Strong traces to degenerate parabolic equations

We prove existence of strong traces at $t=0$ for quasi-solutions to the degenerate parabolic equations under non-degeneracy assumptions. In order to solve the problem, we introduce a defect measure type functional and combine it with the blow up method

Degenerate parabolic equations -- compactness and regularity of solutions

We introduce a new method which resolves the problem of regularity and compactness of entropy solutions for nonlinear degenerate parabolic equations under non-degeneracy conditions on the sphere. In particular, we address a problem of regularity of entropy solutions to homogeneous (autonomous) degenerate parabolic PDEs and existence of weak solutions to heterogeneous degenerate parabolic PDEs (non-autonomous PDEs -- with flux and diffusion explicitly depending on the space and time variables). The method of proof is reduction of the equation to a specific kinetic formulation involving two transport equations, one of the second and one of the first order. In the heterogeneous situation, this enables us to use (variants of) the H-measures to get velocity averaging lemmas and then, consequently, existence of a weak solution. In the homogeneous case, the kinetic reformulation makes it possible to get necessary estimates of the solution on the Littlewood-Paley dyadic blocks of the dual space.Comment: 32 page

Uticaj apsorbovane doze zračenja na stepen oksidativnog stresa u organima kunića nakon kompjuterizovane tomografije obavljene upotrebom različitih parametara snimanja

Usage of computed tomography (CT) is very frequent, both in human and veterinary medicine. Bearing in mind that the radiation dose, that patient receive during CT examination, is several times higher than during conventional radiography, much attention is devoted to evaluate necessity of this diagnostic procedure and its optimization, along with the minimal exposure of patients to the radiation load. According to this, the main goal of these investigations was to explore a correlation between absorbed radiation doses and the degree of activity of antioxidant enzymes in rabbit organs following CT examination performed by different tube voltage and amperage values. Experiment was conducted on 66 mature male New Zealand rabbits divided in 11 groups, consisting of six animals each. Animals from the control groups (NT) were not irradiated and were sacrificed immediately after two hours (group A1) and seven days (group A2) following anesthesia induced by ketamine and xylasine. Animals from the remaining eight groups were anesthetized, prior to irradiation, to ensure still positioning during CT examination. All examinations were performed under the following conditions: U 110 kV, I 63 mA, te 1 s, T 10 mm, CTDIw 17.9 mGy (groups I1 and I2); U 130 kV, I 63 mA, te 1 s, T 10 mm, CTDIw 25.2 mGy (groups II1 and II2); U 110 kV, I 105 mA, te 1 s, T 10 mm, CTDIw 29.8 mGy (groups III1 and III2) and U 130 kV, I 105 mA, te 1 s, T 10 mm, CTDIw 42.1 mGy (groups IV1 and IV2). Animals from the groups I1, II1, III1 and IV1 were sacrificed two hours following irradiation, while rabbits from the groups I2, II2, III2 and IV2 were sacrificed after seven days. Immediately after sacrifice, performed by decapitation method, organ samples were taken (blood – erythrocytes, brain, lungs, heart, liver, spleen, kidney, small intestine and testicles) for estimation of the following antioxidant enzyme activity: superoxide dismutase (SOD), Mn superoxide dismutase (MnSOD), Copper-Zinc superoxide dismutase CuZnSOD, catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione reductase (GR). Values, of the antioxidant enzyme activities in investigated samples, were then compared with values of the absorbed doses calculated on the previously constructed voxel phantom of the representative rabbit. According to the fact, that erythrocytes and small intestine can't be presented in voxel geometry, the degree of oxidative changes in these structures was compared to CTDIw values...Upotreba kompjuterizovane tomografije (CT) je veoma frekventna, kako u humanoj, tako i u veterinarskoj medicini. Imajući u vidu činjenicu da su doze zračenja koje pacijent primi prilikom CT pregleda višestruko veće od doza koje primi tokom konvencionalne rendgenografije, velika paţnja se posvećuje proceni opravdanosti ove vrste dijagnostičkog postupka i njegovoj optimizaciji, uz minimalno izlaganje pacijenata radijacionom opterećenju. Shodno tome, osnovni cilj ovog istraţivanja je podrazumevao ispitivanje korelacije izmeĎu apsorbovanih doza zračenja i stepena aktivnosti antioksidativnih enzima u pojedinim organima kunića nakon CT pregleda obavljenog pri različitim vrednosti napona i jačine struje u rendgenskoj cevi. Eksperiment je izvršen na 66 polno zrelih muţjaka novozelandskog belog kunića, rasporeĎenih u 11 eksperimentalnih grupa, sa po šest ţivotinja u svakoj. Kontrolne grupe kunića nisu izlagane zračenju već su ţrtvovane odmah (grupa NT), odnosno dva sata (grupa A1) i sedam dana (grupa A2) nakon primene anestezije koja je postignuta upotrebom ketamina i ksilazina. Ţivotinje iz preostalih osam grupa su, pre izlaganja x-zračenju, najpre anestezirane, kako bi se obezbedilo njihovo mirovanje tokom CT pregleda. Sva snimanja su izvršena pod sledećim uslovima: U 110 kV, I 63 mA, te 1 s, T 10 mm, CTDIw 17,9 mGy (I1 i I2 grupa); U 130 kV, I 63 mA, te 1 s, T 10 mm, CTDIw 25,2 mGy (II1 i II2 grupa); U 110 kV, I 105 mA, te 1 s, T 10 mm, CTDIw 29,8 mGy (III1 i III2 grupa) i U 130 kV, I 105 mA, te 1 s, T 10 mm, CTDIw 42,1 mGy (IV1 i IV2 grupa). Ţivotinje iz I1, II1, III1 i IV1 grupe su bile ţrtvovane dva sata nakon snimanja, dok su kunići iz I2, II2, III2 i IV2 grupe ţrtvovani nakon sedam dana. Neposredno po ţrtvovanju obavljenom metodom dekapitacije, od svih ţivotinja je prikupljan biološki materijal (uzorci krvi eritrocita, mozga, pluća, srca, jetre, slezine, bubrega, tankog creva i semenika) u kojima je odreĎivana aktivnost sledećih antioksidativnih enzima: superoksid dismutaze (SOD), mangan superoksid dismutaze (MnSOD), bakar-cink superoksid dismutaze (CuZnSOD), katalaze (CAT), glutation peroksidaze (GSH-Px) i glutation reduktaze (GR). Izmerene aktivnosti antioksidativnih enzima u ispitivanim uzorcima su komparirane sa vrednostima asporbovanih doza koje su izračunate na predhodno konstruisanom voksel fantomu reprezentativnog kunića. S obzirom na činjenicu da eritrocite i tanko crevo nije moguće prikazati u voksel geometriji, stepen oksidativnih promena u ovim strukturama je poreĎen sa CTDIw vrednostima..

