Critical Kauffman networks under deterministic asynchronous update

We investigate the influence of a deterministic but non-synchronous update on Random Boolean Networks, with a focus on critical networks. Knowing that ``relevant components'' determine the number and length of attractors, we focus on such relevant components and calculate how the length and number of attractors on these components are modified by delays at one or more nodes. The main findings are that attractors decrease in number when there are more delays, and that periods may become very long when delays are not integer multiples of the basic update step.Comment: 8 pages, 3 figures, submitted to a journa

Murine startle mutant Nmf11 affects the structural stability of the glycine receptor and increases deactivation

Dysfunctional glycinergic inhibitory transmission underlies the debilitating neurological condition, hyperekplexia, which is characterised by exaggerated startle reflexes, muscle hypertonia and apnoea. Here we investigated the N46K missense mutation in the GlyR α1 subunit gene found in the ethylnitrosourea (ENU) murine mutant, Nmf11, which causes reduced body size, evoked tremor, seizures, muscle stiffness, and morbidity by postnatal day 21. Introducing the N46K mutation into recombinant GlyR α1 homomeric receptors, expressed in HEK cells, reduced the potencies of glycine, β-alanine and taurine by 9-, 6- and 3-fold respectively, and that of the competitive antagonist strychnine by 15-fold. Replacing N46 with hydrophobic, charged or polar residues revealed that the amide moiety of asparagine was crucial for GlyR activation. Co-mutating N61, located on a neighbouring β loop to N46, rescued the wild-type phenotype depending on the amino acid charge. Single-channel recording identified that burst length for the N46K mutant was reduced and fast agonist application revealed faster glycine deactivation times for the N46K mutant compared with the WT receptor. Overall, these data are consistent with N46 ensuring correct alignment of the α1 subunit interface by interaction with juxtaposed residues to preserve the structural integrity of the glycine binding site. This represents a new mechanism by which GlyR dysfunction induces startle disease

BKM Lie superalgebra for the Z_5 orbifolded CHL string

We study the Z_5-orbifolding of the CHL string theory by explicitly constructing the modular form tilde{Phi}_2 generating the degeneracies of the 1/4-BPS states in the theory. Since the additive seed for the sum form is a weak Jacobi form in this case, a mismatch is found between the modular forms generated from the additive lift and the product form derived from threshold corrections. We also construct the BKM Lie superalgebra, tilde{G}_5, corresponding to the modular form tilde{Delta}_1 (Z) = tilde{Phi}_2 (Z)^{1/2} which happens to be a hyperbolic algebra. This is the first occurrence of a hyperbolic BKM Lie superalgebra. We also study the walls of marginal stability of this theory in detail, and extend the arithmetic structure found by Cheng and Dabholkar for the N=1,2,3 orbifoldings to the N=4,5 and 6 models, all of which have an infinite number of walls in the fundamental domain. We find that analogous to the Stern-Brocot tree, which generated the intercepts of the walls on the real line, the intercepts for the N >3 cases are generated by linear recurrence relations. Using the correspondence between the walls of marginal stability and the walls of the Weyl chamber of the corresponding BKM Lie superalgebra, we propose the Cartan matrices for the BKM Lie superalgebras corresponding to the N=5 and 6 models.Comment: 30 pages, 2 figure

Wood mitigates the effect of hydropeaking scour on periphyton biomass and nutritional quality in semi-natural flume simulations

The daily fluctuating discharge from hydroelectric power plants, known as hydropeaking, has been shown to cause catastrophic drift in aquatic insect communities and limit secondary production, but relatively little attention has been given to its effects on periphyton, an important food resource for consumers. We simulated daily 5-h hydropeaking events over the course of 5 days in spring and summer in an open air, experimental flume system fed by a pristine 2nd order stream in the Italian Alps. We hypothesized that hydropeaking would suppress periphyton biomass and especially nutritional quality (i.e., fatty acid content). Hydropeaking resulted in decreased periphyton Chl-a and AFDM on tiles, but there was no corresponding loss on wood. Hydropeaking did not alter periphyton elemental nutrient stoichiometry but led to a disproportionate loss of periphyton fatty acid content on both substrates. Ordination of overall fatty acid profiles indicated different periphyton fatty acid profiles by substrate and a shift from physiologically important highly-unsaturated fatty acids to non-essential saturated fatty acids after hydropeaking. These results suggest that hydropeaking may have the potential to depress primary biomass and nutritional quality in downstream ecosystems, and that availability of wood substrate may mitigate part, but not all, of this effect. Since food nutritional quality, especially fatty acid content, has been suggested to be a limiting resource on production in aquatic systems, this may generate an indirect and potentially overlooked limiting effect on aquatic consumers in hydropeaking-impacted alpine rivers

Are there gender differences in acute management and secondary prevention of acute coronary syndromes in Barbados? A cohort study.

