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Enhancing Cold-Start Recommendations with Content-Based Profiles and Latent Factor Models
No full textRecommendation systems have become an important tool for enhancing personalized recommendations across various domains. However, these systems face challenges, including the cold start problem, data sparsity, etc. In this paper, we present a novel recommendation model that integrates content-based and collaborative approaches to overcome these challenges. The proposed model uses TF-IDF vectorization over multiple item attributes to compute content similarity scores, and the SVD collaborative model captures latent user-item interactions. To further strengthen user preferences, a time-aware exponential decay function is used to acquire the most recent user preferences during the construction of user profiles for content-based prediction. Finally, the rating prediction is generated through a weighted fusion of content and collaborative models. Compared to benchmark models, our approach reduces RMSE by 3.06% and MAE by 3.23%, demonstrating an improvement in prediction accuracy. Furthermore, our method shows stable performance, with only a slight increase in prediction error (MAE with 8% and RMSE with 1.5% with a hybrid weight of 0.5) under cold-start conditions, indicating that the proposed method maintains strong stability and robustness even in data sparsity scenarios
Molecular and morpho-physiological analyses revealed inter- and intra-generic diversity of filamentous cyanobacteria from saline/alkaline soils
Get PDFCyanobacteria play important roles in soil fertility and soil productivity. Diverse filamentous cyanobacteria due to their ability to add nitrogen and organic carbon to soil and to maintain the physical properties of soil are undoubtedly one of the important groups of cyanobacteria. The present study aimed to understand the diversity of filamentous cyanobacteria (both heterocystous and non-heterocystous) obtained from saline/alkaline soils of Uttar Pradesh, India. Fuzzy cluster analyses of 47 filamentous cyanobacteria based on their cellular dimensions showed high inter-generic diversity among heterocystous cyanobacteria while in non-heterocystous cyanobacteria both inter- and intra-generic diversity was observed. The results of the present study indicated that the dimensions of vegetative cells and heterocysts can be useful for the identification and differentiation of cyanobacteria belonging to Hapalosiphon and Lyngbya. Physiological characterization also revealed a great deal of variation (5-15%) in salinity tolerance. Multiplex HIP fingerprinting revealed a higher genetic diversity in heterocystous (12-76% similarity) than in non-heterocystous cyanobacteria (13-90% similarity). Heterocystous cyanobacteria like Aulosira laxa O. Kirchner ex Bornet & Flahault, Hapalosiphon sp. and Nostoc sp. showed high intra-generic variability while among the non-heterocystous ones, Lyngbya was found to be genetically highly heterogeneous. The results of the present study highlight the importance of morpho-physiological and genetic analyses in deciphering the diversity of filamentous cyanobacteria for the understanding of their population structure, ecology and adaptations
THE ROLE OF ONLINE REVIEWS IN THE CHOICE OF RESTAURANTS: PERCEPTIONS OF DOMESTIC GUESTS IN CROATIA
No full textKorisničke recenzije predstavljaju važan izvor informacija i za ugostitelje i za goste. Iako je njihov utjecaj opsežno istražen u sektoru ugostiteljstva, većina radova usredotočena je na hotele ili općenito ponašanje potrošača, dok su restorani relativno zanemareni, osobito u manjim europskim tržištima poput Hrvatske. Ovo istraživanje popunjava navedenu prazninu raščlambom načina na koji domaći gosti percipiraju i koriste se namrežnim recenzijama prilikom odabira restorana. Na temelju ankete provedene na 315 hrvatskih ispitanika, rezultati pokazuju da korisnici najviše cijene osvrte koji se odnose na okus hrane, uslužnost osoblja i vrijednost za novac. Predodžbena točnost recenzije snažnije doprinosi vjerodostojnosti nego sam broj osvrta. Utvrđene su razlike s obzirom na dob i razinu obrazovanja, a gosti restorana višeg cjenovnog razreda pokazali su veću osjetljivost na ekstremne (pozitivne ili