Biomechanical strength of triceps tendon repairs: systematic review and meta-regression analysis of human cadaveric studies.

PURPOSE: It is unclear which triceps tendon repair constructs and techniques produce the strongest biomechanical performance while minimizing the risk of gap formation and repair failure. We aimed to determine associations of construct and technique variables with the biomechanical strength of triceps tendon repairs. PubMed, Embase, Cochrane Library, Web of Science, Scopus, and ClinicalTrials.gov were systematically searched for peer-reviewed studies on biomechanical strength of triceps tendon repairs in human cadavers. 6 articles met the search criteria. Meta-regression was performed on the pooled dataset (123 specimens). Outcomes of interest included gap formation, failure mode, and ultimate failure load. Covariates were fixation type; number of implants; and number of sutures. Stratification by covariates was performed. We found no association between fixation type and ultimate failure load; however, suture anchor fixation was associated with less gap formation compared with transosseous direct repair (ß = - 1.1; 95% confidence interval [CI]:- 2.2, - 0.04). A greater number of implants was associated with smaller gap formation (ß = - 0.77; 95% CI: - 1.3, - 0.28) while a greater number of sutures was associated with higher ultimate failure load ( ß= 3; 95% CI: 21, 125). In human cadaveric models, the number of sutures used in triceps tendon repairs may be more important than the fixation type or number of implants for overall strength. If using a transosseous direct repair approach to repair triceps tendon tears, surgeons may choose to use more sutures in their repair in order to balance the risk of larger gap formation when compared to indirect repair techniques. LEVEL OF EVIDENCE: Level III.

Developing Demonstration Test Catchments as a platform for transdisciplinary land management research in England and Wales.

Whilst a large body of plot and field-scale research exists on the sources, behaviour and mitigation of diffuse water pollution from agriculture, putting this evidence into a practical, context at large spatial scales to inform policy remains challenging. Understanding the behaviour of pollutants (nutrients, sediment, microbes and pesticides) and the effectiveness of mitigation strategies over whole catchments and long timeframes requires new, interdisciplinary approaches to organise and undertake research. This paper provides an introduction to the demonstration test catchments (DTC) programme, which was established in 2009 to gather empirical evidence on the cost-effectiveness of combinations of diffuse pollution mitigation measures at catchment scales. DTC firstly provides a physical platform of instrumented study catchments in which approaches for the mitigation of diffuse agricultural water pollution can be experimentally tested and iteratively improved. Secondly, it has established national and local knowledge exchange networks between researchers and stakeholders through which research has been co-designed. These have provided a vehicle to disseminate emerging findings to inform policy and land management practice. The role of DTC is that of an outdoor laboratory to develop knowledge and approaches that can be applied in less well studied locations. The research platform approach developed through DTC has brought together disparate research groups from different disciplines and institutions through nationally coordinated activities. It offers a model that can be adopted to organise research on other complex, interdisciplinary problems to inform policy and operational decision-making.

Changes in water quality of the River Frome (UK) from 1965 to 2009: is phosphorus mitigation finally working?

The water quality of the River Frome, Dorset, southern England, was monitored at weekly intervals from 1965 until 2009. Determinands included phosphorus, nitrogen, silicon, potassium, calcium, sodium, magnesium, pH, alkalinity and temperature. Nitrate-N concentrations increased from an annual average of 2.4 mg l⁻¹ in the mid to late 1960s to 6.0 mg l⁻¹ in 2008-2009, but the rate of increase was beginning to slow. Annual soluble reactive phosphorus (SRP) concentrations increased from 101 µg l⁻¹ in the mid 1960s to a maximum of 190 µg l⁻¹ in 1989. In 2002, there was a step reduction in SRP concentration (average=88 µg l⁻¹ in 2002-2005), with further improvement in 2007-2009 (average=49 µg l⁻¹), due to the introduction of phosphorus stripping at sewage treatment works. Phosphorus and nitrate concentrations showed clear annual cycles, related to the timing of inputs from the catchment, and within-stream bioaccumulation and release. Annual depressions in silicon concentration each spring (due to diatom proliferation) reached a maximum between 1980 and 1991, (the period of maximum SRP concentration) indicating that algal biomass had increased within the river. The timing of these silicon depressions was closely related to temperature. Excess carbon dioxide partial pressures (EpCO2) of 60 times atmospheric CO2 were also observed through the winter periods from 1980 to 1992, when phosphorus concentration was greatest, indicating very high respiration rates due to microbial decomposition of this enhanced biomass. Declining phosphorus concentrations since 2002 reduced productivity and algal biomass in the summer, and EpCO2 through the winter, indicating that sewage treatment improvements had improved riverine ecology. Algal blooms were limited by phosphorus, rather than silicon concentration. The value of long-term water quality data sets is discussed. The data from this monitoring programme are made freely available to the wider science community through the CEH data portal (http://gateway.ceh.ac.uk/).

