Dynamics of an SIR epidemic model with limited medical resources, revisited and corrected

This paper generalizes and corrects a famous paper (more than 200 citations) concerning Hopf and Bogdanov-Takens bifurcations due to L. Zhou and M. Fan, "Dynamics of an SIR epidemic model with limited medical resources revisited", in which we discovered a significant numerical error. Importantly, unlike the paper of Zhou and Fan and several other papers that followed them, we offer a notebook where the reader may recover all the results and modify them for analyzing similar models. Our calculations lead to the introduction of some interesting symbolic objects, "Groebner eliminated traces and determinants" - see (4.5), (4.6), which seem to have appeared here for the first time and which might be of independent interest. We hope our paper might serve as yet another alarm bell regarding the importance of accompanying papers involving complicated hand computations by electronic notebooks

On the Connectedness of the Moduli Space of Calabi--Yau Manifolds

We show that the moduli space of all Calabi-Yau manifolds that can be realized as hypersurfaces described by a transverse polynomial in a four dimensional weighted projective space, is connected. This is achieved by exploiting techniques of toric geometry and the construction of Batyrev that relate Calabi-Yau manifolds to reflexive polyhedra. Taken together with the previously known fact that the moduli space of all CICY's is connected, and is moreover connected to the moduli space of the present class of Calabi-Yau manifolds (since the quintic threefold P_4[5] is both CICY and a hypersurface in a weighted P_4, this strongly suggests that the moduli space of all simply connected Calabi-Yau manifolds is connected. It is of interest that singular Calabi-Yau manifolds corresponding to the points in which the moduli spaces meet are often, for the present class, more singular than the conifolds that connect the moduli spaces of CICY's.Comment: 22 pages plain TeX, Tables and references adde

Reduction and reconstruction of stochastic differential equations via symmetries

An algorithmic method to exploit a general class of infinitesimal symmetries for reducing stochastic differential equations is presented and a natural definition of reconstruction, inspired by the classical reconstruction by quadratures, is proposed. As a side result the well-known solution formula for linear one-dimensional stochastic differential equations is obtained within this symmetry approach. The complete procedure is applied to several examples with both theoretical and applied relevance

Bankruptcy risk forecasting for the metallurgical branch in Romania

All investment decisions require a thorough analysis of the retrospective evolution of the entities from the concerned area, in order to estimate the long-term evolution perspectives. In this context, the present study analyzes the evolution of the entities from the Romanian metallurgical sector based on the accounting and financial information published for the period 2008 - 2012 and, in fact, it justifies the situation from the perspective of users (managers, investors, auditors) and of the economic environment specific to Romania. Starting from this premise we created a regression model particularly useful in forecasting the evolution of the ability to deal with debt for the entities from the Romanian metallurgical sector

Determinant factors for the growing of shareholders’ equity in the metallurgical sector in Romania

The article provides a statistical monograph of the financial position and performance for the period 2008 – 2012 of the entities from the Romanian metallurgical sector whose financial statements in the period 2004 – 2012 have become the object of the financial audit. There are tested five types of regression models in order to separately determine the evolution of equity in accordance with the variation of turnover, total assets, average number of employees and net result. After determining the most appropriate simple regression model, one proceeds at establishing a multiple regression model which would simultaneously reflect the evolution of equity in accordance with the above mentioned variables. The study’s importance is enhanced by certain statistically-based concrete measures which management should consider in order to increase the shareholders’ equity

An Abundance of K3 Fibrations from Polyhedra with Interchangeable Parts

Even a cursory inspection of the Hodge plot associated with Calabi-Yau threefolds that are hypersurfaces in toric varieties reveals striking structures. These patterns correspond to webs of elliptic-K3 fibrations whose mirror images are also elliptic-K3 fibrations. Such manifolds arise from reflexive polytopes that can be cut into two parts along slices corresponding to the K3 fibers. Any two half-polytopes over a given slice can be combined into a reflexive polytope. This fact, together with a remarkable relation on the additivity of Hodge numbers, explains much of the structure of the observed patterns.Comment: 30 pages, 15 colour figure

Results regarding the study of reproduction indexes at brown breed cow population from Vrancea County

On a population of 1520 Brown cows, from 15 farms located in Vrancea County were evaluated the main reproductive indicators on the basis of data from official control in farms. Were evaluated the following indicators: rank of lactation, age at first calving (AFC), service period(SP), dry period (DP), calving interval (CI)and number of artificial inseminations for one gestation (IA). From analysis of mean values could be observed that average age at first calving was of approximately 33 month ranking between 29 and 35 month, the analysed population having precocity under the standard of Brown breed. Number of inseminations for one gestation was 2.09, at the farms level being recorded a poor management of frozen seminal material.Reproduction indicators had means values which prove that reproduction function was poor technically managed

