Lower Values Research Articles

Structural damage detection using a sensitivity-based model updating approach with autocorrelation function data

ABSTRACT This study presents a novel sensitivity equation for estimating structural parameters using autocorrelation function (ACF) data of dynamic responses. The proposed method reduces the need for extensive excitation frequencies, making structural parameter identification more practical and cost-effective, especially for large-scale structures. Furthermore, due to the quadratic relationship between ACF and the structural dynamic response, this approach exhibited greater sensitivity to damage than time-history-based methods. The method’s effectiveness was evaluated using simulated data from truss and offshore jacket platform models. Incomplete measurements were addressed by using partially measured structural characteristics without model reduction and data expansion processes. Measurement and modelling errors were simulated by adding uniformly distributed random error into the damaged structure data. The low values of the coefficient of variation indicated the method’s robustness against these errors. The accuracy of the method was confirmed through low root mean square error (RMSE) values and high variance accounted for (VAF) values.

Numerical study of turbulent eddy self-interaction in tokamaks with low magnetic shear. Part I: Linear simulations

Abstract This study examines the impact of low and zero magnetic shear, along with rational values of safety factor, on linear mode behavior in tokamak plasmas. We focus on how magnetic field line topology and parallel domain length influence linear mode structures and growth rates as magnetic shear decreases. Our results
show that as magnetic shear is reduced to low values, linear modes can transition between different branches, significantly affecting their characteristics. At zero magnetic shear, accurate modeling requires precisely capturing magnetic topology, as small deviations near rational surfaces can greatly impact growth rates. These findings are extended to nonlinear simulations in a companion paper (Volčokas, 2024), revealing that long turbulent eddies and magnetic field line topology play a crucial role in turbulence self-interaction and plasma transport.

Morphological, ecological and genetic characteristics of the sandy sculpin (<i>Leocottus kesslerii</i>, Cottidae) from the lakes Baikal, Arakhlei and Gusinoe, Transbaikalia

Studies on local forms of the Sandy sculpin, Leocottus kesslerii, in the lakes Baikal, Arakhlei and Gusinoye show that the differences between lake forms in terms of external morphology lie in the head length to width ratio. In the Baikal form, the head is wider than long, vs the opposite in both Apakhlei and Gusinoe forms. In the Baikal and Gusinoe forms, there is a gap between the dorsal fins, a gap being absent from the Arakhlei form and the dorsal fins are in touch with each other. In the Arakhlei form, the anal fin is long (37.4–43%, on average 39.3% SL). In the Baikal form, the length of the A base reaches 32.9% SL (29.0–34.5%). In the Baikal and Arakhlei forms, small and sparse bone prickles are present on the body, these being large and dense in the Gusinoe form. The differences identified show a low level of morphological isolation of the forms. More significant differences are established in ecological features: growth rate, food spectrum, reproductive characteristics, and fecundity values. The differences in ecological features are due to the adaptation of the Sandy sculpin forms to specific conditions of the lakes they inhabit. Studies on genetic differentiation were carried out using the control region (CR) of mtDNA. The study forms of the Sandy sculpin revealed weak genetic isolation. The p-distances between the L. kesslerii forms averaged from 0.33 ± 0.12 to 0.51 ± 0.24%. Such low values of genetic distances clearly lie within the limits of intraspecific variability. The data obtained on the morphological, ecological and genetic differentiation of lake forms of the Sandy sculpin show that fish from the lakes Baikal, Arakhlei and Gusinoe belong to the same nominative subspecies, Leocottus kesslerii kesslerii.

