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A Segmented Total Energy Detector (sTED) optimized for (n, ) cross-section measurements at n_TOF EAR2
No full textThe neutron time-of-flight facility n_TOF at CERN is a spallation source dedicated to measurements of neutroninduced reaction cross-sections of interest in nuclear technologies, astrophysics, and other applications. Since 2014, Experimental ARea 2 (EAR2) is operational and delivers a neutron fluence of ∼ 4 ⋅ 107 neutrons per nominal proton pulse, which is ∼50 times higher than the one of Experimental ARea 1 (EAR1) of ∼ 8 ⋅ 105 neutrons per pulse. The high neutron flux at EAR2 results in high counting rates in the detectors that challenged the previously existing capture detection systems. For this reason, a Segmented Total Energy Detector (sTED) has been developed to overcome the limitations in the detector’s response, by reducing the active volume per module and by using a photo-multiplier (PMT) optimized for high counting rates. This paper presents thenmain characteristics of the sTED, including energy and time resolution, response to -rays, and provides as well details of the use of the Pulse Height Weighting Technique (PHWT) with this detector. The sTED has been validated to perform neutron-capture cross-section measurements in EAR2 in the neutron energy range from thermal up to at least 400 keV. The detector has already been successfully used in several measurements at n_TOF EAR2
Skewness and kurtosis of mean transverse momentum fluctuations at the LHC energies
No full textThe first measurements of skewness and kurtosis of mean transverse momentum (⟨T⟩) fluctuations are reported in Pb–Pb collisions at √NN = 5.02 TeV, Xe–Xe collisions at √NN = 5.44 TeV and pp collisions at √ = 5.02 TeV using the ALICE detector. The measurements are carried out as a function of system size ⟨dch∕d⟩ 1∕3 ||< T < 3.0 GeV/c and || < 0.8, respectively. In Pb–Pb and Xe–Xe collisions, positive skewness is observed in the fluctuations of ⟨T⟩ for all centralities, which is significantly larger than what would be expected in the scenario of independent particle emission. This positive skewness is considered a crucial consequence of the hydrodynamic evolution of the hot and dense nuclear matter created in heavy-ion collisions. Furthermore, similar observations of positive skewness for minimum bias pp collisions are also reported here. Kurtosis of ⟨T⟩ fluctuations is found to be in good agreement with the kurtosis of Gaussian distribution, for most central Pb–Pb collisions. Hydrodynamic model calculations with MUSIC using Monte Carlo Glauber initial conditions are able to explain the measurements of both skewness and kurtosis qualitatively from semicentral to central collisions in Pb–Pb system. Color reconnection mechanism in PYTHIA8 model seems to play a pivotal role in capturing the qualitative behavior of the same measurements in pp collisions
Novel Cascade Alpha Satellite HORs in Orangutan Chromosome 13 Assembly: Discovery of the 59mer HOR—The largest Unit in Primates—And the Missing Triplet 45/27/18 HOR in Human T2T-CHM13v2.0 Assembly
No full textFrom the recent genome assembly NHGRI_mPonAbe1-v2.0_NCBI (GCF_028885655.2) of orangutan chromosome 13, we computed the precise alpha satellite higher-order repeat (HOR) structure using the novel high-precision GRM2023 algorithm with Global Repeat Map (GRM) and Monomer Distance (MD) diagrams. This study rigorously identified alpha satellite HORs in the centromere of orangutan chromosome 13, discovering a novel 59mer HOR—the longest HOR unit identified in any primate to date. Additionally, it revealed the first intertwined sequence of three HORs, 18mer/27mer/45mer HORs, with a common aligned “backbone” across all HOR copies. The major 7mer HOR exhibits a Willard’s-type canonical copy, although some segments of the array display significant irregularities. In contrast, the 14mer HOR forms a regular Willard’s-type HOR array. Surprisingly, the GRM2023 high-precision analysis of chromosome 13 of human genome assembly T2T-CHM13v2.0 reveals the presence of only a 7mer HOR, despite both the orangutan and human genome assemblies being derived from whole genome shotgun sequences
