BackgroundClinicians commonly examine posture and movement in people with the belief that correcting dysfunctional movement may reduce pain. If dysfunctional movement is to be accurately identified, clinicians should know what constitutes normal movement and how this differs in people with low back pain (LBP). This systematic review examined studies that compared biomechanical aspects of lumbo-pelvic movement in people with and without LBP.MethodsMEDLINE, Cochrane Central, EMBASE, AMI, CINAHL, Scopus, AMED, ISI Web of Science were searched from inception until January 2014 for relevant studies. Studies had to compare adults with and without LBP using skin surface measurement techniques to measure lumbo-pelvic posture or movement. Two reviewers independently applied inclusion and exclusion criteria, and identified and extracted data. Standardised mean differences and 95% confidence intervals were estimated for group differences between people with and without LBP, and where possible, meta-analyses were performed. Within-group variability in all measurements was also compared.ResultsThe search identified 43 eligible studies. Compared to people without LBP, on average, people with LBP display: (i) no difference in lordosis angle (8 studies), (ii) reduced lumbar ROM (19 studies), (iii) no difference in lumbar relative to hip contribution to end-range flexion (4 studies), (iv) no difference in standing pelvic tilt angle (3 studies), (v) slower movement (8 studies), and (vi) reduced proprioception (17 studies). Movement variability appeared greater for people with LBP for flexion, lateral flexion and rotation ROM, and movement speed, but not for other movement characteristics. Considerable heterogeneity exists between studies, including a lack of detail or standardization between studies on the criteria used to define participants as people with LBP (cases) or without LBP (controls).ConclusionsOn average, people with LBP have reduced lumbar ROM and proprioception, and move more slowly compared to people without LBP. Whether these deficits exist prior to LBP onset is unknown.

Using a spatially explicit cellular automaton model with local competition, we investigate the potential for varied levels of competitive intransitivity (i.e., nonhierarchical competition) to promote species coexistence. As predicted, on average, increased levels of intransitivity result in more sustained coexistence within simulated communities, although the outcome of competition also becomes increasingly unpredictable. Interestingly, even a moderate degree of intransitivity within a community can promote coexistence, in terms of both the length of time until the first competitive exclusion and the number of species remaining in the community after 500 simulated generations. These results suggest that modest levels of intransitivity in nature, such as those that are thought to be characteristic of plant communities, can contribute to coexistence and, therefore, community-scale biodiversity. We explore a potential connection between competitive intransitivity and neutral theory, whereby competitive intransitivity may represent an important mechanism for "ecological equivalence."

BackgroundThe aims of this pilot trial were to (i) test the hypothesis that modifying patterns of painful lumbo-pelvic movement using motion-sensor biofeedback in people with low back pain would lead to reduced pain and activity limitation compared with guidelines-based care, and (ii) facilitate sample size calculations for a fully powered trial.MethodsA multicentre (8 clinics), cluster-randomised, placebo-controlled pilot trial compared two groups of patients seeking medical or physiotherapy primary care for sub-acute and chronic back pain. It was powered for longitudinal analysis, but not for adjusted single-time point comparisons. The intervention group (n = 58) received modification of movement patterns augmented by motion-sensor movement biofeedback (ViMove, dorsaVi.com) plus guidelines-based medical or physiotherapy care. The control group (n = 54) received a placebo (wearing the motion-sensors without biofeedback) plus guidelines-based medical or physiotherapy care.Primary outcomes were self-reported pain intensity (VAS) and activity limitation (Roland Morris Disability Questionnaire (RMDQ), Patient Specific Functional Scale (PSFS)), all on 0–100 scales. Both groups received 6–8 treatment sessions. Outcomes were measured seven times during 10-weeks of treatment and at 12, 26 and 52 week follow-up, with 17.0 % dropout. Patients were not informed of group allocation or the study hypothesis.ResultsAcross one-year, there were significant between-group differences favouring the intervention group [generalized linear model coefficient (95 % CI): group effect RMDQ −7.1 (95 % CI–12.6;–1.6), PSFS −10.3 (−16.6; −3.9), QVAS −7.7 (−13.0; −2.4); and group by time effect differences (per 100 days) RMDQ −3.5 (−5.2; −2.2), PSFS −4.7 (−7.0; −2.5), QVAS −4.8 (−6.1; −3.5)], all p < 0.001. Risk ratios between groups of probability of improving by >30 % at 12-months = RMDQ 2.4 (95 % CI 1.5; 4.1), PSFS 2.5 (1.5; 4.0), QVAS 3.3 (1.8; 5.9).The only device-related side-effects involved transient skin irritation from tape used to mount motion sensors.ConclusionsIndividualised movement retraining using motion-sensor biofeedback resulted in significant and sustained improvements in pain and activity limitation that persisted after treatment finished. This pilot trial also refined the procedures and sample size requirements for a fully powered RCT.This trial (Australian New Zealand Clinical Trials Registry NCT01572779) was equally funded by dorsaVi P/L and the Victorian State Government.

