Browse
Abstract
Campylobacter infections and campylobacteriosis-associated post-infectious sequelae are a significant global health burden that needs to be addressed from a specific African perspective. We conducted a comprehensive literature search on NCBI PubMed to compile a comprehensive narrative review article on Campylobacter infections in Africa, focusing on key aspects in human and veterinary medicine as well as food hygiene. We specifically focused on the epidemiology of enteropathogenic Campylobacter spp. in sub-Saharan and North Africa considering antimicrobial susceptibility. The most significant sequela resulting from molecular mimicry to Campylobacter surface structures is the Guillain-Barré syndrome, which was mainly examined in the context of limited studies conducted in African populations. A dedicated subsection is allocated to the limited research on the veterinary medically important species Campylobacter fetus. There are significant differences in the composition of the gut microbiome, especially in rural areas, which affect the colonization with Campylobacter spp. and the manifestation of campylobacteriosis. There may be a problem of overdiagnosis due to asymptomatic colonization, particularly in the detection of Campylobacter using molecular biological techniques. To reduce the colonization and infection rate of Campylobacter, we propose implementing several control measures and urge further research to improve the current understanding of the peculiarities of campylobacteriosis in Africa.
Asymptotic uniform upper density, shortened as a.u.u.d., or simply upper density, is a classical notion which was first introduced by Kahane for sequences in the real line.
Syndetic sets were defined by Gottschalk and Hendlund. For a locally compact group 𝐺, a set 𝑆 ⊂ 𝐺 is syndetic, if there exists a compact subset 𝐶 ⋐ 𝐺 such that 𝑆𝐶 = 𝐺. Syndetic sets play an important role in various fields of applications of topological groups and semigroups, ergodic theory and number theory. A lemma in the book of Fürstenberg says that once a subset 𝐴 ⊂ ℤ has positive a.u.u.d., then its difference set 𝐴 − 𝐴 is syndetic.
The construction of a reasonable notion of a.u.u.d. in general locally compact Abelian groups (LCA groups for short) was not known for long, but in the late 2000’s several constructions were worked out to generalize it from the base cases of ℤ𝑑 and ℝ𝑑. With the notion available, several classical results of the Euclidean setting became accessible even in general LCA groups.
Here we work out various versions in a general locally compact Abelian group 𝐺 of the classical statement that if a set 𝑆 ⊂ 𝐺 has positive asymptotic uniform upper density, then the difference set 𝑆 − 𝑆 is syndetic.
This study aims to answer the question whether the ancient Cēra kings sailed the seas and, if so, whether their technology was suitable for crossing the Indian Ocean, while it tries to summarize what we know about shipbuilding in ancient Southwest India. On the following pages, an attempt is made to introduce the most important passages of the Old Tamil Caṅkam literary sources in order to analyse their data in the light of Greek and Latin sources, and of Indian and Mediterranean inscriptions. It can be concluded that although inscriptions of Tamil traders can be found from Egypt to Thailand, and the Cēra kings built a maritime fleet for probably the first time in the history of ancient South India in order to punish their enemy, the kaṭampu tribe by sailing on the seas, their nautical contribution to the long-distance trade of the Arabian Sea as well as their engagement in coastal shipping can be classified as moderate and incidental in the antiquity.
Abstract
While three-dimensional measurement technology is spreading fast, its meaningful application to sedimentary geology still lacks content. Classical shape descriptors (such as axis ratios, circularity of projection) were not inherently three-dimensional, because no such technology existed. Recently a new class of three-dimensional descriptors, collectively referred to as mechanical descriptors, has been introduced and applied for a broad range of sedimentary particles. First-order mechanical descriptors (registered for each pebble as a pair {S, U} of integers), refer to the respective numbers of stable and unstable static equilibria and can be reliably detected by hand experiments. However, they have limited ability of distinction, as the majority of coastal pebbles fall into primary class
Abstract
Stable hydrogen isotope compositions of metamorphic rocks and minerals can provide information on the origin of metamorphic fluids, which is especially important in systems that had experienced multiple metamorphic events. The Sopron orthogneiss-micaschist complex is a good target as it records signs of Variscan and Alpine metamorphic events as well as Variscan granitic magmatism. In this study tourmaline-bearing rocks (pegmatitic orthogneisses and kyanite-chlorite-muscovite schists) of the Sopron metamorphic complex were sampled and their tourmaline grains were analyzed for stable hydrogen isotope compositions (δ2H). The δ2H values (−23 ± 1‰, relative to V-SMOW) are in accordance with a fluid flux from devolatilization of subducted, seawater-containing rocks. Tourmaline-chlorite hydrogen isotope fractionations correspond to about 550 °C, indicating that δ2H values formed close to peak metamorphic temperatures are preserved without retrograde isotope exchange during cooling.
Abstract
Real estate crowdfunding is a relatively new alternative financing and investing method. This research aims to identify factors which might increase investors' willingness to participate in real estate crowdfunding campaigns. We analyse 195 lending-based real estate crowdfunding campaigns from four Spanish platforms. Project success is measured by duration, i.e. the time required to reach the funding target. We assess the impact of the funding target, the annual return, the loan duration, several risk-related metrics and the minimum investment amount. We find that the higher the funding target and the minimum investment amount, the longer it takes to reach the target. We document that investors prefer projects where the maturity of the loan is shorter. We also find that construction-type projects reach the funding target faster than other type of fundraising goals. At the same time, we do not find any association between the annual return or risk-related metrics and project success. To assure successful fundraising, real estate crowdfunding platforms should prioritize those real estate projects which are highly popular among investors (i.e. construction-type projects with short maturity). Real estate developers, in turn, should crowdfund projects which are demanded by the crowdinvestors and use their traditional financing methods for the remaining projects.