OBJECTIVES: In Barbados, high case fatality rates have been reported after myocardial infarction (MI) with higher rates in women than men. To explore this inequality, we examined documented pharmacological interventions for ST-segment elevated myocardial infarction (STEMI), non-STEMI (NSTEMI) and unstable and chronic angina in women and men. DESIGN: Prospective cohort registry data for STEMI and NSTEMI and retrospective chart review for unstable and chronic angina. SETTING: Tertiary care (acute coronary syndromes) and primary care (chronic angina) centres in Barbados. PARTICIPANTS: For the years 2009-2016, a total of 1018 patients with STEMI or NSTEMI were identified via the prospective study. For unstable and chronic angina, 136 and 272 notes were reviewed respectively for the years 2010-2014. OUTCOME MEASURES: The proportions of patients prescribed recommended medication during the first 24 hours after an acute event, at discharge and for chronic care were calculated. Prescribed proportions were analysed by gender after adjustment for age. RESULTS: Between 2009 and 2016, for the acute management of patients with NSTEMI and STEMI, only two (aspirin and clopidogrel) of six drugs had documented prescription rates of 80% or more. Patients with STEMI (n=552) had higher prescription rates than NSTEMI (n=466), with gender differences being more pronounced in the former. Among patients with STEMI, after adjustment for age, diabetes, hypertension and smoking, men were more likely to receive fibrinolytics acutely, OR 2.28 (95% CI 1.24 to 4.21). Compared with men, a higher proportion of women were discharged on all recommended treatments; this was only statistically significant for beta-blockers: age-adjusted OR 1.87 (95% CI 1.16 to 3.00). There were no statistically significant differences in documented prescription of drugs for chronic angina. CONCLUSION: Following acute MI in Barbados, the proportion of patients with documented recommended treatment is relatively low. Although women were less likely to receive appropriate acute care than men, by discharge gender differences were reversed

Survey of the needs of patients with spinal cord injury: impact and priority for improvement in hand function in tetraplegics\ud

Objective: To investigate the impact of upper extremity deficit in subjects with tetraplegia.\ud \ud Setting: The United Kingdom and The Netherlands.\ud \ud Study design: Survey among the members of the Dutch and UK Spinal Cord Injury (SCI) Associations.\ud \ud Main outcome parameter: Indication of expected improvement in quality of life (QOL) on a 5-point scale in relation to improvement in hand function and seven other SCI-related impairments.\ud \ud Results: In all, 565 subjects with tetraplegia returned the questionnaire (overall response of 42%). Results in the Dutch and the UK group were comparable. A total of 77% of the tetraplegics expected an important or very important improvement in QOL if their hand function improved. This is comparable to their expectations with regard to improvement in bladder and bowel function. All other items were scored lower.\ud \ud Conclusion: This is the first study in which the impact of upper extremity impairment has been assessed in a large sample of tetraplegic subjects and compared to other SCI-related impairments that have a major impact on the life of subjects with SCI. The present study indicates a high impact as well as a high priority for improvement in hand function in tetraplegics.\ud \u

First Fruits of the Spitzer Space Telescope: Galactic and Solar System Studies

This article provides a brief overview of the Spitzer Space Telescope and discusses its initial scientific results on galactic and solar system science.Comment: Review article to appear in slightly different format in Vol.44 of Annual Reviews of Astronomy and Astrophysics, 200

Two New Nova Shells associated with V4362 Sagittarii and DO Aquilae

A classical nova is an eruption on the surface of a white dwarf in an accreting binary system. The material ejected from the white dwarf surface generally forms an axisymmetric shell. The shaping mechanisms of nova shells are probes of the processes that take place at energy scales between planetary nebulae and supernova remnants. We report on the discovery of nova shells surrounding the post-nova systems V4362 Sagittarii (1994) and more limited observations of DO Aquilae (1925). Distance measurements of 0.5p/m1.4 kpc for V4362 Sgr and 6.7 p/m 3.5 kpc -0.2 for DO Aql are found based on the expansion parallax method. The growth rates are measured to be 0.07``/year for DO Aql and 0.32``/year for V4362 Sgr. A preliminary investigation into the ionisation structure of the nova shell associated with V4362 Sgr is presented. The observed ionisation structure of nova shells depends strongly on their morphology and the orientation of the central component towards the observer. X-ray, IR and UV observations as well as optical integral field unit spectroscopy are required to better understand these interesting objects

Effects of intermediate scales on renormalization group running of fermion observables in an SO(10) model

In the context of non-supersymmetric SO(10) models, we analyze the renormalization group equations for the fermions (including neutrinos) from the GUT energy scale down to the electroweak energy scale, explicitly taking into account the effects of an intermediate energy scale induced by a Pati--Salam gauge group. To determine the renormalization group running, we use a numerical minimization procedure based on a nested sampling algorithm that randomly generates the values of 19 model parameters at the GUT scale, evolves them, and finally constructs the values of the physical observables and compares them to the existing experimental data at the electroweak scale. We show that the evolved fermion masses and mixings present sizable deviations from the values obtained without including the effects of the intermediate scale.Comment: Comments: 20 pages, 3 figures. Final version published in JHE

Subitizing with Variational Autoencoders

Numerosity, the number of objects in a set, is a basic property of a given visual scene. Many animals develop the perceptual ability to subitize: the near-instantaneous identification of the numerosity in small sets of visual items. In computer vision, it has been shown that numerosity emerges as a statistical property in neural networks during unsupervised learning from simple synthetic images. In this work, we focus on more complex natural images using unsupervised hierarchical neural networks. Specifically, we show that variational autoencoders are able to spontaneously perform subitizing after training without supervision on a large amount images from the Salient Object Subitizing dataset. While our method is unable to outperform supervised convolutional networks for subitizing, we observe that the networks learn to encode numerosity as basic visual property. Moreover, we find that the learned representations are likely invariant to object area; an observation in alignment with studies on biological neural networks in cognitive neuroscience