26 research outputs found
Pesticidi u zemljištu: delovanje na mikroorganizme
Since their discovery to the present day, pesticides have been an inevitable segment of
agricultural production and efforts have been made to synthesize compounds that would
share a required efficacy along with selectivity, sufficient persistence on the object of protection
and favourable toxicological and ecotoxicological characteristics so as to minimize
their effect on the environment.
When a pesticide gets into soil after application, it takes part in a number of physical,
chemical and biological processes that depend not only on the compound itself, but a
number of other factors as well, such as: physical, chemical and biological characteristics of
soil; climatic factors, equipment used, method of application, method of storage, handling
and disposal of waste, site characteristics (proximity of ground and underground waters,
biodiversity and sensitivity of the environment). Microorganisms play an important role in
pesticide degradation as they are able to utilize the biogenic elements from those compounds,
as well as energy for their physiological processes. On the other hand, pesticides
are more or less toxic substances that can have adverse effect on populations of microorganisms
and prevent their development, reduce their abundance, deplete their taxonomic
complexity and create communities with a lower level of diversity and reduced physiological
activity.
The article discusses complex interactions between pesticides and microorganisms
in soil immediately after application and over the ensuing period. Data on changes in the
abundance of some systematic and physiological groups of microorganisms, their microbial
biomass and enzymatic activity caused under pesticide activity are discussed as indicators
of these processes.Od otkrivanja pa do danas, pesticidi su ezaobilazni segment poljoprivredne proizvodnje,
a u njihovom razvoju teži se ka sintezi jedinjenja
koja će imati potrebnu efikasnost i selektivnost,
dovoljnu dužinu zadržavanja na objektu i povoljne
toksikološke i ekotoksikološke karakteristike, kako
bi imali što manji neželjeni uticaj na životnu sredinu u celini. Kad se nakon primene nađe u zemljištu, pesticidno jedinjenje biva izloženo brojnim fizičkim, hemijskim i biološkim procesima
razgradnje koji zavise ne samo od osobina jedinjenja, već i od čitavog niza drugih faktora,
kao što su: fizičke, hemijske i biološke karakteristika zemljišta i klimatski faktori.
U procesima razgradnje pesticida u zemljištu
značajnu ulogu imaju mikroorganizmi, imajući
u vidu da su sposobni da iz njihovih molekula
koriste biogene elemente i energiju za svoje
fiziološke procese. S druge strane, pesticidi
koji su sami po sebi manje ili više toksične supstance, mogu štetno da deluju na populacije
mikroorganizma i da dovedu do zaustavljanja
njihovog razvoja, smanjenja brojnosti, osiromašenja taksonomskog sastava,
stvaranja zajednica sa nižim
stepenom raznovrsnosti i smanjenom
fiziološkom aktivnošću. U ovom radu razmatraju
se uzajamni procesi i odnosi koji
se uspostavljaju u zemljištu između
pesticida i mikroorganizama neposredno,
kao i u periodu posle primene. Kao pokazatelji
ovih procesa dati su podaci o promeni
brojnosti pojedinih sistematskih i fizioloških
grupa mikroorganizama, mikrobiološke
biomase i aktivnosti enzima koji su nastali
pod uticajem pesticida
Delovanje atrazina na mikroorganizme u zemljištu
Effects of the herbicide atrazine on soil microorganisms was investigated. Trials were set
up in laboratory, on a clay loam soil. Atrazine was applied at 8.0, 40.0 and 80.0 mg/kg soil
rates. The abundance of total microorganisms, fungi, actinomycetes, cellulolytic microorganisms
and amino-heterotrophs was recorded. Soil samples were collected 1, 7, 14, 21, 30
and 60 days after atrazine treatment for microbiological analyses.
The results showed that the intensity of atrazine effect on soil microorganisms depended
on treatment rate, exposure time and group of microorganisms. Atrazine had an inhibiting
effect on cellulolytic microorganisms and amino-heterotrophs. Initially, it inhibited fungi
and actinomycetes but its effect turned into a stimulating one once a population recovered.
Atrazine had a stimulating effect on total abundance of microorganisms.U radu je ispitivano delovanje atrazina na mikroorganizme u zemljištu. Ogled je postavljen u laboratorijskim uslovima na zemljištu tipa glinovita ilovača. Atrazin je primenjen u količinama od 8.0, 40.0 i 80.0 mg/kg zemljišta. Praćen je ukupan broj mikroorganizama, broj gljiva, aktinomiceta, celulolitskih mikroorganizama i aminoheterotrofa. Uzorci za mikrobiološke analize uzimani su 1, 7, 14, 21, 30 i 60 dana posle primene atrazina.
Dobijeni rezultati su pokazali da delovanje atrazina na zemljišne mikroorganizme zavisi od primenjene količine, dužine delovanja i vrste mikroorganizama. Atrazin je inhibitorno delovao na celulolitske mikroorganizme i aminoheterotrofe. Na aktinimicete i gljive delovao je prvo inhibitorno, a kasnije, zbog obnavljanja populacija stimulativno. Na ukupan broj mikroorganizama atrazin je delovao stimulativno
Acute onset of tinnitus in patients with sudden deafness
Objective: We made hypotheses that tinnitus will appear more likely in patients with sudden deafness with superior hearing in unaffected ear or with more severe acute hearing loss.
