Brain connectivity measures: computation and comparison

In this article computation and comparison of causality measures which are used in determination of brain connectivity patterns is investigated. Main analyzed examples included published computation and comparisons of Directed Transfer Function ‐ DTF and Partial Directed Coherence ‐ PDC. It proved that serious methodology mistakes were involved in measure computations and comparisons. It is shown that the neighborhood of zero is of accented importance in such evaluations and that the issues of semantic stability have to be treated with more attention. Published results on the relationship of these two important measures are partly unstable with small changes of zero threshold and pictures of involved brain structures deduced from the cited articles have to be corrected. Analysis of the operators involved in evaluation and comparisons is given with suggestions for their improvement and complementary additional actions

THE IMPACT OF EMOTIONAL CHARACTERISTICS IN THE CHRONICITY OF POSTTRAUMATIC STRESS DISORDER

Background: The research objective was to identify overstated emotional characteristics in armed conflict veterans as well as both the similarities and differences in personality profiles between patients suffering from acute and chronic forms of posttraumatic stress disorder (PTSD). Subjects and methods: Our study’s sample consisted of 60 participants in the armed conflict in Kosovo that lasted from 28 February, 1998 until 11 June, 1999. All of them were diagnosed with PTSD, during the six months period after their return from active duty. In 2014 we retested the same subjects to see their current psychological state. Diagnoses of PTSD were made using Structure Clinical Interview for DSM–IV (SCID-I), while the assessment of emotional characteristics was made using Plutchik\u27s emotion profile index (PIE). Results: We established no statistically significant difference in PIE profiles between both groups in recent re-testing. The only significant difference as per PIE classification was found earlier when the subjects were initially diagnosed. The amplified emotional dimension was exploration, and only the group of chronic PTSD patients displayed significantly higher values (p<0.05). Conclusion: Emotional profiles, as a whole, proved to be very similar amongst subjects with both acute and chronic form of the PTSD. The only noted difference is in the significantly higher values of exploration emotional dimension, but only at the time when they were first given initial diagnosis, and only in the group of subjects who later developed the chronic form of PTSD which can indicate that exploration is a factor of vulnerability which is important in chronicity

A note on the earliest distribution, cultivation and genetic changes in bitter vetch (vicia ervilia) in ancient Europe

Bitter vetch (Vicia ervilia (L.) Willd.) was a part of the everyday diet of the Eurasian Neanderthal population and the modern human Palaeolithic hunter-gatherers at the end of the last Ice Age. The major criteria to determine the domestication in bitter vetch and other ancient grain legumes are non-dehiscent pods, larger seed size and smooth seed testa. Bitter vetch seeds were found among the earliest findings of cultivated crops at the site of Tell El-Kerkh, Syria, from 10th millennium BP. Along with cereals, pea and lentil, bitter vetch has become definitely associated with the start of the 'agricultural revolution' in the Old World. Bitter vetch entered Europe in its south-east regions and progressed into its interior via Danube. Its distribution was rapid, since the available evidence reveals its presence in remote places at similar periods. Recently the first success has been obtained in the extraction of ancient DNA from charred bitter vetch seeds. The linguistic evidence supports the fact that most of Eurasian peoples have their own words denoting bitter vetch, meaning that its cultivation preceded the diversification of their own proto-languages

Prostorna varijabilnost morfoloških obilježja iglica populacija jele (Abies alba Mill.) na Balkanskom poluotoku u odnosu na klimatske čimbenike

