Fingerprints of extreme climate events in Pinus sylvestris tree rings from Bulgaria

Tree-ring studies may help better understand climate variability and extreme climate event frequency and are especially useful in regions where detailed meteorological records lack. We studied the effect of droughts and unusually cold periods on Pinus sylvestris tree-ring width and wood anatomy. Study sites were selected along an altitudinal gradient on Vitosha Mountain, Bulgaria. Drought conditions caused the formation of narrow tree rings or light rings if the drought occurred in July-August at the lower altitude sites. In years with droughts in June and the first half of July, followed by precipitation in the middle of July, intra-annual density fluctuations (IADFs) were formed. Trees in the zone with optimal growth conditions produced fewer light rings and narrow rings in years with either strongest droughts or unusually cold summers. At the timberline zone, low summer temperature triggered narrow tree rings and light rings. Frost rings were formed when there was a drop in temperatures below the freezing point in the second half of May or at the beginning of June. Our findings show that studies of tree-ring anatomy may contribute to obtain further knowledge about extreme climatic events in the Balkan Peninsula and in other regions where meteorological data lac

Containment Lining Solutions and Hydrodynamic Stability of Tailings Dam

The study investigates the impact of reservoir lining on the hydrodynamic stability of a tailings dam. A 3D coupled fluid-solid finite element model was used for detailed seepage analyses based on conventional flow-net and steady seepage conditions. Pore pressure, stationary seepage velocities, static liquefaction and the ratio between manifested and critical hydraulic gradients were predicted under three different lining conditions. The highest potential for internal erosion and heave was observed in the lined reservoir and starter dam scenario. Although there are environmental benefits, the incorporation of liners in dam design requires a comprehensive engineering assessment of the negative hydrodynamic effects

Equity market contagion during global financial and Eurozone crises: Evidence from a dynamic correlation analysis

The devastation resulting from the recent global financial and Eurozone crises is immense. Most researchers commonly believe that the global financial crisis originated in the United States, and spread immediately to global financial hubs where it eventually became the Eurozone crisis. Several studies have been conducted on financial market contagion during both global and Eurozone crises; however, the issue of whether equity market contagion spreads from the United States to the world equity markets during these crises has not been addressed yet. Through using US dollar-denominated MSCI daily indices from fifty-five equity markets for the period 2003–2013, we have found evidence of contagion in developed and emerging markets during the global and Eurozone crises. We show that contagion spread from the United States to the world markets during both crises. Our regression results identify that the bank risk transfer between the United States and other countries is the key transmission channel for cross-country correlations. This study has an important policy implication for portfolio diversification between the United States and other countries during these crises

Interdisziplinäre Produktentwicklung

Aus der Einleitung: "Innovative interdisziplinäre Produktentwicklung erfordert ein Überdenken von heutigen Methoden, Prozessen, IT-Lösungen und Organisationsformen. Insbesondere fehlt es an Unterstützung durch geeignete IT-Lösungen für die funktionale Beschreibung und Auslegung von Systemarchitekturen. Für die disziplinübergreifende Systemmodellierung der Konzeptphase gibt es nur eingeschränkte IT-Unterstützung. Elektronik und Software stellen einen immer stärkeren Anteil im Produktentwicklungsprozess (PEP) dar. Konstruktions- und Entwurfsmethoden dieser Disziplinen sollten auf den Prüfstand gestellt und ihre Tauglichkeit für einen moderne interdisziplinären Konstruktionsansatz überprüft werden. Model Based Systems Engineering (MBSE) könnte sich als integrative Methode etablieren und eine Brücke zwischen den verschiedenen Ingenieurdisziplinen bilden. Als »Enabler« für das MBSE werden Systemmodellierungssprachen wie z.B. SysML vorgestellt, die ein Werkzeug für eine interdisziplinäre Systembeschreibung darstellen. Auf konkreterer Stufe können Simulationssprachen, wie z.B. Matlab/Simulink oder Modelica eine frühe multidisziplinäre Simulation ermöglichen, die in Verbindung mit Systembeschreibungssprachen eine frühe Konzeptformulierung erlauben. Dieser Beitrag soll neue Methoden, Prozesse und IT-Lösungen für eine interdisziplinäre virtuelle Produktentwicklung aufzeigen (Anderl et al. 2012).