Velocity averaging for diffusive transport equations with discontinuous flux

We consider a diffusive transport equation with discontinuous flux and prove the velocity averaging result under non-degeneracy conditions. As a corollary, we show the existence of a solution for the Cauchy problem for nonlinear degenerate parabolic equation with discontinuous flux. In order to achieve the results, we introduce a new variant of micro-local defect functionals which are able to "recognise" changes of the type of the equation

Der realistische Begriff des Rechts

The law is an extremely complex phenomenon. It is very difficult to determine it precisely as the complete comprehension and ultimate definition of the law are beyond human capabilities. Also, the law never coincides with its concept, nor does the concept of the law coincide with its definition. This fact shows that the real human capabilities for the comprehension, determination and definition of the law are very limited and the limits are unreliable. The concept of the law is relative as well, which is why all the definitions of the law are also relative. The concept and the definition of the law are also relative because they are of necessity subjective. It is for this reason that they are never truthful. However, even when they are not truthful, they are always useful. Because of these essential cognitive shortcomings and limitations, the law is determined and defined realistically – in a conventional and operative manner – whenever it is possible to do so. Additional difficulties are created by the fact that the number of conventional concepts and definitions of the law is almost limitless. Fortunately, only a number of them, considered operative, are used in the law. And all this because of a possible usefulness. Should the law be useful, then its realistic concept can be determined by the establishment of its common characteristics. On the basis of having at its disposal the mentioned common characteristics, the concept of the law can be operationally determined in both the expanded sense and the restricted sense. Also, it is possible to tell the difference between the three main layers in the concept of the law: complete (perfect), incomplete (imperfect) and unfinished (illusionary or naked) law. Obviously, the realistically determined concept of the law is not one-sided, nor is it monolithic, but complex, detailed and as a whole composed of layers of different degrees of being legal. They are used to finely tune the ordering of the relationships between different importance and the degree of the conflict and, which is also important, to legally regulate even those social areas that would otherwise be exclusively regulated with the state or with the social norms. Otherwise, even the Ten Commandments alone would be insufficient to regulate all human relationships. However, the law did not come into being out of leisure time, but out of dire human need to protect the society from self-destruction. Contrary to the realistic concept of the law, there also exist its idealistic, idealized and ideal concepts. However, the idealistic concept of the law is inoperative, the idealized concept of the law is not correct, while the ideal concept of the law is out of human reach.Pravo predstavlja izuzetno složenu pojavu. Njega je veoma teško točno odrediti, jer su potpuna spoznaja i konačno definiranje prava izvan ljudskih mogućnosti. Također, pravo se nikada ne podudara sa svojim pojmom, niti se pojam prava podudara sa svojom definicijom. Ta činjenica pokazuje da su stvarne ljudske mogućnosti za spoznavanje, određivanje i definiranje prava veoma ograničene, a granice nepouzdane. Pojam prava je i relativan, zbog čega su relativne i sve definicije prava. Pojam i definicija prava su relativni i zbog toga što su nužno subjektivni. Zbog toga oni nikada nisu istiniti. Ali, i kada nisu istiniti, oni su uvijek korisni. Zbog tih bitnih spoznajnih nedostataka i ograničenja, pravo se određuje i definira realistički – na konvencionalan i operativan način – kad god je to moguće. Dodatnu teškoću predstavlja činjenica da konvencionalnih pojmova i definicija prava ima gotovo beskonačno. Srećom, u pravu se koristi samo nekoliko njih koje se smatraju operativnima. I sve to zbog moguće korisnosti. Ako pravo treba biti korisno, tada se njegov realistički pojam može odrediti utvrđivanjem njegovih zajedničkih svojstava. Na osnovu raspoloživosti navedenih zajedničkih svojstava, pojam prava može se operativno odrediti u proširenom i suženom smislu. Također, mogu se razlikovati tri glavna sloja u pojmu prava: potpuno (savršeno), nepotpuno (nesavršeno) i nedovršeno (prividno ili golo) pravo. Očigledno, realistički određen pojam prava nije jednoobrazan ni monolitan, već složen, iznijansiran i u cijelosti satkan od slojeva različitih stupnjeva pravnosti. Njima se fino podešava uređivanje odnosa različitog značaja i stupnja konfliktnosti i, što je također važno, na odgovarajući način se pravno reguliraju i ona društvena područja koja bi isključivo bila regulirana državnim ili društvenim normama. Da nije tako, i Deset božjih zapovijedi bi bilo dovoljno za uređivanje svih ljudskih odnosa. Ali, pravo nije nastalo iz dokolice, već iz prijeke ljudske potrebe za očuvanjem društva od samouništenja. Nasuprot realističkom pojmu prava postoji njegov idealistički, idealizirani i idealni pojam. Ali, idealistički pojam prava nije operativan, idealizirani pojam prava nije točan, dok je idealni pojam prava ljudski nedostižan.Le droit est un phénomène particulièrement complexe. Il est très difficile à déterminer avec précision puisqu’une pleine compréhension et la