Daily Samples Research Articles

Comparing machine learning techniques for neonatal mortality prediction: insights from a modeling competition.

Predicting mortality risk in neonatal intensive care units (NICUs) is challenging due to complex, variable clinical and physiological data. Machine learning (ML) offers potential for more accurate risk stratification. To compare the performance of various ML models in predicting NICU mortality using a team-based modeling competition. We conducted a modeling competition with five neonatologist-led teams applying ML techniques-logistic regression, CatBoost, neural networks, random forest, and XGBoost-to a shared dataset from over 6,000 NICU admissions. The dataset included static demographic and clinical variables, alongside daily samples of heart rate and oxygen saturation. Each team developed models to predict mortality risk at baseline and within 7 days. Models were evaluated using the area under the receiver operator characteristic curve (AUC). Results were presented at a national meeting, where an audience poll ranked models before AUC results were revealed. The audience favored the most complex model (CNN) for real-world application, though logistic regression achieved the highest AUC on test data. Teams employed varied feature selection, tuning, and evaluation strategies. Logistic regression outperformed more complex models, highlighting the importance of selecting modeling methods based on data characteristics, interpretability, and expertise rather than model complexity alone. By demonstrating that model complexity does not necessarily equate to better predictive performance, this research encourages the careful selection of modeling approaches.

Age and growth of American Eel in lower St. Johns River in northeast Florida

AbstractObjectiveLittle is known about American Eel Anguilla rostrata populations across much of the species' large geographic range. This study aimed to collect important information on the life history and population biology of American Eel in a northeast Florida river.MethodsDuring two 12‐week periods, from August to November 2021 and September to December 2022, American Eel were collected from a ~90‐km stretch of the lower St. Johns River via boat electrofishing. Data on length, weight, age, Anguillicoloides crassus parasite infection, and swim bladder condition were recorded for American Eel collected in both years, and additional data on sex, sexual maturity, and fin and eye morphology were recorded for American Eel collected in 2022.ResultOverall, biologists spent more than 63.5 h of effort over 42 sampling days to collect 297 American Eel, ranging in size from 150 to 705 mm total length (TL) with a continental age ranging from 0 to 8 years. American Eel catches were low and varied by section of river and over time; however, no differences in the length–weight relationship or size structure were observed between river sections. Adult parasites were observed in swim bladders of 36% of American Eel, and 57% of eel exhibited some level of swim bladder damage. Although length–weight relationships were similar regardless of swim bladder condition, relative swim bladder length was lower for fish with severe damage. Histological examination of gonads from 160 American Eel in 2022 revealed that the male : female sex ratio was 0.9:1 and nearly all eel were sexually immature. The majority of fish were 2–4 years of age; average growth was modeled with a von Bertalanffy curve for American Eel aged 1–8: TL = 740 × [1 – e−0.12(age + 1.98)].ConclusionGiven the paucity of information about American Eel in this region, the data provided in this study will be critical to informing future decisions on the management of the American Eel stock.

Anidulafungin exposure and population pharmacokinetics in critically ill patients with invasive candidiasis.

Anidulafungin is recommended as a first-line treatment for invasive Candida infections in critically ill patients. Pharmacokinetic (PK) variability is large in critically ill patients, potentially compromising pharmacokinetic-pharmacodynamic (PKPD) target attainment under standard dosing. We aimed to assess anidulafungin exposure, PKPD target attainment, and population (pop)PK in critically ill patients. Adult ICU patients receiving standard anidulafungin dosing [200mg on day 1, then 100mg daily] were included (NCT04045366). We performed rich blood sampling on an early (day 2 ± 1) and/or late (day 5 ± 1) treatment day. Using total anidulafungin plasma concentrations, we developed a popPK model (NONMEM7.5) and conducted Monte Carlo simulations (n = 1,000 per virtual patient) to evaluate the impact of patient factors on PKPD target attainment (AUC24h target 83.5mg×h/L). Twenty patients contributed 188 anidulafungin concentrations. PKPD target attainment was 45% and 65% on early and late sampling days, respectively. A two-compartment popPK model with first-order elimination described the data. Anidulafungin clearance increased with bodyweight and central volume of distribution increased as serum albumin decreased. Both bodyweight and serum albumin had a clinically relevant impact on PKPD target attainment at day 1 (area under the ROC curve; AUROC 0.82 and 0.62, respectively), and bodyweight on PKPD target attainment at day 14 (AUROC 0.94). Standard anidulafungin dosing regimen fails to achieve adequate target attainment throughout the treatment period. Standard anidulafungin dosing is insufficient for achieving adequate exposure in critically ill patients. An interactive simulation tool is provided to aid dose-finding research and explore different dosing strategies and targets.

