New phosphorus losses via tile drainage depend on fertilizer form, placement, and timing

Agricultural phosphorus (P) losses are harmful to water quality, but knowledge gaps about the importance of fertilizer management practices on new (recently applied) sources of P may limit P loss mitigation efforts. Weighted regression models applied to subsurface tile drainage water quality data enabled estimating the new P losses associated with 155 P applications in Ohio and Indiana, USA. Daily discharge and dissolved reactive P (DRP) and total P (TP) loads were used to detect increases in P loss following each application which was considered new P. The magnitude of new P losses was small relative to fertilizer application rates, averaging 79.3 g DRP ha-1 and 96.1 g TP ha-1 , or <3% of P applied. The eight largest new P losses surpassed 330 g DRP ha-1 or 575 g TP ha-1 . New P loss mitigation strategies should focus on broadcast liquid manure applications; on average, manure applications caused greater new P losses than inorganic fertilizers, and surface broadcast applications were associated with greater new P losses than injected or incorporated applications. Late fall applications risked having large new P losses applications. On an annual basis, new P contributed an average of 14% of DRP and 5% of TP losses from tile drains, which is much less than previous studies that included surface runoff, suggesting that tile drainage is relatively buffered with regard to new P losses. Therefore old (preexisting soil P) P sources dominated tile drain P losses, and P loss reduction efforts will need to address this source.

Uncertainty in phosphorus fluxes and budgets across the U.S. long-term agroecosystem research network

Phosphorus (P) budgets can be useful tools for understanding nutrient cycling and quantifying the effectiveness of nutrient management planning and policies; however, uncertainties in agricultural nutrient budgets are not often quantitatively assessed. The objective of this study was to evaluate uncertainty in P fluxes (fertilizer/manure application, atmospheric deposition, irrigation, crop removal, surface runoff, leachate) and the propagation of these uncertainties to annual P budgets. Data from 56 cropping systems in the P-FLUX database, which spans diverse rotations and landscapes across the U.S. and Canada, were evaluated. Results showed that across cropping systems, average annual P budget was 22.4 kg P ha^-1 (range = -32.7 to 340.6 kg P ha^-1 ), with an average uncertainty of 13.1 kg P ha^-1 (range = 1.0 to 87.1 kg P ha^-1 ). Fertilizer/manure application and crop removal were the largest P fluxes across cropping systems and, as a result, accounted for the largest fraction of uncertainty in annual budgets (61 and 37%, respectively). Remaining fluxes individually accounted for <2% of the budget uncertainty. Uncertainties were large enough that determining whether P was increasing, decreasing, or not changing was inconclusive in 39% of the budgets evaluated. Findings indicate that more careful and/or direct measurements of inputs, outputs, and stocks are needed. Recommendations for minimizing uncertainty in P budgets based on the results of the study were developed. Quantifying, communicating, and constraining uncertainty in budgets among production systems and multiple geographies is critical for engaging stakeholders, developing local and national strategies for P reduction, and informing policy. This article is protected by copyright. All rights reserved.

Development of a rapid field testing method for metals in horizontal directional drilling residuals with XRF sensor

Portable X-ray fluorescence (pXRF) spectrometer allows fast in-situ elemental determination without wet digestion for soils or geological materials, but the use of XRF on wet materials is not well documented. Our objective was to develop a rapid field method using pXRF to measure metals in the residues from horizontal directional drilling (HDD) operations so that proper disposal decisions can be made in-situ. To establish the procedure, we spiked soil samples with 4 concentrations of Cr, Ni, Cu, Zn, As, Cd, and Pb up to 1000 mg kg⁻¹, and then the metal concentrations were determined by wet chemical method after drying and acid digestion (standard method), and by pXRF, also at laboratory conditions, after drying and at two different moisture conditions. The measurements by pXRF and standard method after drying and after removal of excess water (AREW) were highly correlated with slopes ranging from 0.83 ± 0.01 to 1.08 ± 0.01 (P < 0.001) for all metals. The relationship was better AREW than the saturated paste without removal of excess water and the moisture content affected only the accuracy of As, Cd, and Pb. The procedure established was successfully used for HDD residues collected from 26 states of US with moisture content ranging from 14 to 83% AREW. The pXRF was proven to be a reliable tool for fast detection of common metals in dried soils and HDD residues, and samples containing < 30% moisture content without needing to correct for moisture. If the moisture is > 30%, excess water in samples need to be removed with a commercially available filter press to achieve high accuracy. The developed procedures reduce time of metal detection from days to about an hour which allows drilling operators to make quick decisions on soil or HDD disposal.