Interpopulation and intrapopulation variability of three morphological needle traits (length, width and thickness) was investigated in 16 natural silver fir populations in the Balkan Peninsula. The populations represent refugial areas of silver fir (Abies alba Mill.). This paper aims to provide a comprehensive analysis of the influence of climatic factors (mean annual temperature, number of days with temperatures &lt; 0, &gt; 5, &lt; 18, &gt; 18oC, Hargreaves climatic moisture deficit and De Martonne aridity index, on the pattern of morphological needle traits within each population. Populations showed variation in the analyzed morphological needle traits, which could not be clearly defined by any of the analyzed climatic factors. The De Martonne aridity index and Hargreaves climatic moisture deficit had the greatest impact on the trait values, whereas the mean annual precipitation had the lowest. Evolutionary ecology research of the silver fir needle morphology is a valuable contribution to the comprehention of the present genetic variability as a prerequisite for adaptation to the rapid climate change and conservation of the species area in the Balkan Peninsula region.Interpopulacijska i intrapopulacijska varijabilnost triju morfoloških osobina iglica (dužina, širina i debljina) istraživana je u 16 prirodnih populacija jele na Balkanskom poluotoku. Populacije predstavljaju refugijalna područja jele (Abies alba Mill.). Ovaj rad ima za cilj pružiti opsežnu analizu utjecaja klimatskih čimbenika (srednja godišnja temperatura, broj dana s temperaturama &lt; 0, &gt; 5, &lt; 18, &gt; 18°C, Hargreavesov klimatski deficit vlage i De Martonneov indeks aridnosti) na obrazac morfoloških obilježja iglica unutar svake populacije. Populacije su pokazale varijacije u analiziranim morfološkim obilježjima iglica koje se nisu mogle jasno definirati niti jednim od analiziranih klimatskih čimbenika. Najveći utjecaj na vrijednosti obilježja imao je klimatski deficit vlage po Hargreavesu, a zatim najniže vrijednosti srednje godišnje količine oborina. Evolucijska ekološka istraživanja morfologije iglica jele vrijedan su doprinos razumijevanju sadašnje genetske varijabilnosti kao preduvjeta za prilagodbu na brze klimatske promjene i očuvanje vrste na području Balkanskog poluotoka

VORTEX ENTERPRISE: DECENTRALIZED VIRTUAL REALITY BLOCKCHAIN-BASED PLATFORM

Virtual Reality (VR) has been used in industries since the 1960s. However, the recent development of hardware and software has made it possible for VR technologies to become widely adopted by the mass market with the highest level of immersion and affordable price. However, building platforms for VR technologies will require many active users and their engagement in project development. Those activities will include platform activities, content creation, social media marketing, processing power, and storage. For that purpose, we introduce VoRtex enterprise high-level software architecture and decentralized blockchain solution. Introduced VoRtex enterprise high-level software architecture will be used to develop blockchain-based virtual world (VW) platform with VR support. The goal of the VW platform is to support the development of education, certification and massive open online courses (MOOC). A blockchain component inside the VW platform will be used for engaging users in project development through collaboration and content sharing. Active users that promote platform content will get rewards for contributions using cryptocurrency. Also, we will showcase this feature on the VoRtex platform prototype where the user earns cryptocurrencies for activity inside the VW. In the end, we will evaluate the proposed solutio

Assessment of health literacy in patients with diabetes mellitus at the primary level of health care