Detection of levamisole and its metabolites in horses after oral levamisole administration over seven days.

Levamisole is a regulated substance sometimes administered to racehorses to treat equine protozoal myelitis. Metabolites include compound II, aminorex, and pemoline. Aminorex and pemoline are Horseracing Integrity and Safety Authority-banned substances. Previous studies have examined single doses of the drug. This study examined the disposition of levamisole after 7 days of dosing. 6 healthy Thoroughbred geldings. Horses were treated with 500 mg (approx 0.91 to 1 mg/kg) of compounded levamisole hydrochloride paste PO every 12 hours for a total of 13 doses over 7 days. Serum and urine samples were analyzed for levamisole and its metabolites over a 28-day period. The terminal half-life of levamisole in serum was variable between horses. Following the last dose of levamisole on day 7, serum levamisole levels took 3 to 14 days (days 10 to 21) to fall below the limit of detection (LOD) in 5 of 6 horses. Serum from 1 horse remained over LOD on the last testing day (day 28). In urine, following the final dose (day 7), levamisole was below LOD on day 13 (6 days after final dose) and aminorex was below LOD on day 10 (3 days after final dose). Compound II was above LOD in 4 of 5 horses sampled on the last sampling day (day 28). Levamisole and its metabolites can be detected for variable lengths of time in horses, with detection lasting for days to weeks following multiple doses. This study supports the Racing Medication and Testing Consortium Advisory on levamisole, which suggests that clearance sample testing should be conducted on treated horses to verify elimination of levamisole and its metabolites.

Recent infection testing to inform HIV prevention responses and surveillance in a programme context: lessons from implementation within a nationally scaled female sex worker programme in Zimbabwe.

In the context of key population HIV testing programmes, identifying new HIV acquisitions, tracking incidence, and responding with prevention and treatment interventions will be critical for achieving HIV epidemic control. Laboratory tests for recently acquired HIV used as part of a "recent infection testing algorithm" (RITA), offer a potential tool to support this work. We implemented a RITA for female sex workers (FSWs) in Zimbabwe to explore opportunities and programmatic benefits. Between October 2021 and January 2023, recency testing was offered to FSWs attending the Centre for Sexual Health and HIV/AIDS Research (CeSHHAR) Zimbabwe's key populations programme. Dried blood spot (DBS) samples were taken at 86 clinic sites across 10 provinces and Laboratory LAg Avidity and viral load testing conducted. RITA results were analysed and linked to programme data to explore geographical differences and calculate HIV incidence. We describe concurrent efforts in HIV testing for social (social network testing [SNT]) and sexual (index case testing [ICT]) contacts of those testing HIV positive. Among 24,976 FSWs tested at programme sites, 9.5% (2363/24,976) were confirmed HIV positive. We enrolled 55.5% (1311/2363) of eligible HIV-positive FSWs to our study, of whom 11.7% (153/1311) were identified as having recently acquired HIV. It took a median of 37 days (IQR 20-67) for samples to be processed. Enrolment rates varied between provinces but the proportion of recently acquired HIV was similar (range: 18.4% to 4.0%). Overall HIV incidence was 3.4 (95% CI 2.7-4.0) per 100py. Where results could be linked to routinely collected data, we found no evidence of a difference in test-positivity between the ICT and SNT contacts of those with recently acquired compared to those with long-term HIV. Implementation of a RITA was possible within a nationally scaled sex worker programme, and while challenging to implement, can provide an understanding of transmission dynamics and HIV incidence in this context. Sub-optimal recruitment and data linkage limited the interpretation of our findings and opportunities for strategic gains though focusing on HIV prevention efforts.