Patterns of natural vegetation removal in the Caatinga biome in Prodes Project scope

Abstract. The native vegetation removal (NVR) of Caatinga Brazilian biome has been mapped by Prodes Project coordinated by National Institute for Spatial Research (INPE) between 2000 to 2023 year. Prodes is considered an official government product for achieving Brazilian and international targets for the conservation of natural vegetation. Therefore, Prodes is committed to achieving the highest possible accuracy associated with the history of mapping already carried out, by visual interpretation of satellite images and the use of past mapping masks techniques. Mapping NVR in Caatinga biome is a major challenge compared to biomes where the tree canopy with native vegetation prevails. Caatinga is one of the least protected of Brazilian biomes and is in one of the most pressured semi-arid regions on the planet. This work aims to present the NVR in Caatinga biome from Prodes data, in terms of its trajectory and main geographical patterns, concerning the municipalities, and areas that are the focus of monitoring, conservation or restoration. According to Prodes results, by 2023, the cumulative NVR in the entire Caatinga reached 43,05%; in 2000, this figure was 29,54%. The major NVR occurred in the easternmost areas of Caatinga and regions of Serrinha and Feira de Santana in Bahia State. Also, there are areas with considerable NVR further inside the biome, such as, Irecê and Guanambi region in Bahia, west of Pernambuco and Paraíba States and South and North of Ceará State. Areas prioritized for conservation actions showed high NVR values, indicating the urgent need for implementation of such actions. The fact that Desertification Cores showed low NVR values is important, and these regions should be closely monitored to prevent uncontrolled NVR rates. The two regions with high anthropic pressure or speculation showed contrasting behaviors; while the Araripe Gypsum Pole exhibited higher NVR levels compared to the control area, the São Francisco River integration project (PISF) so far does not appear significantly different from the rest of the biome. Overall, this study clearly demonstrates the potential of monitoring the Caatinga through Prodes in understanding and integrating the various factors influencing changes in the biome's native vegetation cover. Future approaches should move beyond descriptive studies to increasingly contribute to the territorial management of this important Brazilian region.

Kinetic study on the degradation of Acid Red 88 azo dye in a constructed wetland-microbial fuel cell inoculated with Shewanella oneidensis MR-1.

Removal of Acid Red 88 (AR88) as an azo dye from the synthetic type of wastewater was studied in a laboratory-made constructed wetland microbial fuel cell (CW-MFC) inoculated with Shewanella oneidensis MR-1 (SOMR-1). Plant cultivation was implemented using a typical CW plant known as Cyperus alternifolius. The complexity of the SOMR-1 cell membrane having different carriers of electrons and H+ ions gives the microbe special enzymatic ability to participate in the AR88 oxidation link to the O2 reduction. Nernst equation developed based on analyzing the involved redox potential values in these electron exchanges is describable quantitatively in terms of the spontaneity of the catalyzed reaction. Power density (PD) at 100mg/L of the AR88 under closed-circuit conditions in the presence of the plant was 11.83 mW/m2. Reduction of internal resistance positively affected the PD value. In determining degradation kinetics, two approaches were undertaken: chemically in terms of first- and second-order reactions and biochemically in terms of the mathematical equations for rate determination developed on the basis of substrate inhibitory concept. The first-order rate constant was 0.263h-1 without plant cultivation and 0.324h-1 with plant cultivation. The Haldane kinetic model revealed low ks and ki values indicating effective degradation of the AR88. Moreover, the importance of acclimatization in terms of the crucial role of lactate was discussed. These findings suggest that integrating the SOMR-1 electrochemical role with CW-MFC could be a promising approach for the efficient degradation of azo dyes in wastewater treatment.

Empirical Study on the Influencing Factors of Cultural Space Communication Effect in Lou Di City

In the rapidly evolving media landscape, subcultural communication has attracted much attention. However, due to its long duration and low entertainment value, it struggles to create a lasting impact on collective and social memory. This research explores the potential of physical cultural spaces as a new avenue for effective cultural communication. Through quantitative research, the study focuses on the factors influencing the communication impact of public cultural spaces in Lou Di City. The results indicate that attributes such as attention-grabbing, engagement, innovation, ambiance, uniqueness, relevance, clarity, usefulness, recommendations, and satisfaction significantly influence the communication impact of cultural spaces. These findings can guide the enhancement and theoretical reconstruction of cultural spaces.

