bluuebunny/crossref_metadata_2025 huggingface dataset:
The Role of Ultrasound in Multiple Pregnancy
Authors: Arabin Birgit , van Eyck Jim
Published: May 2007

The advances in reproductive technologies have changed the demographics of multifetal pregnancies. In the first trimester, ultrasound allows to diagnose the number of multiples, chorionicity and amnionicity, the presence or absence of nuchal translucency, early growth discordance, severe malformations and the origin of activities and contacts between multiples. In the second and third trimester, the opportunity to examine the cervix by transvaginal ultrasound should not be missed to detect the risk of premature delivery. Ultrasound is essential for the early grading and treatment of twin-to-twin transfusion syndrome (TTTS), the diagnosis of malformations and growth disturbances. Doppler velocimetry has proven to be able to reduce perinatal mortality in twin pregnancies. Finally, ultrasound is used for the detection of the position of multiples and the decision of the optimal route of delivery. This is of main importance in delayed interval delivery and expectant management of multifetal pregnancies and early cervical dilatation.
Abstracts from the 10th International Congress on Twin Studies
Authors: Kirk Katherine
Published: May 2007

Programme Committee: Elizabeth Bryan, Isaac Blickstein, Nick Martin, Pat Preedy, Tim Spector
Use of Monozygotic Twins in Search for Breast Cancer Susceptibility Loci
Authors: Försti Asta , Jin Qianren , Sundqvist Lena , Söderberg Magnus , Hemminki Kari
Published: May 2007

We have used Swedish monozygotic twins concordant for breast cancer to study genetic changes associated with the development of breast cancer. Because loss of heterozygosity (LOH) at a specific genomic region may reflect the presence of a tumour suppressor gene, loss of the same allele in both of the twins concordant for breast cancer may pinpoint a tumour suppressor gene that confers a strong predisposition to breast cancer. DNA samples extracted from the matched tumour and normal tissues of nine twin pairs were analysed for allelic imbalance using a set of microsatellite markers on chromosomes 1, 13, 16 and 17, containing loci with known tumour suppressor genes. The two main regions, where more twin pairs than expected had lost the same allele, were located at 16qtel, including markers D16S393, D16S305 and D16S413, and at 17p13, distal to the p53 locus. Our results show that the monozygotic twin model can be used to suggest candidate regions of potential tumour suppressor genes, even with a limited number of twin pairs.
Ascertainment of a Mid-Western US Female Adolescent Twin Cohort for Alcohol Studies: Assessment of Sample Representativeness Using Birth Record Data
Authors: Heath Andrew C. , Howells William , Bucholz Kathleen K. , Glowinski Anne L. , Nelson Elliot C. , Madden Pamela A. F.
Published: May 2007

Female twin pairs were identified from birth records, and their families invited to participate in a prospective study of the determinants of alcohol problems in women. We investigated sampling biases arising because of failure to locate families, or non-cooperation of families. Out of 2644 families with a live-born pair (born between July 1975 and December 1986) who survived beyond infancy, contact was established and a brief screening interview completed with 90% (N = 2380). Fewer than 6% of located families declined to participate in the initial screening interview. Predictors of failure to locate a family or to obtain a screening interview were identified from information recorded in birth records, and from neighborhood characteristics identified from 1990 US Census block group data for the family residence when the twins were born. African-American families were under-represented in the final sample, but this effect was barely significant when other variables were controlled for. Under-represented were families where the mother was 19 or younger at the birth of the twins, where the mother herself was born out-of-state, or where information about biological father was not reported in the birth record. Non-participating families on average came from neighborhoods with a higher proportion of residents living in poverty, and with a higher proportion of African-American residents. Sampling biases were however small. The unusual cooperativeness in research of families with twins persists.
Estimating Two-Stage Models for Genetic Influences on Alcohol, Tobacco or Drug Use Initiation and Dependence Vulnerability in Twin and Family Data
Authors: Heath Andrew C. , Martin Nicholas G. , Lynskey Michael T. , Todorov Alexandre A. , Madden Pamela A. F.
Published: May 2007

Genetic research on risk of alcohol, tobacco or drug dependence must make allowance for the partial overlap of risk-factors for initiation of use, and risk-factors for dependence or other outcomes in users. Except in the extreme cases where genetic and environmental risk-factors for initiation and dependence overlap completely or are uncorrelated, there is no consensus about how best to estimate the magnitude of genetic or environmental correlations between Initiation and Dependence in twin and family data. We explore by computer simulation the biases to estimates of genetic and environmental parameters caused by model misspecification when Initiation can only be defined as a binary variable. For plausible simulated parameter values, the two-stage genetic models that we consider yield estimates of genetic and environmental variances for Dependence that, although biased, are not very discrepant from the true values. However, estimates of genetic (or environmental) correlations between Initiation and Dependence may be seriously biased, and may differ markedly under different two-stage models. Such estimates may have little credibility unless external data favor selection of one particular model. These problems can be avoided if Initiation can be assessed as a multiple-category variable (e.g. never versus early-onset versus later onset user), with at least two categories measurable in users at risk for dependence. Under these conditions, under certain distributional assumptions, recovery of simulated genetic and environmental correlations becomes possible. Illustrative application of the model to Australian twin data on smoking confirmed substantial heritability of smoking persistence (42%) with minimal overlap with genetic influences on initiation.
Fundal Height as a Predictor of Early Preterm Triplet Delivery
Authors: Yokoyama Yoshie
Published: May 2007

