Microplastic in riverine fish is connected to species traits.

Microplastic is a contaminant of concern worldwide. Rivers are implicated as major pathways of microplastic transport to marine and lake ecosystems, and microplastic ingestion by freshwater biota is a risk associated with microplastic contamination, but there is little research on microplastic ecology within freshwater ecosystems. Microplastic uptake by fish is likely affected by environmental microplastic abundance and aspects of fish ecology, but these relationships have rarely been addressed. We measured the abundance and composition of microplastic in fish and surface waters from 3 major tributaries of Lake Michigan, USA. Microplastic was detected in fish and surface waters from all 3 sites, but there was no correlation between microplastic concentrations in fish and surface waters. Rather, there was a significant effect of functional feeding group on microplastic concentration in fish. Neogobius melanostomus (round goby, a zoobenthivore) had the highest concentration of gut microplastic (19 particles fish-1) compared to 10 other fish taxa measured, and had a positive linear relationship between body size and number of microplastic particles. Surface water microplastic concentrations were lowest in the most northern, forested watershed, and highest in the most southern, agriculturally dominated watershed. Results suggest microplastic pollution is common in river food webs and is connected to species feeding characteristics. Future research should focus on understanding the movement of microplastic from point-source and diffuse sources and into aquatic ecosystems, which will support pollution management efforts on inland waters.

Direct observation of finite size effects in chains of antiferromagnetically coupled spins.

Finite spin chains made of few magnetic ions are the ultimate-size structures that can be engineered to perform spin manipulations for quantum information devices. Their spin structure is expected to show finite size effects and its knowledge is of great importance both for fundamental physics and applications. Until now a direct and quantitative measurement of the spatial distribution of the magnetization of such small structures has not been achieved even with the most advanced microscopic techniques. Here we present measurements of the spin density distribution of a finite chain of eight spin-3/2 ions using polarized neutron diffraction. The data reveal edge effects that are a consequence of the finite size and of the parity of the chain and indicate a noncollinear spin arrangement. This is in contrast with the uniform spin distribution observed in the parent closed chain and the collinear arrangement in odd-open chains.

Patterns of delayed detection and persistence of bovine tuberculosis in confirmed and unconfirmed herd breakdowns in cattle and cattle herds in Great Britain.

Approximately 1500/6000 cattle farms that were depopulated during the foot and mouth epidemic in GB in 2001 had been repopulated and subjected to two unrestricted (herd considered free from bovine tuberculosis (bTB)) herd tests. Factors associated with herd breakdown(s) (HBD) and individual cattle reactor status at the second test were investigated. There were 96 HBD in total, with a 3-fold increased risk of HBD in herds that had had a HBD at the first test after restocking. Two mixed effect models were used to investigate factors associated with 324/246,060 reactor cattle at the second bTB test; 228 reactors were at confirmed HBD and 96 at unconfirmed HBD; 253 (79%) reactors at the second test were present and test negative at the first test. In confirmed HBD, the odds of cattle reacting were higher if the restocked farm had a history of bTB before 2001 and if the source and restocked farms were high frequency tested (HFT) farms (routine bTB tests at ≥1 per 2 years). Reacting cattle were more likely to have been born on the restocked farm before the first test after FMD and less likely to have been purchased from a low frequency tested (LFT) farm (routine bTB tests at 3-4 year intervals) after the first test compared with a baseline of cattle purchased from a LFT farm before the first test. Unconfirmed HBD at the second test was more likely when the first test was a confirmed HBD and when there was a history of bTB in the restocked farm. In contrast to confirmed HBD, cattle purchased from a LFT farm after the first test were at increased risk of reacting at an unconfirmed HBD at the second test. We conclude that a farm history of bTB suggests persistence of bTB on the farm. Confirmed tests indicate exposure to bTB for some time indicated by the increased risk from HFT source and restocked farms and a farm history of bTB. The risks for reactors are related to the farm and herd and duration of exposure to these risks. Therefore, the spread of bTB to naïve herds would be reduced if farmers only introduced cattle known not to have been in herds and on farms exposed to bTB. Management of bTB on farms with bTB is complicated because there is undisclosed infection in cattle and environmental contamination.