Увод: Ниска здравствена писменост (Health literacy – HL) повезана је са лошим здравственим исходима, а код дијабетеса (ДМ) здравствено писменији пацијенти боље контролишу гликемију, имају мању преваленцу компликација, боље управљaју терапијом и комуницирају са здравственим радницима. Циљ рада: Проценити HL и домене HL пацијената на примарном нивоу здравствене заштите и испитати разлике према социодемографским карактеристикама. У субпопулацији дијабетичара проценити нивое HL применом два инструмента и испитати разлике у нивоима и доменима HL у односу на тип дијабетеса, место становања, пол и ниво образовања. Материјал и методе: Спроведена је проспективна студија пресека од децембра 2019. до марта 2020. године у апотеци и дому здравља. Коришћени су: Општи упитник о пацијентима, Европски упитник за процену HL (HLS-EUQ12), Упитник за брзу процену HL (BRIEF-3Q – у популацији ДМ). Нивои HL према HL скору били су неадекватна, маргинална, довољна и одлична, а према DHL скору неадекватна и адекватна. Резултати: Од 143 пацијента, 48 је било са дијабетесом, предоминантно са ДМТ2 (68,75%). Ниску HL (HL скор ≤ 32) имало је нешто више од половине испитаника (54,6%) у укупном узорку и међу ДМ ( 52,2%). Неадекватну HL (DHL скор ≤ 9) имало је 31,25% ДМ, више оних са ДМТ2. Од 4 домена HL (доступност, разумевање, процена, примена) најлошије вреднсти код ДМ су биле у домену доступности информација. Од свих 12 питања дијабетичари су најтеже перципирали способност примене информaције када одлучују како да побољшају сопствено здравље, а најлакшим су перципирали разумевање потребе за превентивним прегледима. Виши DHL и HL скор повезан је са женским полом, факултетским и последипломским образовањем, животом у већем граду и већим месечним примањима. Закључак: Преваленца неадекватне HL код пацијената са ДМ на примарном нивоу здрваствене заштите је висока, без обзира на уочене разлике у дистрибуцији нивоа HL у зависности од инструмента за процену. Даља истраживања предиктора ниске HL код ДМ су неопоходна.Introduction: Low health literacy (HL) is associated with poor health outcomes. More health literate diabetes mellitus (DM) patients control glycemia better, have a lower prevalence of complications, manage therapy better and communicate with healthcare professionals. The Aim: Тo assess HL and HL domains of patients at the primary level of health care and examine the differences according to sociodemographic characteristics; to assess HL levels using two instruments in DM patients and examine differences in HL levels and domains in relation to the type of diabetes, the place of residence, gender, income and level of education. Material and Methods: A prospective cross-sectional study was conducted from December 2019 to March 2020 at primary care using general patient questionnaire, Short Version of the European Health Literacy Survey Questionnaire (HLS-EUQ12), and BRIEF-3Q (only for DM). HL levels were calculated as inadequate, marginal, sufficient and excellent HL scores; and according to the BRIEF-3Q as adequate and inadequate DHL scores. Results: Of the 143 patients, 48 had diabetes, predominantly DM2 (68.75%). In total, low HL (HL score ≤ 32) has more than half of the respondents (54.6%) and 52.2% among DM. However, assessed by BRIEF-3Q there were less diabetics with inadequate HL (DHL score ≤ 9) - 31.25% DM. Of the 4 HL domains (availability, understanding, processing, application), the worst values in DM were in questions for the information availability domain. The higher DHL and HL scores is related to females, university and postgraduate education, life in a bigger city, and higher monthly incomes. Conclusion: The prevalence of inadequate HL at the primary level DM patients is high, tough we observed differences in the distribution of HL levels depending on the assessment instrument. Further research into the predictors of low HL in DM patients is necessary