Governance of rural solid waste under a multi-subject governance model

Rural solid waste (RSW) exhibits distinct characteristics compared to municipal solid waste (MSW), such as dispersed distribution, long governance chains, and low recycling value, making it unsuitable to apply the same management measures as MSW. Government-led RSW management results in excessive administrative costs, and the inherent characteristics of RSW reduce market enthusiasm for its management. To address these issues, this paper integrates the “ multi-subject governance “ model with RSW management and establishes a systematic evaluation index system for RSW governance. Utilizing the Best-Worst Method (BWM), key factors were identified. Utilizing the VIKOR method, representative provinces in China were used as case studies to validate the scientific nature of the evaluation indices. The research findings indicate that the multi-subject governance model is an effective approach for RSW management. Key factors influencing RSW management effectiveness include various governmental measures, waste sorting, and a long-term multi-subject governance mechanism. Case analysis reveals a strong correlation between the level of economic development and the effectiveness of RSW management. However, constructing a government-led, multi-subject collaborative urban-rural interconnected RSW management model can effectively address RSW management issues in economically underdeveloped areas. This research provides innovative solutions for RSW management, contributing to high-quality and sustainable development in rural areas.

Effects of a Mouthrinse Containing Silver Nanoparticles on Polymicrobial Oral Biofilms.

To investigate the antimicrobial effects of a mouthrinse containing silver nanoparticles (AgNP) on polymicrobial biofilms in vitro. Polymicrobial biofilms were grown on glass cover slips following the method of Exterkate. Saliva collected from a healthy human was added to McBain medium (including 0.2% sucrose) to achieve a 50-fold dilution. Glass coverslips were attached to the lid of a 24-well culture plate and suspended in the medium of each well. After 24 h of cultivating, coverslips with biofilms were immersed in each of four treatment solutions or sterile deionized water for 5 min. The control and four treatment groups were as follows: 1) control: sterile deionized water; 2) nanosilver (NS): mouthrinse containing AgNP; 3) 0.05C: 0.05% chlorhexidine gluconate; 4) 0.2C: 0.2% chlorhexidine gluconate; 5) Xyl: 25% xylitol. The biofilms were further regrown for 48 h. After removing the biofilms ultrasonically, they were cultured on blood agar, viable cells were counted, and the amount of lactic acid in the biofilms was analysed using a colorimetric assay. Mouthrinse containing AgNP suppressed viable cells in the biofilm to the same degree or more than with chlorhexidine gluconate. Amounts of lactic acid after 72 h cultivation of biofilms treated with 0.2C and NS showed consistently low values. The mouthrinse containing AgNP suppressed viable cells in polymicrobial biofilms to the same level as 0.2% chlorhexidine or higher.

Formation of requirements for impact resistance and wear resistance of grinding balls

The article presents the results of a study of the operation processes of steel grinding balls in semi-autogenous grinding mills (SAG). It was determined that the balls experience both abrasive and impact loads. The properties of steel grinding balls with the same production technology are determined by the chemical composition and the formed microstructure over the entire cross-section of the ball. Balls made using 3 different technologies were studied. The balls of sets 1 and 2 show high hardness values at the surface, sufficient to ensure good resistance to wear during operation, and a sharp decrease in hardness at a distance of ~(15–20) mm from the surface as the volume of pearlite structures increases. At the same time, the balls of the 1st and 2nd sets showed low values of impact strength and insufficient resistance to impact. The lowest hardness values from the surface to the center were observed for set 3. Also, the highest mass loss during the abrasive wear test was recorded for set 3, which is explained by the lowest hardness values. The balls of set 3 showed higher values of impact strength and no splitting during the ball-on-ball test, which is explained by the soft ferrite-pearlite structure both on the surface and across the cross section of the ball, due to the reduced carbon content and the presence of nickel in the chemical composition. At the same time, the balls from set 3 showed the worst result in terms of abrasive wear. In the course of the conducted research, it was established that for successful operation in SAG, steel grinding balls must have a surface with high hardness due to the martensitic structure and a viscous core with a ferrite-pearlite structure. A promising direction in the development of technology for the production of steel grinding balls will be to obtain a steel ball microstructure that decreases uniformly from the surface to the center, which will allow maintaining high wear resistance and increasing the resistance to ball splitting

