340 research outputs found
Analysis of diet of piscivorous fishes in Bovan, Gruža and Šumarice Reservoir, Serbia
Diet of adult pikeperch Sander lucioperca, Eurasian perch Perca fluviatilis, northern pike Esox lucius and European catfish Silurus glanis as top predators in aquatic ecosystems in Serbia was investigated during 2011, in order to understand their relationship to their prey and to investigate their food consumption, feeding and assimilation rate, cannibalism, and habitat segregation. Northern pike, Eurasian perch, pikeperch and European catfish were collected in three reservoirs in Serbia. Prey items that were found in all four species included fish, mollusks, insect larvae and crustaceans. A total of 11 taxonomic groups were found, but they were not all represented as a prey in all four species. Eurasian perch were present in the diet of all four predatory fish species, mollusks were recorded only in that of European catfish. Roach Rutilus rutilus and bleak Alburnus alburnus were prey to all species, except northern pike. Chub Squalius cephalus, bream Brama brama and Gammaridae were found only in stomach of pikeperch. Analysis of similarity showed that difference for diet between predatory fish species was significant for their due to significant differences existing between northern pike and pikeperch and northern pike and Eurasian perch
Weak Pseudogap Behavior in the Underdoped Cuprate Superconductors
We report on an exact solution of the nearly antiferromagnetic Fermi liquid
spin fermion model in the limit \pi T << \omega_{sf}, which demonstrates that
the broad high energy features found in ARPES measurements of the spectral
density of the underdoped cuprate superconductors are determined by strong
antiferromagnetic (AF) correlations and precursor effects of an SDW state. We
show that the onset temperature, T^{cr}, of weak pseudo-gap (pseudoscaling)
behavior is determined by the strength, \xi, of the AF correlations, and obtain
the generic changes in low frequency magnetic behavior seen in NMR experiments
with \xi(T^{cr}) \approx 2, confirming the Barzykin and Pines crossover
criterion.Comment: REVTEX, 4 pages, 3 EPS figure
Gestion des équipages aériens durant le jour d'opération
Le problème de la gestion des horaires d'équipage aérien durant les opérations quotidiennes -- Gestion simultanée des horaires d'équipage à un seul membre et des horaires de vol durant le jour d'opération -- Gestion simultanée des horaires d'équipage à plusieurs membres et des horaires de vol durant le jour d'opération
Revealing complex relations between personality and fitness: HEXACO personality traits, life-time reproductive success and the age at first birth
HEXACO personality framework represents one of the most prominent models of human personality traits. Despite of this, there are no empirical studies that estimate the fitness outcomes of HEXACO traits, although this topic represents a basic foundation for the study of the contemporary evolution of personality. In the present research we explored the relations between HEXACO personality traits, and three fitness indicators: the number of children, the number of grandchildren and the age at first birth. Participants were selected from the community population of individuals in a post-reproductive stage (N = 255; Mage = 64.9 years). Results from the regression analyses showed that the number of children was associated with lower scores on Honesty and Openness and higher scores on Emotionality; Agreeableness was positively associated with this criterion but only in males. The number of grandchildren was predicted by low Openness and marginally by high Conscientiousness, while Honesty had positive zero-order correlation with the criterion measure. Individuals with higher Extraversion tended to reproduce earlier in their lifetime. Findings contribute to the empirical data which suggest that personality is related to biological fitness in contemporary human populations: this means that personality is likely under natural selection and hence, it continues to evolve.This is the peer-reviewed version of the following article: Međedović, J.; Šoljaga, M.; Stojković, A.; Gojević, I. Revealing Complex Relations between Personality and Fitness: HEXACO Personality Traits, Life-Time Reproductive Success and the Age at First Birth. Pers. Individ. Differ. 2018, 129, 143–148. [https://doi.org/10.1016/j.paid.2018.03.014
Theory of the Optical Conductivity in the Cuprate Superconductors
We present a study of the normal state optical conductivity in the cuprate
superconductors using the nearly antiferromagnetic Fermi liquid (NAFL)
description of the magnetic interaction between their planar quasiparticles. We
find that the highly anisotropic scattering rate in different regions of the
Brillouin zone, both as a function of frequency and temperature, a benchmark of
NAFL theory, leads to an average relaxation rate of the Marginal Fermi Liquid
form for overdoped and optimally doped systems, as well as for underdoped
systems at high temperatures. We carry out numerical calculations of the
optical conductivity for several compounds for which the input spin fluctuation
parameters are known. Our results, which are in agreement with experiment on
both overdoped and optimally doped systems, show that NAFL theory explains the
anomalous optical behavior found in these cuprate superconductors.Comment: REVTEX file, 8 PostScript figure
Biopharmaceutical characterisation of ciprofloxacin metallic cation interaction
Biofarmaceutska karakterizacija podrazumeva sprovođenje odgovarajućih in vitro, in vivo i in silico ispitivanja s ciljem da se deo in vivo ispitivanja u ljudi zameni reproduktivnim i dobro standardizovanim laboratorijskim testovima. Mogućnost in vitro simuliranja dešavanja u ljudskom organizmu dobila je veći značaj sa primenom Biofarmaceutskog sistema klasifikacije lekova i primenom in vitro metoda u cilju predviđanja lek/lek interakcija i otkrivanja potencijalnih uzroka koji dovode do promena u apsorpciji lekovite supstance u gastrointestinalnom traktu. U in vitro uslovima se ne mogu u potpunosti reprodukovati uslovi koji postoje u organizmu, ali pažljiv odabir eksperimentalnih uslova može dati korisne podatke koji su u korelaciji sa in vivo podacima. Takođe, razvoj računarskih programa koji simuliraju proces apsorpcije iz gastrointestinalnog trakta, omogućio je korišćenje in silico metoda u predviđanju potencijalnih interakcija.