The purpose of this study was to create graphs of fundal height parameters in triplet pregnancies compared with those in twin pregnancies, and to investigate whether larger fundal heights in triplet pregnancies would predispose them to earlier delivery (before 34 weeks). The subjects were 727 twin pregnant women and 133 triplet pregnant women, who delivered after 1984. Triplet pregnancies showed significantly higher fundal heights compared with twin pregnancies at each gestational age (weeks). In triplet pregnancies, a single fundal height measurement above the 90th percentile before 34 weeks yielded a sensitivity of 31.3% and specificity of 82.4% for delivery before 34 weeks, with a positive predictive value of 50.0% and a negative predictive value of 68.0%. After adjusting for each associated factor using logistic regression, the risk of preterm labour was not significantly associated with a single fundal height measurement above the 90th percentile recorded before 34 weeks.
Paternal Familial Twinning: Hypothesis and Genetic/Medical Implications
Authors: Golubovsky Michael
Published: May 2007

The phenomenon of paternally dependent familial twinning has been known in human and animal genetics since the 1920s, but still remains without any theoretical explanation and is indeed a neglected field of inquiry. Over the last two decades investigations in reproduction biology have discovered the significant role of multiple paternally dependent errors in fertilization including androgenic triploidy and moles. We suggest the hypothesis that the fathers of twins in the relevant families carry gene variants that increase the probability of dispermy, diplospermy and male pronucleus heterochrony as well as involvement of two male pronuclei in the fertilization of two female meiotic products. Any resulting twins would be an exceptional intermediate between MZ and DZ twins — and might properly be described as “sesquizygotic” (SZ). Paternal familial twinning may also go together with infertility due to triploidy, moles and chimerism. The hypothesis: (i) places the curiosities of paternally derived twinning within the framework of current knowledge of reproductive genetics and verifiable phenomena; (ii) predicts the existence of families in which twinning is associated with reproductive abnormalities; (iii) predicts an occurrence in relevant families of the third and intermediate category of SZ twins. Families with paternal twinning may thus provide the natural selective system for the search of unusual cases of primary chimeras, the frequency of which is still unknown.
Heritabilities of Apolipoprotein and Lipid Levels in Three Countries
Authors: Beekman Marian , Heijmans Bastiaan T. , Martin Nicholas G. , Pedersen Nancy L. , Whitfield John B. , DeFaire Ulf , van Baal G. Caroline M. , Snieder Harold , Vogler George P. , Slagboom P. Eline , Boomsma Dorret I.
Published: May 2007

This study investigated the influence of genes and environment on the variation of apolipoprotein and lipid levels, which are important intermediate phenotypes in the pathways toward cardiovascular disease. Heritability estimates are presented, including those for apolipoprotein E and AII levels which have rarely been reported before. We studied twin samples from the Netherlands (two cohorts;n= 160 pairs, aged 13–22 andn= 204 pairs, aged 34–62), Australia (n= 1362 pairs, aged 28–92) and Sweden (n= 302 pairs, aged 42–88). The variation of apolipoprotein and lipid levels depended largely on the influences of additive genetic factors in each twin sample. There was no significant evidence for the influence of common environment. No sex differences in heritability estimates for any phenotype in any of the samples were observed. Heritabilities ranged from 0.48–0.87, with most heritabilities exceeding 0.60. The heritability estimates in the Dutch samples were significantly higher than in the Australian sample. The heritabilities for the Swedish were intermediate to the Dutch and the Australian samples and not significantly different from the heritabilities in these other two samples. Although sample specific effects are present, we have shown that genes play a major role in determining the variance of apolipoprotein and lipid levels in four independent twin samples from three different countries.
The Validity and Heritability of Self-Report Osteoarthritis in an Australian Older Twin Sample
Authors: Kirk Katherine M. , Bellamy Nicholas , O'Gorman Louise E. , Kuhnert Petra M. , Klestov Alex , Muirden Ken , Tesar Paul , Walker Duncan , Martin Nicholas G.
Published: May 2007

In order to investigate the genetic and environmental antecedents of osteoarthritis (OA), self-report measures of joint pain, stiffness and swelling were obtained from a popula-tion-based sample of 1242 twin pairs over 50 years of age. In order to provide validation for these self-report measures, a subsample of 118 twin pairs were examined according to the American College of Rheumatology clinical and radiographic criteria for the classification of osteoarthritis. A variety of statistical methods were employed to identify the model derived from self-report variables which would provide optimal prediction of these standardised assessments, and structural equation modelling was used to determine the relative influences of genetic and environmental influences on the development of osteoarthritis. Significant genetic effects were found to contribute to osteoarthritis of the hands, hips and knees in women, with heritability estimates ranging from 30–46% depending on the site. In addition, the additive genetic effects contributing to osteoarthritis in various parts of the body were confirmed to be the same. Statistically significant familial aggregation of osteoarthritis in men was also observed, but it was not possible to determine whether this was due to genetic or shared environmental effects.
Norwegian Twin Registers and Norwegian Twin Studies — An Overview
Authors: Bergem A.L. Mina
Published: May 2007