définition ultime du droit sont au-delà des capacités humaines. Également, le droit ne coïncide jamais avec son concept ni le concept de droit ne coïncide avec sa définition. Ce fait montre que les capacités réelles de l’homme de connaître, déterminer et définir le droit sont très limitées et que les limites sont peu fiables. Le concept de droit est en outre relatif ; c’est pourquoi toute définition du droit est relative aussi. Le concept et la définition du droit sont également relatifs parce que nécessairement subjectifs. C’est pourquoi ils ne sont jamais fidèles. Néanmoins, même quand ils ne sont pas fidèles, ils sont utiles. En raison des ces défauts et limites cognitives essentielles, le droit est déterminé et défini réalistement – de façon conventionnelle et opérationnelle – à chaque fois que cela est possible. Une difficulté supplémentaire réside dans le fait qu’il existe un nombre quasiment illimité de concepts et de définitions conventionnels du droit. Heureusement, seulement quelques- unes, considérées comme opérationnelles, sont utilisées dans le droit. Et tout ceci à cause d’une potentielle utilité. Si le droit doit être utile, alors son concept réaliste peut être déterminé en établissant ses caractéristiques communes. S’appuyant sur la disponibilité des caractéristiques communes mentionnées, le concept du droit peut être déterminé opérationnellement dans un sens élargi et un sens étroit. Egalement, il est possible de distinguer trois couches principales dans le concept de droit : complet (parfait), incomplet (imparfait) et inachevé (apparent ou nu). A l’évidence, le concept de droit déterminé de manière réaliste n’est ni unilatéral ni monolithique mais complexe, nuancé et dans l’ensemble tissé de couches à différents degrés de légalité. Elles servent à accorder les rapports de signification et de degré de conflictualité différents et, ce qui est également important, à réguler légalement même les domaines sociaux qui autrement seraient régulés exclusivement par le biais des normes d’État ou sociales. Sinon, même les Dix Commandements suffiraient à réguler tous les rapports humains. Cependant, le droit n’est pas né du loisir, mais d’un besoin terrible de protéger la société de l’auto-destruction. Contrairement au concept réaliste de droit, il existe également son concept idéaliste, idéalisé et idéal. Cependant, le concept idéaliste du droit n’est pas opérationnel, le concept idéalisé n’est pas correct, tandis que le concept idéal du droit est hors de la portée de l’homme.Das Recht stellt ein immens vielfältiges Phänomen dar. Ihn präzise festzulegen entpuppt sich als unsäglich schwierig, denn eine lückenlose Erkenntnis sowie endgültige Definition des Rechts liegt jenseits des menschlichen Vermögens. Zudem geht weder das Recht mit dessen Begriff konform, noch tut es der Begriff des Rechts mit eigener Bestimmung. Dieser Tatbestand lässt durchblicken, die wahre menschliche Befähigung zum Erkennen, Determinieren sowie Definieren des Rechts sei höchst begrenzt, wobei sich ebendiese Schranken als unzuverlässig erzeigen. Die Notion des Rechts ist ebenso relativ, weswegen hiernach sämtliche Begriffsbestimmungen des Rechts relativ sind. Der Begriff einschließlich der Definition des Rechts ist auch aufgrund der ihnen notwendigerweise innewohnenden Subjektivität relativ. Aus diesem Grund sind sie niemals wahrheitsgetreu. Allerdings, auch wenn sie der Wahrheit nicht entsprechen, sind sie stets von Nützlichkeit. Wegen der angebrachten essenziellen erkenntnismäßigen Unzulänglichkeiten und Limitierungen wird das Recht realistisch bestimmt und definiert – in einer konventionellen bzw. operativen Manier – wann immer dies durchführbar ist. Zusätzliche Erschwernisse werden von der Tatsache geschaffen, dass die Zahl der gebräuchlichen Begriffe und Definitionen des Rechts schier unermesslich ist. Glücklicherweise werden lediglich etliche, als operativ angesehene, im Bereich von Recht eingesetzt. Und all dies der denkbaren Nützlichkeit halber. Sollte das Recht nützlich sein, dann lässt sich dessen realistischer Begriff per Gründung seiner gemeinsamen Wesenszüge festsetzen. Auf der Basis der vorhin angeschnittenen, ihm zu Gebote stehenden angehörigen Merkmale, kann der Begriff des Rechts operational determiniert werden, sowohl im erweiterten als auch im engeren Sinne. Ebenfalls ist der Unterschied erkennbar zwischen drei Hauptschichten in dem Begriff des Rechts: vollständiges Recht (vollkommen), unvollständiges Recht (unvollkommen) und unvollendetes Recht (scheinbar oder nackt). Augenscheinlich ist der realistischerweise bestimmte Begriff des Rechts weder einseitig noch monolithisch, stattdessen ist er komplex, detailliert und als Ganzes aus Schichten von ungleichem Rechtlichkeitsgrad zusammengestellt. Man gebraucht sie zur Feinabstimmung der Beziehungsordnung zwischen der unterschiedlichen Wichtigkeit und dem Grad des Konflikts, und, was genauso Gewicht hat, um sogar jene Gesellschaftszonen rechtmäßig zu regeln, die anderenfalls ausschließlich seitens der staatlichen bzw. gesellschaftlichen Normen geregelt würden. Ansonsten würden selbst die Zehn Gebote nicht genügen, um menschliche Verhältnisse in ihrer Gänze zu ordnen. Jedoch ist das Recht nicht als Freizeitaktivität entstanden, sondern im Gegenteil als unentbehrliches menschliches Bedürfnis nach Bewahrung der Menschheit vor Selbstauflösung. Der realistischen Notion des Rechts entgegengesetzt existieren parallel dessen idealistische, idealisierte und ideale Begriffe. Dabei gilt der idealistische Begriff als inoperativ, der idealisierte als inkorrekt, während der ideale Begriff außerhalb der menschlichen Reichweite liegt

