Separability problem for multipartite states of rank at most four

One of the most important problems in quantum information is the separability problem, which asks whether a given quantum state is separable. We investigate multipartite states of rank at most four which are PPT (i.e., all their partial transposes are positive semidefinite). We show that any PPT state of rank two or three is separable and has length at most four. For separable states of rank four, we show that they have length at most six. It is six only for some qubit-qutrit or multiqubit states. It turns out that any PPT entangled state of rank four is necessarily supported on a 3x3 or a 2x2x2 subsystem. We obtain a very simple criterion for the separability problem of the PPT states of rank at most four: such a state is entangled if and only if its range contains no product vectors. This criterion can be easily applied since a four-dimensional subspace in the 3x3 or 2x2x2 system contains a product vector if and only if its Pluecker coordinates satisfy a homogeneous polynomial equation (the Chow form of the corresponding Segre variety). We have computed an explicit determinantal expression for the Chow form in the former case, while such expression was already known in the latter case.Comment: 19 page

Organizational and economic aspects of farm business for production of table eggs

Производња конзумних јаја представља једну од најинтензивнијих линија сточарске производње која произвођачима обезбеђује добијање значајног обима производње током читаве године. Успешност пословања фарми за производњу конзумних јаја зависи од великог броја организационих и технолошких чинилаца, при чему су у спроведеном истраживању у обзир узети систем држања носиља, начин обезбеђења хране за носиље и степен аутоматизације производног процеса, као најважнији фактори. Ради постизања основног циља истраживања, установљавања економских законитости које владају у области производње конзумних јаја и сагледавања могућности за њихово коришћење у правцу осигуравања пословног успеха фарми које се баве овом производњом, извршена је квантификација утицаја посматраних фактора. За опис, прогнозу и објашњење карактеристика и понашања фарми у постојећим и измењеним условима пословања, најпре су на основу четири посматране фарме за производњу конзумних јаја, различите у погледу наведених организационих параметара, креирана четири модела. Упоредивост добијених резултата обезбеђена је формулсањем модела на бази фарми које гаје исти хибрид кокоши – Lohmann brown-classic и примењују исту технологију производње, и то за исти период посматрања у трајању од 57 недеља и уз коришћење истих цена инпута и аутпута при израчунавању показатеља успешности пословања. Анализа производних перформанси извршена је применом анализе варијансе и одговарајућих тестова, док је економска ефикасност пословања посматраних модела фарми мерена на основу показатеља економичности, рентабилности и продуктивности. По утврђивању показатеља успешности пословања у постојећим условима, примењен је метод сценарио анализе како би се предвиделе промене које би ови показатељи претрпели у измењеним условима пословања. На крају је спроведена и упоредна анализа резултата остварених у постојећим условима и резултата који би се постигли у случају реализације креираних сценарија и то у функцији обезбеђења основе за сагледавање развојних алтернатива и доношење одлука о правцима унапређења производње конзумних јаја...The production of table eggs represents one of the most intensive line of livestock production, which provides farmers with a significant production volume during the year. Business success of farms for the production of table eggs depends on a large number of organizational and technological factors, while the conducted research considered housing system, ways to provide food for layers and the degree of automation of the production process as the most important ones. In order to achieve the basic research goal, establishing the economic laws governing the production of table eggs and examining the alternatives to ensure the business success for these farms, quantification of the impact for the considered factors was carried out. To describe, forecast and interpret characteristics and patterns of farm behavior in the existing and altered business conditions four models were created, based on four observed farms for production of table eggs, different in terms of the mentioned organizational parameters. The comparability of the obtained results was ensured by formulating models which refer to farms using the same layer hybrid – Lohmann brown-classic and production technology for the 57-week observation period with application of the same input and output prices in performance calculations for all the observed farms. Production performance analysis was carried out using the analysis of variance and appropriate tests, while the economic efficiency of the observed farm models was measured through calculated indicators of cost-effectiveness, profitability and productivity. After determining the performance indicators in the existing conditions, the method of scenario analysis was applied in order to anticipate the changes that these indicators would suffer in the changed business conditions. Finally, in order to provide foundation for understanding development alternatives and making decisions on ways to improve the production of table eggs, a comparative analysis of the results achieved in the existing conditions and in case of the created scenarios realization was carried out..

