What can ecosystems learn? Expanding evolutionary ecology with learning theory

Background: The structure and organisation of ecological interactions within an ecosystem is modified by the evolution and coevolution of the individual species it contains. Understanding how historical conditions have shaped this architecture is vital for understanding system responses to change at scales from the microbial upwards. However, in the absence of a group selection process, the collective behaviours and ecosystem functions exhibited by the whole community cannot be organised or adapted in a Darwinian sense. A long-standing open question thus persists: Are there alternative organising principles that enable us to understand and predict how the coevolution of the component species creates and maintains complex collective behaviours exhibited by the ecosystem as a whole?Results: Here we answer this question by incorporating principles from connectionist learning, a previously unrelated discipline already using well-developed theories on how emergent behaviours arise in simple networks. Specifically, we show conditions where natural selection on ecological interactions is functionally equivalent to a simple type of connectionist learning, ‘unsupervised learning’, well-known in neural-network models of cognitive systems to produce many non-trivial collective behaviours. Accordingly, we find that a community can self-organise in a well-defined and non-trivial sense without selection at the community level; its organisation can be conditioned by past experience in the same sense as connectionist learning models habituate to stimuli. This conditioning drives the community to form a distributed ecological memory of multiple past states, causing the community to: a) converge to these states from any random initial composition; b) accurately restore historical compositions from small fragments; c) recover a state composition following disturbance; and d) to correctly classify ambiguous initial compositions according to their similarity to learned compositions. We examine how the formation of alternative stable states alters the community’s response to changing environmental forcing, and we identify conditions under which the ecosystem exhibits hysteresis with potential for catastrophic regime shifts.Conclusions: This work highlights the potential of connectionist theory to expand our understanding of evo-eco dynamics and collective ecological behaviours. Within this framework we find that, despite not being a Darwinian unit, ecological communities can behave like connectionist learning systems, creating internal conditions that habituate to past environmental conditions and actively recalling those conditions.Theoretical ecology, Communityassembly, Network structures, Ecological memory, Associative learning, Regime shifts, Community matrix*Correspondence

Surfaces roughness effects on the transmission of Gaussian beams by anisotropic parallel plates

Influence of the plate surfaces roughness in precise ellipsometry experiments is studied. The realistic case of a Gaussian laser beam crossing a uniaxial platelet is considered. Expression for the transmittance is determined using the first order perturbation theory. In this frame, it is shown that interference takes place between the specular transmitted beam and the scattered field. This effect is due to the angular distribution of the Gaussian beam and is of first order in the roughness over wavelength ratio. As an application, a numerical simulation of the effects of quartz roughness surfaces at normal incidence is provided. The interference term is found to be strongly connected to the random nature of the surface roughness.Comment: 18 pages, Journal of Physics D: Applied Physics, volume 36, issue 21, pages 2697 - 270

Investigating Genetic Determinants of Plasma Inositol Status in Adult Humans

BACKGROUND: Myo-inositol (MI) is incorporated into numerous biomolecules, including phosphoinositides and inositol phosphates. Disturbance of inositol availability or metabolism is associated with various disorders, including neurological conditions and cancers, while supplemental MI has therapeutic potential in conditions such as depression, polycystic ovary syndrome and congenital anomalies. Inositol status may be influenced by diet, synthesis, transport, utilisation and catabolism. OBJECTIVES: We aimed to investigate potential genetic regulation of circulating MI status and to evaluate correlation of MI concentration with other metabolites. METHODS: Gas chromatography mass spectrometry was used to determine plasma MI concentration of more than 2,000 healthy, young adults (aged 18-28 years) from the Trinity Student Study. Genotyping data was used to test association of plasma MI with SNPs in candidate genes, encoding inositol transporters and synthesising enzymes, and test for genome-wide association. We evaluated potential correlation of plasma MI with D-chiro inositol, glucose and other metabolites by Spearman's rank correlation. RESULTS: Mean plasma MI showed a small but significant difference between males and females (28.5 and 26.9 µM, respectively). Candidate gene analysis revealed several nominally significant associations with plasma MI, most notably for SLC5A11, encoding a sodium-coupled inositol transporter, also known as SMIT2 (sodium-dependent myo-inositol transporter 2). However, these did not survive correction for multiple testing. Subsequent testing for genome-wide association with plasma MI did not identify associations of genome-wide significance (p < 5 × 10-8). However, 8 SNPs exceeded the threshold for suggestive significant association with plasma MI concentration (p < 1 × 10-5), 3 of which were located within or close to genes: MTDH, LAPTM4B and ZP2. We found significant positive correlation of plasma MI concentration with concentration of D-chiro-inositol and several other biochemicals including glucose, methionine, betaine, sarcosine and tryptophan. CONCLUSION: Our findings suggest potential for modulation of plasma MI in young adults by variation in SLC5A11 which is worthy of further investigation