Velocity averaging under minimal conditions for deterministic and stochastic kinetic equations with irregular drift

This study investigates the $L^1_{\operatorname{loc}}$ compactness of velocity averages of sequences of solutions $\{u_n\}$ for a class of kinetic equations. The equations are examined within both deterministic and stochastic heterogeneous environments. The primary objective is to deduce velocity averaging results under conditions on $u_n$ and the drift ${\mathfrak f}={\mathfrak f}(t,{\boldsymbol x},{\boldsymbol \lambda})$ that are more lenient than those stipulated in previous studies. The main outcome permits the inclusion of highly irregular drift vectors ${\mathfrak f} \in L^q$ that adhere to a general non-degeneracy condition. Moreover, the sequence $\{u_n\}$ is uniformly bounded in $L^p$ -- for an exponent $p$ allowed to be strictly smaller than $2$ -- under the requirement $\frac{1}{p} + \frac{1}{q} < 1$. Resolving the matter of strong compactness in velocity averages, considering these assumptions, has remained an open problem for a long time. The cornerstone of our work's progress lies in the strategic employment of the broader concept of $H$-distributions, moving beyond the traditional reliance on $H$-measures. Notably, our study represents one of the first significant uses of $H$-distributions in this context

The influence of absorbed radiation dose on the degree of oxidative stress in rabbitsʹ organs after computed tomography performed by different protocols

Upotreba kompjuterizovane tomografije (CT) je veoma frekventna, kako u humanoj, tako i u veterinarskoj medicini. Imajući u vidu činjenicu da su doze zračenja koje pacijent primi prilikom CT pregleda višestruko veće od doza koje primi tokom konvencionalne rendgenografije, velika paţnja se posvećuje proceni opravdanosti ove vrste dijagnostičkog postupka i njegovoj optimizaciji, uz minimalno izlaganje pacijenata radijacionom opterećenju. Shodno tome, osnovni cilj ovog istraţivanja je podrazumevao ispitivanje korelacije izmeĎu apsorbovanih doza zračenja i stepena aktivnosti antioksidativnih enzima u pojedinim organima kunića nakon CT pregleda obavljenog pri različitim vrednosti napona i jačine struje u rendgenskoj cevi. Eksperiment je izvršen na 66 polno zrelih muţjaka novozelandskog belog kunića, rasporeĎenih u 11 eksperimentalnih grupa, sa po šest ţivotinja u svakoj. Kontrolne grupe kunića nisu izlagane zračenju već su ţrtvovane odmah (grupa NT), odnosno dva sata (grupa A1) i sedam dana (grupa A2) nakon primene anestezije koja je postignuta upotrebom ketamina i ksilazina. Ţivotinje iz preostalih osam grupa su, pre izlaganja x-zračenju, najpre anestezirane, kako bi se obezbedilo njihovo mirovanje tokom CT pregleda. Sva snimanja su izvršena pod sledećim uslovima: U 110 kV, I 63 mA, te 1 s, T 10 mm, CTDIw 17,9 mGy (I1 i I2 grupa); U 130 kV, I 63 mA, te 1 s, T 10 mm, CTDIw 25,2 mGy (II1 i II2 grupa); U 110 kV, I 105 mA, te 1 s, T 10 mm, CTDIw 29,8 mGy (III1 i III2 grupa) i U 130 kV, I 105 mA, te 1 s, T 10 mm, CTDIw 42,1 mGy (IV1 i IV2 grupa). Ţivotinje iz I1, II1, III1 i IV1 grupe su bile ţrtvovane dva sata nakon snimanja, dok su kunići iz I2, II2, III2 i IV2 grupe ţrtvovani nakon sedam dana. Neposredno po ţrtvovanju obavljenom