Automatic Construction of Predictive Neuron Models through Large Scale Assimilation of Electrophysiological Data.

We report on the construction of neuron models by assimilating electrophysiological data with large-scale constrained nonlinear optimization. The method implements interior point line parameter search to determine parameters from the responses to intracellular current injections of zebra finch HVC neurons. We incorporated these parameters into a nine ionic channel conductance model to obtain completed models which we then use to predict the state of the neuron under arbitrary current stimulation. Each model was validated by successfully predicting the dynamics of the membrane potential induced by 20-50 different current protocols. The dispersion of parameters extracted from different assimilation windows was studied. Differences in constraints from current protocols, stochastic variability in neuron output, and noise behave as a residual temperature which broadens the global minimum of the objective function to an ellipsoid domain whose principal axes follow an exponentially decaying distribution. The maximum likelihood expectation of extracted parameters was found to provide an excellent approximation of the global minimum and yields highly consistent kinetics for both neurons studied. Large scale assimilation absorbs the intrinsic variability of electrophysiological data over wide assimilation windows. It builds models in an automatic manner treating all data as equal quantities and requiring minimal additional insight

Computing NodeTrix Representations of Clustered Graphs

NodeTrix representations are a popular way to visualize clustered graphs; they represent clusters as adjacency matrices and inter-cluster edges as curves connecting the matrix boundaries. We study the complexity of constructing NodeTrix representations focusing on planarity testing problems, and we show several NP-completeness results and some polynomial-time algorithms. Building on such algorithms we develop a JavaScript library for NodeTrix representations aimed at reducing the crossings between edges incident to the same matrix.Comment: Appears in the Proceedings of the 24th International Symposium on Graph Drawing and Network Visualization (GD 2016

A new class of Matrix Models arising from the W-infinity Algebra

We present a new class of hermitian one-matrix models originated in the W-infinity algebra: more precisely, the polynomials defining the W-infinity generators in their fermionic bilinear form are shown to expand the orthogonal basis of a class of random hermitian matrix models. The corresponding potentials are given, and the thermodynamic limit interpreted in terms of a simple plasma picture. The new matrix models can be successfully applied to the full bosonization of interesting one-dimensional systems, including all the perturbative orders in the inverse size of the system. As a simple application, we present the all-order bosonization of the free fermionic field on the one-dimensional lattice.Comment: 8 pages, 1 figur

Oral glucose tolerance test and continuous glucose monitoring for gestational diabetes diagnosis: a survey study of women and health care professionals

Aims: The oral glucose tolerance test (OGTT), used for gestational diabetes mellitus (GDM) diagnosis for over 65 years, has poor acceptability and tolerability. Continuous glucose monitoring is being considered as potential alternative. The aim of our study was to formally assess women’s and health care professionals’ perception of both tests as diagnostic tools for GDM. Methods: Participants in a pilot study on continuous glucose monitoring for GDM diagnosis were invited to fill two questionnaires, each of 6 Likert-scale and one optional open-ended question. A range of healthcare practitioners were also invited to fill a questionnaire of 13 Likert-scale and 7 optional open-ended questions. Results: Sixty women completed the OGTT and 70 the continuous glucose monitoring questionnaire. OGTT was reported as poorly acceptable. Continuous glucose monitoring was described as significantly more tolerable (81% vs 27% 5/5 general acceptability rate, p < 0.001); ninety-three percent of the participants would recommend it for GDM diagnosis. Thirty health care professionals completed the survey. Most of them (73%) had confidence in OGTT as a diagnostic test for GDM with 66% raising some concerns. Doubts on continuous glucose monitoring were raised in terms of costs, accessibility and accuracy for GDM diagnosis due to “lack of evidence”. Conclusions: Continuous glucose monitoring was substantially better tolerated for women than OGTT. Current lack of evidence for diagnostic accuracy for GDM underlines the need for studies on correlation between continuous glucose monitoring parameters and pregnancy outcomes to strengthen evidence for its use as diagnostic test for GDM

Fetal abdominal wall defects in an Australian tertiary setting: contemporary characteristics, ultrasound accuracy, and outcome