Denitrifying woodchip bioreactor and phosphorus filter pairing to minimize pollution swapping

Pairing denitrifying woodchip bioreactors and phosphorus-sorbing filters provides a unique, engineered approach for dual nutrient removal from waters impaired with both nitrogen (N) and phosphorus (P). This column study aimed to test placement of two P-filter media (acid mine drainage treatment residuals and steel slag) relative to a denitrifying system to maximize N and P removal and minimize pollution swapping under varying flow conditions (i.e., woodchip column hydraulic retention times (HRTs) of 7.2, 18, and 51 h; P-filter HRTs of 7.6-59 min). Woodchip denitrification columns were placed either upstream or downstream of P-filters filled with either medium. The configuration with woodchip denitrifying systems placed upstream of the P-filters generally provided optimized dissolved P removal efficiencies and removal rates. The P-filters placed upstream of the woodchip columns exhibited better P removal than downstream-placed P-filters only under overly long (i.e., N-limited) retention times when highly reduced effluent exited the woodchip bioreactors. The paired configurations using mine drainage residuals provided significantly greater P removal than the steel slag P-filters (e.g., 25-133 versus 8.8-48 g P removed m^-3 filter media d^-1, respectively), but there were no significant differences in N removal between treatments (removal rates: 8.0-18 g N removed m^-3 woodchips d^-1; N removal efficiencies: 18-95% across all HRTs). The range of HRTs tested here resulted in various undesirable pollution swapping by-products from the denitrifying bioreactors: nitrite production when nitrate removal was not complete and sulfate reduction, chemical oxygen demand production and decreased pH during overly long retention times. The downstream P-filter placement provided a polishing step for removal of chemical oxygen demand and nitrite.

Evaluation of a universal flow-through model for predicting and designing phosphorus removal structures

Phosphorus (P) removal structures have been shown to decrease dissolved P loss from agricultural and urban areas which may reduce the threat of eutrophication. In order to design or quantify performance of these structures, the relationship between discrete and cumulative removal with cumulative P loading must be determined, either by individual flow-through experiments or model prediction. A model was previously developed for predicting P removal with P sorption materials (PSMs) under flow-through conditions, as a function of inflow P concentration, retention time (RT), and PSM characteristics. The objective of this study was to compare model results to measured P removal data from several PSM under a range of conditions (P concentrations and RT) and scales ranging from laboratory to field. Materials tested included acid mine drainage residuals (AMDRs), treated and non-treated electric arc furnace (EAF) steel slag at different size fractions, and flue gas desulfurization (FGD) gypsum. Equations for P removal curves and cumulative P removed were not significantly different between predicted and actual values for any of the 23 scenarios examined. However, the model did tend to slightly over-predict cumulative P removal for calcium-based PSMs. The ability of the model to predict P removal for various materials, RTs, and P concentrations in both controlled settings and field structures validate its use in design and quantification of these structures. This ability to predict P removal without constant monitoring is vital to widespread adoption of P removal structures, especially for meeting discharge regulations and nutrient trading programs.