The Norwegian Twin Registers include several sets of population-based sub-registers, and covers twin pairs born between 1895 and today. Except for the missing birth years 1960 to 1967, the register is almost complete. Most of the register contains information about both same-sexed and opposite-sexed twin pairs, except for twin pairs born between 1946 and 1960, where only same-sexed twins are registered. In a substantial part of the register, information about zygosity is obtained, mainly by a mailed questionnaire and in some cases supported by DNA testing. These are the birth years 1915 to 1960 and the birth years 1967 to 1979. Zygosity information is further obtained in the different twin studies derived from the twin register. In 1990 the whole register was made available in a computerized form. Several twin studies have been derived from the different parts of the register. In this article, studies from the two earliest parts of the register are reviewed and grouped by recruitment specifics. Finally, future plans for the register and twin studies are discussed.
Fluid Exchanges: The Negotiation of Intimacy between Tourist Women and Local Men in a Transnational Town in Caribbean Costa Rica
Authors: FROHLICK SUSAN
Published: May 2007

In a transnational tourist town in black Caribbean Costa Rica situated both on the margins of “white” Costa Rican society and squarely in global tourism, the mobility of European and North American women tourists in and out constitute a significant tourist flow. Central to the town's social sexual history and modes of sociability are economically ambiguous sexual and often intimate relations between female tourists and local predominantly black Caribbean men. I use the concept of “fluid exchanges” to comprehend the fluidity and corporeality of these relationships in which, I argue, intimacy plays a significant role. Local men, who are situated outside of hegemonic masculinity, use sexual knowledge and masculine privilege to “give” intimacy freely as well as to bargain for payment and acquire cosmopolitan identities, and to regulate the unfettered mobility of First World women tourists within a disparate global sex market and era where new erotic subjectivities and transnational intimate relations are being forged in hybrid and fluid places like Puerto Viejo, Costa Rica.
Chronic Ventilator Need in the Community: A 2005 Pediatric Census of Massachusetts
Authors: Graham Robert J. , Fleegler Eric W. , Robinson Walter M.
Published: May 2007

OBJECTIVES. The purpose of this study was to describe the population of children with chronic mechanical ventilation in Massachusetts and their patterns of medical care.

PATIENTS AND METHODS. Investigators surveyed all of the Massachusetts home ventilator clinics, pediatric pulmonary services, hospital-based pediatric services for special health care needs, insurers, home care vendors, nursing agencies, the Massachusetts Department of Public Health, selected individual providers, and rehabilitation and long-term care facilities providing services to children with chronic respiratory support needs. Support was defined as daily use of noninvasive, negative-pressure, or invasive/transtracheal ventilators. Subsequent matching of demographic data, including date of birth, zip code, and gender supported maximal census yield without duplications. Geographic information systems were used to create distribution maps and estimate distances between children with chronic mechanical ventilator needs and key resources.

RESULTS. A total of 197 children were identified as requiring chronic mechanical respiratory support in Massachusetts in 2005, which was a nearly threefold increase in this population in the 15-year interval since the last census. Congenital or perinatal-acquired neurologic or neuromuscular disorders constituted the majority of primary diagnoses (n = 107 [54%]). Chronic lung disease attributed to prematurity represented only 7% of the sample.

CONCLUSIONS. Children receiving chronic mechanical respiratory support are a growing population. The shift in underlying diagnoses from pulmonary disease to neurogenic respiratory insufficiency has implications for hospital and community-based providers from all disciplines in extending services to the home setting. Barriers encountered when performing this study, however, reflect an overall lack of coordination among the many individuals and agencies involved in their care. Coordinated and centralized care efforts require a clear and managed flow of information; census reports such as this one are only the beginning. Direct needs assessments and quality-of-life surveys from families are needed to design and implement programmatic changes and advocacy efforts.
Engaging Student Teachers' Hearts and Minds in the Struggle to Address (Il)literacy in Content Area Classrooms
Authors: Alger Christianna L.
Published: May 2007

Although research supports the importance and impact of using reading strategies in content area classrooms to improve students' comprehension, many secondary teachers do not use this knowledge to improve the delivery of content. This article describes a themed literature circle curriculum developed as part of a reading course for content area credential candidates. Literature circles were used to enhance these preservice teachers' understanding about the connections between literacy and social justice. Using qualitative methods, the author explored changes in participants' mental models about literacy. Participants reported new understandings and new commitment to integrating literacy into their content classes.
Inviting Reluctant Adolescent Readers Into the Literacy Club: Some Comprehension Strategies to Tutor Individuals or Small Groups of Reluctant Readers
Authors: Ambe Elizabeth BiFuh
Published: May 2007

Developing students' ability to read is a critical educational goal, necessary in order that students can become successful members of society. Proficiency in reading increases opportunities for higher education and promotes positive social change.