Associations between membership of farm assurance and organic certification schemes and compliance with animal welfare legislation.

Animal health (AH) defines the outcome of their inspections of livestock holdings as full compliance with the legislation and welfare code (A), compliance with the legislation but not the code (B), non-compliance with legislation but no pain, distress or suffering obvious in the animals (C) or evidence of unnecessary pain or unnecessary distress (D). The aim of the present study was to investigate whether membership of farm assurance or organic certification schemes was associated with compliance with animal welfare legislation as inspected by AH. Participating schemes provided details of their members, past and present, and these records were matched against inspection data from AH. Multivariable multilevel logistic binomial models were built to investigate the association between compliance with legislation and membership of a farm assurance/organic scheme. The percentage of inspections coded A, B, C or D was 37.1, 35.6, 20.2 and 7.1 per cent, respectively. Once adjusted for year, country, enterprise, herd size and reason for inspection, there was a pattern of significantly reduced risk of codes C and D compared with A and B, in certified enterprises compared with the enterprises that were not known to be certified in all species.

Effect of mobility score on milk yield and activity in dairy cattle.

Previous studies have indicated that lame cows have reduced milk yield both before and after they are treated for lameness. One explanation for the reduction in yield before treatment is delay to treatment; that is, cows have impaired mobility for some time before they are treated. The aim of this study was to test this hypothesis by investigating temporal associations between change in milk yield and change in mobility score. Mobility score (MS, on a scale from 0 to 3), milk yield, treatments for lameness, and cow activity were recorded on 312 cows in a dairy herd in Somerset, UK, for 1 yr. The MS was scored every 2 wk and compared with daily yield and activity (mean log steps/h) averaged over the previous 16 d. Approximately 52% of MS changed within 14 d, usually by 1 unit. Overall, milk yields of cows with MS 1 were greater than those of cows with other scores. Cows with MS 2 and 3 produced 0.7 (95% confidence interval: 0.35-0.97) and 1.6 (0.98-2.23) kg less milk/d, respectively, compared with cows with MS 1. In addition, cows with MS 1 were significantly more active than cows with MS 0, 2, or 3. Cows with MS 2 and 3 were 0.02 (0.01-0.03) and 0.03 (0.01-0.05) mean log steps less active than cows with MS 1. Six to 8 wk before nonlame cows became MS 2 or 3, their daily milk yield decreased by a mean (95% CI) of 0.5 kg (0.12-0.47) and 0.9 kg (0.16-1.65) respectively. Daily yield remained lower by 0.42 kg (0.09-0.75) for 4 wk after cows with MS 2 had recovered. The activity of cows was significantly less (0.01 mean log steps) with increasing MS; the associations between activity and parity (means 0.03-0.11) and month of lactation (means 0.03-0.36) were quantitatively larger. Results from a multistate model indicated that once cows were lame they remained lame or became lame again despite treatment. In conclusion, cows' milk production started to decline before their mobility was visibly impaired.

Risk factors for increased rates of sole ulcers, white line disease, and digital dermatitis in dairy cattle from twenty-seven farms in England and Wales.

Claw lesion treatment records were recorded by farmers on 27 dairy farms (3,074 cows, 36,432 records) in England and Wales between February 2003 and February 2004. These were combined with farm environment and management data collected using a combination of direct observations, interviews with farmers, and milk recording data. Multilevel models were constructed for the 3 most frequently reported lesions related to lameness, namely, sole ulcers, white line disease, and digital dermatitis. Risks associated with an increased incidence of sole ulcers were parity 4 or greater, the use of roads or concrete cow tracks between the parlor and grazing, the use of lime on free stalls, and housing in free stalls with sparse bedding for 4 mo or more. The risks for white line disease were increasing parity and increasing herd size, cows at pasture by day and housed at night, and solid grooved concrete floors in yards or alleys. Solid grooved flooring was also associated with an increased risk of digital dermatitis, and cows 6 or more months after calving had a decreased risk of a first case of digital dermatitis. These results improve our understanding of the specific risks for 3 important lesions associated with bovine lameness and could be used as interventions in future clinical studies targeted at the reduction of specific lesions.