Probing the friction mechanism of diamond-like carbon films in aqueous environments based on molecular dynamics simulations

Abstract The frictional behavior of diamond-like carbon (DLC) films in an aqueous environment is of tremendous interest. To compare the impacts of the quantity of water molecules, sliding velocity, and loading on the friction behavior of DLC films, a molecular model of DLC films in an aqueous environment was built. The results show that the DLC film under high load and high sliding velocity leads to severe friction behavior, but the water molecules can prevent the occurrence of this severe friction behavior. Also increasing the number of water molecules can effectively reduce the increase in friction during the running-in stage and keep it at a low value. The primary explanation is that if there are enough water molecules, they will create a stable water film at the friction interface and prevent large-scale contact and distortion between the upper and lower DLC films, significantly reducing friction.

First report on the diversity of domestic pigeons (Columba livia) using plumage coloration and patterning in Saravena, Arauca, Colombia

The domestic pigeon (Columba livia Gmelin, 1789), native to Africa and Eurasia, is extensively found across Europe, Western Asia, Africa, and the Americas. The pigeon (Columba livia) was domesticated several centuries ago and holds a privileged place as a symbol of peace, love, fidelity, and ornamentation in parks. In recent decades, an increase in the populations of these pigeons has been detected. The Spanish brought Columba livia to Colombia in the 15th century. The objective of this study was to evaluate the genetic diversity of the domestic pigeon using loci related to plumage coloration and patterning in Saravena. Random sampling was conducted in six colonies between March and April 2024. Through urban visits, direct observation, and photographic records, a phenotypic classification of each of the 580 pigeons from the different flocks studied was carried out. Autosomal markers associated with coloration and plumage were analysed: Grizzle, Spread, Checker, and the sex-linked locus Ash-Red. Genetic profiles were calculated using indices: allele frequency, genetic diversity, and population structure, estimated with the PopGene 1.31 program. Diversity was assessed using the FSTAT program. The dendrogram was constructed with the MEGA X program. The marker with the highest allele frequency was Grizzle (P=0.1834), while the Spread marker had the lowest values (P=0.0300). The highest HT value was 0.3002 for the Grizzle marker, GST showed figures of 0.0360, and gene flow was 20.6; the FIS and FIT statistics reported values of 0.2779 and 0.2848, and FIT was 0.0091. Moderate genetic diversity, a deficit of heterozygotes, and an excess of homozygotes were observed, along with low interpopulation genetic differentiation and high gene flow between subpopulations. Low genetic distance values were also found between the studied subpopulations. The populations are closely related genetically, which may be due to their geographical proximity, which has favoured genetic exchange.

NIR spectroscopy prediction model for capsaicin content estimation in chilli: A rapid mining tool for trait-specific germplasm screening

Chilli is a widely produced crop, highly valued for its capsaicin content, a key economic trait. Traditional wet chemistry methods for estimating capsaicin are time-taking and laborious, while non-destructive methods like NIRS coupled with chemometrics, offer efficient alternatives, simplifying and accelerating biochemical assessments. This study is the first to develop and validate and tested for applicability of NIRS-based prediction model for capsaicin content in Indian chilli germplasm using MPLS regression. Various mathematical treatments were performed, and the most suited model was selected based on high RSQexternal, RPD and lower SEP values in the external validation set, indicating strong prediction accuracy and minimal error. The model achieved high RSQexternal value of 0.808, RPD value of 2.088 and low SEP value of 3.415 for capsaicin content, demonstrating excellent prediction performance. A paired sample t-test p-value of 0.757 (p > 0.05) showed non-significant difference between wet lab and predicted values, confirming the model’s accuracy. The applicability of the model was validated on fresh harvest germplasm the following year, showing a higher reliability score of 0.949, further confirming model’s reliability. This model would aid in high-throughput, accurate screening of chilli germplasm for capsaicin, accelerating chilli crop improvement programs and the development of new high-capsaicin varieties.