Methods: A retrospective cohort study was performed. Five hundred forty-one patients were identified with idiopathic sudden sensorineural hearing loss (ISSHL) from January 1995 to August 2006. The exclusion criteria for this study were as follows: bilateral sudden hearing loss and Meniere disease, previous tinnitus or bilateral tinnitus at initial evaluation, and onset of hearing loss less than 7 days. The cohort enrolled 454 patients. The enrolled patients were classified into two groups: patient with acute onset tinnitus in the affected ear and patients without tinnitus at initial visit. Main outcome measures were patient age, the presence or absence of vertigo and tinnitus, audiometric patterns, the severity of hearing loss, and hearing in the unaffected ear.
Results: Better contralateral hearing (n = 220 versus n = 72, P < 0.001) and younger age (48 versus 55 years, P < 0.001) were independently associated with the acute onset of tinnitus in patients with ISSHL. The degree of asymmetry between the ears did not differ significantly between patients with and without tinnitus. The sex, presence of vertigo, shape of audiogram, and severity of hearing loss were not correlated with tinnitus occurrence.
Conclusions: Tinnitus triggered by ISSHL was more frequent in patients with better contralateral hearing and of a younger age, irrespective of the severity of hearing loss on the affected side or the asymmetry between the ears
Delovanje metribuzina na aktivnost nekih enzima u zemljištu
Eeffects of metribuzin on the activity of some enzymes in soil was investigated. Trials
were set up in the laboratory on a clay loam soil. Metribuzin was applied at 12.0, 24.0 and
60.0 mg/kg soil rates and soil samples were collected 3, 7, 15, 30 and 45 days after metribuzin
treatment for analyses. Alkaline phosphatase, acid phosphatase, dehydrogenase, urease
and β-glucosidase were recorded.
The results showed that the intensity of metribuzin effects on the activity of enzymes
depended on treatment rate, exposure time and enzyme group. Metribuzin had an inhibiting
effect on acid phosphatese and dehydrogenase, as well as on alkaline phosphatase in
the initial stage before it turned into a stimulating one, while metribuzin stimulated urease
and had no effect on β-glucosidase.U radu je ispitivano delovanje metribuzina na aktivnost nekih enzima u zemljištu. Ogled
je postavljen u laboratorijskim uslovima na zemljištu tipa černozem. Metribuzin je primenjen
u količinama 12,0, 24,0 i 60,0 mg/kg zemljišta, a uzorci za analizu uzimani su 3, 7, 15, 30
i 45 dana posle primene metribuzina. Praćena je aktivnost enzima alkalna i kisela fosfataza,
dehidrogenaza, ureaza i β-glukozidaza.
Dobijeni rezultati su pokazali da delovanje metribuzina na aktivnost enzima zavisi od
primenjene količine, dužine delovanja i vrste enzima. Metribuzin je delovao inhibitorno na
kiselu fosfatazu i dehidrogenazu, na alkalnu fosfatazu prvo je delovao inhibitorno, a kasnije
stimulativno, na ureazu je delovao stimulativno, dok na β-glukozidazu nije delovao
Zajednica Arctio-Artemisetum vulgaris (Tx. 1942) Oberd. et al. 1967.: najzastupljenija ruderalna zajednica na području Pančevačkog rita
A several-year investigation of distribution, phytocoenological differentiation, floristic
composition and structure of the ruderal flora and vegetation, and relative anthropogenic
influences was conducted in the area of Pančevački rit.
The study focused on the ruderal community Arctio-Artemisetum vulgaris, the most
widespread of 10 ruderal communities identified in a detailed phytocoenological analysis
of the location of Pančevački rit.Na području Pančevačkog rita su obavljena višegodišnja floristička istraživanja rasprostranjenosti,
fitocenološke diferenciranosti, strukturalne i antropogene uslovljenosti ruderalne
vegetacije. U radu je analizirana zajednica Arctio-Artemisetum vulgaris, koja predstavlja
najrasprostranjeniju zajednicu od 10 razvijenih i opisanih ruderalnih zajednica na prostoru
Pančevačkog rita
Hematološki efekti herbicida Avalon® (bentazon + dikamba) za pacova
Hematological effects of the herbicide Avalon (GAL-57), a mixture of bentazon and dicamba,
were tested on rats. Avalon was administered by gavage at three and four dose levels
(250, 500, 1000 and 1250 mg/kg weight/day) for 28 and 90 days.
Hematological parameters, number of erythrocytes, leukocytes and platelets, hemoglobin
concentration, hematocrit and erythrocyte indexes (MCV, MCH and MCHC) were
monitored.
The results showed that the herbicide Avalon caused decrease in the values of hemoglobin,
hematocrit and erythrocyte indexes (both males and females). The changes
(mostly) correlated with the doses administered and, in most cases, a lower susceptibility
of females than males was observed. The herbicide GAL-57 had no adverse effect on the
number of leukocytes, erythrocytes and thrombocytes (both sexes, all doses tested).