negativne) recenzije. Dobiveni nalazi pridonose boljem razumijevanju uloge digitalnih recenzija u restoranskom kontekstu te nude praktične smjernice za prilagodbu digitalne komunikacije i tržništvenih strategija različitim potrošačkim segmentima.User-generated reviews are an important information source for both restaurateurs and guests. While their impact has been widely studied in hospitality, most research focuses on hotels or general consumer behavior, with limited attention to restaurants—especially in smaller European markets like Croatia. This study addresses that gap by examining how domestic guests perceive and use online reviews when choosing a restaurant. Based on a survey of 315 Croatian respondents, findings show that users value reviews focused on food taste, staff service, and value for money. Perceived accuracy contributes more to review credibility than the number of reviews. Differences emerged by age and education level, while upscale restaurant guests were more responsive to extreme reviews (positive or negative). These findings enhance our understanding of digital review use in the restaurant context and offer practical insights for tailoring online communication and marketing strategies to different consumer segments
LJUDSKI RAZVOJ KROZ PRIZMU FISKALNIH INSTRUMENATA: EMPIRIJSKA ANALIZA ZEMALJA OECD-A
No full textThis research aims to analyze the impact of fiscal instruments on the human development index. The study considers public expenditures, taxes, budgets, and public debt as fiscal instruments and uses panel data analysis. Considering 24 OECD countries and the period between 2004 and 2021, the impact of fiscal instruments on the human development index was analyzed using fixed effects (FE) and Driscoll-Kraay (DK) estimators. The analysis results show that each fiscal instrument impacts the human development index differently. The tax burden negatively affects the human development index, causing it to decrease. On the other hand, public expenditures, debt burden, and budget deficits contribute positively to human development. These findings suggest that fiscal instruments may influence human development index in different directions.Cilj je istraživanja analizirati utjecaj fiskalnih instrumenata na indeks ljudskog razvoja. U studiji se javni rashodi, porezi, proračuni i javni dug razmatraju kao fiskalni instrumenti te se koristi analiza panel podataka. Uzimajući u obzir 24 zemlje OECD-a i razdoblje od 2004. do 2021. godine, utjecaj fiskalnih instrumenata na indeks ljudskog razvoja analiziran je korištenjem estimatorom fiksnih učinaka (FE) i Driscoll-Kraay (DK). Analiza pokazuje da svaki fiskalni instrument ima drugačiji učinak na indeks ljudskog razvoja. Porezno opterećenje negativno utječe na indeks ljudskog razvoja, uzrokujući njegovo smanjenje. S druge strane, javni rashodi, teret duga i proračunski deficit pozitivno doprinose ljudskom razvoju. Rezultati ovog istraživanja ukazuju na to da fiskalni instrumenti imaju različite učinke na indeks ljudskog razvoja
Effect of condensed (quebracho) and hydrolysable (sweet chestnut) tannins on growth performance and contact dermatitis in broilers
No full textThe aim of this study was to evaluate the effects of dietary supplementation with condensed (quebracho) and hydrolysable (sweet chestnut) tannins on growth performance and the severity of contact dermatitis in broiler chickens. A total of 150 Ross 308 broilers were divided into three groups: a control group (no tannins), a group receiving hydrolysable tannins, and a group receiving condensed tannins, each at a dose of 0.75 g/kg of feed over a 42-day fattening period under commercial conditions. Body weight gain, feed conversion ratio, litter moisture, and the severity of footpad dermatitis and hock burn dermatitis were recorded. The group supplemented with hydrolysable tannins had a significantly higher final body weight and average daily gain, compared to the control. Both tannin-supplemented groups showed significantly lower litter moisture and a reduced severity of contact dermatitis lesions throughout the study. In conclusion, this study suggests that tannins, particularly hydrolysable tannins, may improve broiler growth and reduce the severity of contact dermatitis, highlighting their potential as functional feed additives. However, further research is required to determine optimal inclusion levels and elucidate their mechanisms of action