Mental disorders after ischemic stroke

UVOD: Moždani udar spada u grupu masovnih nezaraznih bolesti, koje se smatraju najčešćim oboljenjima savremenog čoveka. On predstavlja jedan od najčešćih uzroka mortaliteta i invaliditeta u savremenom svetu. Među brojnim pratećim komplikacijama moždanog udara, navode se psihički poremećaji: depresija, anksioznost i psihotični poremećaji. Utvrđivanje povezanosti moždanog udara sa psihičkim poremećajima, kao i mehanizma njihovog nastanka predstavlja značajan doprinos boljem razumevanju ovog veoma čestog oboljenja, a njihov rani tretman omogućio bi brži i potpuniji oporavak nakon moždanog udara. CILJ: Utvrditi karakteristike psihičkog funkcionisanja osoba nakon ishemičnog moždanog udara, utvrditi uticaj lokalizacije lezije na nastanak određenih psihičkih poremećaja nakon moždanog udara, utvrditi uticaj vaskularnog statusa na nastanak psihičkih poremećaja, te utvrditi korelaciju između psihičkih komplikacija moždanog udara i brzine i stepena oporavka opšte životne aktivnosti. MATERIJAL I METODE: Istraživanje je izvedeno kao prospektivna studija, obuhvatilo je 101 pacijenta oba pola obolelih od moždanog udara, koji su hospitalno lečeni na Klinici za neurologiju u Novom Sadu. Svim pacijentima je uzeta anamneza o toku bolesti, faktorima rizika za moždani udar, kao i laboratorijska dijagnostika. Svim pacijentima načinjena je kompjuterizovana tomografija (CT) mozga (ili magnetna rezonanca - MRI mozga), ultrazvučni pregled karotidnih arterija, vertebrobazilarnih i krvnih sudova Willisovog poligona. Stepen neurološkog deficita i praćenje funkcionalnog oporavka u akutnoj fazi i nakon 3 meseca vršeno je primenom Skale Moždanog Udara Nacionalnog Instituta za Zdravlje (NIHSS), Rankinove skale i Bartelovog indeksa. Svim pacijentima je načinjena eksploracija psihičkog statusa u akutnoj fazi bolesti primenom Bekove Skale Depresije 2 (BDI-2), Skale procene anksioznosti kao stanja i odlike (STAI), Skale pozitivnih i negativnih sindroma (PANSS) i Kornelovog regrutnog indeksa (CSI). Kontrolno testiranje gore navedenim testovima obavljeno je nakon 3 meseca. Od statističkih metoda korišćena je deskriptivna statistika: tabelarni prikazi učestalosti i procentualna izraženost kod neparametrijski (nominalno ili ordinarno) organizovanih varijabli. Za ukršten prikaz dve varijable korišćene su tabele kontingencije. Takođe su korišćene mere centralne tendencije (aritmetička sredina) i mere disperzije (standardna devijacija) kod parametrijski korektno uređenih varijabli. Pored toga, korišćen je Hi-kvadrat test za utvrđivanje razlika između grupa za varijable nominalnog nivoa merenja, Kramerovo V za utvrđivanje povezanosti između nominalnog nivoa merenja, Pirsonov koeficijent korelacije r, za utvrđivanje povezanosti između varijabli intervalnog nivoa merenja, te analiza varijanse (ANOVA) za utvrđivanje značajnosti razlika između aritmetičkih sredina više grupa. REZULTATI: U ispitivanje je uključen 101 pacijent, 65.3% muškog pola, 34.7% ženskog pola. Prosečna starost bila je 60.69 godina (medijana=62.00, standardna devijacija =10.828, statistička greška=1.077). 38.6% je imalo lokalizaciju u desnoj hemisferi velikog mozga, 34.7% u levoj hemisferi, 4% u cerebelumu, 11.9% u moždanom stablu, dok je 10.9% imalo višestruku lokalizaciju infarkta. 39.6% je imalo teritorijalni infarkt, a 59.4% lakunarni infarkt. Distribucija faktora rizika za moždani udar bila je uobičajena za podneblje na kojem je vršeno istraživanje. 26.7% je imalo uredan nalaz na karotidnim krvnim sudovima, 26.7% je imalo difuznu ateromatozu, 27.7% je imalo stenozu ACI 70%. U odnosu na nalaz u VB slivu, 52.5% je imalo uredan nalaz, a 47.5% patološki nalaz (stenozu i difuznu ateromatozu). 54.5% pacijenata je imalo uredan nalaz na arterijama Willisovog poligona, a 45.5% je imalo patološki nalaz (stenozu i difuznu ateromatozu). 5.9% je imalo depresivni poremećaj, 29.7% anksiozni poremećaj, 9.9% neurotski poremećaj i 2% psihotični poremećaj. U odnosu na pol, depresivni poremećaj javlja kod 3% muškaraca i 11.4% žena, anksiozni kod 25.8% muškaraca i 37.1% žena, neurotski kod 7.6% muškaraca i 14.3% žena i psihotični kod 3% muškaraca, dok kod žena nije zabeležen. U odnosu na životno doba, kod mlađih od 45 godina depresija nije bila prisutna, anksioznih je bilo 30%, 10% psihotičnih, dok neurotičnih nije bilo. U grupi 46-65 godina depresivnih je bilo 6.9%, anksioznih 22.4%, neurotičnih 12.1%, a psihotičnih 1.7%. U grupi starijih od 65 godina, depresivnih je bilo 6.1%, anksioznih 42.4%, neurotičnih 9.1%, dok psihotičnih nije bilo. Distribucija odgfovora dobijenih na BDI-2 skali ukazivala je na veću učestalost depresivnog poremećaja kod lezija u levoj hemisferi velikog mozga. Distribucija odgovora dobijenih primenom STAI ukazivala je na veću učestalost anksioznog poremećaja kod lezija desne hemisfere. Distribucija odgovora dobijenih primenom CSI ukazivala je na veću učestalost neurotskog poremećaja kod višestrukih lezija. Distribucija odgovora dobijenih primenom PANSS ukazivala je na veću učestalost psihotičnog poremećaja kod lezija desne