Phosphorus removal with by-products in a flow-through setting

Phosphorus (P) losses to surface waters can result in eutrophication. Some industrial by-products have a strong affinity for dissolved P and may be useful in reducing nonpoint P pollution with landscape-scale runoff filters. Although appreciable research has been conducted on characterizing P sorption by industrial by-products via batch isotherms, less data are available on P sorption by these materials in a flow-through context integral to a landscape P filter. The objectives of this study were to evaluate several industrial by-products for P sorption in a flow-through setting, to determine material chemical properties that have the greatest impact on P sorption in a flow-through setting, and to explore how retention time (RT) and P concentration affect P removal. Twelve materials were characterized for chemical properties that typically influence P removal and subjected to flow-through P sorption experiments in which five different RTs and P concentrations were tested. The impact of RT and P concentrations on P removal varied based on material chemical properties, mainly as a function of oxalate-extractable aluminum (Al), iron (Fe), and water-soluble (WS) calcium (Ca). Statistical analysis showed that materials elevated in oxalate-extractable Al and Fe and WS Ca and that were highly buffered above pH 6 were able to remove the most P under flow-through conditions. Langmuir sorption maximum values from batch isotherms were poorly correlated with and overestimated P removal found under flow-through conditions. Within the conditions tested in this study, increases in RT and inflow P concentrations increased P removal among materials most likely to remove P via precipitation, whereas RT had little effect on materials likely to remove P via ligand exchange.

The study of child language in South Africa

This paper describes some of the research into child language that has been conducted in South Africa over the past 20 years. It is written from a clinical perspective and it describes the influence of changing demographic, social, educational and political variables on the study of child language. Specifically, the influence of the multilingual and multicultural nature of the society will be considered. Among issues discussed are the increasing research base on the acquisition of normal language, the adaptation of assessment tools and language in education.

Pragmatic assessment and therapy for persons with brain damage: what have clinicians gleaned in two decades?

Pragmatic competence comprises a number of interrelated skills which manifest in real-time in a range of adaptive behaviors and which are driven by underlying cognitive processes that appear to be variably compromised in brain damage. Differential neurological profiles reflect different pragmatic outcomes. The essence of pragmatic assessment and therapy for clinicians is therefore to capture accurately, measure, and, where possible, enhance the ability of the individual to adapt to a changing communicative environment. Assessment measures differ along a number of dimensions. A distinction is drawn between testing and assessment and the argument proposed that for clinical purposes, it is helpful to keep the notions of functional and pragmatic distinct.

Contemporary results of radical radiotherapy for bladder transitional cell carcinoma in a district general hospital with cancer-centre status

OBJECTIVE

To assess the current efficacy and safety of definitive external beam radiotherapy (EBRT) in the treatment of invasive bladder transitional cell carcinoma (TCC) in a district general hospital with cancer-centre status.

PATIENTS AND METHODS

The case notes of all patients with bladder TCC undergoing EBRT with curative intent over an 8-year period (1988-95) were reviewed. Additional missing outcome data were collected.

RESULTS

In all, 120 patients (109 men; median age 70 years, range 34-90) underwent radical EBRT (40-65 Gy; fraction median=20) over the 8-year period. Staging, as assessed by examination under anaesthesia and computed tomography, was T1 in 16%, T2 in 43%, T3 in 38% and T4 in 3%. In 96 patients (80%) the tumour was poorly differentiated (G3). The overall morbidity at 12 months was 12%; proctitis occurred in nine patients (8%) and cystitis in five (4%). Sixty-seven patients (59%) developed a local recurrence and in 36 (30%) this was invasive. The overall median survival was 60 months. Thirty-three patients underwent salvage cystectomy with a subsequent median survival of 12.5 months.

CONCLUSION

Modern radical multifraction EBRT in invasive bladder TCC has a low morbidity, with an overall median survival of 5 years.