Levels of insulin, insulin-like growth factor-I and thyroid hormones in relation to the body condition score changes in periparturient dairy cows

The objective of this study was to determine the levels of insulin, insulin like growth factor I (IGF-I) and thyroid hormones in relation to the body condition score (BCS) of periparturient dairy cows. The study was carried out on twenty Holstein-Friesian dairy cows with average milk production of 7000 L/305 days in the previous lactation, parity ranging from 2-4. All cows were BCS scored during the early dry period, 7±3 days before and after parturition. Based on the BCS at the early dry period, cows were divided in two groups: cows with high BCS (3.75- 4.25, HBCS, n=10), and cows with moderate BCS (2.75-3.75, MBCS, n=10). Blood samples were taken at the time of BCS evaluation. Concentrations of insulin, IGF-I, triiodothyroinine (T3) and thyroxine (T4) were determined by radioimmunoassay (RIA, INEP-Zemun, Serbia). Statistical differences between mean values were determined using Student t-test (p<0.01). Mean BCS values at early dry period were significantly different compared to two other periods (p<0.01) within both groups, but BCS was similar in both groups at 7±3 days after calving (2.69±0.67:2.62± 0.27, p>0.05). IGF-I level in HBCS cows at days 7±3 before calving was significantly higher (16.28±3.07:11.76±2.28, p<0.01), with a reverse relationship after calving (3.77±1.64:8.46±2.37, p<0.01). Insulin level was significantly lower at 7±3 days before calving in HBCS cows (16.26±4.60:20.18±4.96mIU/L, p<0.05). Thyroid hormones levels were significantly lower in HBCS group et all examined periods. [Projekat Ministarstva nauke Republike Srbije, br. III 46002 i br. 31003

PEG-ylated parenteral Nanoemulsions as prospective Carriers for enhanced Brain Delivery with Diazepam as a Model Drug - Physicochemical Characterisation

Parenteral nanoemulsions are regarded as biocompatible drug delivery systems for lypophilic drugs. When it comes to delivering actives to the brain as a target site, prolonged circulation time is desirable. The objective of this study was to conduct physicochemical characterization of PEGylated nanoemulsions as prospective carriers for enhanced brain delivery, using diazepam as a model active substance for brain targeting. Nanoemulsions were prepared by high pressure homogenization method and characterized regarding droplet size, zeta potential, pH, conductivity, viscosity and in vitro release profile. PEG2000-DSPE and PEG5000-DPPE were used for PEGylation. All the formulations were autoclaved and stored at room temperature. After 2 months there were no significant changes in physicochemical parameters in autoclaved formulations which rendered them as good potential templates to incorporate drugs for brain targeted delivery

Efekat interakcije sistematskih faktora na mlečnost krava simentalske rase u standardnim laktacijama

