Primjenjivost različitih modela regresije za procjenu volumena krupnog drva stabala hrasta kitnjaka (Quercus petraea (Matt.) Liebl.) u Bosni i Hercegovini

SummaryIn Bosnia and Herzegovina, there are tariff tables used for estimating the volume of sessile oak trees in high forests, which were created on the basis of two-entry volume tables for oak trees from the area of Germany, authored by Schwappach in 1905. There are indications that the application of the aforementioned tariffs in forest management practice results in certain differences in the estimated amount of merchantable wood volume compared to the real situation. The material for creation of volume tables was the data concerning the measurement of 2,413 model trees in different habitat and stand conditions. A large number of widely used regression models was tested to equalize the volume of merchantable wood volume as a dependent variable in terms of the diameter at breast height and height of the tree as independent variables. Regression models such as Schumacher-Hall and Spurr II provide satisfactory accuracy, that is, they can be used to estimate the merchantable wood volume of sessile oak trees in high forests (pure and mixed) in the territory of Bosnia and Herzegovina, with a permissible deviation. By introducing the third variable into the model, diameter at seven meters height, the accuracy of the tree volume estimation increases significantly, but due to the significant increase in the volume of work on collecting the necessary data, this model is not suitable for use in forest inventories.SažetakU Bosni i Hercegovini za procjenu volumena stabala hrasta u visokim šumama koriste se uređajne tarife, koje su izrađenene na temelju dvoulaznih volumnih tablica za hrast s područja Njemačke autora Schwappach iz 1905. godine. Postoje indicije da se primjenom navedenih tarifa u uređajnoj praksi dobivaju određene razlike u količini procijenjenog volumena krupnog drva u odnosu na stvarno stanje. Materijal za izradu volumnih tablica odnosno modela regresije predstavljali su podaci izmjere i izračuna stvarnog volumena drva 2.413 modelnih stabala u različitim stanišnim i sastojinskim uvjetima. Na osnovi raspodjele stabala po debljinskim stupnjevima možemo zaključiti da je relativno mali broj stabala koja su deblja od 70 cm, u ostalim debljinskim stupnjevima broj stabla veći je od 100, odnosno u intervalu od 111 do 316. Testirani su modeli koji imaju široku primjenu za izjednačenje volumena krupnog drva stabla kao zavisne varijable u ovisnosti o prsnom promjeru i visini stabla kao nezavisnim varijablama. Za usporedbu i analizu upotrebljivosti modela regresije korišten je veći broj kriterija (Srednja apsolutna greška, Korijen prosječne kvadratne pogreške, Koeficijent determinacije i Akaike informacijski kriterij). Uz navede kriterije, testirane su značajnosti razlika pomoću t-testa parova uzoraka između stvarnih i procijenjenih volumena krupnog drveta stabala te utvrđeni postoci odstupanja procijenjenih od stvarnih volumena, po debljinskim stupnjevima i ukupno. Modeli kao što su Schumacher-Hall i Spurr II daju zadovoljavajuću točnost, s obziron na to da su u pitanju općeniti modeli namijenjeni za procjenu volumena stabala na području cijele Bosne i Hercegovine. Uvođenjem u model i treće varijable, promjer debla na sedam metara visine, povećava se značajno točnost procjene volumena stabala. Zbog izmjere promjera na sedam metara visine povećava se značajno i količina rada na terenu na prikupljanju potrebnih podataka, pa ovaj model nije pogodan za primjenu u operativnim inventurama šuma. Uvođenjem visine baze krošnje stabla kao treće varijable, nije se povećala točnost procjene volumena stabla u odnosu na analizirane dvoulazne modele

Analisys of stress state in a plane anisotropic field weakened by a circular hole

It is the fact that mechanical parts with holes are often encountered in practice. A know ledge of stress distribution is of paramount importance for engineering practice. Therefore, the objective of this paper analyzes the impact of the circular hole as a source of stress concentration on the stress state of uniaxial strained orthotropic plate since the practice has shown that the largest number of structures is weakened by the hole shape. In this paper for obtaining the results of stress distribution in a plane anisotropic field weakened by a circular hole, numerical method was used. The methodology was applied enabling the determination of the values of the stress at each point of plate, as well as at points at the hole contour, which is based on the application of the basic equations of the theory of elasticit

Econometric model of non-performing loans determinants

The paper presents the use of the difference GMM and the system GMM for the purposeof determining the critical determinants of non-performing loans. The aim of the paperis to point out the theoretical advantages of GMM in relation to other (often used) panel data estimators in the study of NPLs, and to demonstrate its advantages in the case ofthe emerging markets in the countries of Latin America. The paper seeks to identify arelevant econometric model in order to demonstrate the impact of crucial macro and micro economic variables on the NPLs.No evidence was found in support of the significance of the impact of the inflation rate and the micro economic variables that were the subject of research in this paper