Sociology Back to the Publics

This article is a reading of the `new sociology' that is mainly identified with the works of C. Wright Mills and Alvin Gouldner. Its main argument is that during the past 40 years the new sociology gave back a public face to sociology. This distinguishes it from the `old sociology' that had not been able to free itself from `private' social values. It is argued that Mills' power elite and Gouldner's coming crisis theses provided the foundation for a common enterprise among many `new sociologists' to develop a critical and public sociology that would seek to shape what Mills called the `democratic society of publics'.`New sociologists' share a critique of modern societies, namely, that though most modern societies have formal democracies, a substantial democratic social structure of publics is often lacking, due to the erosion of the public sphere by private values

Effectiveness of Community versus Hospital Eye Service follow-up for patients with neovascular age-related macular degeneration with quiescent disease (ECHoES): a virtual non-inferiority trial

Objectives: To compare the ability of ophthalmologists versus optometrists to correctly classify retinal lesions due to neovascular age-related macular degeneration (nAMD). Design: Randomised balanced incomplete block trial. Optometrists in the community and ophthalmologists in the Hospital Eye Service classified lesions from vignettes comprising clinical information, colour fundus photographs and optical coherence tomographic images. Participants' classifications were validated against experts' classifications (reference standard). Setting: Internet-based application. Participants: Ophthalmologists with experience in the age-related macular degeneration service; fully qualified optometrists not participating in nAMD shared care. Interventions: The trial emulated a conventional trial comparing optometrists' and ophthalmologists' decision-making, but vignettes, not patients, were assessed. Therefore, there were no interventions and the trial was virtual. Participants received training before assessing vignettes. Main outcome measures: Primary outcome- correct classification of the activity status of a lesion based on a vignette, compared with a reference standard. Secondary outcomes-potentially sight-threatening errors, judgements about specific lesion components and participants' confidence in their decisions. Results: In total, 155 participants registered for the trial; 96 (48 in each group) completed all assessments and formed the analysis population. Optometrists and ophthalmologists achieved 1702/2016 (84.4%) and 1722/2016 (85.4%) correct classifications, respectively (OR 0.91, 95% CI 0.66 to 1.25; p=0.543). Optometrists' decision-making was non-inferior to ophthalmologists' with respect to the prespecified limit of 10% absolute difference (0.298 on the odds scale). Optometrists and ophthalmologists made similar numbers of sight-threatening errors (57/994 (5.7%) vs 62/994 (6.2%), OR 0.93, 95% CI 0.55 to 1.57; p=0.789). Ophthalmologists assessed lesion components as present less often than optometrists and were more confident about their classifications than optometrists. Conclusions: Optometrists' ability to make nAMD retreatment decisions from vignettes is not inferior to ophthalmologists' ability. Shared care with optometrists monitoring quiescent nAMD lesions has the potential to reduce workload in hospitals

Learning democracy in social work

In this contribution, we discuss the role of social work in processes of democracy. A key question in this discussion concerns the meaning of ‘the social’ in social work. This question has often been answered in a self-referential way, referring to a methodological identity of social work. This defines the educational role of social work as socialisation (be it socialisation into obedience or into an empowered citizen). However, the idea of democracy as ‘ongoing experiment’ and ‘beyond order’ challenges this methodological identity of social work. From the perspective of democracy as an ‘ongoing experiment’, the social is to be regarded as a platform for dissensus, for ongoing discussions on the relation between private and public issues in the light of human rights and social justice. Hence, the identity of social work cannot be defined in a methodological way; social work is a complex of (institutionalized) welfare practices, to be studied on their underlying views on the ‘social’ as a political and educational concept, and on the way they influence the situation of children, young people and adults in society