hemisfere. Upoređivanje lezije na karotidama i psihičkih poremećaja pokazalo je na progresivni porast učestalosti psihičkih poremećaja sa težinom lezije na karotidnim krvnim sudovima, kao i na potpuno odsustvo psihičkih poremećaja kod osoba koje su imale uredan nalaz na karotidama. Praćenje uticaja psihičkih poremećaja (sumarno i pojedinačno) na funkcionalni oporavak pacijenata nakon moždanog udara, nije pokazalo statistički značajan uticaj. Zabeleženo je statistički značajno udruženo pojavljivanje depresivnog i anksioznog, depresivnog i neurotskog i anksioznog i neurotskog poremećaja, bez značajne interakcije navedenih poremećaja sa psihotičnim poremećajem. ZAKLJUČAK: Kod pacijenata sa ishemičnim moždanim udarom najveća je učestalost anksioznog poremećaja, zatim depresivnog poremećaja, a najređe se javlja psihotični poremećaj. Depresivni i anksiozni poremećaj značajno su češći kod žena, dok se psihotični poremećaji isključivo javljaju kod muškaraca. Depresivni poremećaj značajno se češće javlja u srednjem i starijem životnom dobu, anksiozni poremećaj se češće javlja u mlađem i srednjem životnom dobu, dok se psihotične manifestacije javljaju najčešće u srednjem životom dobu. Depresivni i anksiozni poremećaj jednako se često javljaju kod pacijenata sa teritorijalnim i lakunarnim infarktom, dok se psihotične manifestacije isključivo javljaju kod pacijenata sa teritorijalnim infarktom. Ne postoji značajna korelacija između prisustva faktora rizika za moždani udar i pojave psihičkih poremećaja, iako je upadljivo odsustvo psihičkih poremećaja kod pacijenata bez faktora rizika za moždani udar. Nakon 3 meseca od moždanog udara nije primećena značajnija regresija simptoma psihičkih poremećaja. Anksiozni poremećaj i psihotične manifestacije se statistički značajno češće javljaju kod infarkta u desnoj hemisferi, dok za depresivni poremećaj nije potvrđeno statistički značajno češće pojavljivanje kod infarkta u levoj hemisferi. Psihički poremećaji kod pacijenata sa moždanim udarom češće se javljaju kod pacijenata sa lezijama u karotidnom slivu, što se povećava sa težinom lezije i veličinom stenoze. Ne postoji statistički značajna korelacija između lezija krvnih sudova u vertebrobazilarnom slivu i Willisovom poligonu sa pojavom psihičkih poremećaja. Nije dokazan značajan uticaj psihičkih poremećaja na oporavak bolesnika nakon moždanog udara. Dokazan je visok stepen udruženog javljanja depresivnog i anksioznog poremećaja.INTRODUCTION: Stroke belongs to noninfectious diseases, which are considered the most common diseases of modern man. It is one of the most common causes of mortality and disability in the modern world. The many associated complications of stroke include mental disorders: depression, anxiety and psychotic disorders. Determining the relationship between stroke and mental disorders, as well as enlightening their underlying mechanism, represents a significant contribution to a better understanding of this very frequent disease, and an early treatment of these associated disorders should allow a faster and more complete recovery from stroke. OBJECTIVE: To determine characteristics of mental functioning after ischemic stroke, to determine the impact of lesion localization on development of certain mental disorders after stroke, to determine the impact of vascular status on development of mental disorders, and to determine the correlation between the associated mental disorders and the speed and degree of recovery of general life activities. MATERIALS AND METHODS: The research was conducted as a prospective study that included 101 ischemic stroke patients of both sexes, hospitalized at the Clinic of Neurology in Novi Sad. Data about the course of disease and stroke risk factors was collected and laboratory diagnostics was performed in all patients. All patients underwent brain computed tomography (CT) (or magnetic resonance imaging - MRI), and ultrasound examination of carotid and vertebrobasilar arteries and the circle of Willis. The degree of neurological deficit and functional recovery in the acute phase and at 3-month follow-up were assessed using the National Institute of Health Stroke Severity (NIHSS) scale, the Rankin scale, and the Barthel Index. All patients underwent psychological exploration of the mental status in the acute phase of stroke by using the Beck Depression Inventory 2 (BDI - 2), the State-Trait Anxiety Inventory (STAI), the Positive and Negative Syndrome Scale (PANSS), and the Cornell Services Index (CSI). Follow-up testing with the same tests was performed after 3 months. Statistical analysis included methods of descriptive statistics: tabular presentation of the frequency and percentages in case of nonparametric (nominal or ordinal) variables. Contingency tables were used to present relationships between two variables. In addition, measures of central tendency (arithmetic mean) and measures of dispersion (standard deviation) were used for parametric variables. The chisquared test was used to determine differences between groups for nominal measurement variables, Cramer’s V was used to examine