metodom dekapitacije, od svih ţivotinja je prikupljan biološki materijal (uzorci krvi eritrocita, mozga, pluća, srca, jetre, slezine, bubrega, tankog creva i semenika) u kojima je odreĎivana aktivnost sledećih antioksidativnih enzima: superoksid dismutaze (SOD), mangan superoksid dismutaze (MnSOD), bakar-cink superoksid dismutaze (CuZnSOD), katalaze (CAT), glutation peroksidaze (GSH-Px) i glutation reduktaze (GR). Izmerene aktivnosti antioksidativnih enzima u ispitivanim uzorcima su komparirane sa vrednostima asporbovanih doza koje su izračunate na predhodno konstruisanom voksel fantomu reprezentativnog kunića. S obzirom na činjenicu da eritrocite i tanko crevo nije moguće prikazati u voksel geometriji, stepen oksidativnih promena u ovim strukturama je poreĎen sa CTDIw vrednostima...Usage of computed tomography (CT) is very frequent, both in human and veterinary medicine. Bearing in mind that the radiation dose, that patient receive during CT examination, is several times higher than during conventional radiography, much attention is devoted to evaluate necessity of this diagnostic procedure and its optimization, along with the minimal exposure of patients to the radiation load. According to this, the main goal of these investigations was to explore a correlation between absorbed radiation doses and the degree of activity of antioxidant enzymes in rabbit organs following CT examination performed by different tube voltage and amperage values. Experiment was conducted on 66 mature male New Zealand rabbits divided in 11 groups, consisting of six animals each. Animals from the control groups (NT) were not irradiated and were sacrificed immediately after two hours (group A1) and seven days (group A2) following anesthesia induced by ketamine and xylasine. Animals from the remaining eight groups were anesthetized, prior to irradiation, to ensure still positioning during CT examination. All examinations were performed under the following conditions: U 110 kV, I 63 mA, te 1 s, T 10 mm, CTDIw 17.9 mGy (groups I1 and I2); U 130 kV, I 63 mA, te 1 s, T 10 mm, CTDIw 25.2 mGy (groups II1 and II2); U 110 kV, I 105 mA, te 1 s, T 10 mm, CTDIw 29.8 mGy (groups III1 and III2) and U 130 kV, I 105 mA, te 1 s, T 10 mm, CTDIw 42.1 mGy (groups IV1 and IV2). Animals from the groups I1, II1, III1 and IV1 were sacrificed two hours following irradiation, while rabbits from the groups I2, II2, III2 and IV2 were sacrificed after seven days. Immediately after sacrifice, performed by decapitation method, organ samples were taken (blood – erythrocytes, brain, lungs, heart, liver, spleen, kidney, small intestine and testicles) for estimation of the following antioxidant enzyme activity: superoxide dismutase (SOD), Mn superoxide dismutase (MnSOD), Copper-Zinc superoxide dismutase CuZnSOD, catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione reductase (GR). Values, of the antioxidant enzyme activities in investigated samples, were then compared with values of the absorbed doses calculated on the previously constructed voxel phantom of the representative rabbit. According to the fact, that erythrocytes and small intestine can't be presented in voxel geometry, the degree of oxidative changes in these structures was compared to CTDIw values..