The measurement of emotional reaction and depression in a South African stroke population

The study evaluated the sensitivity of a newly devised scale for measurement of emotional reactions and depression, on a group of 25 stroke patients, with right or left hemisphere damage, and 15 age-matched controls. Four clusters were examined: communication, expression of emotions, sense of self and physical or psychomotor problems. Case history factors such as time since onset, gender, anti-depressant medication and severity of aphasia were related to performance on the scale. Results indicated that the scale allowed for expression of emotion in all three groups tested and that speech and communication items significantly differentiated right and left hemisphere subjects. A strong correlation was found between spouse reports and self reports on selected items of the scale. Time since onset was found to be important in predicting level of depression. These findings have implications for assessment and management of stroke.

Toward a new psychometric definition of social disability in children with attention-deficit hyperactivity disorder

OBJECTIVE

To investigate a new mechanism for identifying social disability in children with attention-deficit hyperactivity disorder (ADHD), employing psychometric methodology used in defining learning disabilities.

METHOD

Two groups of index children were examined: 140 children with ADHD (referred from both psychiatric and pediatric sources) and 120 non-ADHD comparison children. Subjects were defined as socially disabled if they had a value greater than 1.65 on a standardized discrepancy score between observed and expected scores on a measure of social functioning (with expected scores derived as a function of the child's estimated Full Scale IQ). Children identified as socially disabled were compared with non-socially disabled probands on psychopathology, familiality, cognitive functioning, school history, and treatment history.

RESULTS

Using this psychometric approach, 22% of the ADHD probands qualified as socially disabled, whereas none of the comparison probands qualified (p < or = .001). Socially disabled ADHD probands were significantly more impaired than were non-socially disabled ADHD probands in global and specific measures of social functioning and patterns of psychiatric comorbidity.

CONCLUSIONS

The psychometrically defined construct of social disability may identify children with ADHD who are at very high risk for severe social dysfunction and whose course and prognosis may vary from those of other children with ADHD. This subgroup of children with ADHD may be at heightened risk for poor outcome, and their identification may facilitate the development of clinical interventions aimed at ameliorating their specific difficulties.

The persisting communicative difficulties of 'remediated' language-impaired children

This study addresses the effiacy of dismissal criteria used by speech and language pathologists by investigating communicative functioning in children declared 'remediated'. A battery of measures comprising the Language Assessment and Remediation Procedure (LARSP); the Behavioural inventory of Speech Act Performances (BISAP); the BISAP Addendum and the Devereux School Behaviour Rating Scale (DESB) was conducted on five children with language impairment who had been declared 'remediated'. Findings for certain 'remediated' subjects revealed persisting problems. The results suggest that decisions about dismissal from therapy may, in some cases, be premature and point to the need for a broad-based perspective concerning remediation dismissal decisions. An additional study on larger populations and the use of designs which investigate long term outcomes would further inform clinical decision-making concerning dismissal from therapy.

Assessment of urinary incontinence

1. In the past, nursing practice toward incontinence has focused on urine containment and skin protection rather than on proactive treatment-oriented therapeutic care. 2. Accurate assessment and diagnosis of urinary incontinence determine the success of treatment. 3. Efforts directed at early identification, appropriate assessment and treatment, and linkage to community agencies should be initiated by the nurse.

Speech-language evaluation of closed head injured subjects in South Africa: cultural applicability and ecological validity of a test battery

This paper addresses the communicative outcome of a group of closed head injured (CHI) subjects in South Africa. Communicative outcome is evaluated on one test battery currently used for medico-legal assessments in South Africa. It was found that a number of the tests were sensitive to breakdown in this sample, but that the demographic factors of first language and pre-injury education significantly affected performance on some tests. Many test performances were significantly related to return to work, thus confirming the importance of communicative skills in the workplace, and the speech-language pathologist's role in vocational assessment and rehabilitation.

