Intenzivna poljoprivredna proizvodnja bila bi nezamisliva bez učinkovite kemijske zaštite bilja. S obzirom na moguće opasnosti kod pripreme škropiva i aplikacije pesticida, svako nepravilno rukovanje ...može utjecati na zdravlje rukovatelja i zaštitu prirodnog okoliša. Najviše pozornosti bi trebalo posvetiti edukaciji radnika u postupku zaštite bilja, radi velikog broja ozljeda koje nastaju uslijed nestručnog rukovanja poljoprivrednim alatima, strojevima, oruđem, stokom i opasnim tvarima koje se koriste u poljoprivredi. Broj ozljeda koje se događaju tijekom pripreme škropiva i aplikacije pesticida nije moguće precizno utvrditi jer ne postoji obveza njihovog prijavljivanja nadležnim institucijama i tijelima državne uprave. Promjene koje je donio ubrzani tehničko-tehnološki razvoj obilježene su visokim stupnjem automatizacije, a time su se promijenili sadržaj i uvjeti rada te su se stvorile nove opasnosti, rizici i oblici ugrožavanja. Da bi se zaposle- nici zaštitili trebamo primijeniti nove pristupe i mjere u sustavu osiguravanja zdravlja i zaštite istog na radu.
Posljednjih je godina relativno velika učestalost pojave kasnoproljetnih mrazova u trajnim nasadima. Intenzitet pojave mraza za vrijeme cvatnje voćaka bio je takav da su voćari ostali bez cjelokupnog ...uroda, a posljedice su se osjetile duže vrijeme. Sustav navodnjavanja kišenjem u dobroj mjeri može biti učinkovit način zaštite od mraza, ali ima dosta nedostataka jer dolazi do pucanja grana zbog velike količine leda, tlo u nasadu je potpuno raskvašeno pa je otežan prohod traktora, a često se javljaju i bolesti u nasadu. Primjena suvremenog stroja „Frostbuster“ tijekom cvatnje voćaka (jabuka, kruška, breskva, marelica, trešnja, šljiva) osigurava pouzdanu i učinkovitu zaštitu od mraza na površini od 8 do 10 hektara.
U intenzivnom uzgoju povrća nužno je koristiti suvremenu opremu za navodnjavanje jer se samo na taj način navodnjavanje može obaviti pravovremeno i kvalitetno. Navodnjavanje je jedna od najvažnijih ...agrotehničkih mjera jer ima pozitivan učinak na fizikalne, kemijske i biološke procese u tlu. Voda otapa hranjive tvari u tlu koje biljke mogu usvojiti korijenovim sustavom, sudjeluje u procesu fotosinteze prenoseći hranjive tvari iz korijena do lista, poboljšava mikroklimu i mikrofloru tla, smanjuje temperaturu biljaka čime regulira njihov toplinski režim, povećava urod i kvalitetu plodova. U radu je prikazana oprema i različiti sustavi za navodnjavanje povrća.
Metode i tehnologija u voćarskoj i vinogradarskoj proizvodnji su u konstantnom napretku zbog čega tržište nudi niz novih strojeva i uređaja. Primjena bespilotnih sustava (engl. Unmanned Aerial ...System, UAS) nudi novu generaciju metoda i tehnologije nadziranja trajnih nasada s naglaskom na veće površine, kao i na nepristupačna i udaljena područja. Pravovremena detekcija pojave bolesti i štetnika te praćenje kvalitete cjelokupnog nasada omogućuje se jedino redovitim nadzorom trajnih nasada. Tako se izbjegava nepotrebno nanošenje pesticida u cijelom nasadu, tretiranje se obavlja lokalizirano, što je opravdano s ekonomskog i ekološkog stajališta. Sustavi s GNSS senzorima, zbog njihove točnosti i preciznosti primjenjivi su u poljoprivrednoj proizvodnji te imaju sve značajniji doprinos u sadnji, zaštiti, gnojidbi i berbi poljoprivrednih kultura. Neke od brojnih mogućnosti primjene bespilotnih sustava u nadziranju trajnih poljoprivrednih nasada, s naglaskom na njihovu zaštitu, prikazane su u ovom radu. Bespilotni sustav prikuplja prostorne podatke s terena koji su ubrzo nakon njihova prikupljanja dostupne za obradu i analizu. Prostorni podaci, poput prostorne razdiobe vegetacijskog prostora što stvara indeksa prikazane u ovom radu, koja je izračunata iz podataka prikupljenih bespilotnim sustavom senseFly eBee, kompatibilni su sa navigacijskim sustavom traktora, čime se ostvaruje preduvjet za ekonomično i efikasno praćenje i zaštitu trajnih nasada.
