1,913 research outputs found

    Water chemistry and algal phosphatase activity in zinc-contaminated streams

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    A study was carried out on algal phosphatase activity and water chemistry in zinc-contaminated streams in the Northern Pennine Orefield. Fourteen field sites were studied; They ranged from low contaminated to high-zinc sites (0.1 mg 1(^-1) to 19.4 mg 1(^-1) with 7 of the 14 above 1 mg 1(^-1) Zn). Phosphate concentrations were low in the majority of sites (2.2 µg 1(^-1) to 22.8 µg l(^-1) with 13 of the 14 sites below 7.7 µg l(^-1) TFP and 1.8 µg l(^-1) to 8.5 µg 1(^-1) with 13 of the 14 sites below 4.9 µg l(^-1) FRP). Phosphatase activity was tested over a broad pH range (3.0 -11.0) using at least two different buffers at each pH value. Phosphatase activity of samples tested showed different responses to pH. Most of the samples exhibited enzyme activity in the alkaline range. High phosphatase activity was observed in samples with Mougeotia and Stigeoclonium populations. Possible relationships between phosphatase activity and selected environmental variables were examined. Phosphatase activity was significantly correlated with Zn (+ve), TFP (-ve) and FRP (-ve) in the water. The role of phosphatases in these high-zinc environments is discussed

    Longitudinal association between different levels of alcohol consumption and a new onset of depression and generalized anxiety disorder: Results from an international study in primary care

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    BACKGROUND: Several studies that have examined the full range of alcohol consumption have pointed to a possible non-linear association between alcohol use and the common mental disorders. Most of these studies are cross sectional and assessed psychiatric morbidity using non-specific instruments. Our aim was to investigate the longitudinal association between varying levels of alcohol consumption at baseline and the new-onset of depression and generalized anxiety disorder (GAD), in a large international primary care sample. METHODS: The sample consisted of 3201 primary care attenders from 14 countries in the context of WHO Collaborative Study of Psychological Problems in General Health Care. Alcohol use at baseline was assessed using AUDIT and the mental disorders were assessed with the Composite International Diagnostic Interview. RESULTS: Light to moderate alcohol consumption at baseline was associated with a lower incidence of depression and GAD compared to abstinence while excessive alcohol consumption was associated with a higher incidence of depression but not GAD. This non-linear association was not substantially affected after adjustment for a range of possible confounding variables. CONCLUSION: Any causal interpretation of this association is difficult in the context of an observational study and further combined and consistent evidence from different sources is needed

    Formation of ultracold Rb 2 molecules in the v′′ = 0 level of the a 3Σ + u state via blue-detuned photoassociation to the 1 3Π g state

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    We report on the observation of blue-detuned photoassociation in Rb2, in which vibrational levels are energetically above the corresponding excited atomic asymptote. 85Rb atoms in a MOT were photoassociated at short internuclear distance to levels of the 13Πg state at a rate of approximately 5 × 104 molecules s−1. We have observed most of the predicted vibrational levels for all four spin–orbit components; 0+g, 0−g, 1g, and 2g, including levels of the 0+g outer well. These molecules decay to the metastable a3Σ+u state, some preferentially to the v′′ = 0 level, as we have observed for photoassociation to the v′ = 8 level of the 1g component

    When should customers control service delivery? Implications for service design

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    What do a Mongolian stir-fry restaurant and a medical lab providing home testing solutions have in common? They are both innovative services that base their success on customers controlling part of the service delivery. These providers allow service tasks to be performed by the customers as a means of shaping the overall experience and not strictly as a means of "outsourcing" the service. Motivated by such practices, we explore whether and how should providers allocate the control of different tasks of their service to the customers. We model services as multi-step processes with each step affecting customers' experience at other steps. At certain steps the provider may hold an “expert" role and be more capable of performing than the customers, whereas at other steps she holds an “administrative" role and is less capable of performing than the customers. We distinguish between routine services, where the service outcome must conform to standardized specifications, and non-routine services, where the value of the service outcome relies on subjective dimensions. We show that the optimal design is determined by an economically intuitive rule whereby the provider controls the steps based on the marginal benefit she can derive compared to self-service. For routine services, this rule translates to managing “blocks" of steps because the provider benefits from containing the volatility of the experiences across the service even when this implies the provision of service steps with a negative marginal benefit, i.e., steps which she is less capable of performing than the customers. Instead, in non-routine services providers should focus on the value advantage they can ensure through a "core provision" even if this implies forgoing control of steps for which they are more capable of performing than the customers and from which they can derive positive marginal benefit. This implies that in non-routine services the provider exercises more control up to a certain process length; beyond that she delegates more steps to the customers. When customers differ in their abilities to perform the different steps, the provider may offer a service line. Service lines facilitate better segmentation than a single service offering, but their economic benefit exhibits an inverted “U-shaped" relationship with respect to the number of steps that a service comprises. Finally, we find that competition between two providers who differ in their capabilities to perform a service results in service design differentiation where the more capable provider offers a higher-end "focused service" against a lower-end "super-service" offered from the less capable provider

    Paedophiles in the community: inter-agency conflict, news leaks and the local press

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    This article explores the leaking of confidential information about secret Home Office plans to house convicted paedophiles within a local community (albeit inside a prison). It argues that a politics of paedophilia has emerged in which inter-agency consensus on the issue of ‘what to do’ with high-profile sex offenders has broken down. Accordingly, the article situates newspaper ‘outing’ of paedophiles in the community in relation to vigilante journalism and leaked information from official agencies. The article then presents research findings from a case study of news events set in train following a whistle-blowing reaction by Prison Officers’ Association officials to Home Office plans. Drawing from a corpus of 10 interviews with journalists and key protagonists in the story, the article discusses both the dynamics of whistle blowing about paedophiles and also what happens after the whistle has blown
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