Mutations in PROSC Disrupt Cellular Pyridoxal Phosphate Homeostasis and Cause Vitamin B6-Dependent Epilepsy

Pyridoxal 5'-phosphate (PLP), the active form of vitamin B6, functions as a cofactor in humans for more than 140 enzymes, many of which are involved in neurotransmitter synthesis and degradation. A deficiency of PLP can present, therefore, as seizures and other symptoms which are treatable with PLP and/or pyridoxine. Deficiency of PLP in the brain can be caused by inborn errors affecting B6 vitamer metabolism or by inactivation of PLP; by compounds accumulating as a result of inborn errors of other pathways or by ingested small molecules. Whole exome sequencing of 2 children from a consanguineous family with pyridoxine-dependent epilepsy revealed a homozygous nonsense mutation in proline synthetase co-transcribed homolog (bacterial) (PROSC), a PLPbinding protein of hitherto unknown function. Subsequent sequencing of 29 unrelated indivduals with pyridoxine-responsive epilepsy identified 4 additional children with biallelic PROSC mutations. Pretreatment cerebrospinal fluid samples showed low PLP concentrations and evidence of reduced activity of PLP-dependent enzymes. However, cultured fibroblasts showed excessive PLP accumulation. An E.coli mutant, lacking the PROSC homologue (ΔYggS) is pyridoxine-sensitive; complementation with human PROSC restored growth whilst hPROSC bearing p.Leu175Pro, p.Arg241Gln and p.Ser78Ter did not. PLP, a highly reactive aldehyde, poses a problem for cells - how to supply enough PLP for apoenzymes while maintaining free PLP concentrations low enough to avoid unwanted reactions with other important cellular nucleophiles. Whilst the mechanism involved is not fully understood our studies suggest that PROSC is involved in intracellular homeostatic regulation of PLP, supplying this cofactor to apoenzymes while minimizing any toxic side reactions

Intraosseous infusion of the distal phalanx compared to systemic intravenous infusion for marimastat delivery to equine lamellar tissue

No validated laminitis drug therapy exists, yet pharmaceutical agents with potential for laminitis prevention have been identified. Many of these are impractical for systemic administration but may be effective if administered locally. This study compared intraosseous infusion of the distal phalanx (IOIDP) with systemic intravenous constant rate infusion (CRI) to determine which was more effective for lamellar marimastat delivery. Ultrafiltration probes were placed in both forefeet of five horses to collect lamellar interstitial fluid as lamellar ultrafiltrate (LUF). Marimastat solution (3.5 mg/mL) containing lidocaine (20 mg/mL) was infused by IOIDP at 0.15 mL/min for 12 h. After a 12 h wash-out, marimastat (3.5 mg/mL) and lidocaine were infused by constant rate infusion (CRI) at 0.15 mL/min for 12 h. LUF, plasma and lamellar tissue marimastat concentrations were quantified using UPLC-MS. Zymography was used to establish the inhibitory concentrations of marimastat for equine lamellar matrix metalloproteinases (MMPs). Data were analysed non-parametrically. There was no difference between the steady-state marimastat concentration in lamellar ultrafiltrate (LUF[M]) during IOIDP (139[88-497] ng/mL) and CRI (136[93-157] ng/mL). During IOIDP, there was no difference between marimastat concentrations in the treated foot (139[88-497] ng/mL), the untreated foot (91[63-154] ng/mL) and plasma (101[93-118] ng/mL). LUF[M] after IOIDP and CRI were >IC50 of lamellar MMP-2 and 9, but below the concentration considered necessary for in vivo laminitis prevention. Lamellar drug delivery during IOIDP was inconsistent and did not achieve higher lamellar marimastat concentrations than CRI. Modification or refinement of the IOIDP technique is necessary if it is to be consistently effective