The effect of interaction between the farm and calving season, as well as the farm and group of lactations on milk performance traits (milk yield, yield of milk fat, 4% fat corrected milk and milk fat content) was analyzed on sample of 2805 Simmental cows with total 9718 standard lactations, housed on dairy farm 'Zlatiborski suvati' on Zlatibor (578 cows and 1968 lactations), dairy farm of the Agricultural holding Dobričevo in Ćuprija (964 cows and 3237 lactations) and dairy animals housed on family farms/households in the region of Kotraža (1263 cows and 4513 lactations). The significance of the effect of interaction between the farm and calving season, as well as interaction between the farm and group of lactations on all milk performance traits was very high (P (lt) 0.001), which justified their inclusion into models for assessment of the breeding value of dairy cows. The share of variance of interactions in total variance of milk performance traits in standard lactations was low (below and around 4%), which clearly indicated even more systematic factors and their interactions which influence the total variability of observed traits of milk performance of cows in standard lactations.Uticaj interakcije farme i sezone telenja kao i farme i grupe laktacija na osobine mlečnosti (proizvodnja mleka, mlečne masti, 4% mast-korigovanog mleka i sadržaj mlečne masti) analizirano je kod 2805 krava simentalske rase sa ukupno 9718 standardnih laktacija koje su bile smeštene na farmi muznih krava 'Zlatiborski suvati' na Zlatiboru (578 krava i 1968 laktacija), farmi muznih krava na Poljoprivrednom dobru Dobričevo u Ćupriji (964 krava i 3237 laktacija) i području Kotraže na individualnim gazdinstvima (1263 krava i 4513 laktacija). Značajnost uticaja interakcija farme i sezone telenja, kao i interakcije farme i grupe laktacija na sve osobine mlečnosti standardnih laktacija bila je vrlo visoka (P (lt) 0.001), što opravdava njihovo uključivanje u modele za ocenu priplodne vrednosti muznih krava. Udeo varijanse interakcija u ukupnoj varijansi osobina mlečnosti standardnih laktacija bio je nizak (ispod i oko 4%), što jasno ukazuje na još veliki broj sistematskih faktora i njihovih interakcija koji utiču na ukupnu varijabilnost posmatranih osobina mlečnosti krava u standardnim laktacijama

Maceral and biomarker composition of lignite lithotypes - Implications on palaeoenvironment and grindability properties

Maceral and biomarker composition of different lignite lithotypes: matrix-coal, pale yellow xylite-rich coal, dark yellow xylite-rich coal, brown xylite-rich coal, mineral-rich coal and dopplerite originating from the Upper Miocene (“Pontian”) Kostolac Basin, Serbia was studied in detail. The objective was to establish the sources of organic matter and to determine palaeoenvironmental conditions which resulted in formation of different lignite lithotypes. Moreover, the influence of lignite lithotypes on grindability properties has also been assessed. Mineral-rich coal was formed in topogenous fresh water peat mire with open water areas. Formation of matrix coal was performed in reed march. The peatification of pale yellow- and dark yellow xylite proceeded in dry forest swamp. Brown xylite was formed in wet forest swamp, whereas dopplerite could have formed during transition of wet forest swamp into bush mire. Contents of liptinites, inertinites, gelinite, mineral matter, sesquiterpenoids, hopanoids and n-alkanes have positive impact on Hardgrove Grindability Index (HGI), whereas total huminites, telohuminite and total organic carbon content, as well as retene/2-methyl, 1-(4’-methylpentyl), 6-isopropylnaphthalene ratio exhibited negative influence on HGI