Identifying Patient Candidates for IL-1 Inhibition: Lessons From Real-World Cases

A subgroup of patients with gouty arthritis have a chronic recurring form that is particularly difficult to treat. Such patients experience repeated flares and often have abundant tophi. Many also have underlying comorbidities, such as renal impairment, cardiovascular disease, gastrointestinal disorders, obesity, and hypertension, which contraindicate the use of standard anti-inflammatory medications. Five patients with difficult to treat gouty arthritis who were either candidates and/or treated with anti-IL therapy are described.info:eu-repo/semantics/publishedVersio

Minimally invasive approach to colorectal tumors - 3 years of experience in a private hospital

Spitalul Privat ”Sanador”, București, România, Al XIII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” și al III-lea Congres al Societății de Endoscopie, Chirurgie miniminvazivă și Ultrasonografie ”V.M.Guțu” din Republica MoldovaIntroducere: Abordul minim invaziv al tumorilor colo-rectale reprezintă o preocupare a colectivului Spitalului privat Sanador, în pofida adresabilității crescute a cancerelor în stadii avansate, procentul acestora din totalul intervențiilor chirurgicale pentru această patologie rămânând constant, printr-o atentă selecție a pacienților, care sa beneficieze de avantajele laparoscopiei. Material și metode: Studiul prezent analizează intervențiile chirurgicale pentru tumori colo-rectale efectuate între anii 2016-2018 în Spitalul Sanador București. Din totalul de 214 intervenții chirurgicale pentru patologia colo-rectală, 41 au fost prin abord minim invaziv, reprezentând procentual 20% din totalul intervențiilor pentru această patologie, procentul fiind constant în fiecare din acești ani: 2016 – 13 intervenții prin abord minim invaziv din totalul de 68 (19.11%); 2017 – 17 intervenții prin abord minim invaziv din totalul de 79 (21.5%); 2018 – 11 intervenții chirurgicale prin abord minim invaziv dintr-un total de 57 (19.3%). Rezultate: Cele mai frecvente localizări ale tumorilor pentru care indicația a fost de abord minim invaziv, au fost cele recto-sigmoidiene (28). Selecția pacienților s-a facut după stadializarea preoperatorie, admitându-se ca și abord laparoscopic tumori T1, T2, T3, în rare cazuri T4. În cazul tumorilor avansate, substadializate preoperator, s-a tentat efectuarea a cât mai multor timpi din cadrul rezecției, prin abord minim invaziv, iar cazurile in care anastomozele au fost efectuate extracorporeal nu au fost interpretate ca și conversie. Concluzii: Rezultatele bune se înscriu în rândul celor ale centrelor cu volum și experiența mari în abordarea minim invazivă a tumorilor colo-rectale și constituie premize pentru creșterea procentului de astfel de intervenții în clinica noastră.Introduction: The minimally invasive approach of colorectal tumors is a concern of the Sanador private hospital team, despite the increased addressability of cancers in advanced stages, their percentage of total surgical interventions for this pathology remaining constantly through a careful selection of patients who benefit from the advantages of laparoscopy. Material and methods: The present study examines surgical interventions for colorectal tumors performed between 2016-2018 at Sanador Hospital Bucharest. Of the total of 214 surgical procedures for rectal pathology, 41 were by minimally invasive approach, accounting for 20% of all interventions for this pathology, the percentage being constant in each of these years: 2016-13 interventions through the minimally invasive approach of the total of 68 (19.11%); 2017 - 17 interventions through minimally invasive approach from the total of 79 (21.5%); 2018 - 11 minimally invasive surgical interventions from a total of 57 (19.3%). Results: The most common tumor localizations for which the indication was minimally invasive were the recto-sigmoid (28). Selection of patients was made after preoperative staging, admitting as a laparoscopic approach T1, T2, T3 tumors, in rare cases T4. In the case of advanced tumors, pre-operative substations, it was tempting to perform as many times as possible in the resection through a minimally invasive approach, and the cases in which the anastomoses were performed extracorporeally were not interpreted as conversion. Conclusions: Good results are among those with large volume centers and great experience in the minimally invasive approach of colorectal tumors and are prerequisites for increasing the percentage of such interventions in our clinic