The Effectiveness, cost-effectiveness and acceptability of Community versus Hospital Eye Service follow-up for patients with neovascular age-related macular degeneration with quiescent disease (ECHoES): a virtual randomised balanced incomplete block trial

Background Patients with neovascular age-related macular degeneration (nAMD) usually attend regular reviews, even when the disease is quiescent. Reviews are burdensome to health services, patients and carers. Objectives To compare the proportion of correct lesion classifications made by community-based optometrists and ophthalmologists from vignettes of patients; to estimate the cost-effectiveness of community follow-up by optometrists compared with follow-up by ophthalmologists in the Hospital Eye Service (HES); to ascertain views of patients, their representatives, optometrists, ophthalmologists and clinical commissioners on the proposed shared care model. Design Community-based optometrists and ophthalmologists in the HES classified lesions from vignettes comprising clinical information, colour fundus photographs and optical coherence tomography images. Participants’ classifications were validated against experts’ classifications (reference standard). Setting Internet-based application. Participants Ophthalmologists had to have≥3 years post-registration experience in ophthalmology, have passed part 1 of the Royal College of Ophthalmologists, Diploma in Ophthalmology or equivalent examination, and have experience in the age-related macular degeneration service. Optometrists had to be fully qualified, be registered with the General Optical Council for≥3 years and not be participating in nAMD shared care. Interventions The trial sought to emulate a conventional trial in comparing optometrists’ and ophthalmologists’ decision-making, but vignettes, not patients, were assessed; therefore, there were no interventions. Participants received training prior to assessing vignettes Main Outcome Measures Primary outcome–correct classification of the activity status of a lesion based on a vignette, compared with a reference standard. Secondary outcomes–frequencies of potentially sight-threatening errors, participants’ judgements about specific lesion components, participant-rated confidence in their decisions and cost-effectiveness of follow-up by community-based optometrists compared with HES ophthalmologists. Results In total, 155 participants registered for the trial; 96 (48 in each professional group) completed training and main assessments and formed the analysis population. Optometrists and ophthalmologists achieved 1702 out of 2016 (84.4%) and 1722 out of 2016 (85.4%) correct classifications, respectively [odds ratio (OR) 0.91, 95% confidence interval (CI) 0.66 to 1.25; p=0.543]. Optometrists’ decisionmaking was non-inferior to ophthalmologists’ with respect to the pre-specified limit of 10% absolute difference (0.298 on the odds scale). Frequencies of sight-threatening errors were similar for optometrists and ophthalmologists [57/994 (5.7%) vs. 62/994 (6.2%), OR 0.93, 95% CI 0.55 to 1.57;p=0.789]. Ophthalmologists assessed lesion components as present less often than optometrists and were more confident about their lesion classifications than optometrists. The mean care-pathway cost for assessment was very similar by group, namely £397.33 for ophthalmologists and £410.78 for optometrists. The optometrist-led monitoring reviews were slightly more costly and less effective than ophthalmologist-led reviews, although the differences were extremely small. There was consensus that optometrist-led monitoring has the potential to reduce clinical workload and be more patient-centred. However, potential barriers are ophthalmologists’ perceptions of optometrists’ competence, the need for clinical training, the ability of the professions to work collaboratively and the financial feasibility of shared care for Clinical Commissioning Groups Conclusions The ability of optometrists to make nAMD retreatment decisions from vignettes is non-inferior to that of ophthalmologists. Various barriers to implementing shared cared for nAMD were identified. Future Work Recommendations The Effectiveness, cost-effectiveness and acceptability of Community versus Hospital Eye Service follow-up for patients with neovascular age-related macular degeneration with quiescent disease (ECHoES) study web application was robust and could be used for future training or research. The benefit of reducing HES workload was not considered in the economic evaluation. A framework of programme budgeting and marginal analysis could explicitly explore the resource implications of shifting resources within a given health service area, as the benefit of reducing HES workload was not considered in the economic evaluation. Future qualitative research could investigate professional differences of opinion that were identified in multidisciplinary focus groups.</p