Uticaj starosti mladih bikova simentalske rase na randman

Considering the Serbia's potential and tradition in production of quality beef meat as food for human consumption and raw material in the food industry and the demand of the EU market, shows the need to intensify the production of this foodstuff. Aim of this paper was to analyze the effect of age of young Simmental bulls on dressing percentage in slaughterhouse, according to the standard applied in the EU (Council Regulation (EC) No 1234/2007, Commission Regulation (EC) No 1249/2008; Commission European, Directorate-General for Agriculture and Rural Development). Regulations that define more precisely the quality of meat are only partially implemented in Serbia (Official Gazette of the SFRY 34/74, 26/75, 13/78). The accuracy of the slaughter processing of carcasses is assessed as adequate in the facility in which the analysis was conducted. The study was conducted on 116 young bulls carcasses, from redemption. Two groups of young bulls (cattle) were formed, first group the age of 269-350 days and second group the age of 351-450 days. The results show that due to the wider age intervals in the second group (351-450 days) the difference in mass of animals before slaughter and carcass weight after primary processing is statistically significant (P lt 0.05), while the yield difference between the two groups is statistically insignificant (P> 0.05). The obtained results indicate that it is necessary to undertake concrete measures in the primary sector to achieve better yield and meat quality.Posmatrajući potencijal i tradiciju naše zemlje u proizvodnji kvalitetnog goveđeg mesa kao namirnice za ishranu ljudi i sirovine za preradu u prehrambenoj industriji s jedne strane, i potreba tržista EU sa druge strane, neophodno je intenzivirati proizvodnju ove vrste namirnice animalnog porekla. Cilj rada je bio da se analizira uticaj starosti junadi (mladih bikova) simentalske rase na randman, u klanici, prema standardu koji se primenjuje u zemljama Evropske Unije (Council Regulation (EC) No 1234/2007, Commission Regulation (EC) No 1249/2008; Commission European, Directorate-General for Agriculture and Rural Development). U Republici Srbiji se samo delimično primenjuju propisi koji bliže definišu kvalitet mesa (Pravilnik Sl. list SFRJ 34/74, 26/75, 13/78). Ispravnost klanične obrade trupa je ocenjena kao adekvatna u objektu u kome je sprovedena analiza. Ispitivanje je sprovedeno na 116 trupova junadi (mladih bikova) iz otkupa. Formirane su dve grupe junadi (mladih bikova), prva starosti 269-350 dana i druga 351-450 dana. Rezultati pokazuju da su usled širih starosnih intervala u drugoj grupi (351-450 dana) razlike u masi životinja pre klanja i masi trupova nakon primarne obrade statistički značajne (P lt 0.05), dok su razlike između randmana dve posmatrane grupe statistički nesignifikantne (P>0.05). Dobijeni rezultati ukazuju da je neophodno preduzeti konkretne mere u primarnom sektoru radi postizanja boljeg prinosa i kvaliteta mesa

Analiza kvaliteta trupova mladih bikova simentalske rase prema EU standardu

Domestic spotted cattle of Simmental breed with a combined production capacity is mostly grown in the Republic of Serbia. Considering the Serbia's potential and tradition in production of quality beef meat as food for human consumption and raw material in the food industry and the demand of the EU market, imposes the need for changing the present and adopting new regulations. The quality of the slaughtered animals is a subject of interest, of both primary production and meat industry. Procedure of classification of carcasses is performed in slaughterhouses immediately after a veterinary examination and measurement of carcasses weight. This paper examines the quality of young cattle carcasses in a slaughterhouse in the Raska district, according to the standard applied in the EU but not in Republic of Serbia. Examination has been conducted on 80 cattle carcasses (young bulls) weighing 450 - 550 kg. For the quality evaluation and grading of meat the following parameters according to the European standard for the classification of cattle carcasses (SEUROP) were used: weight of the animal, the category of a slaughtered animal according to the age and physiological state, slaughter weight / carcass weight and randman, i.e. the conformation of the carcass, development of the muscles of the carcass as well as the development of basic parts (leg, back and shoulder) and the degree of carcass fat tissue coverage.Domaće šareno goveče u tipu simentalca je rasa goveda kombinovanih proizvodnih sposobnosti koja se najviše gaji u Republici Srbiji. Posmatrajući potencijal i tradiciju naše zemlje u proizvodnji kvalitetnog goveđeg mesa kao namirnice za ishranu ljudi i sirovine za preradu u prehrambenoj industriji s jedne strane, i potreba tržista EU sa druge strane, nameće se potreba za menjanjem postojećih i donošenjem novih propisa. Kvalitet trupova zaklanih životinja je predmet interesovanja, kako primarne proizvodnje, tako i industrije mesa. Postupak klasiranja trupova odnosno polutki sprovodi se u klanicama neposredno nakon veterinarskog pregleda i utvrđivanja mase trupa. U radu je ispitan kvalitet trupova junadi, zaklanih u jednoj klanici u Raškom okrugu, prema standardu koji se primenjuje u zemljama Evropske Unije a koji se još ne primenjuje u Republici Srbiji. Ispitivanje je sprovedeno na 80 trupova junadi (mladih bikova) telesne mase 450 - 550 kg. Za procenu kvaliteta i klasiranje mesa u trupovima korišćeni su parametri, prema Evropskom standardu za klasiranje trupova goveda SEUROP: masa životinje, kategorija zaklane životinje shodno starosti i fiziološkom stanju, klanična težina/masa trupa i randman, konformacija trupa tj. razvijenosti mišića trupa kao i razvijenosti osnovnih delova (but, leđa i plećka) i stepen prekrivenosti trupa masnim tkivom