INFLUENCE OF NUCLEOSIDE ANALOGUES ON THE HETEROGENEITY AND INFECTIVITY OF MUMPS VIRUS
No full textPojava epidemija uzrokovanih virusom zaušnjaka čak i u procijepljenim populacijama ukazuje na potrebu razvoja učinkovitijih cjepiva i specifične antivirusne terapije. U ovom istraživanju ispitan je potencijal triju nukleozidnih analoga (ribavirina, 5-fluorouracila, 5-azacitidina) za moduliranje genske varijabilnosti ovog virusa u smjeru njegove atenuacije ili ekstinkcije metodama virusne kvantifikacije te analize genoma na temelju rezultata sekvenciranja nove generacije. Pokazano je da sva tri nukleozidna analoga u genom uvode specifične promjene, mijenjaju stopu mutacije i smanjuju titar virusa u staničnoj kulturi. Virusi tretirani 5-azacitidinom razvili su rezistentnost na nukleozidni analog. Tretman virusa koncentracijom ribavirina od 500 μM doveo je do ekstinkcije virusa. Rezultati ovog istraživanja pridonose boljem razumijevanju biologije i evolucije virusa zaušnjaka, naglašavajući potencijal mutageneze kao jednog od mehanizama djelovanja sva tri nukleozidna analoga na ovaj virus.Intermittent mumps virus outbreaks within vaccinated populations underscore the imperative for advancing more efficacious vaccines and specific antiviral therapy. This study investigates the potential of three nucleoside analogs (ribavirin, 5-fluorouracil, 5-azacytidine) for modulating the genetic variability of this virus towards its attenuation or extinction using virus quantification methods and next-generation sequencing genome analysis. Results show that these analogs induce specific genomic changes, alter mutation rates, and reduce virus titre in cell culture. Notably, viruses treated with 5-azacytidine exhibit resistance to the nucleoside analog. Additionally, a 500 μM ribavirin concentration leads to virus extinction. The research enhances understanding of mumps virus biology and evolution, emphasizing mutagenesis as a key mechanism for all three nucleoside analogs
Analysis of the results of conceptual questions on physics state matriculation exams
No full textDržavna matura iz fizike je izborni završni pismeni ispit koji učenici polažu nakon završetka četvrtog razreda srednjoškolskog školovanja. Ispit državne mature iz fizike je standardiziran i provodi se na velikom uzorku maturanata srednjih škola te nam je time jedan od najboljih pokazatelja znanja i razumijevanja fizike kod učenika Republike Hrvatske. Analizirani ispiti za ovaj rad sastojali su se od 25 zadataka zatvorenog tipa te 12 zadataka otvorenog tipa. Većina zadataka zatvorenog tipa su konceptualni zadaci, koji su važni za analizu učeničkog razumijevanja sadržaja fizike.
U ovome se radu, na temelju podataka iz nekoliko provedenih ispita državne mature iz fizike, identificiraju i analiziraju odgovori učenika na konceptualna pitanja te pomoću toga njihove pogreške pri razumijevanju koncepata s kojima se susreću tijekom nastave fizike. Zadaci su podijeljeni po područjima fizike i obrazovnim ishodima te su diskutirani oni koji najbolje ukazuju na učeničko razumijevanje koncepata te na moguće pripadne poteškoće.
Prema rezultatima učenika na pojedinim zadacima pokušat će se dati razlozi opaženog stupnja riješenosti i povezanih učeničkih poteškoća te pružiti smjernice za nastavu fizike koja može uroditi boljim razumijevanjem koncepata iz fizike i boljim rezultatima na državnoj maturi iz fizike.Physics state matriculation exam is an optional written exam, that students take after finishing the fourth grade of high school. The state matriculation exam in physics is standardized and is conducted on a large sample of high school graduates, so it is one of the best indicators of knowledge and understanding of physics of high school graduates in the Republic of Croatia. Analyzed exams for this thesis consisted of 25 closed-ended questions and 12 open-ended questions. Most of the closed-ended questions are also conceptual and important for the analysis of student understanding of physics content.