Associations between sole ulcer, white line disease and digital dermatitis and the milk yield of 1824 dairy cows on 30 dairy cow farms in England and Wales from February 2003-November 2004.

The milk yields of 1824 cows were used to investigate the effect of lesion-specific causes of lameness, based on farmer treatment and diagnosis of lame cows, on milk yield. A three-level hierarchical model of repeated test day yields within cows within herds was used to investigate the impact of lesion-specific causes of lameness (sole ulcer, white line disease, digital dermatitis and other causes) on milk yield before and after treatment compared with unaffected cows. Cattle which developed sole ulcer (SU) and white line disease (WLD) were higher yielding cattle before they were diagnosed. Their milk production fell to below that of the mean of unaffected cows before diagnosis and remained low after diagnosis. In cattle which developed digital dermatitis (DD) there was no significant difference in milk yield before treatment and a slightly raised milk yield immediately after treatment. The estimated milk loss attributable to SU and WLD was approximately 570 and 370 kg, respectively. These results highlight that specific types of lameness vary by herds and within herds they are associated with higher yielding cattle. Consequently lesion-specific lameness reduction programmes targeting the cow and farm specific causes of lameness might be more effective than generic recommendations. They also highlight the importance of milk loss when estimating the economic impact of SU and WLD on the farms profitability.

Hydrogen-bond network in cyclodecaamylose hydrate at 20 K; neutron diffraction study of novel structural motifs band-flip and kink in alpha-(1-->4)-D-glucoside oligosaccharides.

A single-crystal neutron diffraction study of cyclodecaamylose (CA10) was carried out at 20 K. CA10 crystallizes with 27.18 water molecules [(C(6)H(10)O(5))(10).27.18H(2)O] in space group C2 with unit-cell constants a = 29.31 (5), b = 9.976 (10), c = 19.34 (2) A, beta = 121.07 (2) degrees. The asymmetric unit contains a half molecule of CA10 and 13.59 water molecules, the other half being related by a crystallographic twofold rotation axis. All H atoms except two water H atoms could be located from difference neutron-density maps; structure refinement converged at R = 0.635. Two of the five CH(2)-O6 groups and one of the 15 O2, O3 hydroxyl groups of CA10 are twofold orientationally disordered. A total of 13.59 water molecules in the asymmetric unit are distributed over 23 positions; 20 of which are in the CA10 cavity, and the other three occupy intermolecular interstices. Of the 123 symmetry-independent hydrogen bonds, 25 (= 20%) are three-centered and 7 (= 6%) are four-centered. Water molecules and O-H groups of CA10 form an extended network with cooperative O-H...O-H...O-H hydrogen bonds. They are arranged in 11 polygons with three, four, five, six and eight O-H bonds and in homodromic, antidromic and heterodromic arrangements. Nine polygons are located within the cavity and the others are outside.

New mode of coordination for the dinitrogen ligand: formation, bonding, and reactivity of a tantalum complex with a bridging N(2) unit that is both side-on and end-on.