The results showed that the herbicide Avalon causes weak anemia to the animals tested.
Reversibility was apparent during the recovery period of 28 days.U radu su ispitivani hematološki efekti herbicida Avalon (GAL-57), koji je mešavina bentazona
i dikambe kao aktivnih materija, na pacovima. Preparat je doziran oralnim putem (sondom
u želudac) u više nivoa doza (250, 500, 1000 i 1250 mg/kg/telesne mase/dan) tokom
28 i 90 dana. Praćeni su sledeći pokazatelji: broj eritrocita, leukocita i trombocita, koncentracija
hemoglobina, hematokrit i eritrocitni indeksi (prosečna zapremina eritrocita, srednja
vrednost hemoglobina po eritrocitu i prosečna koncentracija hemoglobina u eritrocitima).
Rezultati ovih ispitivanja su pokazali da herbicid Avalon kod oba pola izaziva smanjenje
vrednosti hemoglobina, hematokrita i eritrocitnih indeksa, dok kod drugih ispitivanih pokazatelja
(broj leukocita, eritrocita i trombocita) nisu registrovane promene u odnosu na kontrolu.
Sve promene su, najčešće, u korelaciji sa primenjenim dozama a uočena je, u najvećem
broju slučajeva, i nešto manja osetljivost ženki u odnosu na mužjake.
Rezultati ispitivanja su, takođe, pokazali da Avalon izaziva blagu anemiju kod ispitivanih
životinja s tim da je efekat reverzibilnog karaktera; nakon isteka perioda oporavka od 28 dana
vrednosti za sve ispitivane parametre se vraćaju na normalu i ne razlikuju se značajnije
u odnosu na kontrolu
Rimsulfuron u zemljištu: uticaj na mikrobiološke parametre u različitim tipovima zemljišta
The effects of rimsulfuron a sulfonylurea herbicide on the growth and activity of soil
microorganisms under laboratory conditions was investigated in two soils.
The application rates were: 0.2, 2.0 and 20.0 mg a.i kg-1 soil. The lowest concentration
tested was the label rate (0.2 mg a.i kg-1), and the other two were ten and hundred times
higher. No adverse effects on microbiological processes were observed for the label rate.
Decrease in microbial biomass carbon, dehydrogenase activity, fungi and bacteria in comparison
with untreated control, were found at higher rates. The magnitude of these effects
were generally slight and transitory.Na dva tipa zemljišta, u laboratorijskim uslovima, ispitivan je uticaj herbicida rimsulfurona
iz grupe sulfonilurea na brojnost i aktivnost zemljišnih mikroorganizama.
Rimsulfuron je primenjen u koncentracijama 0,2, 2,0 i 20,0 mg a.s. na kilogram zemljišta.
Najmanja ispitivana koncentracija (0,2 mg) odgovarala je količini koja se preporučuje za primenu,
a druge dve su deset i sto puta veće od preporučene.
Kada je primenjen u preporučenoj količini, rimsulfuron nije imao uticaja na ispitivane
mikrobiološke parametre. Smanjenje mikrobiološke biomase ugljenika, dehidrogenazne
aktivnosti, brojnosti gljiva i bakterija utvrđene su kod većih koncentracija rimsulfurona. Intenzitet
ovih promena je, uglavnom, bio slab i prolaznog karaktera
The need for new approaches to the study of traditional architecture in the process of architectural education
When modernizing the curricula at the Faculty of Architecture of the University of Belgrade, some fields of study have been somewhat neglected, including the teaching of traditional architecture, which is currently studied only at a basic level. Many students complete their education without adequate knowledge in this field, and this has affected the current situation of architectural practice in Serbia. Two optional courses were initiated to try to fill this gap, with different approaches to the study of traditional architecture. One course focuses on the study of traditional building techniques and materials related to the historical building context. The other course explores the correlation between traditional and sustainable architecture, following the idea that the latter is closely connected to traditional architecture. These teaching experiences, their problems and their outcome will be presented in this paper.Al modernizar los planes de estudio de la Facultad de Arquitectura de la Universidad de Belgrado, algunos ámbitos de estudio quedaron bastante desatendidos. Éste es el caso de la enseñanza de la arquitectura tradicional, que actualmente sólo se estudia en el nivel básico. Muchos estudiantes terminan su formación sin tener el conocimiento apropiado de este campo y, en consecuencia, esto afecta a la situación actual del ejercicio de la arquitectura en Serbia. Para tratar de llenar este vacío, se iniciaron dos cursos optativos con diferentes enfoques en el estudio de la arquitectura tradicional. Uno de los cursos se centra en el estudio de las técnicas y los materiales de construcción tradicional en lo referente al contexto histórico de los edificios. El otro explora la correlación entre la arquitectura tradicional y la sostenible, conforme a la idea de que esta última está estrechamente relacionada con la arquitectura tradicional. Se presentan en este documento estas experiencias educativas y sus problemas y resultados