Rezultati in vivo studija ukazuju na smanjenje bioraspoloživosti ciprofloksacina nakon istovremene primene sa preparatima koji sadrže jone metala, a kao uzrok interakcije se navodi građenje kompleksa koji ne mogu da permeiraju membranu gastrointestinalnog trakta. Rezultati objavljenih in vitro studija su prilično kontradiktorni. Ispitivanja brzine rastvaranja ciprofloksacina iz tableta u prisustvu jona metala pokazuju usporeno i nepotpuno oslobađanje ciprofloksacina, dok izvesni autori izveštavaju o povećanju rastvorljivosti u prisustvu jona metala.
Cilj ove studije je bio da se otkrije mehanizam interakcije ciprofloksacina i jedinjenja gvožđa, aluminijuma, kalcijuma i cinka i razviju in vitro i in silico modeli za njihovu karakterizaciju kroz pregled rezultata in vivo, in vitro (ispitivanje rastvorljivosti, brzine rastvaranja, karakterizacija nastalih produkata interakcije) i in silico studija.
U okviru eksperimentalnog rada, analizirani su literaturni in vivo podaci, sprovedeno je in vitro ispitivanje rastvorljivosti i brzine rastvaranja ciprofloksacina bez, kao i u prisustvu jedinjenja koja sadrže jone metala (gvožđe, aluminijum, kalcijum, cink). Čvrste faze prikupljene u toku in vitro ispitivanja su analizirane primenom odgovarajućih analitičkih metoda (XRD, DSC, TGA i FTIR). Za in silico simulaciju interakcije između ciprofloksacina i jona metala primenjen je GastroPlustm softverski paket. Kao ulazni parametri neophodni za simulaciju (fizičkohemijske i farmakokinetičke osobine ciprofloksacina) korišćeni su literaturni podaci, eksperimentalno dobijene vrednosti i in silico predviđene vrednosti...Biopharmaceutical characterisation involves relevant in vitro and in silico methods that have been recognized as key tools that should provide an insight into the dosage form in vivo performance. With the introduction of Biopharmaceutics Classification System (BCS) and the increased understanding of gastrointestinal physiology in vitro methodology is increasingly considered as biorelevant and predictive of drug product bioperformance. There is an increased interest for in vitro investigation of drug–drug and food–drug interactions and it has been shown that in vitro studies can be used to predict physicochemical interactions that are likely to influence drug absorption rate in vivo.
Although, in vivo conditions can’t be adequately reproduced in vitro, it is expected that in certain situations, in vitro tests can reflect in vivo drug performance and may be used as a surrogate for in vivo bioequivalence studies. In addition, gastrointestinal simulation technology can be successfully used as a tool for investigating the mechanism of drug-drug interactions observed in vivo.
Numerous in vivo studies have shown reduced bioavailability of ciprofloxacin after simultaneous administration of metallic cations containing preparations. Formation of a nonabsorbable complex has been postulated as the interaction mechanism. However, literature in vitro data related to ciprofloxacin interaction with metallic ions are somewhat contradictory. Ciprofloxacin tablet dissolution has been shown to be retarded, while some solubility studies indicate increased solubility in the presence of metallic ions containing preparations.