The reaction of a mixture of 1 equiv of PhPH(2) and 2 equiv of PhNHSiMe(2)CH(2)Cl with 4 equiv of Bu(n)Li followed by the addition of THF generates the lithiated ligand precursor [NPN]Li(2).(THF)(2) (where [NPN] = PhP(CH(2)SiMe(2)NPh)(2)). The reaction of [NPN]Li(2).(THF)(2) with TaMe(3)Cl(2) produces [NPN]TaMe(3), which reacts under H(2) to yield the diamagnetic dinuclear Ta(IV) tetrahydride ([NPN]Ta)(2)(mu-H)(4). This hydride reacts with N(2) with the loss of H(2) to produce ([NPN]Ta(mu-H))(2)(mu-eta(1):eta(2)-N(2)), which was characterized both in solution and in the solid state, and contains strongly activated N(2) bound in the unprecedented side-on end-on dinuclear bonding mode. A density functional theory calculation on the model complex [(H(3)P)(H(2)N)(2)Ta(mu-H)](2)(mu-eta(1):eta(2)-N(2)) provides insight into the molecular orbital interactions involved in the side-on end-on bonding mode of dinitrogen. The reaction of ([NPN]Ta(mu-H))(2)(mu-eta(1):eta(2)-N(2)) with propene generates the end-on bound dinitrogen complex ([NPN]Ta(CH(2)CH(2)CH(3)))(2)(mu-eta(1):eta(1)-N(2)), and the reaction of [NPN]Li(2).(THF)(2) with NbCl(3)(DME) generates the end-on bound dinitrogen complex ([NPN]NbCl)(2)(mu-eta(1):eta(1)-N(2)). These two end-on bound dinitrogen complexes provide evidence that the bridging hydride ligands are responsible for the unusual bonding mode of dinitrogen in ([NPN]Ta(mu-H))(2)(mu-eta(1):eta(2)-N(2)). The dinitrogen moiety in the side-on end-on mode is amenable to functionalization; the reaction of ([NPN]Ta(mu-H))(2)(mu-eta(1):eta(2)-N(2)) with PhCH(2)Br results in C-N bond formation to yield [NPN]Ta(mu-eta(1):eta(2)-N(2)CH(2)Ph)(mu-H)(2)TaBr[NPN]. Nitrogen-15 NMR spectral data are provided for all the tantalum-dinitrogen complexes and derivatives described.

X-ray and neutron structure of 1,8-(3,6,9-trioxaundecane-1,11-diyldioxy)-9,10-dihydro-10,10-dimethylanthracene-9-ol (P326); some pitfalls of automatic data collection.

The structure of the crown ether 1,8-(3,6,9-trioxaundecane-1,11-diyldioxy)-9,10-dihydro-10,10-dimethylanthracene-9-ol, C(24)H(30)O(6).H(2)O (1), code name P326, the parent compound for a series of derivatives, has been determined by both X-ray diffraction at room temperature and neutron diffraction at very low temperature. The unit cells are very similar at both temperatures and in both cases the crystals exhibit P2(1) symmetry with Z = 4 (two molecules, A and B, respectively, per asymmetric unit) and pseudosymmetry P2(1)/c. The higher symmetry is broken mainly by the two independent water molecules in the unit cell, some reflections which would be absent in P2(1)/c having strong intensities in both the X-ray and neutron data. In both molecules A and B hydrogen bonds involving the water molecule stabilize the macrocyclic ring structure, one involving the macrocyclic O(9) as a donor. Close contacts between the water and macrocyclic O atoms in each molecule also suggest the presence of two bifurcated hydrogen bonds, involving water HW2 to both O(16) and O(18), and water HW1 to both O(18) and O(20), respectively, with considerable variation in the geometry being present. Both molecules A and B exhibit very close pseudosymmetry across a plane perpendicular to the molecular plane and through atoms C(9) and O(18), and in addition are predominantly planar structures. The X-ray analysis failed to reveal one H atom per water molecule, each being subsequently included after location and refinement in the neutron analysis.

Structures of furanosides: geometrical analysis of low-temperature X-ray and neutron crystal structures of five crystalline methyl pentofuranosides.

Crystal structures of all five crystalline methyl D-pentofuranosides, methyl alpha-D-arabinofuranoside (1), methyl beta-D-arabinofuranoside (2), methyl alpha-D-lyxofuranoside (3), methyl beta-D-ribofuranoside (4) and methyl alpha-D-xylofuranoside (5) have been determined by means of cryogenic X-ray and neutron crystallography. The neutron diffraction experiments provide accurate, unbiased H-atom positions which are especially important because of the critical role of hydrogen bonding in these systems. This paper summarizes the geometrical and conformational parameters of the structures of all five crystalline methyl pentofuranosides, several of them reported here for the first time. The methyl pentofuranoside structures are compared with the structures of the five crystalline methyl hexopyranosides for which accurate X-ray and neutron structures have been determined. Unlike the methyl hexopyranosides, which crystallize exclusively in the C(1) chair conformation, the five crystalline methyl pentofuranosides represent a very wide range of ring conformations.