Metallothionein gene methylation reflects epigenetic changes in white stork (Ciconia ciconia L., 1758) nestlings
No full textThe white stork (Ciconia ciconia), a migratory bird from the Ciconiidae family, thrives in open habitats such as floodplains and wet meadows. In recent years, they have increasingly turned to foraging at landfills. Given that, white storks are apex predators and environmental pollutants accumulate in their bodies through the food web. Such exposure to pollutants can result in environmental stress, leading to epigenetic modifications that can influence gene expression. In this study, the percentage of the methylation index of the regulatory region of the metallothionein gene was analysed using methylation-specific real-time PCR to investigate the potential epigenetic effects of environmental pollution on white storks. The results suggest that both hypermethylation and hypomethylation of the MT gene may be associated with exposure to specific metals, depending on the pollutant profile and the nestling's detoxification capacity. Variations in the methylation index point to potential epigenetic responses in white stork nestling populations, which could serve as sensitive indicators of environmental stress. These findings represent the first successful application of DNA methylation analysis in the white stork nestlings in Croatia. Further detailed studies are needed to elucidate the causes of these methylation differences and to explore their relationship with metallothionein gene expression and broader biological outcomes. These results provide a foundation for future research aimed at understanding the influence of environmental pollutants on wildlife health through epigenetic pathways, and highlight the potential of epigenetic tools for wildlife biomonitoring and conservation strategies
Karakterizacija i usporedna ocjena mlijeka i jarduma od ovaca sjeničke pramenke
No full textThe aim of this study was a comparative analysis of selected quality parameters and nutritional value of cooked sheep’s milk and jardum, a traditional dairy product from the Pešter region. Jardum is produced by prolonged thermal processing of sheep’s milk with the addition of table salt, aiming to reduce water content. The results of the analysis show that jardum contains nearly twice as much protein, fat, and lactose, three times more ash, half the amount of water, ten times more salt, a significantly higher energy value (313.60 kcal) compared to pasteurized sheep’s milk (163.20 kcal). The contents of saturated (SFA), monounsaturated (MUFA), and polyunsaturated fatty acids (PUFA) in jardum were 65.13 %, 29.28 %, and 4.32 %, r espectively, while in pasteurized milk these values were 70.79 %, 24.57 %, and 3.45 %, respectively. More favorable lipid indices were found in jardum compared to milk. Differences in cholesterol content were not statistically significant. All evaluated sensory quality parameters, except for the intensity of sweet taste perception, were more pronounced in jardum compared to milk.Cilj ove studije bila je komparativna analiza odabranih parametara kvalitete i nutritivne vrijednosti kuhanog ovčjeg mlijeka i jarduma, tradicionalnog mliječnog proizvoda s Pešterske visoravni. Jardum se proizvodi produženom termičkom obradom ovčjeg mlijeka uz dodatak kuhinjske soli, s ciljem smanjenja sadržaja vode. Rezultati analize pokazuju da jardum sadržava gotovo dvostruko više proteina, masti i laktoze, tri puta više pepela, upola manje vode, deset puta više soli i znatno veću energetsku vrednost (313,60 kcal) u usporedbi s mlijekom (163,20 kcal). Sadržaj zasićenih (SFA), mononezasićenih (MUFA) i polinezasićenih masnih kiselina (PUFA) u jardumu iznosio je 65,13 %, 29,28 % i 4,32 %, dok su u pasteriziranom mlijeku ove vrijednosti bile 70,79 %, 24,57 % i 3,45 %. Jardum je imao povoljnije lipidne indekse u usporedbi s mlijekom. Razlike u sadržaju kolesterola nisu bile statistički značajne. Svi procijenjeni parametri senzorske kvalitete, osim intenziteta percepcije slatkog okusa, bili su izraženiji kod jarduma u usporedbi s ovčjim mlijekom
VREMENSKI PROMJENJIVA NEUČINKOVITOST U PRINOSIMA DEVIZNOG TEČAJA: SLUČAJ EURA U ODNOSU NA GLAVNE VALUTE