Ocena kvaliteta priplodnih jaja Leghorn rase kokoši gajene u poluekstenzivnom sistemu

Analysis results regarding the external traits of breeding eggs quality originating from Leghorn breed reared in semi extensive system are given in this research. Research was done on the 55 egg sample, divided in to two categories according to weight: I group - eggs weighing up to 60 g (≤ 60 g) and II group - eggs weighing over 60 g (> 60 g). Aim of this research was to analyze the influence of weight group to base quality traits of eggs, such as weight, length, width, shape index in above mentioned breeding system. Obtained results point the fact that Leghorn breed in semi extensive breeding system achieves very satisfying results in terms of the base external quality characteristics of the eggs. Results of conducted research show that more attention should be given to the quality of eggs for planting, especially for pure breeds, then towards breeding goals with aim to improve their productive - reproductive traits, therefore preserving genetic potential of different breeds, species and races of poultry.U radu su izloženi rezultati ispitivanja spoljašnjih osobina kvaliteta priplodnih jaja poreklom od Leghorn rase kokoši gajene u poluekstenzivnom sistemu držanja. Ispitivanja su izvršena na uzorku od po 55 jaja, podeljenih u dve težinske grupe i to: I grupa - jaja mase do 60 g (≤ 60 g) i II grupa - jaja mase preko 60 g (> 60 g). Cilj istraživanja je bio da se ispita uticaj težinske grupe na osnovne pokazatelje kvaliteta jaja, kao što su masa, dužina, širina i indeks oblika jaja u navedenom sistemu držanja. Dobijeni rezultati ukazuju na činjenicu da leghorn rasa kokoši u poluekstenzivnom sistemu gajenja ostvaruje zadovoljavajuće rezultate u pogledu osnovnih karakteristika spoljašnjeg kvaliteta jaja. Rezultati sprovedenih istraživanja ukazuju na to da je potrebno posvetiti veću pažnju ispitivanju kvaliteta jaja za nasad, naročito kod čistih rasa kokoši, zatim pravcu odgajivanja u cilju poboljšanja njihovih proizvodno – reproduktivnih sposobnosti, a samim tim i očuvanja genetskog potencijala različitih vrsta, rasa i sojeva živine