Medium and large mammals from a locality in the Cerrado of northwest Minas Gerais, Brazil

The Brazilian Cerrado is the second largest biome in the country, covering around 200 million hectares. The combination of a high taxonomic richness, elevated species endemism, and high degree of threat makes the Cerrado one of the world's hotspots for biodiversity conservation. Cerrado is home to a high mammal species richness, with 251 species, of which 22 are considered endemic. However, the biome is at the center of the expansion of Brazilian agriculture, concentrating the largest portion of national grain production, which has led to high rates of deforestation due to the conversion of native habitats into pastures and agricultural land. In this context, I present data from monitoring medium and large-sized mammals on a private property formed by a mosaic of native vegetation and anthropogenic areas in the northwest of Minas Gerais, southeast of Brazil. Sampling was carried out between June 2021 and November 2022, totaling 42 days of sampling, using different non-invasive methodologies. A total of 24 species of mammals were recorded, including top predators, such as Puma concolor and Leopardus pardalis, which play critical roles in regulating ecosystems and food web dynamics. We have also recorded species vulnerable to extinction, such as Chrysocyon brachyurus and Tapirus terrestris. Moreover, no differences were found in the species composition recorded between the dry and rainy seasons. The study area covers a great diversity of natural and anthropogenic habitats that provide shelter and food for fauna, supporting a rich assemblage of medium and large-sized mammals.

Dissipation kinetics and risk assessment of chlorantraniliprole residues in brinjal

Chlorantraniliprole is used to manage brinjal and shoot borer; however, residues may remain in crops. Therefore, the analysis of chlorantraniliprole residues with correlated dissipation rate and safety evaluations in Brinjal was undertaken at Varanasi, India. The present investigation was undertaken to study the dissipation pattern and safety evaluation of chlorantraniliprole residues in brinjal fruits. The collected brinjal was extracted using a modified ethyl acetate-based extraction method and analyzed by gas-chromatography micro-electron capture detector (GC-µECD). The food safety evaluation was determined by comparing the dietary exposure against maximum permissible intake (MPI) values. The GC-µECD gave good linearity (R 2 ≥ 0.97). The half-lives of chlorantraniliprole residue in brinjal fruits were 1.94, 2.24, and 2.71 days for RD half, RD, and DD, respectively for the year 2019 and for the year 2020, half-lives were 1.82, 1.40, and 2.78 days for RD half, RD, and DD, respectively. Dietary exposures of the residues were less than the MPI of 24.96 mg/person/day on all the sampling days. Thus, chlorantraniliprole can be recommended for spraying treatments in brinjal as a low-risk insecticide.

Dietary enrichment and feed preferences of threatened goitered gazelle (Gazella subgutturosa) in captivity

Arid-adapted ungulates species, such as gazelles, have faced tremendous population declines in recent decades. Numerous breeding stations were established across Asia and the Middle East to facilitate the captive breeding of endangered gazelle species. We intended to improve the feed quality of goitered gazelle (Gazella subguttorosa) in captivity at the Kızılkuyu Gazelle Breeding Station in Şanlıurfa Province in southern Turkey. In a feed choice experiment, five different types of supplementary feed were offered to the gazelles (black barley, white barley, forage wheat, white barley flake and a combination of black barley and white barley flake). Statistical analysis revealed a significant difference between the amount of feed types consumed. The mixture of black barley and white barley flake was the most preferred feed type. Black barley alone was the least preferred feed type, while white barley flake was the second most consumed feed, suggesting that white barley flake was particularly attractive to the gazelles. However, nutrient content analysis revealed no significant difference between feed types. When feed consumption was examined between sampling days, a significant difference was unravelled between day 1, 2, 8 and day 3–7. Results were discussed with respect to improving the gastro-intestinal health of captive gazelles, which is imperative when choosing suitable individuals for reintroduction, which should be in good physical condition to increase the chances for survival in the wild.