Purpose: In this study, we aimed to comprehensively evaluate risk factors, ultrasound estimation of fetal weight, prenatal management, and pregnancy outcomes of gastroschisis and omphalocele at a metropolitan Australian hospital. Material and methods: This was a retrospective single-center cohort study from 2006 to 2014 at a tertiary hospital with colocated neonatal surgical facilities. Demographic, pregnancy, ultrasound, birth and neonatal data were compared between gastroschisis and omphalocele. Correlation between routine (Hadlock 1 &2) and specific (Siemer) estimated fetal weight (EFW) estimation formulae with birth weight (BW) was made for those 50 gastroschisis cases with ≥2 third trimester scans and last scan ≤2 weeks prior to birth. Results: There were 126 abdominal wall defects: 83 gastroschisis and 43 omphalocele. Consistent with international literature, the average maternal age was lower for gastroschisis and rates of smoking higher, while there were more intrauterine deaths and pregnancy terminations in omphalocele. Gastroschisis mothers were more likely living outside Sydney, had more infections in pregnancy and were followed with a larger number of antenatal visits, with a shorter period from the last visit to birth. In omphalocele pregnancies, amniocentesis was more likely performed, with more abnormal results than in gastroschisis fetuses. All EFW formulae had a good correlation between Z score for the last US and actual BW (ICC 0.693–0.815), with Hadlock 2 being the best. Siemer formula had the best correlation from first to the last scan. Gastroschisis newborns were born earlier (36.8 versus 38.2 wks p =.001), with smaller birthweight (2.52 versus 3.03 kg, p <.001), a longer request of intensive care (central line, parenteral nutrition, intubation) and second surgery, along with more multisystem complications (average 1.5 versus 0.7, p =.004) and a longer hospital stay (58.8 versus 36.8 d, p <.001). Conclusion: Demographic, antenatal, and pregnancy outcome data for abdominal wall defects correlated well with the international literature. Hadlock 1–2 gave the most consistent EFW estimate, with all formulae showing good correlation

Aldebaran's angular diameter: how well do we know it?

The bright, well-known K5 giant Aldebaran, alpha Tau, is probably the star with the largest number of direct angular diameter determinations, achieved over a long time by several authors using various techniques. In spite of this wealth of data, or perhaps as a direct result of it, there is not a very good agreement on a single angular diameter value. This is particularly unsettling if one considers that Aldebaran is also used as a primary calibrator for some angular resolution methods, notably for optical and infrared long baseline interferometry. Directly connected to Aldebaran's angular diameter and its uncertainties is its effective temperature, which also has been used for several empirical calibrations. Among the proposed explanations for the elusiveness of an accurate determination of the angular diameter of Aldebaran are the possibility of temporal variations as well as a possible dependence of the angular diameter on the wavelength. We present here a few, very accurate new determinations obtained by means of lunar occultations and long baseline interferometry. We derive an average value of 19.96+-0.03 milliarcseconds for the uniform disk diameter. The corresponding limb-darkened value is 20.58+-0.03 milliarcseconds, or 44.2+-0.9 R(sun). We discuss this result, in connection with previous determinations and with possible problems that may affect such measurements.Comment: 8 pages, 4 figures, accepted for publication in A&

Regional Transport – a supply chain mapping exercise and Brexit exposure check of automotive, aerospace and rail value dependency in the WMCA region

This report presents the findings and key policy recommendations of a combined supply chain mapping exercise and Brexit exposure check of the transport manufacturing sector in the Midlands,funded by the West Midlands Combined Authority. These sectors consisted of automotive, rail and aerospace manufacturers and suppliers, for which 234 firms were surveyed between November 2019 and January 2020. Of these, 25 were exclusively involved in aerospace manufacture; 59 were exclusively involved in automotive manufacture; 3 were exclusively involved in non-auto road vehicles; 32 were exclusively involved in rail manufacture; 27 were mixed manufacturers and; 87 were freight/logistics firms. Key aspects examined in the mapping exercise included: value of automotive businesses in the West Midlands split by vehicle company clients and local authorities; divisions between tiers one and two, and logistics and suppliers, employment mix (UK/EU), major challenges faced by supply chain e.g.transport infrastructure and paperwork; import/export ratios, transport route dependency, and ‘Brexit readiness’

L-Drawings of Directed Graphs

We introduce L-drawings, a novel paradigm for representing directed graphs aiming at combining the readability features of orthogonal drawings with the expressive power of matrix representations. In an L-drawing, vertices have exclusive $x$- and $y$-coordinates and edges consist of two segments, one exiting the source vertically and one entering the destination horizontally. We study the problem of computing L-drawings using minimum ink. We prove its NP-completeness and provide a heuristics based on a polynomial-time algorithm that adds a vertex to a drawing using the minimum additional ink. We performed an experimental analysis of the heuristics which confirms its effectiveness.Comment: 11 pages, 7 figure