Soluble organic nitrogen in agricultural soils

 The existence of soluble organic forms of N in rain and drainage waters has been known for many years, but these have not been generally regarded as significant pools of N in agricultural soils. We review the size and function of both soluble organic N extracted from soils (SON) and dissolved organic N present in soil solution and drainage waters (DON) in arable agricultural soils. SON is of the same order of magnitude as mineral N and of equal size in many cases; 20–30 kg SON-N ha^–1 is present in a wide range of arable agricultural soils from England. Its dynamics are affected by mineralisation, immobilisation, leaching and plant uptake in the same way as those of mineral N, but its pool size is more constant than that of mineral N. DON can be sampled from soil solution using suction cups and collected in drainage waters. Significant amounts of DON are leached, but this comprises only about one-tenth of the SON extracted from the same soil. Leached DON may take with it nutrients, chelated or complexed metals and pesticides. SON/DON is clearly an important pool in N transformations and plant uptake, but there are still many gaps in our understanding. Received: 10 June 1999     

Let's re‐write the scientific paper

The European Journal of Soil Science rapidly established itself as a leader, strong in most branches of soil science. Nevertheless, it would be even more attractive if authors would break away from the misleading formalism and stultifying style of the conventional scientific paper. Let us report our research more nearly as it happened; let us overcome our fear of revealing our humanity, our good luck, even our failings, and acknowledge the contributions from our intuition and imagination as well as the hard graft in the field and at the bench. Let us also liven our prose by writing more in the active voice and so that readers can know who did what and who is responsible. Let us convey the wonder of discovery in our writing without sacrificing scientific rigour; then soil research would be seen to be exciting with a bright future.     

Control of nitrogen export from watersheds by headwater streams

A comparative (15)N-tracer study of nitrogen dynamics in headwater streams from biomes throughout North America demonstrates that streams exert control over nutrient exports to rivers, lakes, and estuaries. The most rapid uptake and transformation of inorganic nitrogen occurred in the smallest streams. Ammonium entering these streams was removed from the water within a few tens to hundreds of meters. Nitrate was also removed from stream water but traveled a distance 5 to 10 times as long, on average, as ammonium. Despite low ammonium concentration in stream water, nitrification rates were high, indicating that small streams are potentially important sources of atmospheric nitrous oxide. During seasons of high biological activity, the reaches of headwater streams typically export downstream less than half of the input of dissolved inorganic nitrogen from their watersheds.     

Photochemistry of halogenated benzene derivatives. Part IX. environmental aquatic phototransformation of bromoxynil (3,5-dibromo-4-hydroxybenzonitrile)

Photochemistry of the herbicide 3,5-dibromo-4-hydroxybenzonitrile (bromoxynil) (I) was investigated by irradiating at approximately 313 nm. Aqueous phase photoreactions of 0.078–7.800 × 10^?5m solutions of I were carried out at different pH values. Quantum yields for the loss of I in buffered solutions were 0.008 (±0.0004), 0.048 (±0.0024), and 0.044 (±0.0022) at pH 2.6, 7.0, and 11.0, respectively. In neutral and basic conditions, I absorbed more strongly at wavelengths > 290 nm, an environmentally significant region. Phototransformation of I was monitored by HPLC and UV-VIS spectrometry. All photoreactions of I gave rise to the generation of two products, 3-bromo-4-hydroxybenzonitrile and 4-hydroxybenzonitrile. The former photoproduct was tentatively identified from its mass spectral data. The photoproducts can be accounted for with a proposed mechanism involving free radicals.     

Thromboelastography: a tool for measuring hypercoagulability, hypocoagulability, and fibrinolysis

Objective: To describe the technique of thromboelastography (TEG) and review the applications of this coagulation test in humans and small animals. Data sources: Data sources included scientific reviews and original research publications. Human data synthesis: TEG in humans has been used for documentation of hypercoagulable and hypocoagulable states and has been shown to be beneficial in patient management. Veterinary data synthesis: Clinical evaluation of TEG in veterinary medicine is limited; however, recent reports have documented evidence of hypercoagulability in dogs with parvovirus and protein‐losing nephropathy. Additionally, many of the research models may be relevant to veterinary patients. Conclusions: TEG provides information about coagulation that is not available through routine coagulation tests. The application of TEG monitoring to veterinary patients shows promise; however, prospective clinical studies are needed.     

Clinical course, diagnostic findings and necropsy diagnosis in dyspneic cats with primary pulmonary parenchymal disease: 15 cats (1996–2002)

Objective: Correlate the necropsy diagnosis with the history, diagnostic findings, and clinical course of dyspneic cats with primary lung parenchymal disease. Design: Retrospective study. Setting: Matthew J. Ryan Veterinary Hospital of the University of Pennsylvania. Animals: Client‐owned cats over 6 months of age hospitalized in the Intensive Care Unit (ICU) with a primary problem of respiratory distress that had pulmonary parenchymal disease on thoracic radiographs, and a complete necropsy. Interventions: None. Measurements and main results: Cats included were assigned into 2 groups based on the pulmonary histopathology: inflammatory (n=8) and neoplastic (n=7) disease. No statistical difference was found between the groups with regard to age, body weight, clinical signs, duration of clinical signs, physical examination findings, thoracic radiography, duration of hospitalization, treatment, and outcome. Cats with neoplasia had a statistically higher mean total white blood cell count (26.60 k/μL±10.41) than those with inflammatory lung disease (11.59 k/μL±4.49; P=0.026). Cats with bacterial or viral pulmonary disease had a significantly shorter median duration of illness (5 days, range 1–7 days) than all other cats (30 days, range 7–365 days; P=0.0042). Ultrasound guided pulmonary fine‐needle aspiration (FNA) provided an accurate diagnosis in 5/5 cases. Conclusions: Forty‐seven percent of cats with pulmonary parenchymal disease had neoplasia. The clinical diagnosis was difficult to obtain ante‐mortem; lung FNA appeared to be the most helpful diagnostic tool in these cases.     

Distribution of fenvalerate and permethrin residues on cattle hair following variable application rates of impregnated ear tags

Fenvalerate and permethrin residues on hair of groups of cattle that received either two tags per adult animal or one tag for every other adult animal were determined using gas chromatography over a three-month period in 1987 and 1988. Cattle with two tags had consistently higher residues than cattle with one tag. This difference was statistically significant (P < 0.05) in the first month for residues on the head and in the first two weeks for residues from the body in 1987. Residues on cattle with one tag and without a tag in the same herd were similar (P > 0.05) on each sampling day on all regions. Residues on the hair from the head of cattle with two tags were greater than on the body and rump (P < 0.05) during the first 28 days. Residues found on hair on days 14 and 84 following tag application declined by 80–86% on the head, 73–78% on the body, and 36–86% on the rump. Isomeric compositions of fenvalerate (range 51–61% SR, RS: 39–49% SS, RR) and permethrin (range 61–67% trans: 33–39% cis) were consistent during the study. Rainfall reduced residues on hair.     

Evaluation of Internal Obturator Muscle Transposition in Treatment of Perineal Hernia in Dogs

A technique that utilizes transposition of the internal obturator muscle for repair of perineal hernias was evaluated. Forty-two male dogs were followed for at least one year after surgery. The repair failed in only one animal, a dog with previously operated bilateral hernias. Microangiography demonstrated an adequate blood supply to the transposed internal obturator muscles of two dogs examined at three weeks and three months after surgery.