Unfortunately, many students struggle with comprehension, especially in the content areas. Some have special learning needs, but others are simply reluctant learners. Direct systematic instruction in comprehension strategies and the use of enjoyable texts can encourage nonreaders to become part of our reading culture. This article describes strategies that

Enhance motivation

Develop prior knowledge

Improve vocabulary acquisition

Foster comprehension of both expository and narrative texts that students are likely to find in the content areas

This article is also the source for a Class Acts podcast. Download “Supporting struggling adolescent readers” from

www.reading.orgresourcespodcastsindex.html
Extracurricular Reading Habits of College Students in Taiwan: Findings From Two National Surveys
Authors: Chen Su‐Yen
Published: May 2007

The Chinese people have great regard for those who read widely, yet little is known of the extracurricular reading behaviors of Chinese students. This study drew on data from two national surveys to investigate the amount of time Taiwanese college students spend on extracurricular reading. Findings are interpreted in relation to prior research on the reading habits of college students internationally. The study found that

Female students on average did not spend more time on extracurricular reading than males

Students from public institutions, who generally have higher academic competence, did not spend more time reading than students from private institutions

Education majors spent the least time on extracurricular reading

Newspapers, magazines, and bestsellers were the most popular reading materials, but manga (graphic novels) had medium popularity

Crosscultural differences might have an impact on the amount of time spent reading and on reading interests
Preservice Teacher Understandings of Adolescent Literacy Development: Naive Wonder to Dawning Realization to Intellectual Rigor
Authors: Freedman Lauren , Carver Cynthia
Published: May 2007

How do secondary teacher candidates learn about their responsibility for the ongoing literacy development of their students? How do they gain the understandings and knowledge of instructional practices necessary to meet this responsibility within their content teaching?

The authors document three stages of development their students progress through in the two integrated preservice courses they teach. In the first stage of “naive wonder,” the students exhibit enthusiasm for adolescent literacy development but provide only superficial, simplistic, and clichéd responses. At the stage of “dawning realization,” students begin to recognize the challenges involved and shift their focus from themselves as teachers to their students as learners. By the end of the two integrated courses, the students were in the third stage and approaching their responsibility for literacy development with intellectual rigor.
“I Was Bitten by a Scorpion”: Reading in and out of School in a Refugee's Life
Authors: Sarroub Loukia K. , Pernicek Todd , Sweeney Tracy
Published: May 2007

This study examined the progress of Hayder, a high school student, in becoming a reader within an English language learner (ELL) reading program. The authors delve into the relationships between this young man's masculinity as a Yezidi Kurdish refugee, the reading instruction he received, his attempts to stay in school, and his successful literacy practices at home and in his workplace.

There is a relatively small body of published literature on youth cultures and literacy in secondary schools, especially as it relates to ELL students who take part in innovative reading programs based on elementary reading research and curricula. Findings indicate that the reading instruction the teachers implement works for students such as Hayder when certain support structures are in place and when teachers are aware of the multiple literacies with which students engage outside of school.
Summer Reading: Books Too Good to Miss
Authors: Livingston Nancy , Kurkjian Catherine
Published: May 2007

The books reviewed in this column make great additions to summer reading lists. Reading over the summer is an excellent way for students to maintain their skills, and these books will hold their interest and entertain them.
“I Learned That There's a State Called Victoria and He Has Six Blue‐Tongued Lizards!”
Authors: Charron Nancy Necora
Published: May 2007

In the study described in this article, fourth‐grade teachers and students of different abilities and language backgrounds were interviewed before, during, and after participating in an Internet pen pal program. Results reveal that the program's authentic tasks and texts facilitated communication and enabled students to learn about a different culture. Enthusiasm generated by the program was evidenced in student writing.

This program motivated students to write. It facilitated problem solving and supported critical thinking in written‐language acquisition.
Summer Reading Loss
Authors: Mraz Maryann , Rasinski Timothy V.
Published: May 2007

Summer reading loss is a documented reality for many students. It is often of greatest concern for those who are already at risk, who typically have limited access to reading materials at home and whose parents or caregivers may be reluctant or unsure of how to help. By raising parents' awareness of the importance of supporting their children's reading development during vacation periods and by providing concrete guidelines on how to do so, teachers and students may be better able to pick up instead of starting from scratch when the next school year begins.
Geophysical investigation of landslides : a review
Authors: Jongmans Denis , Garambois Stéphane
Published: May 2007

In the last two decades, shallow geophysics has considerably evolved with the emergence of 2D spatial imaging, then 3D spatial imaging and now 4D time and space imaging. These techniques allow the study of the spatial and temporal variations of geological structures. This paper aims at presenting a current state-of-the-art on the application of surface geophysical methods to landslide characterization and focuses on recent papers (after 1990) published in peer-reviewed international journals. Until recently, geophysical techniques have been relatively little used for the reconnaissance of landslides for at least two main reasons. The first one is that geophysical methods provide images in terms of physical parameters, which are not directly linked to the geological and mechanical properties required by geologists and engineers. The second reason shown through this study probably comes from a tendency among a part of the geophysicists to overestimate the quality and reliability of the results. This paper gave the opportunity to review recent applications of the main geophysical techniques to landslide characterisation, showing both their interest and their limits. We also emphasized the geophysical image characteristics (resolution, penetration depth), which have to be provided for assessing their reliability, as well as the absolute requirements to combine geophysical methods and to calibrate them with existing geological and geotechnical data. We hope that this paper will contribute to fill the gaps between communities and to strength of using appropriate geophysical methods for landslide investigation.
Hydrogeochemistry in landslide research: a review
Authors: Bogaard Thom , Guglielmi Yves , Marc Vincent , Emblanch Christophe , Bertrand Catherine , Mudry Jacques
Published: May 2007

