Approaching the non-linear Shannon limit

We review the recent progress of information theory in optical communications, and describe the current experimental results and associated advances in various individual technologies which increase the information capacity. We confirm the widely held belief that the reported capacities are approaching the fundamental limits imposed by signal-to-noise ratio and the distributed non-linearity of conventional optical fibres, resulting in the reduction in the growth rate of communication capacity. We also discuss the techniques which are promising to increase and/or approach the information capacity limit

Training on a Lower Body Positive Pressure Treadmill With Body Weight Support does not Improve Aerobic Capacity

International Journal of Exercise Science 14(7): 829-839, 2021. This study examined the physiological changes resulting from training on a lower body positive pressure treadmill (LBPPT) at three different levels of body weight support (BWS). Thirty-three healthy college aged students (22.3 ± 3.1 years) completed the study. Participants performed a graded exercise test (GXT) to exhaustion and were placed into one of three experimental groups corresponding to 100%, 75%, and 50% of their normal BW. Participants trained at their experimental BW levels for eight-weeks. Training speed was monitored by heart rate (HR) and speed was adjusted to elicit approximately 60% of participant’s peak oxygen uptake (V̇O2peak) at normal BW prior to including body weight support (BWS). One-way analysis of variance (ANOVA) was used to compare the change in aerobic capacity. The 100% BW group improved their relative V̇O2peak (1.42 ± 1.52 ml · min-1 · kg-1) when compared to the 50% BW group (-0.87 ± 2.20 ml · min-1 · kg-1 [p = .022]) but not the 75% BW group (-0.16 ± 1.92 ml · min-1 · kg-1, [p = .14]). Furthermore, no statistical differences in V̇O2peak were observed between the 75% and 50% BW groups (p = .66). Based on this study, training at 75% and 50% of normal BW on a LBPPT does not improve aerobic capacity compared to training with no BWS when using training speeds derived from a GXT with full BW. The outcome of this study may help to prescribe training speeds while utilizing a LBPPT to maintain or improve aerobic capacity

A Comparison of Muscle Activation Among the Front Squat, Overhead Squat, Back Extension and Plank

International Journal of Exercise Science 13(1): 714-722, 2020. The purpose of this study was to compare the muscle activation of the scapula, leg, and trunk among the front squat (FS), overhead squat (OHS), back extension (BE) and plank (PL). Seven recreationally trained men (age: 28 ± 3.6 years, body mass: 92 ± 26.1 kg, height: 175 ± 5.3 cm, 3-RM front squat test: 125 ± 49.8 kg, 3-RM overhead squat test: 91 ± 15.5 kg) participated in this within-subject crossover design. Two isometric exercises (plank and Biering-Sorenson back extension) were also included for trunk musculature comparisons. Neuromuscular activitation of the vastus lateralis (VL), biceps femoris (BF), thoracic region of erector spinae (ES), middle trapezius (MT), rectus abdominis (RA), external oblique (EO), serratus anterior (SA), and anterior deltoid (AD). The neuromuscular activity of the FS and OHS were analyzed using a 2 X 3 (squat variation X intensity) repeated measures analysis of variance (ANOVA). Effects were further analyzed by Bonferroni corrected paired t-tests. Results showed that AD activity was significantly greater (p \u3c .05) during the FS compared to OHS at 65 and 95% of the 3-RM, while MT activity was significantly greater (p \u3c .05) during the OHS than the FS at 80 and 95% of the 3-RM. ES activity was significantly greater (p\u3c .05) during both the FS and OHS compared to the BE, but PL elicited significantly greater EO and RA activity than both the FS and OHS. These findings reveal that the FS and OHS can help facilitate the activation of muscles supporting the shoulder complex, scapula and lower back

Listeriolysin S, a Novel Peptide Haemolysin Associated with a Subset of Lineage I Listeria monocytogenes

peer-reviewedStreptolysin S (SLS) is a bacteriocin-like haemolytic and cytotoxic virulence factor that plays a key role in the virulence of Group A Streptococcus (GAS), the causative agent of pharyngitis, impetigo, necrotizing fasciitis and streptococcal toxic shock syndrome. Although it has long been thought that SLS and related peptides are produced by GAS and related streptococci only, there is evidence to suggest that a number of the most notorious Gram-positive pathogenic bacteria, including Listeria monocytogenes, Clostridium botulinum and Staphylococcus aureus, produce related peptides. The distribution of the L. monocytogenes cluster is particularly noteworthy in that it is found exclusively among a subset of lineage I strains; i.e., those responsible for the majority of outbreaks of listeriosis. Expression of these genes results in the production of a haemolytic and cytotoxic factor, designated Listeriolysin S, which contributes to virulence of the pathogen as assessed by murine- and human polymorphonuclear neutrophil–based studies. Thus, in the process of establishing the existence of an extended family of SLS-like modified virulence peptides (MVPs), the genetic basis for the enhanced virulence of a proportion of lineage I L. monocytogenes may have been revealed.Work is funded by the Irish Government under the National Development Plan, through a Science Foundation Ireland Investigator award to CH, PR and PC (06/IN.1/B98)

