Randomly Evolving Idiotypic Networks: Structural Properties and Architecture

We consider a minimalistic dynamic model of the idiotypic network of B-lymphocytes. A network node represents a population of B-lymphocytes of the same specificity (idiotype), which is encoded by a bitstring. The links of the network connect nodes with complementary and nearly complementary bitstrings, allowing for a few mismatches. A node is occupied if a lymphocyte clone of the corresponding idiotype exists, otherwise it is empty. There is a continuous influx of new B-lymphocytes of random idiotype from the bone marrow. B-lymphocytes are stimulated by cross-linking their receptors with complementary structures. If there are too many complementary structures, steric hindrance prevents cross-linking. Stimulated cells proliferate and secrete antibodies of the same idiotype as their receptors, unstimulated lymphocytes die. Depending on few parameters, the autonomous system evolves randomly towards patterns of highly organized architecture, where the nodes can be classified into groups according to their statistical properties. We observe and describe analytically the building principles of these patterns, which allow to calculate number and size of the node groups and the number of links between them. The architecture of all patterns observed so far in simulations can be explained this way. A tool for real-time pattern identification is proposed.Comment: 19 pages, 15 figures, 4 table

Enhancing Critical Thinking Across The Undergraduate Experience: An Exemplar From Engineering

Faculty in a large, urban school of engineering designed a longitudinal study to assess the critical thinking skills of undergraduate students as they progressed through the engineering program. The Paul-Elder critical thinking framework was used to design course assignments and develop a holistic assessment rubric. The curriculum was re-designed to include deliberate teaching of critical thinking and assessment in at least one key course for every student each year of their undergraduate curriculum. The critical thinking scores for seniors using the holistic rubric were significantly higher than their baseline critical thinking scores as freshmen (p = .004). This case-study can serve as an exemplar for other units, departments, or programs to model or replicate

Critical Thinking Development In Undergraduate Engineering Students From Freshman Through Senior Year: A 3-Cohort Longitudinal Study

Critical thinking is considered a necessary learning outcome for all college students and essential for academic and career success.  There are many challenges to developing a comprehensive approach to teaching and assessing critical thinking skills. Although the literature has many examples of the incorporation of critical thinking and assessment into courses, longitudinal studies following engineering students through their undergraduate career are lacking.  This study assessed the impact of using the Paul-Elder Critical Thinking Framework to enhance undergraduate students’ critical thinking skills with the hypothesis: There will be a significant increase in undergraduate students’ critical thinking abilities from the freshman to the senior year with the explicit and strategic incorporation of critical thinking assignments. The research question was, “How do the critical thinking skills of undergraduate engineering students change as they progress through the engineering program with the explicit and strategic incorporation of critical thinking assignments?” The study was a descriptive, longitudinal study of three engineering student cohorts as they progressed through the four year undergraduate program. The study was approved by the university’s Institutional Review Board. There was a statistically significant increase in critical thinking scores over the four years for each of the three cohorts. Integrating and evaluating critical thinking assignments into engineering curricula is possible, but a major challenge to critical thinking assessment using a holistic rubric is training engineering faculty in their use.  The results are encouraging, and participating faculty agree; but sustaining these efforts to imbed critical thinking assignments throughout the engineering college curriculum will require effort and administrative support

A Schanuel property for exponentially transcendental powers

We prove the analogue of Schanuel's conjecture for raising to the power of an exponentially transcendental real number. All but countably many real numbers are exponentially transcendental. We also give a more general result for several powers in a context which encompasses the complex case.Comment: 5 page

Localization dynamics in a binary two-dimensional cellular automaton: the Diffusion Rule

We study a two-dimensional cellular automaton (CA), called Diffusion Rule (DR), which exhibits diffusion-like dynamics of propagating patterns. In computational experiments we discover a wide range of mobile and stationary localizations (gliders, oscillators, glider guns, puffer trains, etc), analyze spatio-temporal dynamics of collisions between localizations, and discuss possible applications in unconventional computing.Comment: Accepted to Journal of Cellular Automat

A Two-Player Game of Life

We present a new extension of Conway's game of life for two players, which we call p2life. P2life allows one of two types of token, black or white, to inhabit a cell, and adds competitive elements into the birth and survival rules of the original game. We solve the mean-field equation for p2life and determine by simulation that the asymptotic density of p2life approaches 0.0362.Comment: 7 pages, 3 figure

The influence of comorbidities on the treatment outcome in symptomatic lumbar spinal stenosis: A systematic review and meta-analysis