In this thesis, based on the data from several physics state matriculation exams, students' answers to conceptual questions and their errors in understanding the concepts encountered during physics classes are identified and analyzed. The physics problems are divided by areas of physics and educational outcomes, and the problems that best indicate the high school graduate's understanding of the concepts and the possible difficulties that may arise with them are discussed.
According to the students' results on individual tasks, an attempt will be made to give reasons for the observed degree of success and related student difficulties, and to provide guidelines for teaching physics that can result in a better student understanding of concepts in physics and better results at the state matriculation exam in physics
The influence of chirality of 3-aryl-3-hydroxypropanoate-based molecules on mesogenic properties of liquid crystals
No full textZbog svojih optičkih i mehaničkih svojstava kiralni tekući kristali (LC) predstavljaju interesantne materijale za znanost i tehnologiju. U okviru ove doktorske disertacije sintetizirana je serija dimernih LC molekula s kiralnim centrom unutar fleksibilne razmaknice, uvedenim pomoću 3-aril-3-hidroksipropanoatne skupine. Molekule su sintetizirane u racemičnom i enantiomerno čistom obliku uz variranje duljine razmaknice i mezogene jedinice. Time je istražen utjecaj kiralnog centra u sprezi s paritetom razmaknice i različito polarizabilnim mezogenim jedinicama na mezogena svojstva dimera i njihovu sposobnost prijenosa kiralnosti na akiralni medij. Pokazano je da neparni dimeri posjeduju bogatiji mezomorfizam od parnih te je opažen efekt pariteta u prijenosu kiralnosti. Polarizabilnija mezogena skupina uz kiralni centar stabilizira mezogena svojstva te inducira temperaturnu inverziju zavojnice. Razlika u morfologiji površine između racemične i kiralne „twist-bend“ nematičke faze (N*TB) sugerira da kiralnost u razmaknici promiče kiralnu hijerarhiju. Ovi rezultati ističu važnost položaja i fleksibilnosti kiralne skupine unutar dimerne molekule za mezomorfna svojstva i prijenos kiralnosti.Chiral liquid crystals (LCs) are promising materials for science and technology due to their optical and mechanical properties. Within this dissertation, a series of dimeric LC molecules with a chiral center within a flexible spacer, introduced via a 3-aryl-3-hydroxypropanoate group, were synthesized. The molecules were synthesized in racemic and enantiomerically pure forms with variations in the spacer length and mesogenic unit. The influence of the chiral center in conjunction with the spacer parity and differently polarizable mesogenic units on their mesogenic properties was investigated, as well as their ability to transfer chirality to an achiral medium. It was demonstrated that odd dimers exhibit a richer mesomorphism than even ones, and that chirality transfer was affected by the spacer parity. A more polarizable mesogenic group alongside the chiral center stabilizes mesogenic properties and induces a temperature inversion of the helix. The difference in surface morphology between the racemic and chiral N*TB phases suggests that chirality in the spacer promotes chiral hierarchy. These results highlight the importance of the position and flexibility of the chiral group within the dimeric molecule for mesomorphic properties and chirality transfer
Non-coding RNA molecules in bacteria
No full textMolekule RNA u bakterijama obavljaju razne uloge uz to što kodiraju ili pomažu u sintezi proteina. Fokus ovog rada su drugi tipovi molekula RNA: sRNA, riboprekidači i lncRNA, njihove uloge i mehanizmi kojima ih obavljaju. sRNA i riboprekidači dijele sposobnost za regulaciju ekspresije gena inhibicijom na kotranskripcijskoj ili posttranskripcijskoj razini. Dok se sRNA sparuju s ciljnim molekulama mRNA i tako reguliraju njihovu translaciju ili stabilnost, riboprekidači su domene samih mRNA i vezanjem liganda mijenjaju konformaciju, a s njome i ekspresiju gena. lncRNA su rjeđe i slabije istražene, no na otkrivanju njihovih djelovanja se kontinuirano radi i smatra se da obavljaju važne katalitičke i regulatorne uloge. Značaj istraživanja nekodirajućih RNA leži u uvidu koji pružaju u bakterijsku fiziologiju, ali i u potencijalnoj primjeni u jačanju biotehnoloških alata i