New algorithm for the computation of the partition function for the Ising model on a square lattice

A new and efficient algorithm is presented for the calculation of the partition function in the $S=\pm 1$ Ising model. As an example, we use the algorithm to obtain the thermal dependence of the magnetic spin susceptibility of an Ising antiferromagnet for a $8\times 8$ square lattice with open boundary conditions. The results agree qualitatively with the prediction of the Monte Carlo simulations and with experimental data and they are better than the mean field approach results. For the $8\times 8$ lattice, the algorithm reduces the computation time by nine orders of magnitude.Comment: 7 pages, 3 figures, to appear in Int. J. Mod. Phys.

Evaluation of load capacity of concrete railway slab spans with defects

Tese de Doutoramento - Área do Conhecimento em EstruturasThis study presents a complete methodology for the load capacity assessment of existing damaged railway slab spans made of reinforced concrete. The databases of the Polish (PKP) and Portuguese (REFER) railway infrastructure administrations are analysed. Furthermore, a study on the reports of international scientific projects i.e. “Sustainable Bridges” and “SAMCO” have lead to a conclusion that from among existing railway bridge stock, simply supported spans are the most common form of construction. Moreover, the spans carrying single tracks dominate in this group. The statistical information based on these sources has been presented in this study. Based on the Author’s observations, consultations with bridge inspectors as well as the literature study, a uniform and multi-level classification system of bridge defects has been presented. This system reflects all the defects that may occur during a bridges service life. Their influence on the load capacity is emphasized. To evaluate the load capacity of damaged structure information on defect parameters is essential. For this reason the Author presented a survey of testing methods to be applied in bridge condition appraisal. To explain the nature of defects in terms of their causes, the taxonomy of degradation mechanisms, leading to these defects, is presented as well. The defects considered in this study have also been presented in terms of their modelling using of various geometry models. The conception of a numerical defect modelling by means of three parameters (i.e. intensity, location and extent) is included. Conclusions following from the statistical survey on the railway bridge stock have induced the Author to analyse the possibility of application of a simplified geometry model of a span – simply supported beam. In order to compare results of the load capacity assessment several numerical analyses have been performed. The range of application of the simplified span model has been established by means of a 5% threshold of difference between results obtained by the considered models. To perform effective analyses of the load capacity of an existing span, the Author created and presented his own program called “Damage Assessment Graphic Analyser” (DAGA). By means of a built-in graphic editor this program allows visualizations in a three dimensional space of a span with defects in the concrete and reinforcing steel, i.e. losses of material and material parameters modifications. This tool automatically performs the static-strength analysis and results, presented as envelopes of cross-section load capacity (for designed as well as current condition – with defects) and bending moments for various load classes. Using the DAGA program a set of parametric analyses (static-strength) has been carried out. Their results have been collected in a knowledge base to be implemented in an expert tool, called ANAlisys of CONcrete DAmages (ANACONDA) based on the hybrid network technology with analytical and neural components incorporated, designed by the Author. At the end of this Thesis the conclusions and directions of further investigation can be found.A presente tese apresenta uma metodologia avançada para a análise / avaliação da capacidade resistente de pontes ferroviárias com tabuleiro em laje de betão. A análise das bases de dados das administrações ferroviárias polaca (PKP) e portuguesa (REFER), para além do estudo de relatórios recentes de projectos científicos internacionais, tais como exemplo os projectos " Sustainable Bridges" e "SAMCO", permitiram concluir que das pontes ferroviárias existentes a maioria corresponde a soluções simplesmente apoiadas. Entre estas as pontes com via única são claramente o tipo dominante. Neste estudo é apresentada toda a informação estatística dos dados coligidos nessas fontes. Tendo por base as observações do autor, as consultas aos inspectores de pontes, assim como o estudo exaustivo da literatura existente, foi apresentado um sistema de classificação uniforme e multi-nível das anomalias mais comuns em pontes. Este sistema reproduz as anomalias que ocorrem durante o período de vida útil de uma ponte. A influência destas anomalias na capacidade resistente é devidamente abordada. A resposta a este problema tem sido objecto de grande atenção pela comunidade técnica e científica, devido aos desenvolvimentos ocorridos nos métodos experimentais de apoio às inspecções e ao aprofundamento do conhecimento da classificação dos mecanismos de degradação. As anomalias acima mencionadas foram apresentadas, em termos da sua modelação, através de vários modelos geométricos. Para o efeito a modelação numérica de qualquer anomalia é efectuada tendo por base três parâmetros – intensidade, localização e extensão. As conclusões retiradas da análise estatística das pontes ferroviárias existentes induziram o autor a desenvolver um sistema de análise da possibilidade de aplicação de um modelo geométrico, simplificado, para a modelação do efeito das anomalias neste tipo de pontes. O campo de aplicação do modelo simplificado foi estabelecido como válido para as situações correspondentes a 5% de diferença entre os resultados obtidos pelos modelos em questão. Para efectuar as análises da capacidade resistente das pontes em questão, o autor desenvolveu um programa de cálculo automático designado "DAGA – Damage Assessment Graphic Analyser" (DAGA). Através da inserção de um editor gráfico o programa permite a visualização 3D das anomalias existentes no betão e armaduras (perda de materiais e modificação das propriedades dos materiais). Esta ferramenta permite a análise e visualização das envolventes da capacidade resistente para diversos casos de carga e para diversos cenários de anomalias. Mediante a utilização programa DAGA foram efectuados estudos paramétricos (comportamento estático) e os seus resultados foram coligidos numa base de dados a ser posteriormente usada modelos de inteligência artificial. Para o efeito desenvolveu, ainda, um programa de cálculo designado por "ANACONDA – ANAlisys of CON crete DAmages" baseada na tecnologia de redes híbridas com componentes analíticas e neuronais incorporadas. Finalmente, são apresentadas as principais conclusões e a recomendação de futuras linhas de investigação neste campo