This review aims to give an overview of the potential hydrogeochemical information can have for landslide research and analyses the use of hydrogeochemical information to unravel the hydrological processes in landslide triggering. Landslides are well known for their data shortage; especially in case the hydrogeology is heterogeneous and difficult to measure. In this article we analyse the impact hydrogeochemical processes has on physical properties of the soil material and rock slopes, i.e. the relation with deformation rate and the relation of pore fluid composition and residual shear strength of soil material. Furthermore, the paper looks at the subsurface information that can be gained, i.e. the geological information of subsurface architecture and the hydrological information on origin of water, flow paths and travel times (using isotope analyses). Hydrochemical information used in both hard and soft rocks enables the display of clusters of water types, which is useful to identify contribution of different aquifers to the landslide area. Moreover, it can demonstrate the existence of lithologies and structures that are not visible with surface based geological investigations. Kinetic-based modelling is shown to be very useful in the interpretation of hydrogeochemical information. Lastly, it is shown that chemical information such as cation exchange properties coming from cored drilling is worthwhile for hydrological interpretations of landslides.
Seismic noise-based methods for soft-rock landslide characterization
Authors: Méric Ombeline , Garambois Stéphane , Malet Jean-Philippe , Cadet Héloïse , Guéguen Philippe , Jongmans Denis
Published: May 2007

In order to better understand the mechanics and dynamic of landslides, it is of primary interest to image correctly their internal structure and their slip surface. Several active geophysical methods are able to provide the geometry of a given landslide, but were rarely applied in 3 dimensions in the past. The main disadvantages of methods like seismic reflection and electrical tomography are that there are heavy to set up and/or to process, and they consequently are expensive and time consuming. Moreover, in the particular case of soft-rock landslides, their respective sensitivity and resolution are not always adequate to locate the potential slip surfaces. Passive methods may represent an interesting alternative particularly for landslides difficult to access, as they require lighter instrumentation and easier processing tools. Among them, the seismic noise based methods have shown increasing applications and developments, in particular for seismic hazard mapping in urban environment. In this paper, we present seismic noise investigations carried out on two different sites, the “Super Sauze” mudslide and the “Saint Guillaume” translational clayey landslide (France), where independent measurements (geotechnical and geophysical tests) were performed earlier. Our investigations were composed of electrical tomography profiles, seismic profiles for surface-wave inversions, H/V measurements, which are fast and easy to perform in the field, in order to image shear wave contrasts (slip surfaces), and seismic noise array method, which is heavier to apply and interpret, but provides (S)-waves velocity profile versus depth. For both sites, landslide bodies are characterized by lower S wave velocity (Vs < 300 m.s−1) and lower resistivity (ρ < 60 Ohm.m) than in the stable part (Vs > 550 m.s−1; ρ > 150 ohm.m). Their thickness vary from a few m to 50 m. Comparison between geophysical investigations and geotechnical data proved the applicability of such passive methods in 3D complex structures, with however some limitations.
Nitrogen and Phosphorus Runoff Losses from Variable and Constant Intensity Rainfall Simulations on Loamy Sand under Conventional and Strip Tillage Systems
Authors: Franklin D. , Truman C. , Potter T. , Bosch D. , Strickland T. , Bednarz C.
Published: May 2007

Further studies on the quality of runoff from tillage and cropping systems in the southeastern USA are needed to refine current risk assessment tools for nutrient contamination. Our objective was to quantify and compare effects of constant (Ic) and variable (Iv) rainfall intensity patterns on inorganic nitrogen (N) and phosphorus (P) losses from a Tifton loamy sand (Plinthic Kandiudult) cropped to cotton (Gossypium hirsutumL.) and managed under conventional (CT) or strip‐till (ST) systems. We simulated rainfall at a constant intensity and a variable intensity pattern (57 mm h−1) and collected runoff continuously at 5‐min intervals for 70 min. For cumulative runoff at 50 min, the Iv pattern lost significantly greater amounts (p< 0.05) of total Kjeldahl N (TKN) and P (TKP) (849 g N ha−1and 266 g P ha−1for Iv; 623 g N ha−1and 192 g P ha−1for Ic) than did the Ic pattern. However, at 70 min, no significant differences in total losses were evident for TKN or TKP from either rainfall intensity pattern. In contrast, total cumulative losses of dissolved reactive P (DRP) and NO3–N were greatest for ST‐Ic, followed by ST‐Iv, CT‐Ic, and CT‐Iv in diminishing order (69 g DRP ha−1and 361 g NO3–N ha−1; 37 g DRP ha−1and 133 g NO3–N ha−1; 3 g DRP ha−1and 58 g NO3–N ha−1; 1 g DRP ha−1and 49 g NO3–N ha−1). Results indicate that constant‐rate rainfall simulations may overestimate the amount of dissolved nutrients lost to the environment in overland flow from cropping systems in loamy sand soils. We also found that CT treatments lost significantly greater amounts of TKN and TKP than ST treatments and in contrast, ST treatments lost significantly greater amounts of DRP and NO3–N than CT treatments. These results indicate that ST systems may be losing more soluble fractions than CT systems, but only a fraction the total N (33%) and total P (11%) lost through overland flow from CT systems.
Assessment of Vegetation Stress Using Reflectance or Fluorescence Measurements
Authors: Campbell P. K. E. , Middleton E. M. , McMurtrey J. E. , Corp L. A. , Chappelle E. W.
Published: May 2007