Competitive intransitivity, a situation in which species' competitive ranks cannot be listed in a strict hierarchy, promotes species coexistence through "enemy's enemy indirect facilitation." Theory suggests that intransitivity-mediated coexistence is enhanced when competitive interactions occur at local spatial scales, although this hypothesis has not been thoroughly tested. Here, we use a lattice model to investigate the effect of local vs. global competition on intransitivity-mediated coexistence across a range of species richness values and levels of intransitivity. Our simulations show that local competition can enhance intransitivity-mediated coexistence in the short-term, yet hinder it in the long-term, when compared to global competition. This occurs because local competition slows species disaggregation, allowing weaker competitors to persist longer in the shifting spatial refuges of intransitive networks, enhancing short-term coexistence. Conversely, our simulations show that, in the long-term, local competition traps disaggregated species in unfavorable areas of the competitive arena, where they are excluded by superior competitors. As a result, in the long-term, global intransitive competition allows a greater number of species to coexist than local intransitive competition.

Summary1. As they grow old, most organisms experience progressive physiological deterioration resulting in declining rates of survival and reproduction -a seemingly maladaptive phenomenon known as senescence. 2. Although senescence is usually defined with respect only to survival and reproduction, a third component of fitness, offspring quality, may also decline with age. Few studies, however, have assessed age-related changes in offspring quality using measures that truly reflect fitness. 3. In a controlled environment, we tested for age-related declines in three demographic components of fitness (survival, reproduction and offspring quality) in Lemna minor, a small aquatic plant in the subfamily Lemnoideae (the duckweeds) with a short life span and rapid rate of asexual reproduction. Our primary measure of offspring quality, the intrinsic rate of increase, more closely approximates fitness than measures used in previous studies such as size, life span and total reproductive output. 4. We observed strong age-related declines in all three components of fitness: old plants had lower rates of survival and reproduction, and produced lower-quality offspring than younger plants. 5. Theoretical and empirical research on the evolutionary biology of senescence should devote more attention to offspring quality. This often unrecognized component of fitness may change with age -as we have shown in L. minor -and may be shaped by, and feed back into, the same evolutionary forces that give rise to senescence.

Game theory predicts that the evolutionarily stable level of root production is greater for plants grown with neighbours compared to plants grown alone, even when the available resources per plant are constant. This follows from the fact that for plants grown alone, new roots compete only with other roots on the same plant, whereas for multiple plants grown in a group, new roots can also compete with the roots of other plants, thereby potentially acquiring otherwise unavailable resources at their neighbours' expense. This phenomenon, which results in plants grown with neighbours over-proliferating roots at the expense of above-ground biomass, has been described as a 'tragedy of the commons', and requires that plants can distinguish self from non-self tissues. While this game theoretical model predicts the evolutionarily stable strategies of individual plants, it has only been tested on average allocation patterns of groups of plants. This is problematic, because average patterns can appear to reflect a tragedy of the commons, even when none has occurred. In particular, assuming (1) a decelerating relationship between individual plant biomass and the amount of resources available, and (2) greater size inequality in plants grown with neighbours compared to plants grown alone (due to asymmetric competition), then plants grown with neighbours should, at least on average, be smaller than plants grown alone. This is a manifestation of 'Jensen's Inequality', which states that for decelerating functions, the average value of the function is less than the function of the average value. We suggest that Jensen's Inequality should serve as an appropriate null hypothesis for examining biologically-based explanations of changes in biomass allocation strategies.Plants compete in two distinct arenas: above-and below-ground (e.g., Clements et al. 1929;Donald 1958;Wilson 1988b;McPhee and Aarssen 2001). Above-ground, plant leaves and shoots compete primarily for light, while below-ground, roots compete for water and several macro-and micronutrients. Plant traits that confer a high competitive ability for acquiring each of these resource types (i.e., above-vs. below-ground resources) are obviously quite different and trade-offs between the two major components of plant competition are likely to arise (Mooney 1972; Wilson and Tilman 1993). One important example of such a trade-off is the often-observed negative correlation between a plant's shoot to root ratio and the ratio of light to nutrient availability (Chapin Plant Ecology (2005) 179:127-131 Ó Springer 2005

Summary1. Age-dependent increases in mortality have been documented in a variety of species of insect under laboratory conditions. However, while strong statistical evidence has been presented for senescence in vertebrate populations in the wild, we know little about the rate and shape of senescence in wild populations of insects. 2. Odonates (damselflies and dragonflies) provide excellent candidate species for evaluating demographic senescence as they are large enough to be marked individually and they are easily re-sighted without recapture. The prevailing opinion -based entirely on qualitative examination of the declines in log numbers alive with time since marking -is that odonates exhibit age-independent daily survivorship. 3. Here, we examine mark-recapture data on the Azure Damselfly Coenagrion puella over two consecutive seasons. For the first time, we evaluate and compare the fit of quantitative models that not only account for weather-dependent daily variation in daily re-sighting rates, but also age-dependent variation in daily survivorship. 4. Models with age-dependent declines in daily survivorship provide a more parsimonious explanation for the data than similar models without these age-dependent effects. In general, models in which mortality increases in an exponential (Gompertz) fashion explain the mark-recapture sequences more efficiently than a range of alternative models, including those in which mortality increases as a power function (Weibull) or reaches a plateau (logistic). These results are indicative of a general senescent decline in physiological functioning, which is particularly marked after 15 days as a mature adult. 5. Weather (temperature, sun and precipitation) and initial mite load influenced the probability of daily re-sighting. Weather and mite load also influenced daily survivorship, but their effects differed between seasons. 6. Overall, fitting models with age as an explicit covariate demonstrates that odonates do indeed senesce. This contradicts previously held assumptions that Odonata do not exhibit age-dependent survivorship in the wild.

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