The aim of this study was to investigate the potential mechanisms of ciprofloxacin metallic ions interaction observed in vivo by performing in vitro solubility and dissolution studies in the reactive media containing different metallic compounds. Different compounds of iron, calcium, aluminium and zinc have been used throughout the study. In order to identify the nature of any physicochemical interactions, characterisation of the solid phases formed was performed. Gastrointestinal mechanistic simulation model was employed in order to simulate interactions between ciprofloxacin and the selected metallic ions and elucidate potential interaction mechanism/s.
A detailed survey of the literature data available on ciprofloxacin–metallic ions interaction has been performed. Solubility and dissolution studies were performed without and with metallic compounds addition. The solid phases generated from the interaction mixture of ciprofloxacin hydrochloride and metallic compounds were examined by powder XRD, DSC, TGA, and FTIR. Commercially available software GastroPlustm was used for gastrointestinal simulations of drug absorption. The required input parameters related to ciprofloxacin physicochemical and pharmacokinetic characteristics were experimentally determined, in silico generated or taken from the literature..
Prospective study of cognitive impairment in Parkinson's disease: clinical, neuropsychological and morphological predictors
Kognitivni poremećaji predstavljaju važan nemotorni simptom Parkinsonove bolesti
(PB) i značajno utiču na kvalitet života, prognozu bolesti i smrtnost obolelih. Prevalenca blagog
kognitivnog poremećaja u PB (PB-BKP) procenjena je na 19-38%, u zavisnosti od primenjenih
dijagnostičkih kriterijuma. U ranijim istraživanjima kod PB-BKP pacijenata najčešće su
prijavljivani ispadi na planu egzekutivnih funkcija, pažnje i u vizuospacijalnom domenu, dok
je primena najnovijih dijagnostičkih preporuka Radne grupe Društva za poremećaje pokreta,
iz 2012. godine, ukazala na značajnu zastupljenost ispada u domenu pamćenja. Studije praćenja
su pokazale da oko 80% pacijenata razvija demenciju (PBD) nakon 20 godina trajanja PB.
Međutim, neki pacijenti godinama ostaju kogintivno očuvani, dok se kod drugih oštećenja
kognicije javljaju ubrzo po postavljanju dijagnoze PB, a neurobiološki osnov ovog relativno
stabilnog ili progresivnog toka nije sasvim jasan. Godine starosti, dužina trajanja PB, veća
motorna onesposobljenost, depresija, apatija, halucinacije, poremećaji sna i ortostatska
hipotenzija identifikovani kao prediktori PBD. Vaskularno opterećenje je, takođe, povezivano
sa kognitivnim oštećenjima u PB, a poslednjih godina posebno je aktuelno ispitivanje
vaskularnih faktora rizika koji se mogu modifikovati. Nekonvencionalnim metodama
magnetne rezonance (MR) moguće je ustanoviti stepen i distribuciju atrofije moždane kore,
kao pokušaj „in vivo“ mapiranja promena u centralnom nervnom sistemu koje leže u osnovi
kognitivnih poremećaja u PB. Kod PB-BKP pacijenata ustanovljena je atrofija temporalnog,
parijetalnog i frontalnog korteksa, dok su PBD pacijenti akumulirali difuzne kortikalne
promene u frontalnim, temporalnim, parijetalnim i okcipitalnim režnjevima. Prospektivne
studije koje su se bavile ovom problematikom, na većem broju ispitanika, su retke.
Ciljevi: a) utvrditi učestalost i tip kognitivnih poremećaja u našoj grupi pacijenata obolelih od
PB; b) ispitati demografske i kliničke karakteristike pacijenata kod kojih postoje PB-BKP i/ili
PBD u poređenju sa PB pacijentima kod kojih se ne beleže kognitivni poremećaji; c) utvrditi
učestalost PB pacijenata kod kojih se, tokom perioda praćenja od četiri godine, beleži
kognitivno pogoršanje, definisano kao prelazak iz stanja očuvane kognicije u stadijum PBPBK
i/ili razvoj PBD; d) definisati demografske i kliničke prediktore kognitivnog pogoršanja
u PB; e) ispitati specifičnosti obrazaca istanjenja moždane kore povezanih sa kognitivnim
pogoršanjem u PB...Cognitive disorders are one of the most important non-motor symptoms of
Parkinson's disease (PD), with significant impact on quality of life, prognosis and mortality.