Current methods for large‐scale vegetation monitoring rely on multispectral remote sensing, which has serious limitation for the detection of vegetation stress. To contribute to the establishment of a generalized spectral approach for vegetation stress detection, this study compares the ability of high‐spectral‐resolution reflectance (R) and fluorescence (F) foliar measurements to detect vegetation changes associated with common environmental factors affecting plant growth and productivity. To obtain a spectral dataset from a broad range of species and stress conditions, plant material from three experiments was examined, including (i) corn, nitrogen (N) deficiency/excess; (ii) soybean, elevated carbon dioxide, and ozone levels; and (iii) red maple, augmented ultraviolet irradiation. Fluorescence and R spectra (400–800 nm) were measured on the same foliar samples in conjunction with photosynthetic pigments, carbon, and N content. For separation of a wide range of treatment levels, hyperspectral (5–10 nm) R indices were superior compared with F or broadband R indices, with the derivative parameters providing optimal results. For the detection of changes in vegetation physiology, hyperspectral indices can provide a significant improvement over broadband indices. The relationship of treatment levels to R was linear, whereas that to F was curvilinear. Using reflectance measurements, it was not possible to identify the unstressed vegetation condition, which was accomplished in all three experiments using F indices. Large‐scale monitoring of vegetation condition and the detection of vegetation stress could be improved by using hyperspectral R and F information, a possible strategy for future remote sensing missions.
Nitrogen Dynamics among Cropland and Riparian Buffers
Authors: Young Eric O. , Briggs Russell D.
Published: May 2007

Nitrate (NO3−) leaching to ground water poses water quality concerns in some settings. Riparian buffers have been advocated to reduce excess ground water NO3− concentrations. We characterized inorganic N in soil solution and shallow ground water for 16 paired cropland‐riparian plots from 2003 to 2005. The sites were located at two private dairy farms in Central New York on silt and gravelly silt loam soils (Aeric Endoaqualfs, Fluvaquentic Endoaquepts, Fluvaquentic Eutrudepts, Glossaquic Hapludalfs, and Glossic Hapludalfs). It was hypothesized that cropland N inputs and soil‐landscape variability would jointly affect NO3− leaching and transformations in ground water. Results showed that well and moderately well drained fields had consistently higher ground water NO3− compared to more imperfectly drained fields receiving comparable N inputs. Average 50‐cm depth soil solution NO3− and ground water dissolved oxygen (DO) explained 64% of average cropland ground water NO3− variability. Cropland ground water with an average DO of <3 mg L−1 tended to have <4 mg L−1 of NO3− with a water table depth (WTD) of ≤1 m. Water table depth and DO explained 83% of ground water NO3− variability among buffers. More poorly drained buffers had low ground water NO3− and DO, a shallow WTD, and higher ground water ammonium and soil organic matter. Chloride patterns indicated that dilution was minor in most buffers, suggesting that denitrification losses were important. Soil‐landscape factors strongly influenced NO3− behavior and suggest the importance of accurately characterizing soil variability along cropland‐riparian zones.
Mechanisms Controlling the Leaching Kinetics of Fixated Flue Gas Desulfurization (FGD) Material under Neutral and Acidic Conditions
Authors: Cheng Chin‐Min , Walker Harold W. , Bigham Jerry M.
Published: May 2007

A number of agricultural and engineering uses for fixated flue gas desulfurization (FGD) material exist; however, the potential for leaching of hazardous elements has limited widespread application and the processes controlling the leaching of this material are poorly understood. In this study, a flow‐through rotating‐disk system was applied to elucidate the relative importance of bulk diffusion, pore diffusion, and surface chemical reaction in controlling the leaching of fixated FGD material under pH conditions ranging from 2.2 to 6.8. Changing the hydrodynamics in the rotating disk system did not affect the leaching kinetics at both pH 2.2 and 6.8, indicating that bulk diffusion was not the kinetic‐limiting step. Application of the shrinking core model (SCM) to the data suggested a surface reaction‐controlled mechanism, rather than a pore diffusion mechanism. The leaching of fixated FGD material increased with decreasing pH, suggesting it can be described by a combination of an intrinsic hydration reaction and a proton‐promoted dissolution reaction. X‐ray diffraction (XRD) and elemental composition analyses before and after leaching suggests that for most elements a number of solid phases controlled the leaching process.
Sample Drying Effects on Lead Bioaccessibility in Reduced Soil
Authors: Furman Olha , Strawn Daniel G. , McGeehan Steve
Published: May 2007