Horses naturally infected with Strongylidae and Ascaridae: Evaluation of hematological and some biochemical parameters

Infectious larvae of equine parasites: Strongylidae and Ascaridae may induce direct as well as indirect damage, during their migration within the host. The aim of this study was to evaluate changes in hematological and biochemical parameters in naturally infected horses, with the above mentioned parasites

Uticaj intenziteta parazitske infekcije sa Strongyloides papillosus i terapije albendazolom na biohemijske parametre u krvi ovaca

The aim of this report was to study the biochemical parameters in sheep blood under conditions of various intensities of parasitic infection with Strongyloides papillosus, as well as after therapy with albendazole (ABZ). Investigations were performed on sheep of the Würtemberg race (n = 30) in which were detected mild, moderate and high intensities of parasitic infection with S. papillosus. The control group (n = 10) was composed of sheep negative to parasitic infections. The degree and type of changes were monitored by determining the concentrations of glucose, total proteins, albumin, A/G ratio, AST, urea, total bilirubin, calcium, phosphorus, total LDH activity and isoenzymatic LDH1-5 distributions. On the basis of the obtained results, we determined, through isoenzymatic LDH distribution, that during parasitic infection with S. papillosus, there is ongoing damage to the liver, heart muscle and lung, while after therapy with ABZ, the liver suffers the most damage. The concentration of glucose, total proteins and albumin fell linearly with the rise in the intensity of parasitic infection (p LT 0.05), while after therapy with ABZ, the fall of these parameters was at a statistically significantly higher level (p LT 0.01). The activity of AST, concentration of urea and total bilirubin also rose linearly with the intensity of parasitic infection (p LT 0.05). After therapy with ABZ, the activity of AST and the concentration of total bilirubin were at a statistically significantly higher level (p LT 0.001), while the concentration of urea retained the same levels as in the case of parasitic infection. Values of calcium concentrations (p>0.05) and phosphorus (p LT 0.05) also fall linearly with the rise of the intesity of the parasitic infection. The trend in the concentration fall of these macroelements, continues also after treatment with albendazole (p LT 0.001). Having in mind our previous studies in the field of oxidative stress and phenomena lying behind these changes, we strongly recommend that in antiparasitic treatment protocols, beside antihelminthics, compounds with antioxidative properties should also be used.Cilj ovog rada je bio da se ispitaju biohemijski parametri u krvi ovaca u uslovima različitog intenziteta parazitske infekcije sa Strongyloides papillosus, kao i nakon terapije sa albendazolom (ABZ). Istraživanje je izvedeno na ovcama Wurtemberg rase (n = 30) kod kojih je utvrđen blagi, srednji i visoki intenzitet parazitske infekcije sa S. papillosus. Kontrolnu grupu (n = 10) činile su ovce negativne na prisustvo parazitske infekcije. Stepen i vrsta promene praćeni su određivanjem koncentracije glukoze, ukupnih proteina, albumina, A/G ratio, AST, urea, ukupnog bilirubina, kalcijuma, fosfora, ukupne aktivnosti LDH i izoenzimske distribucije LDH1-5. Na osnovu dobijenih rezultata utvrdili smo, preko izoenzimske distribucije LDH, da u toku parazitske infekcije sa S. papillosus dolazi do oštećenja jetre, srčanog mišića i pluća, dok nakon terapije sa ABZ jetra je organ koji je najviše oštećen. Koncentracija glukoze, ukupnih proteina i albumina linearno je opadala sa rastom intenziteta parazitske infekcije (p LT 0.05), a nakon terapije sa ABZ pad koncentracije ovih parametara bio je na statistički značajnom većem nivou (p LT 0.01). Aktivnost AST, koncentracija uree i ukupnog bilirubina takođe su linearno rasle sa intenzitetom parazitske infekcije (p LT 0.05). Nakon terapije sa ABZ aktivnost AST i koncentracija ukupnog bilirubina bile su na statistički značajno većem nivou (p LT 0.001), dok je koncentracija uree zadržala iste nivoe kao u slučaju parazitske infekcije. Vrednosti koncentracija kalcijuma (p > 0.05) i fosfora (p LT 0.05) takođe linearno opadaju sa rastom intenziteta parazitske infekcije. Trend pada koncentracije ovih makroelemenata, nastavlja se i nakon terapije sa albendazolom (p LT 0.001). Imajući u vidu naša prethodna istraživanja na polju oksidativnog stresa, fenomena koji se nalazi u osnovi ovih promena, strogo preporučujemo da se u antiparazitske protokole, pored antihelmintika koriste i preparati sa antioksidativnim osobinama

Numerička arealna gustina CD34 i CD117 imunoreaktivnih hematopoetskih ćelija u jetri humanog embriona i fetusa