A talaj katabolikus aktivitás mintázatának elemzése mikrorespirációs (MicroResp™) módszerrel
Analysis of soil catabolic activity patterns by micro-respiration (MicroResp™)
Functional diversity of the soil microbial community participates in most of the soil ecosystem services, often they have an essential role. From the many theoretical and experimental approaches, the catabolic activity pattern based on MicroResp™ technique is shown here. The method is the extension of the old-fashioned substrate induced respiration method to the microplate based multi-substrate induced respiration detection, allowing in situ community level physiological pattern of the soil microbial community. As the substrate utilization of the individual microbes may differ, the substrate utilization pattern of the sample depends on the actual composition and abundance of the soil microbial community. Substrates used in this method can be variable, mainly simple sugars, amino acids, amines or carboxylic acids are applied. The microrespiration method is fast, sensitive and reliable, therefore it is recommended to use in planned experiments and in soil monitoring programs as well.
Abstract
Background and aims
Time perception is a cognitive process involving both the ability to estimate the duration of an event (time estimation, TE) and the subjective perception of its passage (time passage, TP). Studies show that alteration in TE/TP is associated with substance use disorders. However, little is known about the impact of these alterations in potentially problematic online behaviors. We explore TE and TP while participants were exposed to cues related to videogames, pornography, and TV series, and the relationship of TE and TP with scores from instruments that measure problematic gaming (PG), problematic pornography use (PPU), and problematic binge-watching (BW).
Methods
Participants from three independent samples (40 men from Luxembourg; 99 Spanish men, 111 Spanish women) completed an experimental task designed to assess TE and TP while they were exposed to short clips related to videogames, pornography, TV series, and documentaries (control condition). Participants also completed different self-reports.
Results
Whereas men underestimated the time that they were exposed to pornography and TV series, women overestimated it. For videogames, we showed a consistent pattern of overestimation of time duration. Time was systematically perceived as passing faster while participants were presented with TV series and pornography. Regarding the association between time perception and PG, PPU, and BW, TE did not correlate with any of the indicators of problematic engagement assessed; but TP correlated with several of these indicators.
Discussion and conclusions
The present preliminary results showed mixed evidence regarding the involvement of time perception in gaming, pornography use, and binge-watching.
Abstract
Klebsiella pneumoniae is a major human pathogen as it is responsible for various infections. In the past years hypervirulent K. pneumoniae (hvKP) emerged and disseminated worldwide. In this review a summary will be given about epidemiology, detection and antibiotic resistance of hypervirulent K. pneumoniae. A common feature of hypervirulent K. pneumoniae is a combined expression of several virulence factors. A mucoviscosus phenotype, certain capsulare serotypes (e.g.: K1, K2, K28, K47, K63) together with additional genetic markers namely, magA, rmpA or iucABCD, are needed in combinations to achieve the hypervirulent pathotype. Plasmid coded virulence determinants are also detected, that indicates horizontal gene transfer of hypervirulence factors in K. pneumoniae.
Interestingly, infections caused by hypervirulent K. pneumoniae occur usually in the community in otherwise healthy people, and during these infections multiple infection sites are detected. Clinical pictures include both invasive infections and local abscess formation. Pyogenic liver abscess is the most frequently reported clinical manifestation and abscess formation in brain, spleen and lung are also diagnosed. Additionally, meningitis, endophthalmitis, trombophlebitis, pneumonia can also develop.
In the early reports, hypervirulent K. pneumoniae strains exhibited enhanced virulence but these were susceptible to commonly used antibiotics. However, recently KPC, VIM, NDM and OXA-48 carbapenemase producing hypervirulent K. pneumoniae strains are increasingly reported, furthermore, well-known high-risk K. pneumoniae clones (e.g.: ST11, ST147, ST307) can develop hypervirulent pathotype, that poses an even more alarming challenge.
Abstract
Background and aims
The intertemporal and risk decision-making impairments are vital cognitive mechanisms in internet use disorder (IUD). However, the underlying neural mechanisms for these two decision-making dysfunctions in individuals with IUD remain unclear.
Methods
This study employed Functional Near-Infrared Spectroscopy (fNIRS) to record changes in blood oxygen concentration in the prefrontal cortex of individuals with IUD during intertemporal and risk decision-making tasks.
Results
The findings revealed that the intertemporal decision-making deficits in IUD group were primarily associated with reduced activation in the left dorsolateral prefrontal cortex (dlPFC) and orbitofrontal cortex (OFC) and FC from the left dlPFC to the right dlPFC. On the other hand, risk decision-making impairments were linked to decreased OFC activation and weakened functional connectivity from the left dlPFC to the right dlPFC and OFC.
Discussions and Conslusions
These results suggested that while there were common neural mechanisms underlying intertemporal and risk decision-making impairments in individuals with IUD, specific neural foundations existed for each type of dysfunction.