Binding of plasma fibronectin to Candida albicans occurs through the cell binding domain

Candida albicans yeast cells bind soluble human plasma fibronectin (Fn) through a glycoprotein receptor (adhesin) located on the cell surface. This work demonstrates that a 120 kDa proteolytic fragment of Fn encompassing the cell binding domain binds more avidly to the yeast cell adhesin than does the parent Fn molecule. The presence of binding of Fn fragments containing heparin- and gelatin-binding domains of Fn could not be detected. The binding of the 120 kDa fragment is inhibited by a monoclonal antibody to the cell binding domain containing the amino acid sequence, Arginine-Glycine-Aspartic acid (RGD) as well as by an RGD-containing approximately 23-mer Fn peptide, but not with heparin or GRGDSPL. The fact that the cell binding domain of soluble Fn binds more avidly than does the parent molecule may explain the difference in the interaction of soluble Fn and immobilized Fn with Candida. It is possible that, upon immobilization, Fn may expose domains of the molecule previously unexposed when the molecule is in the soluble state.

Interaction of spirochetes with the host

The success of an invading organism must depend on several cytoplasmic, surface-associated and secreted factors. The technical difficulties in handling pathogenic spirochetes like Treponema pallidum and Borrelia burgdorferi have made it difficult to define specific factors involved in entry and long-term survival. The problem of defining virulence factors has been attacked by several strategies: T. pallidum secretes a number of immunogenic low molecular mass proteins. The most predominant are of molecular weight 15.5 and 22 kDa. Preliminary data suggest that antibodies against these proteins induce protective immunity in rabbits experimentally infected with T. pallidum. Many potentially important surface-associated antigens of T. pallidum have now been cloned and characterized. Two of these, TpD and TpE, are lipoproteins which exhibit characteristic size heterogeneity. The apparent molecular weight of TpE from T. pallidum and T. pertenue are different. The clinical symptoms in syphilis and yaws are very different, but sequence analysis of TpE has shown that the TpE proteins are indeed very similar in the two strains. This observation makes it unlikely that heterogeneity of TpE can account for the different clinical symptoms of syphilis and yaws. Sequence data for another newly sequenced surface-associated antigen of T. pallidum (molecular weight 41 kDa) indicate that this protein is involved in glucose transport and chemotaxis/motility. Intracellular factors like the molecular chaperonin GroEL have been documented both in treponemes and borreliae. This stress protein is involved in cellular repair processes and folding/assembly of protein subunits. Indirect evidence suggests that GroEL affects the ability of spirochetes to survive in the stressful environment of the infected host. Several lines of evidence suggest that the Osp proteins of Borrelia are important for host/parasite interaction. Further support for this idea has come from studies of a series of monoclonal antibodies against OspA. A monoclonal antibody against OspA (9B3D) is able to block attachment of B. burgdorferi to a cell monolayer. Borrelia loses infectivity after several passages in vitro. The loss of pathogenicity is associated with loss of specific plasmids and proteins. One of the low-passage-associated proteins (Lap30) has been cloned and sequenced. Lap30 is a lipoprotein encoded by a 38-kb plasmid, not present in high passage B. burgdorferi. Aberrant immunological processes induced by the lipopolysaccharide component of Treponema hyodysenteriae could explain the dramatic intestinal lesions in swine dysenteriae. But analysis by TLC reveals that the LPS of this treponeme is different from classical Salmonella LPS.(ABSTRACT TRUNCATED AT 400 WORDS)

Discourse therapy in multilingual aphasia: a case study

Analysis of the strategies used in narrative and conversational discourse enables a sensitive evaluation of the deficit in mild aphasic patients and a possible alternative to the therapist dealing with multilingual patients for whom standard aphasia testing is not useful. This study describes the characterization of the communication deficit in a multilingual aphasic patient and the development and subsequent implementation of a therapy programme. Standard testing and discourse analysis took place in four languages, but therapy took place in English. Improvement in conversational skills was noted in all four languages and the patient reported increased functional ability, particularly in a work context. The implications of this approach to assessment and therapy are discussed.