Model-independent mean-field theory as a local method for approximate propagation of information.

We present a systematic approach to mean-field theory (MFT) in a general probabilistic setting without assuming a particular model. The mean-field equations derived here may serve as a local, and thus very simple, method for approximate inference in probabilistic models such as Boltzmann machines or Bayesian networks. Our approach is 'model-independent' in the sense that we do not assume a particular type of dependences; in a Bayesian network, for example, we allow arbitrary tables to specify conditional dependences. In general, there are multiple solutions to the mean-field equations. We show that improved estimates can be obtained by forming a weighted mixture of the multiple mean-field solutions. Simple approximate expressions for the mixture weights are given. The general formalism derived so far is evaluated for the special case of Bayesian networks. The benefits of taking into account multiple solutions are demonstrated by using MFT for inference in a small and in a very large Bayesian network. The results are compared with the exact results.

Theory and implementation of infomax filters for the retina.

In the first part of this paper we discuss a technical visual sensory system, which--in analogy with the retina--includes some preprocessing of visual information. In so doing, we use an information-theoretic criterion, the infomax ansatz, to optimize the response of the sensory system. In particular, it is shown that the lattice structure of the photoreceptor array has to be taken into account. By a discrete Fourier transformation on a triangular lattice we derive the frequency response of the infomax filter within the first Brillouin zone. To illustrate the response properties, infomax filters adapted to different noise levels are applied to images with different signal-to-noise ratios. This clearly demonstrates the necessity of adaptation of the filter properties to the given noise level. Furthermore, it is shown how to efficiently implement infomax-like filters by simple networks with only nearest-neighbour interactions. A two-layered network topology proves to be very advantageous in implementing the desired high-pass or low-pass properties. The network topology allows for adaption of the network to low and high noise levels by simply adjusting the nearest-neighbour couplings. In the second part of this paper, we compare the previously described information-theoretic requirements on a visual sensory system with biological facts known from the vertebrate retina. The substantial physiological response properties of the vertebrate retina are in agreement with the main features of the infomax filter. Since available experimental data lacks information which is necessary for a more quantitative comparison, we present suggestions for future experiments. Some key anatomical features of the retina of many vertebrates compare well with our two-layered implementation of the infomax filter. The analogy, in particular, concerns the adaption mechanism. To illustrate this point, we summarize some recent experiments which demonstrate that in the retina of some species adaption is based on the release of the neuromodulator dopamine by the interplexiform cells. This causes the horizontal cells to decouple. On the basis of recently gained understanding of the outer plexiform layer of the retina some further hypotheses about the functionality of the retina become obvious and possible future experiments to verify or refute them are suggested. Finally, we discuss the infomax approach from a more general point of view. In particular, we show that redundancy is essential to obtaining noise robustness of an internal representation of the environment as it is produced by a sensory system such as the retina.

An adolescent symptom checklist for juvenile deliquents.

A rating instrument was developed to assess the personality functioning of problem adolescents who have a brief history of official delinquency. Subjects were 186 residents at a short-term diagnostic detention facility. The instrument that emerged from a factor analysis was tested for reliability, validity, and cross-situational generality. Two major orthogonal factors emerged, Apathy-Withdrawal (I) and Anger-Defiance (II). Each factor was found to be congruent with the corresponding dimension on behavior rating instruments that had previously yielded two orthogonal factors and that had been shown to be relevant to a large number of psychological and educational issues. Significant correlations between the factors and a series of global ratings measuring behavior and measures indicative of the frequency and seriousness of official delinquency provided further evidence of construct and discriminant validity as well as evidence of cross-setting consistency of personality functioning.