razvoju novih antibiotika. Rad pruža pregled tri navedene kategorije nekodirajućih RNA u bakterijama i raspona procesa u kojima sudjeluju.RNA molecules in bacteria perform various functions in addition to coding and assisting in protein synthesis. The focus of this thesis are sRNA molecules, riboswitches and lncRNA molecules, their roles and the mechanisms by which they fulfill them. sRNAs and riboswitches share the ability to regulate gene expression by inhibition at the cotranscriptional or posttranscriptional level. While sRNAs pair with target mRNA molecules and thus regulate their translation or stability, riboswitches are domains of the mRNAs themselves and, by binding ligands, change the mRNA conformation and gene expression together with it. lncRNAs are rarer and less well researched, but the discovery of their functions is continuously being worked on and they are considered to play important catalytic and regulatory roles. The importance of non-coding RNA research lies in the insight they provide into bacterial physiology, but also in their potential application in developing new antibiotics and biotechnological tools. The thesis provides an overview of the three listed categories of non-coding RNAs in bacteria and the range of processes in which they participate
Peroxisomes
No full textPeroksisomi su kuglasti organeli prisutni u gotovo svim eukariotskim stanicama. Obavijeni su jednoslojnom membranom, nemaju vlastiti genetički materijal i osnovna im funkcija je oksidacija različitih supstrata. Glavne metaboličke uloge peroksisoma su β-oksidacija, detoksikacija reaktivnih kisikovih vrsta te glioksilatni ciklus i fotorespiracija u biljnim stanicama. Nastaju diobom postojećih peroksisoma, mehanizmom nalik mitohondrijskom ili de novo pupanjem vezikula s endoplazmatskog retikuluma. Za nastanak peroksisoma važni su proteini peroksini. Proteini peroksisoma sintetiziraju se na slobodnim ribosomima u stanici i unose se posttranslacijski kao smotani ili oligomerni proteini u matriks peroksisoma kroz privremenu poru koja nastaje na njihovoj membrani. Peroksini Pex5 i Pex7 služe kao topljivi receptori za unos proteina matriksa, a Pex19 služi kao receptor za ugradnju proteina membrane peroksisoma. Broj peroksisoma u stanici je reguliran i postoje mehanizmi koji kontroliraju nasljeđivanje peroksisoma. Peroksisomi se većinom degradiraju procesom peksofagije koja je regulirana ubikvitinacijom. Bolesti vezane u peroksisome mogu biti uzrokovane nedostatkom pojedinog enzima, primjerice X-vezana adrenoleukodistrofija ili nedostatkom funkcionalnih peroksisoma, primjerice Zellwegerov sindrom.Peroxisomes are spherical organels present in almost all eukaryotic cells. They are enclosed in a single membrane, they do not have their own genetic material and their primary function is oxidation of different substrates. Key metabolic roles of peroxisomes are β-oxidation, detoxification of reactive oxygen species, and glyoxylate cycle and photorespiration in plant cells. Peroxisomes arise by division of existing peroxisomes by mechanism like that of mitochondria or by de novo biogenesis by budding of vesicles from endoplasmic reticulum. Peroxins are proteins important for peroxisomal biogenesis. Peroxisomal proteins are synthesized on free ribosomes in cells and are posttranslationally imported in folded or oligomeric shape through transient pore on peroxisomal membrane. Peroxins Pex5 and Pex7 are soluble receptors for matrix protein import and Pex19 is a receptor for import of peroxisomal membrane proteins. Number of peroxisomes in cells is regulated and there are mechanisms that direct inheritance of peroxisomes during cell division. Peroxisomes are mostly degraded by pexophagy which is mostly regulated by ubiquitination. Peroxisome disorders can be caused by a single enzyme deficiency, such as in X-linked adrenoleukodystrophy, or by absence of functional peroxisomes, such as in Zellweger syndrome
The demogeographic picture of Međimurje from 2011 to 2021