Agostic deformations based on electron delocalization in the alkyllithium-complex [(2-(Me3Si)2CLiC5H4N)2.

Topological analysis of experimental and theoretical charge densities in the title complex [(2-(Me3Si)2CLiC5H4N)2] 1 reveals the nature of the agostic deformation postulated for this complex: delocalization of the Li-C bonding electrons over the entire agostic alkyl group controls the formation of an acute Li-C-Si angle and thus a sufficient electronic saturation of the electron deficient lithium atom via secondary interactions.

Performance-based planning for hospitals.

It is time for health care planning to evolve through a new phase--from strategic planning to performance-based planning, writes Scott A. Mason, D.P.A., FACHE, president and CEO of eko systems inc.

Randomised placebo controlled trial of nebulised corticosteroids in acute respiratory syncytial viral bronchiolitis.

OBJECTIVE: To evaluate short and long term effects of giving nebulised budesonide early in respiratory syncytial viral (RSV) bronchiolitis. DESIGN: A multicentre randomised double blind placebo controlled trial. SUBJECTS: Infants admitted to hospital with their first episode of RSV positive bronchiolitis. INTERVENTION: Randomisation to receive either 1 mg of nebulised budesonide (Bud) or placebo (Pla) twice daily from admission until 2 weeks after discharge. Follow up was for 12 months. MAIN OUTCOME MEASURES: Duration of hospital admission, time taken to become symptom free, re-admission rates, general practitioner consultation rates, and use of anti-wheeze medication during follow up. RESULTS: 161 infants were studied. Both arms were similar with respect to initial clinical severity, age, sex, socioeconomic class, and tobacco exposure. Median time from first nebulisation to discharge: Bud and Pla, 2 days. Median number of days for 50% of infants to be symptom free for 48 hours: Bud, 10 days; Pla, 12 days. Respiratory re-admission rates in the 12 month follow up: Bud, 16%; Pla, 18%; median difference (95% confidence interval (CI)), -2 (-14 to 10). Median respiratory related general practitioner attendances: Bud, 4.0; Pla, 4.5; median difference (95% CI), -1 (-2 to 0). Percentage of infants receiving at least one prescription for anti-wheeze medication during follow up, corticosteroids: Bud, 50%; Pla, 60%; difference (95% CI), -10 (-26 to 6); bronchodilators: Bud, 60%; Pla, 67%; difference (95% CI), -7 (-22 to 8). CONCLUSIONS: There are no short or long term clinical benefits from the administration of nebulised corticosteroids in the acute phase of RSV bronchiolitis.

Obtaining informed consent to neonatal randomised controlled trials: interviews with parents and clinicians in the Euricon study.

BACKGROUND: Questions have been asked about whether the process of obtaining informed consent from parents to clinical trials on neonates leads to valid consent. We undertook a study in nine European countries to assess this issue and to seek any practical improvements. METHODS: Semi-structured interviews were conducted with parents of 200 babies who had been asked for consent to neonatal trials and 107 neonatologists seeking consent. Analysis assessed the validity of the consent process against four components: parental competence; information given; parental understanding; and voluntariness of consent. FINDINGS: 59 of the 200 parents had given valid consent or refusal but the remainder had problems in one or more of the component areas (42 for competence, 43 for information, 44 for understanding, and 21 for voluntariness). The proportions with impaired consent were greatest for research in an emergency situation and for that associated with risk or discomfort greater than standard treatment. Information sheets were little used by parents in deciding whether to consent. Parents highly valued their involvement in the informed consent process, and clinicians generally agreed on the value of the process. INTERPRETATION: Current standards of informed consent to neonatal research projects could be improved. Research personnel should receive guidance on legal and ethical constraints governing the process. Oral and written information should be given at the same time. Parents could be made aware that research projects have been examined by research ethics committees. Little support was found for the argument that informed consent should be relinquished for the parents' own good. Further study is needed to identify which elements of the process are valued by parents and clinicians in a process that has some unavoidable limitations.