually <10 cm) surface or near‐surface horizons characterized by the predominance of vesicular porosity. They are widespread in arid and semiarid lands, occurring on every continent and covering 156,000 km2of the western United States. Vesicular horizons have critical implications for management due to their role in controlling surface hydrology and dust mobilization. This study evaluates the distribution and variation in expression of vesicular horizons across the western United States using the soil databases available from the USDA. A vesicular horizon index (VHI) that incorporates vesicular horizon thickness and the size and quantity of vesicular pores was developed using soil descriptions from a published chronosequence study. The VHI was applied to descriptions from the soil survey databases to evaluate vesicular horizon expression across the western United States. Vesicular horizons were better expressed (higher VHI) in the Central and Northern Basin and Range compared to the Mojave and Sonoran Basin and Range. This may be due to differences in temperature regime or to larger areas of playas in the Central and Northern Basin and Range that serve as sources of dust that forms the parent material for vesicular horizons. The median VHI was highest in the Aridisols and Mollisols compared to other soil orders. No significant relationship was found between VHI and soil textures. Vesicular horizons are widely distributed in western United States and occur across a wide range of soil types and soil‐forming environments.
Antibacterial activity chemical composition relationship of the essential oils from cultivated plants from Serbia
Authors: Stankovic Nemanja , Comic Ljiljana , Kocic Branislava , Nikolic Dejan , Mihajilov-Krstev Tatjana , Ilic Budimir , Miladinovic Dragoljub
Published: July 2011

The antibacterial effects of essential oils from Serbian cultivated plants,
Thymus vulgaris L. (Lamiace) and Lavandula angustifolia L. (Lamiace) on
different bacteria were investigated, with an emphasis on an antibacterial
activity-chemical composition relationship. Essential oil was obtained from
airdried aerial parts of the plants by hydrodistillation for 3 h using a
Clevenger-type apparatus. The essential oil analyses were performed
simultaneously by gas chromatography (GC) and gas chromatography-mass
spectrometry (GC-MS) systems. The main constituents of thyme oil were thymol
(59.95%) and p-cymene (18.34%). Linalyl acetate (38.23%) and linalool
(35.01%) were main compounds in lavender oil. The antibacterial activity of
the essential oils samples was tested towards 5 different bacteria:
laboratory control strain obtained from the American Type Culture Collection
and clinical isolates from different pathogenic media. Gram negative bacteria
were represented by Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC
43895 and Salmonella enteretidis ATCC 9027 while researched Gram positive
strains were Bacillus cereus ATCC 8739 and Staphylococcus aureus ATCC 25923.
A broth microdilution method was used to determine the minimum inhibitory
concentration (MIC) and minimum bactericidal concentration (MBC). Essential
oils from thyme have been found to have antimicrobial activity against all
microorganisms tested, with a range of MIC values from 0.025 to 0.10 l/ml and
MBC values from 0.05 to 0.78 l/ml. Lavender oils demonstrated MIC values from
0.025 to 0.20 l/ml and MBC values from 0.05 and 0.78 l/ml. Reference
antibiotic tetracycline was active in concentrations between 0.025 and 0.05
l/ml. The Gram-positive bacteria were more sensitive to the essential oil of
thyme, while Gram-negative bacteria were more sensitive to the essential oil
of lavender. Essential oils from thyme and lavender may be used at low
concentrations for prevention and treatment of infective diseases in animals
and humans caused by pathogenic bacterial species.
Exact solutions for rotational flow of a fractional Maxwell fluid in a circular cylinder
Authors: Siddiqu Imran , Vieru Dumitru
Published: July 2011

This paper deals with the rotational flow of a fractional Maxwell fluid in an
infinite circular cylinder, due to the torsional variable time-dependent
shear stress that is prescribed on the boundary of the cylinder. The
fractional calculus approach in the constitutive relationship model of a
Maxwell fluid is introduced. The velocity field and the resulting shear
stress are determined by means of the Laplace and finite Hankel transforms to
satisfy all imposed initial and boundary conditions. The solutions
corresponding to ordinary Maxwell fluids as well as those for Newtonian
fluids, performing the same motion, are obtained as limiting cases of our
general solutions. Finally, the influence of the relaxation time and the
fractional parameter on the velocity of the fluid is analyzed by graphical
illustrations.
Converting fractional differential equations into partial differential equations
Authors: He Ji-Huan , Li Zheng-Biao
Published: July 2011

A transform is suggested in this paper to convert fractional differential
equations with the modified Riemann-Liouville derivative into partial
differential equations, and it is concluded that the fractional order in
fractional differential equations is equivalent to the fractal dimension.
Fractional model for heat conduction in polar bear hairs
Authors: Wang Qing-Li , He Ji-Huan , Li Zheng-Biao
Published: July 2011

Time-fractional differential equations can accurately describe heat
conduction in fractal media, such as wool fibers, goose down and polar bear
hair. The fractional complex transform is used to convert time-fractional
heat conduction equations with the modified Riemann-Liouville derivative into
ordinary differential equations, and exact solutions can be easily obtained.
The solution process is straightforward and concise.
Ultrasound enhances the healing of orthodontically induced root resorption in rats
Authors: Liu Zhifeng , Xu Juan , E Lingling , Wang Dongsheng
Published: July 2011

Objective:

To examine the effect of low-intensity pulsed ultrasound (LIPUS) on orthodontically induced root resorption in rats.