Effects of amount of lactose in milk replacer on gastrointestinal function of dairy calves

The objective of this study was to evaluate the effects of feeding milk replacer (MR) at different lactose amount while keeping osmolality constant on gastrointestinal function, blood parameters, and inflammation-related mRNA expression in the livers of dairy calves. Fifteen Holstein bull calves were assigned to one of three dietary treatments differing in MR lactose content (L: 38 %, M: 41 %, and H: 46 %). Feeding of the test diets was started at 1 day of age and gradually increased to a maximum feeding rate at 20 days of age (L: 1.16 kg/d, M: 1.21 kg/d, and H: 1.26 kg/d DM). Under these conditions, the lactose dosages for the treatments were 441 g/d, 496 g/d, and 580 g/d, respectively. The MR were prepared to ensure isocaloric and iso-osmotic (451 mOsm/kg) conditions. Fecal scores were recorded daily, and at 14 and 28 days of age, blood and breath samples were collected before and after MR feeding. In addition, feces and urine were collected for 2 consecutive days. Then, the calves were slaughtered to evaluate intestinal permeability and liver mRNA expression. The permeability in the duodenum and ileum was lower in H and M than in L; the permeability in the jejunum was also lower in H than in L. The hepatic mRNA expressions of toll-like receptor-2, IL-1β, and tumor-necrosis factor-α were lower in H and M than L. Nitrogen retention was higher in H than in L, and linear and quadratic increasing trends were observed in tissue ratio of gastrointestinal tract with the increase in lactose amount. Postprandial increase in plasma glucose concentration was smaller and postprandial increase in TG concentration was higher in H than in L. Fecal properties, digestibility, and breath hydrogen concentrations were not affected by treatment. These results indicate that feeding high-lactose MR may increase gastrointestinal weight and decrease permeability in the small intestine of calves.

Algorithms, spreadsheets and functions: exploring middle graders’ functional reasoning during a STEM entrepreneurial pitch competition

This paper reports on a five-day study exploring six middle school students’ developing understanding of algorithms and functions during the Building Algorithms challenge, an entrepreneurial Design & Pitch Challenge in STEM. Students proposed businesses and built automated spreadsheet algorithms to inform users’ decision making by assigning ratings to objects (e.g. videos, music, racetracks) based on their preferences. Part of a larger NSF study of students’ participation in entrepreneurial experiences with mathematical connections, the study used a design-based research methodology. Qualitative data (video of teams working, team interviews, and daily work samples) were analysed to answer the research question: How do students demonstrate functional reasoning as they build entrepreneurial solutions to the Building Algorithms challenge? Three themes emerged that describe how the challenge and its entrepreneurial framing enhanced students’ engagement with key processes of function building, including: (1) identifying personally meaningful functional relationships; (2) defining and operationalising authentic variables and function rules; and (3) making sense of writing, testing, and refining function rules. This study contributes to the field’s understanding of functions, demonstrating how entrepreneurship and a math-focused design challenge can elicit and enhance specific and targeted middle grades mathematics content.

Translational assessment of anhedonia components: Significant associations between reward anticipation measured via behavioural task performance, daily smartphone reports, and general anhedonia questionnaires

Anhedonia, a reduction in pleasure in previously enjoyed activities, is a hallmark feature of depression and is also of transdiagnostic relevance to many psychiatric disorders. Treatment and measurement of anhedonia are significant challenges. We examine anhedonia components, combining experimental training, with multimodal anhedonia assessment, comprising standard questionnaire instruments, a widely-used behavioural task, and daily reports of reward experience. Seventy-eight adults (74.4% female) completed both positive and negative cognitive bias modification training, a laboratory-based behavioural measure of reward anticipation and motivation, the Effort-Expenditure for Reward Task (EEfRT), and seven days of experience sampling via their smartphones.We found no evidence that cognitive bias modification training affected choices to engage in the high-effort trials on the EEfRT task, theorised to reflect reward anticipation. We also did not find the expected associations between baseline measures of anhedonia and reward sensitivity and response to training. Behavioural performance on the low probability EEfRT trials indicating higher reward anticipation was significantly associated with daily reports of anticipated reward. Daily reported reward anticipation and consumption were also associated with the questionnaire measure of anhedonia. Our findings demonstrate that traditional anhedonia questionnaire measures, and a laboratory-based measure of an anhedonia component, can translate to reported experiences of reward in real-world contexts. We demonstrate the specificity of associations between the laboratory measure, designed to measure reward anticipation and not consumption, and real-world reports.