Biobased Sulfur- and Phosphate-Containing High-Refractive-Index Polymers: Substituent Effects on Optical Properties of Polymers.

Four biobased phosphate-containing aryl monomers with methoxy, allyl, and vinyl groups as substituents have been successfully synthesized. Copolymerizing these monomers with thiophenol or mercaptans via the photoclick thiol-ene reaction gives the polymers with refractive indices (nD) of 1.63-1.70 and Abbe numbers (vD) of 12.8-38.5. An investigation of the relationship of the vD values with the substituents on the benzene rings of the monomers indicates that methoxy and vinyl groups can collectively increase the vD values. In comparison with allyl groups, vinyl groups endow the polymers with both higher nD and vD. Moreover, these polymers also display high transmittance, high thermostability, and low haze values in the visible-light region, suggesting that these biobased functional monomers are satisfactory precursors used in the fabrication of optical devices.

ECC at LLETZ—An Exploratory Retrospective Cohort Study

Background: The aim of this study is to evaluate the distribution of the histological results of the endocervical curettage (ECC) at large loop excision of the transformation zone (LLETZ) as well as the additional diagnostic information and its impact on further clinical treatment recommendations in accordance with national guidelines. The ECC in addition to LLETZ can serve to detect (pre)cancerogenic lesions above the endocervical cone margin, although its predictive value as well as diagnostic accuracy remains vague due to limited studies performed on this topic. Methods: In this retrospective cohort study, 1121 patients who underwent LLETZ and concomitant ECC during a twelve-year period (2009–2021) were analyzed. The main outcome parameters were the histological diagnosis and incidence of adequate or inadequate ECC specimens. Results: In 1.7% of the specimens, ECC performed at the completion of LLETZ yielded additional diagnostic information. The histological result of the ECC had an impact on subsequent therapeutic approach in 2 of the 1121 patients (0.2%). Furthermore, a negative ECC yielded a low negative predictive value (NPV) of 43.8% for the detection of residual disease. Conclusions: As current guidelines increasingly support the performance of an HPV test six months after LLETZ as an indicator of treatment success irrespective of the margin status, the routine performance of an ECC at LLETZ remains questionable.

Improving the biodiesel production in the marine diatom Thalassiosira pseudonana cultivated in nutrient deficiency and sewage water.

The use of microalgae as a feedstock in biofuel production is highly encouraging. The marine diatom in this study, Thalassiosira pseudonana, was used as a test organism to evaluate the impact of nitrogen or phosphorus limitation and sewage water on improving biodiesel production. The growth rate is more affected in cultures without phosphorus by 41.8% lower than in control and the highest dry weight estimated in control. The cellular dry weight significantly increased in cultures treated with mix1 and mix2 wastewater compared to the control cultures. Chlorophyll a content decreased in the absence of nitrogen and phosphorous and in sewage water cultures. Lipid content in algal cultures without nitrogen or phosphorus and in sewage water accumulated nearly twice as much lipid content in synthetic medium. T. pseudonana showed high FAME contents; the two most abundant fatty acids, stearic acid (C18:0) and palmitoleic acid (C16:1), in the algal extracts revealed that T. pseudonana was predominantly composed of these fatty acids. T. pseudonana grown in nitrogen or phosphorus-deficient conditions exhibited an extreme percentage of saturated fatty acids (SFAs) by 87.38% and 85.47%, respectively, of the total fatty acids (TFAs). More importantly, the low polyunsaturated fatty acid content in oils indicates a high cetane number, low iodine value, and low corrosion for biodiesel quality indicators. Producing biodiesel that closely meets worldwide biodiesel requirements (ASTM D6751 and EN 14214) is the goal of this work, which shows that growing T. pseudonana under nutrient limitations leads to algal metabolism in that direction.