Background Lumbar spinal stenosis (LSS) affects mainly elderly patients. To this day, it is unclear whether comorbidities influence treatment success. The aim of this systematic review and meta-analysis was to assess the impact of comorbidities on the treatment effectiveness in symptomatic LSS. Methods We conducted a systematic review and meta-analysis and reviewed prospective or retrospective studies from Medline, Embase, Cochrane Library and CINAHL from inception to May 2020, including adult patients with LSS undergoing surgical or conservative treatment. Main outcomes were satisfaction, functional and symptoms improvement, and adverse events (AE). Proportions of outcomes within two subgroups of a comorbidity were compared with risk ratio (RR) as summary measure. Availability of ≥3 studies for the same subgroup and outcome was required for meta-analysis. Results Of 72 publications, 51 studies, mostly assessing surgery, there was no evidence reported that patients with comorbidities were less satisfied compared to patients without comorbidities (RR 1.06, 95% confidence interval (CI) 0.77 to 1.45, 94%), but they had an increased risk for AE (RR 1.46, 95% CI 1.06 to 2.01, 72%). A limited number of studies found no influence of comorbidities on functional and symptoms improvement. Older age did not affect satisfaction, symptoms and functional improvement, and AE (age >80 years RR 1.22, 95% CI 0.98 to 1.52, 60%). Diabetes was associated with more AE (RR 1.72, 95% CI 1.19 to 2.47, 58%). Conclusion In patients with LSS and comorbidities (in particular diabetes), a higher risk for AE should be considered in the treatment decision. Older age alone was not associated with an increased risk for AE, less functional and symptoms improvement, and less treatment satisfaction

Correção e adubação do solo para a cultura da soja ( Glycine max) em um latosol roxo distrófico

A field experiment was conducted on Erexim soil at Chapecó, Santa Catarina, Brazil, in 1970, to study the effects of liming and fertilizers on soybean (Glycine max (L.) Merril). No significance was registered for nitrogen, or potassium, in soybean yield. Doses of dolomitic calcareous, or P2O5 applied seperately, gave significantly response than when both were applied in combination. The technic critical level of phosphorus in soil was estimated at 10.0 ppm of P, obtained by applying 246 kg/ha as P2O5. This fertilizer P applied in combination with 6.6 t/ha liming correction (1/2 SMP) produced 3,098 kg/ha of soybean. The economic critical level was estimated at 6.4 ppm of P, obtained by applying 116 kg/ha of P2O5, producing 2,750 kg/ha of soybean. The average percentage of the applied phosphorus remaining available in soil after P fertilization was 12.8%, where as for K was 42.2%, measured by the North Caroline method.Em experimento instalado sobre solo Latosol Roxo Distrófico, unidade de mapeamento Erexim, em Chapecó, SC, em 1970, foram determinados os efeitos da correção do solo e da adubação sobre o rendimento da soja (Glycine max (L.) Merril, var. Bienville. Foi constatado não haver efeitos significativos com a adição de nitrogênio, ou potássio, sobre o rendimento da soja. Doses de calcário dolomítico, ou P2O5, aplicadas isoladamente diferiram significativamente dos melhores rendimentos obtidos com as combinações de ambos. O nível crítico técnico de fósforo no solo foi estimado em 10,0 ppm de P, ao qual correspondem a aplicação de 246 kg/ha de P2O5 e o rendimento do soja de 3.098 kg/ha, ao nível de correção do solo de 6,6 t/ha de calcário dolomítico (1/2 SMP pH 6,5). Estimou-se o nível crítico econômico de fósforo em 6,4 ppm de P, ao qual correspondem a aplicação de 116 kg/ha de P2O5 e o rendimento de soja de 2.750 kg/ha. As percentagens médias de aparecimento de ppm de P e K no solo, determinadas pelo método de análise de Carolina do Norte, foram de 12,8% e de 42,2%,  respectivamente

Extrasolar Planet Transits Observed at Kitt Peak National Observatory

We obtained J-, H- and JH-band photometry of known extrasolar planet transiting systems at the 2.1-m Kitt Peak National Observatory Telescope using the FLAMINGOS infrared camera between October 2008 and October 2011. From the derived lightcurves we have extracted the mid-transit times, transit depths and transit durations for these events. The precise mid-transit times obtained help improve the orbital periods and also constrain transit-time variations of the systems. For most cases the published system parameters successfully accounted for our observed lightcurves, but in some instances we derive improved planetary radii and orbital periods. We complemented our 2.1-m infrared observations using CCD z'-band and B-band photometry (plus two Hydrogen Alpha filter observations) obtained with the Kitt Peak Visitor's Center telescope, and with four H-band transits observed in October 2007 with the NSO's 1.6-m McMath-Pierce Solar Telescope. The principal highlights of our results are: 1) our ensemble of J-band planetary radii agree with optical radii, with the best-fit relation being: (Rp/R*)J = 0.0017 + 0.979 (Rp/R*)optical, 2) We observe star spot crossings during the transit of WASP-11/HAT-P-10, 3) we detect star spot crossings by HAT-P-11b (Kepler-3b), thus confirming that the magnetic evolution of the stellar active regions can be monitored even after the Kepler mission has ended, and 4) we confirm a grazing transit for HAT-P-27/WASP-40. In total we present 57 individual transits of 32 known exoplanet systems.Comment: 33 pages, 6 figures, accepted in Publications of the Astronomical Society of the Pacifi