association between nominal levels of measurement. Association between interval measurement variables was measured by the Pearson correlation coefficient (r), and significance of differences between arithmetic means of more groups was determined by the analysis of variance (ANOVA). RESULTS: The study included 101 patients, 65.3% male and 34.7% female. The average age of patients was 60.69 years (median=62.00, standard deviation=10.828, statistical error=1.077). Stroke localizations were as follows: the right cerebral hemisphere in 38.6%, the left hemisphere in 34.7%, the cerebellum in 4%, the brainstem in 11.9%, and 10.9% of patients had multiple localizations. In 39.6% of patients, stroke was territorial, and in 59.4% lacunar. The distribution of risk factors for stroke was typical for the study area. Normal carotid arteries were found in 26.7%, 26.7% had diffuse atheromatosis, 27.7% had 70% ACI stenosis. As regards VB circulation, 52.5% had normal findings and 47.5% had pathological findings (stenosis and diffuse atheromatosis). As regards the circle of Willis, 54.5% had normal findings and 45.5% had pathological findings (stenosis and diffuse atheromatosis). Regarding mental functioning, 5.9% had depressive disorder, 29.7% had anxiety disorder, 9.9% had neurotic disorder, and 2% had psychotic disorder. In relation to sex, mental disorders were present as follows: depressive disorder in 3% of men and 11.4% of women, anxiety disorder in 25.8% of men and 37.1% of women, neurotic disorder in 7.6% of men and 14.3% of women, and psychotic disorder in 3% of men and none of women. With respect to age, among patients under 45 years of, age none had depressive disorder, 30% had anxiety disorder, 10% had psychotic disorder, and none had neurotic disorder. In the group of patients aged 46-65 years, 6.9% had depressive disorder, 22.4% had anxiety disorder, 12.1% had neurotic disorder, and 1.7% had neurotic disorder. In the group above 65 years of age, 6.1% had depressive disorder, 42.4% had anxiety disorder, 9.1% had neurotic disorder, and none had psychotic disorder. The distribution of responses obtained on the BDI-2 showed a higher prevalence of depressive disorder in patients with lesions in the left cerebral hemisphere. The distribution of responses obtained on the STAI showed a higher prevalence of anxiety disorder in patients who had lesion of the right hemisphere. The distribution of responses obtained on the CSI showed a higher prevalence of neurotic disorder in those who had multiple lesions. The distribution of responses obtained by the PANSS indicated a higher prevalence of psychotic disorder in those with lesion of the right hemisphere. Comparison of carotid artery lesions and mental disorders showed a progressive increase in the prevalence of mental disorders with increasing severity of the lesions, as well as a complete absence of mental disorders in people who had normal findings on carotids. The follow-up results showed that mental disorders (generally and individually) did not have a statistically significant effect on functional recovery of stroke patients. There were statistically significant comorbidities of depressive disorder and anxiety disorder, depressive disorder and neurotic disorder, and anxiety disorder and neurotic disorder, and no significant interactions of any of these disorders with psychotic disorder. CONCLUSION: In patients with ischemic stroke, anxiety disorder has the highest prevalence, followed by depressive disorder, whereas psychosis is the rarest. Depressive and anxiety disorders are significantly more common in women, while psychotic disorder occurs exclusively in men. Depressive disorder is significantly more common in the middle and old ages, anxiety disorder is more frequent in the younger and middle ages, while psychotic manifestations occur most often in the middle age of life. Depressive and anxiety disorders are similarly prevalent in patients with territorial and lacunar strokes, while psychotic manifestations occur exclusively in patients with territorial stroke. There is no significant correlation between the presence of stroke risk factors and mental disorders, although there is an evident absence of mental disorders in patients without stroke risk factors. Three months after stroke, no significant regression of the symptoms of mental disorders was observed. Anxiety disorder and psychotic manifestations are significantly more common in right hemispheric stroke, while as regards depressive disorder, there is no statistically significant association with left-hemispheric stroke. Mental disorders in stroke patients are more common in those with carotid lesions and increase in severity with increasing severity of lesion and degree of stenosis. There are no statistically significant correlations between lesions in the vertebrobasilar circulation or the circle of Willis and development of mental disorders. No significant impact of mental disorders on recovery from stroke was found. A high prevalence of comorbid depressive and anxiety disorders was proven/confirmed