The origin and evolution of the CII deficit in HII regions and star-forming molecular clouds

We analyse synthetic emission maps of the CII 158 mu m line and far-infrared (FIR) continuum of simulated molecular clouds (MCs) within the SILCC-Zoom project to study the origin of the observed CII deficit, that is, the drop in the CII /FIR intensity ratio caused by stellar activity. All simulations include stellar radiative feedback and the on-the-fly chemical evolution of hydrogen species, CO, and C$^+$. We also account for further ionisation of C$^+$ into C$^ $ inside HII regions, which is crucial to obtain reliable results. Studying individual HII regions, we show that $I_ FIR $ is initially high in the vicinity of newly born stars, and then moderately decreases over time as the gas is compressed into dense and cool shells. In contrast, there is a large drop in $I_ CII $ over time, to which the second ionisation of C$^+$ into C$^ $ contributes significantly. This leads to a large drop in deficit inside HII regions, with deficit decreasing from 10$^ $ at scales above 10 pc to around 10$^ $ at scales below 2 pc. However, projection effects can significantly affect the radial profile of $I_ CII $, $I_ FIR $, and their ratio, and can create apparent HII regions without any stars. Considering the evolution on MC scales, we show that the luminosity ratio, deficitl , decreases from values of gtrsim 10$^ $ in MCs without star formation to values of around $ $ in MCs with star formation. We attribute this decrease and thus the origin of the CII deficit to two main contributors: (i) the saturation of the CII line and (ii) the conversion of C$^+$ into C$^ $ by stellar radiation. The drop in the deficitl ratio can be divided into two phases: (i) During the early evolution of HII regions, the saturation of CII and the further ionisation of C$^+$ limit the increase in $L_ CII $, while $L_ FIR $ increases rapidly, leading to the initial decline of deficitl . (ii) In more evolved HII regions, $L_ CII $ stagnates and even partially drops over time due to the aforementioned reasons. $L_ FIR $ also stagnates as the gas gets pushed into the cooler shells surrounding the HII region. In combination, this keeps the global deficitl ratio at low values of $

News Popularity Prediction in West Sumatera Using Autoregressive Integrated Moving Average

The increasing public interest in reading online news is undoubtedly a challenge for news portals as online news providers. Therefore, this research was conducted to predict news popularity in West Sumatra through the FajarSumbar.com news portal using the Autoregressive Integrated Moving Average (ARIMA) model. This research aims to develop a forecasting model that can assist in estimating the popularity of each news category so that news portals can devise more effective content strategies. The data used in this study includes the number of monthly news impressions from March 2021 to June 2024, which are grouped into various categories such as Religion Culture, Industrial Economics, Criminal Law, etc. Using the ARIMA method, which can handle time series data and overcome data non-stationarity problems through differencing and the use of grid search in optimization to find the best parameters based on the lowest evaluation metric. The results show that the ARIMA model can provide reasonably accurate predictions, although the level of accuracy varies between categories. The Mean Absolute Percentage Error (MAPE) values obtained are as follows: Religion Culture 26%, Industrial Economy 29%, Criminal Law 29%, Health 40%, Sports 38%, Tourism Entertainment 26%, Education 27%, Government Politics 31%, Social Environment 27%, and Technology 51%. The Technology and Health news categories show higher error rates than others, while Religion Culture and Tourism Entertainment have better accuracy rates. Thus, the ARIMA model can be used to predict future trends in news popularity, helping editors plan content strategies that are more relevant and interesting to readers. However, improvements are needed for news categories that have high variability.

Levels and Classification of Microplastics and Their Impact on the Wellbeing of Selected Commercially Important Fish Species in Kisumu Bay, Lake Victoria.