Multinuclear NMR study has demonstrated that G-quadruplex adopted by d(G3T4G4) exhibits two cation binding sites between three of its G-quartets. Titration of tighter binding K+ ions into the ...solution of d(G3T4G4)2 folded in the presence of \batchmode \documentclassfleqn,10pt,legalpaper{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \( {}^{15}\hbox{ NH }_{4}^{+} \) \end{document} ions uncovered a mixed mono-K+-mono-\batchmode \documentclassfleqn,10pt,legalpaper{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \( {}^{15}\hbox{ NH }_{4}^{+} \) \end{document} form that represents intermediate in the conversion of \batchmode \documentclassfleqn,10pt,legalpaper{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \( \hbox{ di- }{}^{15}\hbox{ NH }_{4}^{+} \) \end{document} into di-K+ form. Analogously, \batchmode \documentclassfleqn,10pt,legalpaper{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \( {}^{15}\hbox{ NH }_{4}^{+} \) \end{document} ions were found to replace Na+ ions inside d(G3T4G4)2 quadruplex. The preference of \batchmode \documentclassfleqn,10pt,legalpaper{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \( {}^{15}\hbox{ NH }_{4}^{+} \) \end{document} over Na+ ions for the two binding sites is considerably smaller than the preference of K+ over \batchmode \documentclassfleqn,10pt,legalpaper{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \( {}^{15}\hbox{ NH }_{4}^{+} \) \end{document} ions. The two cation binding sites within the G-quadruplex core differ to such a degree that \batchmode \documentclassfleqn,10pt,legalpaper{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \( {}^{15}\hbox{ NH }_{4}^{+} \) \end{document} ions bound to the site, which is closer to the edge-type loop, are always replaced first during titration by K+ ions. The second binding site is not taken up by K+ ion until K+ ion already resides at the first binding site. Quantitative analysis of concentrations of the three di-cation forms, which are in slow exchange on the NMR time scale, at 12 K+ ion concentrations afforded equilibrium binding constants. K+ ion binding to sites U and L within d(G3T4G4)2 is more favorable with respect to \batchmode \documentclassfleqn,10pt,legalpaper{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \( {}^{15}\hbox{ NH }_{4}^{+} \) \end{document} ions by Gibbs free energies of approximately −24 and −18 kJ mol−1 which includes differences in cation dehydration energies, respectively.
BackgroundSequencing of SARS-CoV-2 PCR-positive samples was introduced in Slovenia in January 2021. Our surveillance programme comprised three complementary schemes: (A) non-targeted sequencing of at ...least 10% of samples, (B) sequencing of samples positive after PCR screening for variants of concern (VOC) and (C) sequencing as per epidemiological indication.AimWe present the analysis of cumulative data of the non-targeted surveillance of SARS-CoV-2 and variant-dependent growth kinetics for the five most common variants in Slovenia for the first 9 months of 2021.MethodsSARS-CoV-2 PCR-positive samples, from January to September 2021, were selected for sequencing according to the national surveillance plan. Growth kinetics studies were done on Vero E6 cells.ResultsAltogether 15,175 genomes were sequenced and 64 variants were detected, of which three successively prevailed. Variant B.1.258.17 was detected in ca 80% of samples in January and was replaced, within 9 weeks, by the Alpha variant. The number of cases decreased substantially during the summer of 2021. However, the introduction of the Delta variant caused a fourth wave and completely outcompeted other variants. Other VOC were only detected in small numbers. Infection of Vero E6 cells showed higher replication rates for the variants Alpha and Delta, compared with B.1.258.17, B.1.258, and B.1.1.70, which dominated in Slovenia before the introduction of the Alpha and Delta variants.ConclusionInformation on SARS-CoV-2 variant diversity provided context to the epidemiological data of PCR-positive cases, contributed to control of the initial spread of known VOC and influenced epidemiological measures.
NMR study has shown that DNA oligonucleotide d(G3T4G4) adopts an asymmetric bimolecular G-quadruplex structure in solution. The structure of d(G3T4G4)2 is composed of three G-quartets, overhanging ...G11 residue and G3, which is part of the loop. Unique structural feature of d(G3T4G4)2 fold is the orientation of the two loops. Thymidine residues T4-T7 form a diagonal loop, whereas T15-T18 form an edge type loop. The G-quadruplex core of d(G3T4G4)2 consists of two stacked G-quartets with syn - anti - anti - anti alternation of dG residues and one G-quartet with syn - syn - anti - anti alternation. Another unusual structural feature of d(G3T4G4)2 is a leap between G19 and G20 over the middle G-quartet and chain reversal between G19 and G20 residues. The presence of one antiparallel and three parallel strands reveals the hitherto unknown G-quadruplex folding motif consisting of antiparallel/parallel strands and diagonal as well as edge type loops. Further examination of the influence of different monovalent cations on the folding of d(G3T4G4) showed that it forms a bimolecular G-quadruplex in the presence of K+, Na+, and NH4 + ions with the same general fold.