No full textU radu se analizira stanovništvo Međimurja od 2011. do 2021. godine na temelju njegova prirodnog, mehaničkog i općeg kretanja te strukturnih obilježja. Nastoje se protumačiti najvažniji demografski trendovi prisutni u tom razdoblju te uočiti promjene u strukturi međimurskog stanovništva. Kao glavni izvor podataka korišteni su podaci Popisa stanovništva 2011. i 2021. godine te godišnja priopćenja Državnog zavoda za statistiku. Podaci pokazuju da je Međimurje u promatranom razdoblju bilo zahvaćeno depopulacijom, koja je u najvećoj mjeri rezultat vrlo negativne migracijske bilance. Ona je dobrim dijelom posljedica pristupanja Hrvatske Europskoj uniji 2013. godine. Međimurje je zabilježilo i negativnu prirodnu promjenu, ali ona je još uvijek znatno slabijeg intenziteta od hrvatskog prosjeka. Veliku ulogu u tome imaju izrazito visoke stope nataliteta kod romskoga stanovništva. Uzimajući u obzir činjenicu da prirodni pad postaje sve izraženiji te da je udio staroga stanovništva znatno nadmašio udio mladoga, nameće se potreba promišljenog provođenja pronatalitetne populacijske politike. Struktura međimurskog stanovništva 2021. godine u određenoj je mjeri izmijenjena u odnosu na 2011., ovisno o promatranom obilježju, a ona upućuje i na posebnost Međimurja u mnogima od tih obilježja u odnosu na Hrvatsku u cjelini.The paper analyzes the population of Međimurje from 2011 to 2021 based on its natural, mechanical and general movement and structural features. It tries to interpret the most important demographic trends present in that period and to observe changes in the structure of the Međimurje population. Data from the 2011 and 2021 Census of Population and the annual announcements of the Croatian Bureau of Statistics were used as the main data sources. The data show that Međimurje was affected by depopulation in the observed period, which was largely the result of a very negative migration balance. It is largely a consequence of Croatia´s accession to the European Union in 2013. Međimurje has also recorded a negative natural change, but it is still significantly less intense than the Croatian average. The extremely high birth rates of the Roma population play a big role in this. Taking into account the fact that the natural decline is becoming more and more pronounced and that the share of the old population has significantly exceeded the share of the young, the need for a well-thought-out implementation of the prenatal population policy arises. The structure of the Međimurje population in 2021 has changed to a certain extent compared to 2011, depending on the feature observed, and it also points to the uniqueness of Međimurje in many of these features compared to Croatia as a whole
The effect of the gut microbiota on learning and memory in mammals
No full textOs mikrobiom-crijevo-mozak dvosmjerni je komunikacijski sustav kojim crijevna mikrobiota djeluje na niz kognitivnih funkcija. Sve je više istraživanja koja pokazuju utjecaj crijevnog mikrobioma na učenje i pamćenje povezano s hipokampusom, moždane procese koji su pogođeni u mnogim neurodegenerativnim i mentalnim bolestima. Mikrobiom stoga predstavlja potencijalni terapijski i dijagnostički alat u nizu neuroloških bolesti i poremećaja. Ovaj završni rad predstavlja kratki pregled dosadašnjeg istraživanja o učinku crijevnog mikrobioma na učenje i pamćenje povezano s hipokampusom kod sisavaca. Taj je učinak opisan kroz četiri međusobno povezana puta, koji čine komponente osi mikrobiom-crijevo-mozak: živac vagus, os HPA, imunosni sustav i metaboliti. Nadalje, u radu su ukratko opisane različite vrste pamćenja kao i procesi koji su uključeni u nastanak pamćenja u hipokampusu.The microbiome-gut-brain axis is a bidirectional communication system through which the gut microbiota affects a variety of cognitive functions. An accumulating number of studies have shown the effect of the gut microbiome on hippocampus-dependent learning and memory - brain processes that are disordered in a multitude of neurodegenerative diseases and mental disorders. The microbiome therefore represents an exciting potential therapeutic and diagnostic tool in a variety of neurological diseases and disorders. This thesis provides a short review of the current research on the gut microbiome’s effect on hippocampus-dependent learning and memory in mammals. This influence is described through four interconnected pathways, components of the microbiome-gut-brain axis: the vagus nerve, the HPA axis, the immune system and metabolites. Furthermore, this thesis contains a short description of the different types of memory as well as the processes involved in the hippocampus-dependent memory formation