Risk‐assessment tests of contaminated wetland soils often use experimental protocols that artificially oxidize the soils. Oxidation may impact bioavailability of contaminants from the soils, creating erroneous results and leading to improper management and remediation. The goal of this study was to determine if oxygenation of reduced sediments and soils influences Pb bioaccessibility measurements. The study site is located on the Coeur d'Alene River floodplain, downstream from the Silver Valley Mining District in Idaho. A physiologically based extraction test designed to simulate the gastrointestinal tract of waterfowl (W‐PBET) was used to measure relative Pb bioavailability (bioaccessibility) from the soils. The soils were collected from a submerged wetland. One set of samples was allowed to air‐dry, another set was freeze‐dried, and a third set was analyzed wet. The wet soil showed decreased Pb bioaccessibility compared with the air‐ and freeze‐dried soils. The changes in extractability of Fe and Mn on air‐drying were opposite from each other: Fe extractability decreased while Mn increased. The results from this study show that redox changes may have significant impacts on Pb bioavailability, and should be considered when assessing Pb contamination risks in reduced soils.
Dissolved Organic Carbon in Runoff and Tile‐Drain Water under Corn and Forage Fertilized with Hog Manure
Authors: Royer Isabelle , Angers Denis A. , Chantigny Martin H. , Simard Régis R. , Cluis Daniel
Published: May 2007

Dissolved organic carbon (DOC) export from soils can play a significant role in soil C cycling and in nutrient and pollutant transport. However, information about DOC losses from agricultural soils as influenced by management practices is scarce. We compared the effects of mineral fertilizer (MF) and liquid hog manure (LHM) applications on the concentration and molecular size of DOC released in runoff and tile‐drain water under corn (Zea mays L.) and forage cropping systems. Runoff and tile‐drain water samples were collected during a 2‐mo period (October to December 1998) and DOC concentration was measured. Characterization of DOC was performed by tangential ultrafiltration with nominal cut‐offs at 3 and 100 kDa. Mean concentration of DOC in runoff water (12.7 mg DOC L−1) was higher than in tile‐drain water (6.5 mg DOC L−1). Incorporation of corn residues increased the DOC concentration by 6‐ to 17‐fold in surface runoff, but this effect was short‐lived. In runoff water, the relative size of the DOC molecules increased when corn residues and LHM were applied probably due to partial microbial breakdown of these organic materials and to a faster decomposition or preferential adsorption of the small molecules. The DOC concentration in tile‐drain water was slightly higher under forage (7.5 mg DOC L−1) than under corn (5.4 mg DOC L−1) even though the application rates of LHM were higher in corn plots. We suggest that preferential flow facilitated the migration of DOC to tile drains in forage plots. In conclusion, incorporation of corn residues and LHM increased the concentration of DOC and the relative size of the molecules in surface runoff water, whereas DOC in tile‐drain water was mostly influenced by the cropping system with relatively more DOC and larger molecules under forage than corn.
Changes in Crested Wheatgrass Root Exudation Caused by Flood, Drought, and Nutrient Stress
Authors: Henry Amelia , Doucette William , Norton Jeanette , Bugbee Bruce
Published: May 2007

Root exudates can chelate inorganic soil contaminants, change rhizosphere pH, and may increase degradation of organic contaminants by microbial cometabolism. Root‐zone stress may increase exudation and enhance phytoremediation. We studied the effects of low K+, high NH4+/NO3− ratio, drought, and flooding on the quantity and composition of exudates. Crested wheatgrass (Agropyron cristatum) was grown in Ottawa sand in sealed, flow‐through glass columns under axenic conditions for 70 d. Root exudates were collected and analyzed for total organic carbon (TOC) and organic acid content to compare treatment effects. Plants in the low K+ treatment exuded 60% more TOC per plant per day (p = 0.01) than the unstressed control. Drought stress increased cumulative TOC exuded per gram dry plant by 71% (p = 0.05). The flooded treatment increased TOC exuded per gram dry plant by 45%, although this was not statistically significant based on the two replicate plants in this treatment. Exudation from the high NH4+/NO3− ratio treatment was 10% less than the control. Exudation rates in this study ranged from 8 to 50% of rates in four other published studies. Gas chromatography‐mass spectrometry (GC–MS) analysis indicated that malic acid was the predominant organic acid exuded. Fumaric, malonic, succinic, and oxalic acids were also detected in the exudates of all treatments. These results demonstrate that nutrient and water stress have significant effects on the quantity and composition of root exudates. Cultural manipulations to induce stress may change the quantity of root exudates and thus increase the effectiveness of phytoremediation.
Atrazine Degradation and Residues Distribution in Two Acid Soils from Temperate Humid Zone
Authors: Mahía J. , Díaz‐Raviña M.
Published: May 2007