Uvod. Hematopoeza je proces stvaranja krvnih ćelija i uobličenih elemenatakrvi. Ovaj dinamičan proces se postnatalno odvija u koštanoj srži, dok jeprenatalna hematopoeza raspršena na više lokalizacija. Počinje u žumančanojkesi, u intraembrionalnim ostrvcima hematopoeze, nastavlja se ujetri, slezini i koštanoj srži, a prema novim saznanjima i u placenti. Jetra jekao najveći hematopoetski organ intrauterinog razvoja izvor matičnih ćelijahematopoeze. Cilj rada je identifikacija i kvantifikovanje CD34 i CD117imunoreaktivnih hematopoetskih ćelija u jetri humanog embriona i fetusa.Metode. Korišćeno je 5 jetri humanih embriona i 25 jetri humanog fetusastarosti od 7 do 38 nedelja gestacije. Uzorci jetre podvrgnuti su rutinskojobradi do parafinskih kalupa. Tkivni presjeci, debljine 5 μm bojeni su hematoksilinomi eozinom, kao i imunohistohemijskim dokazivanjem CD34i CD117 antigena. Kvantifikacija je urađena morfometrijski određivanjemnumeričke arealne gustine. U statističkoj analizi korišćen je Hi-kvadrat test.Rezultati. Numerička arealna gustina CD34 imunoreaktivnih hematopoetskihćelija u jetri u embrionalnom periodu razvića je iznosila 0,35%, 0,30%u prvom trimestru (koji obuhvata i embrionalni i fetalni period), 0,46% udrugom trimestru i 0,10% u trećem trimestru. Numerička vrijednost arealnegustine CD117 imunoreaktivnih hematopoetskih ćelija u jetri za embrionalniperiod je iznosila 0,28%, 0,50% u prvom trimestru (koji obuhvata i embrionalnii fetalni period), 0,11% u drugom trimestru i 0,09% u trećem trimestru.Zaključak. Jetra embriona i fetusa predstavlja značajan izvor CD34 i CD117imunoreaktivnih hematopoetskih ćelija

Detection Limit for an Adsorption-Based Mercury Sensor

A novel readout procedure for the determination of detection limit at an adsorption-based mercury sensor is described. The procedure is based on the evaluation of the initial voltage slope in time evolution of adsorbed elementary mercury. The Langmuir time-dependent adsorption theory is utilized to derive it. This procedure gives the theoretical minimum for the detection for this type of the sensor, which is estimated at 180 ng/m3. This is five times lower than the best previously reported results. This procedure can also be used for regular sensor readout. This work describes the experimental procedure for mercury sensor fabrication as well as its measurement cycle. The sensor is working in the cycles of mercury adsorption and evaporation induced by heating. It is shown that every part of the cycle can be monitored by measuring output voltage of the sensor without any additional measurements like surface temperature or rate of the evaporation

Models of dynamic process of forming stugotine

The oscillating elements obradog system in principle is conditional on the dynamic character of the process of formation filings. It is necessary to let the frequency of natural oscillation elements of the system tool - workpiece - accessories - machine is approximately equal to the frequency of forming segments filings to lead to the emergence of chatter (Landberg). Studies have found that the process of forming filings do not affect the characteristics of rigidity machines (Ferrarezzi). Today the world literature meets a large number of analytical and mechanistic models, with more or less accuracy realistically describe the real process of forming filings. In recent years, with the advent of powerful computers and application programs based on the finite element method (FEM) modeling of the dynamic processes of formation filings, as well as other processes that take place in the cutting zone, are the subject of numerical methods

Supervisory system for physical objects spatial location detection

In this paper was proposed the simple concept and realization of the technical system, for physical objects spatial location detection, with optimization methods for low quality hardware. This computer system consists of computers, software applications, video cameras, computer network, active and passive network equipment. The basic idea of the system is the principle of triangulation by the visual images and time data from at least 4 cameras with high number of frames per second. The system then creates photorealistic graphical 3D animation of object trajectory and space, using the calculated spatial location data. Experimental results and a computer simulation of a real system indicated that the proposed concept improves objects spatial location detection and 3D graphics on medium quality technical equipment

An adsorption-based mercury sensor with continuous readout

A novel readout procedure for a mercury sensor has been proposed. The sensor is based on the surface adsorption. Mercury vapor is adsorbed at the surface of a thin gold layer patterned into four meanders which are connected into a Wheatstone bridge configuration. Sensing is achieved by the resistivity change of the gold film during mercury adsorption. Direct output from the sensor is electric voltage. It takes an additional procedure to convert voltage to mercury concentration. This type of sensor is improved by introducing continuous readout procedure for the voltage–concentration conversion. By using this readout procedure it is possible to monitor mercury vapor concentration as a function of time. Readout is based on the Langmuir time–dependent adsorption theory. This paper illustrates a practical implementation of the new readout procedure