Diagnosis and treatment of enterovesical fistulas

A fistula is an atypical connection between two epithelial surface. We studied retrospectively four male pa­tients with enterovesical fistulas treated in our departments between March 2016 - March 2017. These in­cluded colovesical, rectovesical and ileovesical fistulas. Patients presented with urinary symptoms (pneu­maturia, faecaluria and recurrent urinary tract infections). One patient had received radiotherapy after rec­tal resection for rectal carcinoma. For another of the cases the fistula was being due to periprostatic abscess. The third patient was diagnosed with bladder carcinoma with rectal invasion. The fourth patient was with direct invasion of sigmoid cancer to the bladder. The most common investigations included abdominal ul­trasound, CT scan, cystoscopy and colonoscopy. Enteral stoma was performed in all cases as a part of sur­gical treatment.All patients underwent open procedure, as a main rule enteral stoma was performed to cease the contami­nation, and primary repair of the bladder was performed. No recurrences were recorded, but there were sev­eral complications, including Clavien-Dindo gr. V. Most of the complications were treated by interventional urology. In conlusion, enteral division and primary repair of the bladder are safe approaches for treatment of enterovesical fistulas. As a rule ceasing of contamination should always be performed. Cystoscopy can manage most of the complications occurring in the early postoperative period. Scr Sci Med 2017; 49(3): 53-5

Seismic resistance of existing buildings with added light timber structure storeys

U ovom se radu problem vertikalne nadogradnje razmatra u okviru analize potresne otpornosti građevina s dodanim katovima. Provedena je opsežna parametarska studija koja potvrđuje utjecaj broja dodanih katova i promjene njihove krutosti na potresni odziv građevina. Primjeri prikazani u radu pokazuju kako se krutost konstrukcija od laganih drvenih okvira i križno lameliranog drva lako može promijeniti mijenjanjem vrste i rasporeda spojnih sredstava. Poznati se postupci primjenjuju za izračunavanje krutosti zidnih elemenata lakog drvenog okvirnog sustava, a novi je postupak razvijen za određivanje krutosti križno lameliranih drvenih zidnih elemenata. U radu je prikazano kako promjena krutosti vertikalne nadogradnje može bitno utjecati na potresni odziv te da u nekim slučajevima takva nadogradnja može povoljno utjecati na potresnu otpornost, i to bez obzira na manje povećanje težine konstrukcije.In the presented paper, the problem of vertical expansions is treated in terms of seismic resistance of structures with added storeys. A large parametric study has been performed, confirming the impact of different number of added storeys, and the change of their stiffness, on the seismic response of structures. The paper shows examples of how stiffness in light timber frame and cross laminated timber structures can be easily altered just by changing the type and distribution of fasteners. Known procedures are used to calculate the stiffness of the wall elements of a light timber frame system, and a new procedure is developed for determining the stiffness of cross laminated timber wall elements. The study shows how changing the stiffness of the vertical expansion can have a significant impact on the seismic response and that, in some cases, vertical expansion can have a favourable effect on seismic resistance, despite a minor increase in the mass of the structure

SOME RESULTS OF COMPUTER SIMULATION OF MUTUAL BEHAVIOR OF PREDATORS AND PREY ON EARLY STAGES OF EVOLUTION

This article describes some results of the experiments conducted to determine the optimal strategy of behavior of the victim and of the predator in the early stages of evolution, obtained by computer simulation in a specially created software environment, which has specific conditions. The results obtained by the experiments, differing from each other by various input parameters characterizing the behavior of both types of organisms