Mineralization of atrazine and formation of extractable and non‐extractable “bound” residues were followed under laboratory conditions in two contrasting soils (organic C, texture, and atrazine application history) from northern Spain. The soils, a Humic Cambisol (MP) and a Gleyic Cambisol (G) were incubated with labeled atrazine (ring‐13C atrazine) at field application dose and measurements were made at different time intervals during 3 mo. Fate and behavior of atrazine along the incubation showed different patterns between the two soils, the time taken for degradation of 50% (DT50) being 9 and 44 d for MP and G soils, respectively. In MP soil, with 40 yr of atrazine application and lower organic C and clay content, more than 89% of U‐13C‐atrazine added was mineralized after 12 wk, with most mineralization occurring within the first 2 wk. G soil, with 10 yr of atrazine application, exhibited a more progressive U‐13C‐atrazine mineralization, reaching 54% of initially added atrazine at 12 wk. Hydroxyatrazine and deisopropylatrazine were the metabolites founded in the extractable fraction, demonstrating that both chemical and biological processes are involved in atrazine degradation. Soil G showed during all the incubation times an extractable residues fraction greater than that in MP soil, indicating a high potential risk of soil and water contamination. Rapid microbial degradation through s‐triazine ring cleavage was proposed to be the main decomposition pathway of atrazine for the two soils studied. Bound residues pool also differed notably between soils accounting for 9 and 41% of initially added atrazine, the higher values shown by soil with higher organic matter and clay content (G soil).
Ozonation of synthetic versus natural textile tannins: recalcitrance and toxicity towards Phaeodactylum tricornutum
Authors: Germirli Babuna F. , Yilmaz Z. , Okay O.S. , Arslan Alaton I. , Iskender G.
Published: May 2007

A sound in-plant pollution control strategy can only be defined by paying due attention to bio-recalcitrance and toxicity. In this context the levels of toxicity and inert COD introduced to textile dyebath discharges by two alternative auxiliary chemicals, namely natural tannin (NT) and synthetic tannin (ST), were investigated. The effect of 40 minutes ozonation at 1,000 mg h−1 at pH 3.5 on the segregated effluent streams containing the above-mentioned tannin formulations was evaluated in terms of changes in toxicity and recalcitrance. The effect of ozonation on the COD distribution of raw and ozonated NT and ST samples according to their molecular weight cut-offs was also assessed. Both untreated tannin formulations exerted high acute toxicity towards marine microalgae Phaeodactylum tricornutum. Moderate decrease in the toxicity levels of both tannins was observed upon ozonation. The raw NT formulation with a COD content more than twice that of its alternative raw ST had an initially inert soluble COD content of only 25 mg/L, while the initially inert COD was 135 mg/L for ST. As the initially inert soluble COD content of NT was considerably lower, this textile auxiliary did not need chemical pretreatment to improve its biodegradability. On the other hand, the initially inert soluble COD content of ST was reduced by 70% by ozone pretreatment. In terms of residual COD contents achievable after passing through a biological treatment system, raw NT and pretreated ST formulations yielded 100 and 95 mg/L COD, respectively. The highest proportion of COD (46% for NT and 88% for ST) was found in the <1 kDa range. The same fraction increased to 93% for NT after ozonation, while for ST no significant change was observed in the COD distribution of the molecular weight cut-offs after ozonation.
Application of a sequential batch reactor system for textile dyes degradation: comparison between azo and phthalocyanine dyes
Authors: Harrelkas F. , Pons M.-N. , Zahraa O. , Yaacoubi A. , Lakhal E.K.
Published: May 2007

Photocatalysis on supported TiO2 was combined with aerobic biological treatment in a sequential batch reactor to compare the degradation of two textile dyes: a blue azo dye (DR KBL CDG) and a green phthalocyanine dye (DR K4GN). Three reactors were run in parallel. SBR1 was used as a reference and was fed with urban wastewater only. SBR2 and SBR3 were fed with the same urban wastewater combined with pretreated (for SBR2) and non-pretreated (for SBR3) dye solution. For an azo dye concentration of 12 mg/L decolouration yields of 78 and 27% were achieved, respectively, in SBR2 and SBR3. For the phthalocyanine dye, the decolouration yields decreased to 24 and 15%, respectively. Concerning COD removal it decreases for both dyes with and without pretreatment, when the dye concentration increases. Although a detrimental effect on biomass could be observed, bacteria were able to cope with the inhibitory effect of the dyes.
MBR pilot plant for textile wastewater treatment and reuse
Authors: Lubello C. , Caffaz S. , Mangini L. , Santianni D. , Caretti C.
Published: May 2007

An experimental study was carried out in order to evaluate the possibility of upgrading the conventional activated sludge WWTP of Seano (Prato, Italy) which treats municipal and textile wastewaters, by using membrane bioreactor (MBR) technology. The MBR pilot plant, set up within Seano WWTP, was fed with mixed municipal–industrial wastewaters during the first experimental period and with pure industrial wastewaters during the second. Performances and operation of the MBR were evaluated in terms of permeate characteristics and variability (COD, colour, surfactants, total N and P) and other operational parameters (sludge growth and observed yield). According to the experimental results the MBR permeate quality was always superior to the Seano WWTP one and it was suitable for industrial reuse in the textile district of the Prato area. Respirometric tests provided a modified IWA ASM1 model which fits very well the experimental data and can be used for the design and the monitoring of a full-scale MBR pilot plant.