Assessment of load capacity of railway RC slab spans with reinforcement losses

Framework Programme of European Union - Project “Sustainable Bridges – Assessment for Future Traffic Demands and Longer Lives”, contract No TIP3-CT-2003-00165

Concrete railway bridges : taxonomy of degradation mechanisms and damages identified by NDT methods

The aim of this work is creating basis for unified and more objective assessment of bridge condition and for application of expert tools in evaluation process. The degradation processes and the relevant NDT techniques are presented on the background of the causes and the effects of these processes, taking into account: factors which influence degradation processes, mechanisms of degradation and effects of degradation with proposed methodology of identification and classification of the damages in concrete bridge structures. The proposed uniform taxonomy of degradation processes of the concrete railway bridges as well as presented analysis of the available NDT methods can be applied in evaluation of bridge condition and in modelling of structure lifetime.Framework Programme of European Union - "Sustainable Bridges – Assessment for Future Traffic Demands and Longer Lives” nº TIP3-CT-2003-001653

Pituitary tumours — a large retrospective single-centre study of over 2300 cases. Experience of a tertiary reference centre

Introduction: Pituitary adenomas (PAs), also known as a pituitary neuroendocrine tumours (PitNET), are usually benign tumours of the anterior lobe of the pituitary gland and account for the third most common intracranial neoplasm. The most common type of pituitary adenoma is lactotroph adenoma, in which dopamine agonists are the first-line treatment. Nevertheless, in selected cases surgery or even radiotherapy may be required. In the current study, we aimed to analyse all patients who underwent surgery due to intrasellar mass in order to evaluate frequency of particular pituitary tumours, clinical diagnosis, and pathology findings. Material and methods: We retrospectively analysed all cases of patients consecutively operated due to intrasellar mass between 1st January 2010 and 31st December 2018 at the Department of Neurosurgery, Military Institute of Medicine in Warsaw, Poland. Results: Our database included 2348 cases: 1390 women (59.2%) and 958 men (40.8%). The mean age for women was 48.4 years (SD ± 15.72; median 49) and for men 50.9 years (SD ± 14.94; median 53). In our cohort we found: 869 gonadotroph and null cell adenomas, 751 somatotroph and mammosomatotroph adenomas, 386 corticotroph adenomas, 71 plurihormonal adenomas, 59 craniopharyngiomas, 44 lactotroph adenomas, 18 purely thyrotroph adenomas, and other rare cases of pituitary tumours including one pituitary carcinoma metastasising to the liver (corticotroph origin). Conclusions: We provide a comprehensive analysis of both clinical and pathological findings of the largest cohort of patients operated on for pituitary adenomas in one tertiary reference centre. To the best of our knowledge, this is the largest up-to-date published analysis in our country.