Microplastics (MPs) are emerging pollutants of concern in aquatic ecosystems. Fish ingest MPs accidentally during normal feeding because they resemble prey or by ingesting prey that previously consumed them. Despite severe plastic pollution in Africa, some countries, including Kenya have implemented laws to curb this pollution menace. MPs have scantly been studied in African freshwaters. This study provides empirical data and describes the levels of MPs in four commercially important fish species in Lake Victoria. A total of 95 fish samples were collected from four sampling sites (inshore-offshore waters) between March and May 2022. Microscopy and Attenuated Total Reflectance Fourier Transformed Infrared (ATR-FTIR) spectroscopy methods were used to identify MPs. In this study, 62 out of 95 (65.26%) of the gastrointestinal tracts of the sampled fish contained MPs. The four species showed different proportions of detected MPs among the sampled individuals: 75.00% (Clarias gariepinus), 75.00% (Synodontis victoriae), 71.43% (Lates niloticus), and 59.26% (Oreochromis niloticus). Polystyrene (PS) and poly (perfluorobutadiene) were the main plastic polymers in the fish samples. The condition factors estimated for O. niloticus, S. victoriae, and L. niloticus were > 1 and < 1 for C. gariepinus, respectively. Positive correlations were observed between microplastic numbers and fish length and microplastic numbers and fish weight. However, the low R2 values obtained implied no strong relationship exists between these parameters. These findings provide evidence of microplastic contamination in fish in Kisumu Bay.

Flemish consensus statement on the prevention, diagnosis and treatment of urinary tract infections in older nursing home residents.

Urinary tract infections (UTIs) are one of the most commonly reported infections in Belgian nursing home residents. In older adults, UTI diagnosis and management is complex, often leading to over-diagnosis and irrational antimicrobial use, stressing the need for a guideline approach. A consensus statement on the prevention, diagnosis and treatment of UTIs in older adults residing in nursing homes was developed in a collaborative effort between the Flemish Hospital Outbreak Support Teams, the Flemish Agency for Care and Health, the Association of the Flemish Coordinating and Advising General Practitioners, the Belgian Association of Urology, the Belgian Society for Gerontology and Geriatrics and PhD researchers based on a combination of clinical expertise, (inter)national guidelines and peer-reviewed studies. Optimizing fluid intake, appropriate toilet behaviour and posture, mobilization and local estrogen therapy in women are of proven value in UTI prevention, whereas the use of cranberry and probiotics is not to be advocated. The importance of avoiding bladder catheterization is stressed. In older nursing home residents, the diagnosis of UTIs remains challenging, mostly due to atypical systemic symptoms. A consensus diagnostic algorithm for UTI among residents with and without a urinary catheter was developed, including the presence of suggestive clinical symptoms and a positive urine culture. Urine dipsticks have a high negative but a low positive predictive value. C-reactive protein point-of-care testing is not recommended. Asymptomatic bacteriuria should not be screened for, in order to avoid unnecessary triggers for treatment. In cystitis, nitrofurantoin is the primary choice for treatment, with fosfomycin as an alternative; in prostatitis and uncomplicated pyelonephritis a fluoroquinolone is the advocated empirical antimicrobial.

Estimating an adjusted risk difference in a cluster randomized trial with individual-level analyses.

In cluster randomized trials (CRTs) with a binary outcome, intervention effects are usually reported as odds ratios, but the CONSORT statement advocates reporting both a relative and an absolute intervention effect. With a simulation study, we assessed several methods to estimate a risk difference (RD) in the framework of a CRT with adjustment on both individual- and cluster-level covariates. We considered both a conditional approach (with the generalized linear mixed model [GLMM]) and a marginal approach (with the generalized estimating equation [GEE]). For both approaches, we considered the Gaussian, binomial, and Poisson distributions. When considering the binomial or Poisson distribution, we used the g-computation method to estimate the RD. Convergence problems were observed with the GEE approach, especially with low intra-cluster coefficient correlation values, small number of clusters, small mean cluster size, high number of covariates, and prevalences close to 0. All methods reported no bias. The Gaussian distribution with both approaches and binomial and Poisson distributions with the GEE approach had satisfactory results in estimating the standard error. Results for type I error and coverage rates were better with the GEE than GLMM approach. We recommend using the Gaussian distribution because of its ease of use (the RD is estimated in one step only). The GEE approach should be preferred and replaced with the GLMM approach in cases of convergence problems.