Measurement and analysis of vibrations on the helicopter structure in order to detect defects of operating elements

U radu je prezentovan praktičan primer merenja i analize vibracija na helikopterskoj strukturi sa ciljem da se otkriju potencijalna oštećenja radnih elemenata. Sveobuhvatna metodologija merenja vibracija je predstavljena u ovom članku i sprovedena sa ciljem da se utvrdi ispravan rad rotirajućih komponenata. Poseban osvrt je dat na analizi uzdužnih i vertikalnih vibracija trupa helikoptera u frekventnom domenu za različite profile leta. Merenje i analiza vibracija na određenim lokacijama helikopterske strukture, rezultiralo je blagovremenim tehničkim pregledom odgovarajuće komponente i otkrivanjem njenog površinskog oštećenja. Praktična upotreba predložene metodologije merenja i analize je moguće implementirati na više vrsta letelica u cilju produženja životnog veka.A practical example of the measurement and analysis of vibrations on helicopter structures in order to detect defects on operating elements is presented in this paper. A comprehensive methodology of vibration testing is presented in this article and implemented in order to determine the correct operation of rotating components. A particular attention is given to the analysis of longitudinal and vertical vibrations on the helicopter fuselage in the frequency domain for different flight profiles. The vibration measurement and analysis on specific locations on a helicopter structure resulted in a timely technical review of a relevant component and a disclosure of the damage on its surface. The proposed methodology of measurement and analysis can be implemented on different types of aircraft in order to extend their life expectancy.