Multi-black holes from nilpotent Lie algebra orbits

For N \ge 2 supergravities, BPS black hole solutions preserving four supersymmetries can be superposed linearly, leading to well defined solutions containing an arbitrary number of such BPS black holes at arbitrary positions. Being stationary, these solutions can be understood via associated non-linear sigma models over pseudo-Riemaniann spaces coupled to Euclidean gravity in three spatial dimensions. As the main result of this paper, we show that whenever this pseudo-Riemanniann space is an irreducible symmetric space G/H*, the most general solutions of this type can be entirely characterised and derived from the nilpotent orbits of the associated Lie algebra Lie(G). This technique also permits the explicit computation of non-supersymmetric extremal solutions which cannot be obtained by truncation to N=2 supergravity theories. For maximal supergravity, we not only recover the known BPS solutions depending on 32 independent harmonic functions, but in addition find a set of non-BPS solutions depending on 29 harmonic functions. While the BPS solutions can be understood within the appropriate N=2 truncation of N=8 supergravity, the general non-BPS solutions require the whole field content of the theory.Comment: Corrected version for publication, references adde

Petrographical and organic geochemical study of the lignite from the Smederevsko Pomoravlje field (Kostolac Basin, Serbia)

Three Upper Miocene (Pontian) lignite seams are present in the Smederevsko Pomoravlje field (Kostolac Basin, Serbia). The origin of their organic matter (OM), the characteristics of the depositional environment and certain utilisation properties have been evaluated based on petrographic data, bulk organic geochemical parameters, biomarker patterns and their isotope signatures. Moreover, results of isotopic analysis were used for the investigation of the influence of diagenetic aromatisation on delta C-13 signatures of biomarkers. The studied lignites are typical humic coals. The OM of lignites is derived from woody vegetation and herbaceous peat-forming plants, with a strong prevalence of the former. The peat-forming vegetation is dominated by decay resistant conifers, including gymnosperm families Cupressaceae, Taxodiaceae, and Pinaceae. Angiosperms occurred in lower amounts. Minor contribution of ferns, fungi and emergent aquatic macrophyta to the biomass is also evident. Chemoautotrophic- and heterotrophic bacteria played an import role during diagenesis. Diagenetic alterations, associated with change in the number of carbon atoms, influence delta C-13 ratios. Diagenetic aromatisation of di- and non-hopanoid triterpenoids is accompanied with C-13 depletion, whereas aromatisation of hopanoids displays the opposite trend. Peatification proceeded in a fresh water environment under variable, anoxic to slightly oxic redox conditions. The lowermost coal seam III accumulated in a topogenous fresh water peat mire with open water areas, which changed occasionally into a wet forest swamp. This resulted in the deposition of mineral-rich coal. The characteristics of lignite in coal seam II are similar to those of coal seam III. This is supported also by generally similar delta C-13 values of individual biomarkers. Coal seam I is dominated by xylite-rich coal, formed under mesotrophic to ombrotrophic conditions. Rapid flooding of the bogs stopped peat growth in all three coal seams. The ratios of ring-A-degraded and non-degraded aromatic diterpenoids and non-hopanoid triterpenoids, proposed in this study, as well as degree of aromatisation of these biomarkers, reflect changes in the water table. Calorific values of the samples indicate that they meet basic requirements for utilisation in the thermal power plants. None of the lignite samples is suitable for coal briquetting, whereas, based on petrographic data, lignite from coal seam I possesses certain potential for fluidized bed gasification