Consistent Point Data Assimilation in Firedrake and Icepack

We present methods and tools that significantly improve the ability to estimate quantities and fields which are difficult to directly measure, such as the fluidity of ice, using point data sources, such as satellite altimetry. These work with both sparse and dense point data with estimated quantities and fields becoming more accurate as the number of measurements are increased. Such quantities and fields are often used as inputs to mathematical models that are used to make predictions so improving their accuracy is of vital importance. We demonstrate how our methods and tools can increase the accuracy of results, ensure posterior consistency, and aid discourse between modellers and experimenters. To do this, we bring point data into the finite element method ecosystem as discontinuous fields on meshes of disconnected vertices. Point evaluation can then be formulated as a finite element interpolation operation (dual-evaluation). Our new abstractions are well-suited to automation. We demonstrate this by implementing them in Firedrake, which generates highly optimised code for solving PDEs with the finite element method. Our solution integrates with dolfin-adjoint/pyadjoint which allows PDE-constrained optimisation problems, such as data assimilation, to be solved through forward and adjoint mode automatic differentiation. We demonstrate our new functionality through examples in the fields of groundwater hydrology and glaciology

Comparing placentas from normal and abnormal pregnancies

This report describes work carried out at a Mathematics-in-Medicine Study Group. It is believed that placenta shape villous network characteristics are strongly linked to the placenta’s efficiency, and hence to pregnancy outcome. We were asked to consider mathematical ways to describe the shape and other characteristics of a placenta, as well as forming mathematical models for placenta development. In this report we propose a number of possible measure of placental shape, form, and efficiency, which can be computed from images already obtained. We also consider various models for the early development of placentas and the growth of the villous tree

Editorial:Cross adaptation and cross tolerance in human health and disease

Human physiological responses to heat, cold, hypoxia, microgravity, hyperbaria, hypobaria and fasting are well studied in isolation. However, in the natural world these stressors are often combined or experienced sequentially (Tipton, 2012). Studies examining human responses to these more realistic, yet relatively complex, circumstances remain sparse, but could provide important insights into an emerging area within human physiology: cross-adaptation (Figure 1)(Lunt et al., 2010; Gibson et al., 2017). Much of the current state of knowledge involves data demonstrating benefits of exercising in hot conditions, prior to performance in hypoxia (Gibson et al., 2015; Heled et al., 2012; Lee et al., 2014a, 2014b, 2016; Salgado et al., 2017; White et al., 2016), with cold to hypoxia (Lunt et al., 2010), hypoxia to heat (Sotiridis et al., 2018), combined stressors (Neal et al., 2017; Takeno et al., 2001), and more mechanistic (signalling) data from animal models exposed to substantive volumes of stress (Maloyan & Horowitz, 2002, 2005). The role of nutrient availability and the nutrient-exercise interactions which drive phenotypic adaptations to skeletal muscle exposed to a multitude of stressors is also a growing field of interest (Hawley, Lundby, Cotter, & Burke, 2018). This research topic includes publications which address both clinical and exercise-centric aspects allied to Cross-adaptation and Cross-tolerance in Human Health and Disease

Proteomic analysis of the postsynaptic density implicates synaptic function and energy pathways in bipolar disorder.

The postsynaptic density (PSD) contains a complex set of proteins of known relevance to neuropsychiatric disorders such as schizophrenia and bipolar disorder. We enriched for this anatomical structure in the anterior cingulate cortex of 16 bipolar disorder samples and 20 controls from the Stanley Medical Research Institute. Unbiased shotgun proteomics incorporating label-free quantitation was used to identify differentially expressed proteins. Quantitative investigation of the PSD identified 2033 proteins, among which 288 were found to be differentially expressed. Validation of expression changes of DNM1, DTNA, NDUFV2, SEPT11 and SSBP was performed by western blotting. Bioinformatics analysis of the differentially expressed proteins implicated metabolic pathways including mitochondrial function, the tricarboxylic acid cycle, oxidative phosphorylation, protein translation and calcium signaling. The data implicate PSD-associated proteins, and specifically mitochondrial function in bipolar disorder. They relate synaptic function in bipolar disorder and the energy pathways that underpin it. Overall, our findings add to a growing literature linking the PSD and mitochondrial function in psychiatric disorders generally, and suggest that mitochondrial function associated with the PSD is particularly important in bipolar disorder

Barley Hv CIRCADIAN CLOCK ASSOCIATED 1 and Hv PHOTOPERIOD H1 Are Circadian Regulators That Can Affect Circadian Rhythms in Arabidopsis.

Circadian clocks regulate many aspects of plant physiology and development that contribute to essential agronomic traits. Circadian clocks contain transcriptional feedback loops that are thought to generate circadian timing. There is considerable similarity in the genes that comprise the transcriptional and translational feedback loops of the circadian clock in the plant Kingdom. Functional characterisation of circadian clock genes has been restricted to a few model species. Here we provide a functional characterisation of the Hordeum vulgare (barley) circadian clock genes Hv circadian clock associated 1 (HvCCA1) and Hv photoperiodh1, which are respectively most similar to Arabidopsis thaliana circadian clock associated 1 (AtCCA1) and pseudo response regulator 7 (AtPRR7). This provides insight into the circadian regulation of one of the major crop species of Northern Europe. Through a combination of physiological assays of circadian rhythms in barley and heterologous expression in wild type and mutant strains of A. thaliana we demonstrate that HvCCA1 has a conserved function to AtCCA1. We find that Hv photoperiod H1 has AtPRR7-like functionality in A. thaliana and that the effects of the Hv photoperiod h1 mutation on photoperiodism and circadian rhythms are genetically separable.ZR is grateful to the National Institute of Agricultural Botany for the Award of Scholarship. We acknowledge funding from a Marie Curie Early Stage Training project MEST-CT-2005-020526 for JK and the BBSRC-DTP for funding SC. AARW and MCM are grateful to the BBSRC for the award of BBSRC Grant BB/M006212/1, which supported aspects of the study.This is the final published version. It first appeared at http://dx.doi.org/10.1371/journal.pone.012744