The prevalence of mild cognitive impairment (PD-MCI) is estimated at 19-38%, depending on
the applied diagnostic criteria. In previous PD-MCI studies, executive dysfunctions, attention
and visuospatial deficits were most frequently reported, while the application of the latest
Movement Disorders Society Task Force, diagnostic recommendations, form 2012., pointed
out to the significance of memory impairment. Prospective studies have shown that about 80%
of patients develop dementia (PDD) after 20 years of PD duration. However, some patients
remain cognitively intact for years, while others develop cognitive impairment soon after PD
diagnosis, and the neurobiological basis of this relatively stable or progressive course is not
entirely clear. Age, PD duration, increased motor disability, depression, apathy, hallucinations,
sleep disorders and orthostatic hypotension have been identified as PDD predictors. Vascular
burden has also been associated with cognitive impairment in PD and, in recent years,
examination of vascular risk factors that can be modified is particularly important.
Unconventional magnetic resonance imaging (MR) technics can determine the degree and
distribution of cortical atrophy as an attempt of "in vivo" maping of central nervous system
changes that underlie cognitive deterioration in PD. In PD-MCI patients, atrophy of temporal,
parietal and frontal cortex was established, while PDD patients accumulated extensive cortical
changes in the frontal, temporal, parietal and occipital lobe. Prospective studies addressing this
this issue, on a large number of patients, are rare.
Objectives: a) to examine the frequency and profile of cognitive disorders in our PD cohort; b)
to examine clinical associated with PD-MCI and PDD; b) to determine the frequency of PD
patients with signs of cognitive deterioration during a four-year follow-up, defined as PD-MCI
and/or PDD conversion; c) to define clinical predictors of cognitive deterioration in PD; d) to
investigate specific patterns of cortical damage associated with cognitive decline in PD.
Material and methods: The study included 133 consecutive patients diagnosed according to
the current clinical criteria for PD. The research partly had the characteristics of the crosssection
study, while the other part was a prospective cohort study. A pre-designed semistructured
questionnaire was used to collect data on sociodemographic characteristics of
patients..
Marketing kao faktor reputacije preduzeća
This dissertation depicts the importance of marketing in the process of creating corporate reputation (in this case reputation of banks), as well as significance of thus formed reputation in everyday modern business on a global scale.
Corporate reputation consists of company’s past, present and future activities, which make perceptual representation of a company in stakeholders’ minds and form their opinion and attitude towards company during time. Reputation of any company which provides long-term competitive advantage on the market is a result of adequate and successful management of all business activities, based on a continuous commitment to improve competitive position in the public eye, by building recognizable and attractive features of company’s goodwill that lead to reputation.
A significant number of scholars in this scientific field agree that marketing has a key role in reputation management process in every company. Main task of marketing strategy is to transform company’s identity into desired external perception and to adjust desires, attitudes and opinions of consumers and other stakeholders with company’s strategic position and its vision. Adoption of new-age marketing concept and holistic approach in marketing activities enables company to form reputation, which results in positive attitude of consumers and other stakeholders towards company, as well as harmonization of business goals and objectives of the society.
Corporate social responsibility (CSR), as one of the most important elements of sustainable development, brings another dimension to the concept of corporate responsibility. It is a common knowledge that reputation comes with responsibilities and in modern business, this means being responsible not only to your customers, but to whole society, environment and stakeholders. The significance of holistic marketing is that it covers all activities required by the demands of sustainable development. By doing so, holistic marketing activities create the so called “bigger picture”, which results in better understanding of what needs to be done in order to gain not only positive business results and reputation, but the overall survival as well
Optical Conductivity and Hall Coefficient in High-Tc Superconductors: Significant Role of Current Vertex Corrections
We study AC conductivities in high-Tc cuprates, which offer us significant
information to reveal the true electronic ground states. Based on the
fluctuation-exchange (FLEX) approximation, current vertex corrections (CVC's)
are correctly taken into account to satisfy the conservation laws. We find the
significant role of the CVC's on the optical Hall conductivity in the presence
of strong antiferromagnetic (AF) fluctuations. This fact leads to the failure
of the relaxation time approximation (RTA). As a result, experimental highly
unusual behaviors, (i) prominent frequency and temperature dependences of the
optical Hall coefficient, and (ii) simple Drude form of the optical Hall andge
for wide range of frequencies, are satisfactorily reproduced. In conclusion,
both DC and AC transport phenomena in (slightly under-doped) high-Tc cuprates
can be explained comprehensively in terms of nearly AF Fermi liquid, if one
take the CVC's into account.Comment: 5 page
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