Materials and Methods:

Sixty-four male Wistar rats were divided randomly and equally into four groups (n  =  16 rats each). The rats were untreated (negative control) or treated with orthodontic tooth movement without (positive control) or with LIPUS at 100 or 150 MW/cm2 (LIPUS-treated groups). An initial force of 100 g was applied to the areas between the upper right central incisors and the first molars of the rats for 10 days. Eight rats were randomly chosen from each group, and the root resorption index (RRI) was determined with scanning electron microscopy (SEM). Upper first molar-centered mesial-distal tissue slices were generated from the upper first molars and peridentium of the remaining eight rats from each group. Specimen slices were analyzed with hematoxylin-eosin and tartrate-resistant acid phosphatase staining, osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) immunohistochemistry, and optical microscopy. Analyses of cell number, densitometry, and one-way analysis of variance were performed.

Results:

The LIPUS-treated groups displayed decreased RRI values, decreased osteoclast numbers and activity levels, and increased OPG/RANKL expression ratios. High-power SEM revealed reparative cementum in the LIPUS-treated samples.

Conclusion:

LIPUS regulates osteoclast differentiation via the OPG/RANKL ratio, evoking a reparative effect on orthodontically induced root resorption in rats.
Altered mandibular growth under functional posterior displacement in rats
Authors: Farias-Neto Arcelino , Martins Ana Paula Varela Brown , Figueroba Sidney Raimundo , Groppo Francisco Carlos , de Almeida Solange Maria , Rizzatti-Barbosa Célia Marisa
Published: July 2011

Objective:

To test the null hypothesis that there is no difference in mandibular growth between growing rats with posterior functional mandibular displacement and growing rats without functional mandibular displacement.

Materials and Methods:

Twenty female Wistar rats (5 weeks old) were randomized into two groups: (1) control and (2) mandible posterior displacement in the occluded condition induced by an occlusal guiding appliance. After 8 weeks all animals were sacrificed, cone beam computed tomography scan images of the heads were taken using the classic I-CAT, and acrylic rapid-prototyped templates of the mandibles were constructed. Mandibular length, ramus height, and intercondylar distance were measured. Mandibular length and ramus height were submitted to the two-way analysis of variance, while intercondylar distance was analyzed by nonpaired Student's t-test.

Results:

Mandibular length was bigger (P < .0001) in the control than in the experimental group, but no significant difference was found between the left and right sides (P  =  .9380). No significant differences were observed for ramus height and intercondylar distance.

Conclusions:

The results of this study demonstrated that functional posterior displacement of the mandible in growing rats resulted in shorter mandibular length.
Do enamel microabrasion and casein phosphopeptide-amorphous calcium phosphate affect shear bond strength of orthodontic brackets bonded to a demineralized enamel surface?
Authors: Baysal Asli , Uysal Tancan
Published: July 2011

Objective:

To evaluate and compare the effects of enamel microabrasion, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), and their combination on the shear bond strength (SBS) of orthodontic brackets bonded to demineralized enamel surface.

Materials and Methods:

One hundred human first premolar teeth were randomly allocated to one of five groups. Group I was considered as the control of other groups. For the remaining groups, demineralization was performed via solutions. In group II, brackets were directly bonded to the demineralized enamel surface. CPP-ACP was applied in group III, microabrasion was performed in group IV, and both microabrasion and CPP-ACP application were performed in group V. The specimens were tested for SBS. Bond failures were scored according to the Adhesive Remnant Index (ARI). Analysis of variance and Tukey tests were used to compare the SBS of the groups. ARI scores of the groups were evaluated with a G-test. The statistical significance was set at P <. 05 level.

Results:

Statistically significant difference was found among the five investigated groups (F  =  111.870; P < .001). The SBS of groups II and IV were significantly lower than the other groups. No statistically significant difference was found among groups I (control; mean 24.1 ± 4.1 MPa), III (mean 22.0 ± 3.6 MPa), and V (mean 24.3 ± 1.9 MPa). Microabrasion and combination with CPP-ACP showed higher SBS compared to the control group. The differences between ARI scores of the groups were statistically significant (P < .001).

Conclusion:

CPP-ACP pretreatment, microabrasion of the enamel, and the combination of these two methods improve the bonding to demineralized enamel.