Uticaj procesa izluživanja i načina korišćenja rendzina na sadržaj humusa i njegovu obezbeđenost azotom

Rendzina is a widespread soil type in Serbia that can be found in several stages of evolutionary development and put to different land uses. Our objective was to investigate the effect of decarbonation of rendzina soils in Serbia and several land use variants on humus content and its enrichment in nitrogen. Humus content is mostly high, and rarely medium, in the A horizon of calcaric forest rendzinas; medium or high under grassland, and very low under arable land. In non-calcaric forest rendzinas, humus content in horizon A is medium or low; under grassland it is low and very low, and under arable land again low and very low. Rendzinas are predominantly rich and very rich in total nitrogen in the uppermost layer of horizon A, and medium or well supplied in the layer below it. Enrichment of humus in nitrogen, shown as the C:N ratio, is mostly medium, and rarely low. Decarbonation was caused by decreasing humus content and total nitrogen in soil, while the enrichment of humus in nitrogen (C:N ratio) showed no significant change. Different land uses were found to have significant effect on decreasing humus and total nitrogen contents in rendzinas under grassland, and especially arable land, compared to forest rendzinas, while humus enrichment in nitrogen was significantly higher in rendzinas underlying grassland than forest. .Rendzina je veoma rasprostranjen tip zemljišta u Srbiji u području brdsko-planinskog reljefa, nalazi se u više evolucionih stadijuma razvoja i koristi se na različite načine, odnosno, nalazi se pod različitim biljnim pokrivačima. Cilj našeg rada je zato bio ispitivanje uticaja procesa izluživanja i različitog načina korišćenja zemljišta tipa rendzina u Srbiji na sadržaj humusa i njegovu obezbeđenost azotom. Sadržaj ukupnog C u ispitivanim rendzinama Srbije varira od 1.15 do 6.25%, a u proseku iznosi 3.25%. Sadržaj humusa u A horizontu karbonatnih šumskih rendzina je uglavnom visok, ređe srednji; pod travnjacima srednji ili visok, a pod njivama veoma nizak. U izluženim šumskim rendzinama sadržaj humusa u A horizontu je srednji ili nizak; pod travnjacima nizak i veoma nizak, a u njivskim, takođe, nizak i veoma nizak. Sadržaj ukupnog azota varira u širokom intervalu, od 0,123 do 0.570%, a u proseku iznosi 0.317%; stoga su rendzine pretežno bogato i veoma bogato obezbeđene ukupnim azotom u površinskom delu A horiznonta, a u potpovršinskom obezbeđene su srednje ili dobro. Obezbeđenost humusa azotom, izražena preko odnosa C:N, uglavnom je srednja, a ređe niska. Odnos C:N kreće se od 8.09 do 16.54, a u proseku iznosi 10.09. Procesi izluživanja (ispiranje CaCO3, niži pH i stepen zasićenosti bazama) u zemljištima tipa rendzina u Srbiji uslovili su smanjenje sadržaja humusa i ukupnog azota, pri čemu se obezbeđenost humusa azotom (odnos C:N) nije značajno promenila. Razlike u načinu korišćenja zemljišta (primena ili odsustvo obrade i razlike u količini i kvalitetu biljnih ostataka) statistički su značajno uticale na smanjenje sadržaja humusa i ukupnog azota u rendzinama pod travnjacima i naročito njivama u poređenju sa šumskim rendzinama, dok je obezbeđenost humusa azotom značajno veća u travnjačkim u poređenju sa šumskim rendzinama.