Stable expression of foreign antigens from the chromosome of Salmonella typhimurium vaccine strains

A simple and versatile system has been developed using a new cloning vector which can serve as a vehicle for integrating DNA fragments, which direct the expression of heterologous antigens, into the aroC gene on the Salmonella chromosome. The system is based on Escherichia coli plasmid vectors which contain the DNA fragment, cloned from the chromosome of S. typhimurium C5, which encodes the aroC gene. The aroC gene was modified using synthetic oligodeoxyribonucleotides so that it contained several unique restriction sites into which DNA, directing the expression of heterologous antigens, could be cloned. DNA was integrated into the S. typhimurium chromosome at aroC by transferring the vectors into S. typhimurium polA mutants and allowing homologous recombination to occur between the cloned and chromosomal aroC genes. The vectors were used to integrate nucleotide sequences into the S. typhimurium chromosome which directed the expression of tetanus toxin fragment C and the Treponema pallidum lipoprotein. The expression of both antigens was detected by Western blotting.

Acquired childhood aphasia with convulsive disorder (Landau-Kleffner syndrome). A case report

The Landau-Kleffner syndrome is a rare form of acquired childhood aphasia associated with convulsive disorder. These children are typically misdiagnosed. A 15-year-old girl whose aphasia was not diagnosed until the age of 13 is described. Pitfalls in diagnosis are discussed, particularly with regard to interpretation of the results of audiometric testing. Attention is drawn to the existence of this rare form of aphasia and to the lack of appropriate educational facilities for aphasic children in general.

The role of RNA segment 1 in an in vitro host restriction occurring in an avian influenza virus mutant

A temperature sensitive mutant, ts C47, derived from A/FPV/Rostock/34 and with a ts mutation in RNA segment 8, fails to form plaques in MDCK cells. From data obtained with reassortant viruses using the human influenza isolate A/FM/1/47 it was apparent that more than one mutation contributed to the temperature-sensitive (ts) and host range (hr) phenotypes of ts C47, and the phenotype of reassortants containing RNA segment 1 from A/FM/1/47 indicated that this segment was involved. A single nucleotide substitution at nucleotide 1961, resulting in valine instead of methionine in the predicted amino acid sequence of polypeptide PB2, was found in RNA segment 1 of ts C47, but this mutation did not segregate with the attenuated phenotype on gene reassortment. The following conclusions are drawn: (a) that ts C47 has at least two mutations in addition to that already known to exist in RNA segment 8, one of which (that in RNA segment 1) does not contribute to the observed ts hr phenotypes and (b) that the hr phenotype can be suppressed by substitution of RNA segment 1 by that of another strain.

Identification of the major antigens of Treponema hyodysenteriae and comparison with those of Treponema innocens

Eleven strains of Treponema hyodysenteriae isolated from pigs with swine dysentery were examined by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. T. hyodysenteriae strains formed a homogeneous group with respect to sodium dodecyl sulfate-soluble proteins. However, immunoblotting with antiserum from rabbits immunized with T. hyodysenteriae CN8368 revealed heterogeneity among the lipopolysaccharide complexes of different strains. Polypeptides of molecular weights between 30,000 and 36,000 were the predominant T. hyodysenteriae polypeptides detected by porcine immune serum. In contrast, Treponema innocens did not form a homogeneous group with respect to sodium dodecyl sulfate-soluble proteins. Adsorption studies and immunoblotting identified polypeptide antigens present on cells of T. hyodysenteriae which were not detected on cells of T. innocens. These unique antigens may play a role in the virulence of T. hyodysenteriae.

Compensatory strategies in the language of closed head injured patients

The study reported here examined the nature and effectiveness of compensatory strategies appearing in the conversational discourse of six closed head injured patients. Subject performance on a range of communication measures was compared with their judged abilities on a taxonomy of 32 compensatory strategies. Results indicated that all subjects employed a wide range of strategies but to differential effect. The overall effectiveness of these strategies correlated strongly with performance on the oral language subtest of the Western Aphasia Battery, the Communicative Abilities in Daily Living Test and a pragmatic protocol. The development of compensation following brain injury is viewed as a process of equilibration, determined in part by neurological and subject variables, and in part by ecologic variables. The implications for therapeutic management are discussed.