While neonates have no sophisticated language skills, the neural basis for acquiring this function is assumed to already be present at birth. Receptive language is measurable by 6 months of age and ...meaningful speech production by 10-18 months of age. Fiber tracts supporting language processing include the corpus callosum (CC), which plays a key role in the hemispheric lateralization of language; the left arcuate fasciculus (AF), which is associated with syntactic processing; and the right AF, which plays a role in prosody and semantics. We examined if neonatal maturation of these fiber tracts is associated with receptive language development at 12 months of age.
Diffusion-weighted imaging (DWI) was performed in 86 infants at 26.6 ± 12.2 days post-birth. Receptive language was assessed
the MacArthur-Bates Communicative Development Inventory at 12 months of age. Tract-based fractional anisotropy (FA) was determined using the NA-MIC atlas-based fiber analysis toolkit. Associations between neonatal regional FA, adjusted for gestational age at birth and age at scan, and language development at 12 months of age were tested using ANOVA models.
After multiple comparisons correction, higher neonatal FA was positively associated with receptive language at 12 months of age within the genu (
< 0.001), rostrum (
< 0.001), and tapetum (
< 0.001) of the CC and the left fronto-parietal AF (
= 0.008). No significant clusters were found in the right AF.
Microstructural development of the CC and the AF in the newborn is associated with receptive language at 12 months of age, demonstrating that interindividual variation in white matter microstructure is relevant for later language development, and indicating that the neural foundation for language processing is laid well ahead of the majority of language acquisition. This suggests that some origins of impaired language development may lie in the intrauterine and potentially neonatal period of life. Understanding how interindividual differences in neonatal brain maturity relate to the acquisition of function, particularly during early development when the brain is in an unparalleled window of plasticity, is key to identifying opportunities for harnessing neuroplasticity in health and disease.
d(G
3T
4G
4) oligonucleotide forms a dimeric G-quadruplex structure with a number of unique structural features. The comparative examination of several key interquartet and intraquartet H8–H8, NH–H8 ...and NH–NH NOE cross-peaks in the presence of K
+, Na
+ and
NH
4
+
ions showed only subtle structural differences while the same general fold is retained.
We have recently communicated that DNA oligonucleotide d(G
3T
4G
4) forms a dimeric G-quadruplex in the presence of K
+ ions
J. Am. Chem. Soc.
2003,
125, 7866–7871. The high-resolution NMR structure of d(G
3T
4G
4)
2 G-quadruplex exhibits G-quadruplex core consisting of three stacked G-quartets. The two overhanging G3 and G11 residues are located at the opposite sides of the end G-quartets and are not involved in G-quartet formation. d(G
3T
4G
4)
2 G-quadruplex represents the first bimolecular G-quadruplex where end G-quartets are spanned by diagonal (T4–T7) as well as edge-type loops (T15–T18). Three of the G-rich strands are parallel while one is anti-parallel. The G12–G22 strand demonstrates a sharp reversal in strand direction between residues G19 and G20 that is accommodated with the leap over the middle G-quartet. The reversal in strand direction is achieved without any extra intervening residues. Here we furthermore examined the influence of different monovalent cations on the folding of d(G
3T
4G
4). The resolved imino and aromatic proton resonances as well as (sequential) NOE connectivity patterns showed only minor differences in key intra- and interquartet NOE intensities in the presence of K
+, Na
+ and
NH
4
+
ions, which were consistent with subtle structural differences while retaining the same folding topology of d(G
3T
4G
4)
2 G-quadruplex.
Ultrasonic non-destructive testing (UT) is a proficient method for detecting damage in composite materials; however, conventional manual testing procedures are time-consuming and labor-intensive. We ...propose a semi-automated defect segmentation methodology employing a convolutional neural network (CNN) on 3D ultrasonic data, facilitated by the fusion of X-ray computed tomography (XCT) and Phased-Array Ultrasonic Testing (PAUT) data. This approach offers the ability to develop supervised datasets for cases where UT techniques inadequately assess defects and enables the creation of models with genuine defects rather than artificially introduced ones. During the training process, we recommend processing the 3D volumes as a sequence of 2D slices derived from each technique. Our methodology was applied to segment porosity, a common defect in composite materials, for which characteristics such as void size and shape remain immeasurable via UT. Precision, recall, F1 score, and Intersection over Union (IoU) metrics were used in the evaluation. The results of the evaluation show that the following challenges have to be faced for improvement: (i) achieving accurate 3D registration, (ii) discovering suitable similar keypoints for XCT and UT data registration, (iii) differentiating ultrasonic echoes originating from porosity versus those related to noise or microstructural features (interfaces, resin pockets, fibers, etc.), and, (iv) single out defect echoes located near the edges of the component. In fact, an average F1 score of 0.66 and IoU of 0.5 were obtained.
PDF