No full textThis paper examines the efficiency of the euro's exchange market against the USD, GBP, and CNY, which are generally considered highly efficient. We used two robust tests on a fixed-length rolling window to identify periods of inefficiency. A classification problem was then formulated to link these periods to specific market conditions. The data sample spanned from 1999 to 2025 for EUR/USD and EUR/GBP, and from 2005 to 2025 for EUR/CNY. Our findings show that market efficiency fluctuates over time. EUR/CNY returns were the most inefficient, followed by EUR/USD, with EUR/GBP returns being the most efficient. The detected periods of inefficiency appear to be linked to periods of crisis and high uncertainty. Logistic regression results also suggested that periods of lower volatility are more likely to be predictable or inefficient. These empirical findings align with market microstructure theory.U radu se ispituje učinkovitost deviznog tržišta eura u odnosu na USD, GBP i CNY, valute koje se općenito smatraju vrlo učinkovitima. Koristili smo se dvama robusnim testovima na pomičnom prozoru fiksne duljine kako bismo identificirali razdoblja neučinkovitosti. Zatim je formuliran problem klasifikacije kako bi se ta razdoblja povezala sa specifičnim tržišnim uvjetima. Uzorak podataka obuhvaćao je razdoblje od 1999. do 2025. za EUR/USD i EUR/GBP te od 2005. do 2025. za EUR/CNY. Naši nalazi pokazuju da učinkovitost tržišta varira tijekom vremena. Najizraženija neučinkovitost uočena je pri prinosu EUR/CNY, zatim EUR/USD, dok su prinosi EUR/GBP pokazali najveću razinu učinkovitosti. Čini se da su otkrivena razdoblja neučinkovitosti povezana s razdobljima krize i visoke neizvjesnosti. Rezultati logističke regresije također upućuju na to da su razdoblja niže volatilnosti sklonija predvidljivosti ili neučinkovitosti. Ovi empirijski nalazi u skladu su s teorijom tržišne mikrostrukture
Effect of quenching temperature on microstructure and properties of 50CrMnVA spring steel for piano tuning pins
No full textSpring steel has excellent elasticity, strength, and toughness. 50CrMnVA spring steel is a high-strength spring steel with excellent mechanical properties and pro-cess performance, so it is widely used in piano tuning pins. This paper investi-gates the effect of quenching temperature on the mechanical properties of 50CrMnVA spring steel, including the microstructure, hardness, and tensile prop-erties of the experimental steel after treatment at different quenching temperatures, and clarifies the effect of aging time on the alloy's microstructure, hardness, strength, elongation, and reduction of area. The results show that the mechanical properties are optimal when the quenching temperature is 860 °C
Effect of Solution–ECAP–Aging Treatment on Microstruc-ture and Properties of 7075 Aluminum Alloy
No full text7075 aluminum alloy is widely used as a high-strength structural material in aer-ospace and other fields. However, its traditional casting and rolling process suffers from coarse grains and uneven distribution of secondary phases, which limits its performance potential. Therefore, this study proposes a multi-process coupling method that combines solution treatment, equal-channel angular pressing, and aging treatment. Solution treatment fully dissolves the strengthening phases into the matrix. Equal-channel angular pressing applies segmented tempera-ture-controlled extrusion. Aging treatment promotes the precipitation of nanoscale phases. The L16 (45) orthogonal experiment validates the influence of each process on the alloy's microstructure and properties and also optimizes these influences. In performance tests, this method refines grains to the nanoscale (average 28 nm), increases hardness from 85 HV to 112 HV, enhances tensile strength to 562 MPa, improves elongation at fracture by 21.5 %, and raises electrical conductivity to 55 % IACS. These results indicate that the proposed multi-process coupling method effectively improves the microstructure and properties of 7075 aluminum alloy through synergy between low-temperature strengthening and medi-um-high-temperature plasticity optimization. This study offers technical and practical references for optimizing high-strength aluminum alloys