Analytical solution of a generalized Penna model

In 1995 T.J.Penna introduced a simple model of biological aging. A modified Penna model has been demonstrated to exhibit behaviour of real-life systems including catastrophic senescence in salmon and a mortality plateau at advanced ages. We present a general steady-state, analytic solution to the Penna model, able to deal with arbitrary birth and survivability functions. This solution is employed to solve standard variant Penna models studied by simulation. Different Verhulst factors regulating both the birth rate and external death rate are considered.Comment: 6 figure

Coseismic seafloor deformation in the trench region during the Mw8.8 Maule megathrust earthquake

The Mw 8.8 megathrust earthquake that occurred on 27 February 2010 offshore the Maule region of central Chile triggered a destructive tsunami. Whether the earthquake rupture extended to the shallow part of the plate boundary near the trench remains controversial. The up-dip limit of rupture during large subduction zone earthquakes has important implications for tsunami generation and for the rheological behavior of the sedimentary prism in accretionary margins. However, in general, the slip models derived from tsunami wave modeling and seismological data are poorly constrained by direct seafloor geodetic observations. We difference swath bathymetric data acquired across the trench in 2008, 2011 and 2012 and find ∼3-5 m of uplift of the seafloor landward of the deformation front, at the eastern edge of the trench. Modeling suggests this is compatible with slip extending seaward, at least, to within ∼6 km of the deformation front. After the Mw 9.0 Tohoku-oki earthquake, this result for the Maule earthquake represents only the second time that repeated bathymetric data has been used to detect the deformation following megathrust earthquakes, providing methodological guidelines for this relatively inexpensive way of obtaining seafloor geodetic data across subduction zone

INSPIRE: INvestigating Stellar Population In RElics -- V. Final Data Release: the first catalogue of relics outside the local Universe

This paper presents the final sample and data release of the INvestigating Stellar Population In RElics (INSPIRE) project, comprising 52 ultra-compact massive galaxies (UCMGs) observed with the ESO-VLT X-Shooter spectrograph. We measure integrated stellar velocity dispersion, [Mg/Fe] abundances, ages, and metallicities for all the INSPIRE objects. We thus infer star formation histories and confirm the existence of a degree of relicness (DoR), defined in terms of the fraction of stellar mass formed by $z=2$, the cosmic time at which a galaxy has assembled 75% of its mass and the final assembly time. Objects with a high DoR assembled their stellar mass at early epochs, while low-DoR objects show a non-negligible fraction of later-formed populations and hence a spread in ages and metallicities. A higher DoR correlates with larger [Mg/Fe], super-solar metallicity, and larger velocity dispersion values. The 52 UMCGs span a large range of DoR from 0.83 to 0.06, with 38 of them having formed more than 75% of their mass by $z=2$, which translates in a lower limit to the number density of relics at $z\sim0.3$ of $\log \rho \approx 2.8 \times 10^{-7} \text{Mpc}^{-3}$.. Nine relics are extreme (DoR$>0.7$), since they formed almost the totality ($>98\%$) of their stellar mass by redshift $z=2$. With INSPIRE, we have increased the number of fully confirmed relics by more than a factor of 10, also pushing the redshift boundaries, hence building the first sizeable sample of relics outside the local Universe, opening up an important window to explain the mass assembly of massive galaxies in the high-z Universe.Comment: submitted to MNRAS, 20 pages, 16 figures, 3 table

The physical basis of natural units and truly fundamental constants

The natural unit system, in which the value of fundamental constants such as c and h are set equal to one and all quantities are expressed in terms of a single unit, is usually introduced as a calculational convenience. However, we demonstrate that this system of natural units has a physical justification as well. We discuss and review the natural units, including definitions for each of the seven base units in the International System of Units (SI) in terms of a single unit. We also review the fundamental constants, which can be classified as units-dependent or units-independent. Units-independent constants, whose values are not determined by human conventions of units, may be interpreted as inherent constants of nature.Comment: 17 pages, to be published in European Physical Journal-Plus, The final publication is available at www.epj.or