Sample size calculations based on day-to-day variability of stress biomarkers in persons with dementia and their family caregivers

Introduction: Accurate estimates of intra-individual variability are necessary for proper design of clinical trials and epidemiological studies where the stress biomarkers cortisol and dehydroepiandrosterone sulfate (DHEA-S) are measured for dyads of persons with dementia (PWDs) and their family caregivers (FCGs). The aim is to determine the number of consecutive sampling days required to detect effect differences in clinical trials, and to accurately estimate regression coefficients in epidemiological studies where stress biomarkers are exposure variables in regression models with future disease as outcome. Methods: Clinical trial data from dyads of PWDs and their FCGs were used. Salivary cortisol and DHEA-S samples were collected five days a week, for eight consecutive weeks. From this data, we created formulas and graphical tools for the number of required sampling days needed to detect effect differences, and we calculated number of days needed for regression coefficients to be estimated with<10% bias. Results: A total of 5791 salivary samples from 34 dyads were used. For morning cortisol, five consecutive sampling days at baseline and an equal number of days at study termination is sufficient to detect a treatment difference>5% of baseline level with>20 dyads per group. When stress biomarkers are used in epidemiological studies at least six consecutive sampling days are required. Conclusion: Based on a large number of consecutive measurements of stress biomarkers we calculated the sufficient numbers of sampling days for clinical trials and for epidemiological studies to produce credible results. Our findings will aid researchers in the study design phase.

The Effect of Sampling Schedule on Assessment of Dietary Measures: Evidence From Blue Monkeys (Cercopithecus mitis stuhlmanni).

Accurately assessing primate diets is important in studies of behavioral ecology and evolution. While previous research has compared sampling methods (scan, focal), we examined how sampling schedule influences accuracy of dietary measures. We define sampling schedule as the combined distribution (random vs. consecutive) and frequency of sampling days within a given month. Under field conditions, time may be required to locate a study group, and we therefore also subtracted 1, 2, or 3 h from the beginning of all non-consecutive days in each sampling schedule to mimic observation time lost to search. From a dense (near daily) 5-year record of feeding behavior derived from focal animal follows of adult females in five wild blue monkey (Cercopithecus mitis) groups, we created data subsets matching various sampling schedules, and compared monthly dietary measures calculated from each subset to those based on the full data set. These measures included (1) the proportion of observation time feeding on fruit, (2) diet composition (three top-ranked food items), (3) species richness of plant diet, (4) Shannon-Wiener diversity index based on plant species, and (5) Holmes-Pitelka index expressing dietary overlap with the previous month. We used generalized linear mixed models to assess how frequency and sampling type (a combination of distribution and hours lost) relate to a subset's deviation from the full data set, where a smaller deviation (or higher chance of matching, for diet composition) implies greater accuracy. For all dietary measures, increasing observation frequency increased accuracy. The response to distribution varied among measures, but sampling types generally differed more at lower frequencies. Deviation varied widely within and between dietary measures, and some sampling schedules resulted in values with large percentage differences from the "full" data. Accordingly, when designing and comparing studies, researchers should consider how sampling schedules may influence the accuracy of the dietary measures of interest.

COMPARATIVE EVALUATION OF SORBENTS BASED ON NATURAL MATERIALS FOR CLEANING OIL-POLLUTED SOILS IN THE KOLA NORTH

The article presents the results of using sorbents based on natural materials as soil reclamation agents in the Arctic zone of the Russian Federation to reduce the negative impact of oil and oil product spills. It has been established that the most effective are composite sorbents based on sphagnum moss and peat in various combinations with excess activated sludge. The effectiveness of sorbents based on natural materials is compared with the commercial sorbent OilSorb. High dynamics of reducing the content of oil products in the first days in soil samples with the addition of composite sorbents, including natural sorption material and activated sludge, is noted.

Neutrophil percentages in bronchoalveolar lavage fluid: Implications for diagnosing bacterial pneumonia in patients with immunocompromise and neutropenia.

Pneumonia is the most common infection in ICU patients and a leading cause for death. Assessment of bronchoalveolar lavage fluid (BALF) cellularity can aid in pneumonia diagnosis. Low percentages (<50%) of BALF neutrophils have a high negative predictive value for bacterial pneumonia in a general medical ICU population. The operating characteristics in patients with immunocompromise and neutropenia are less clear. To compare BALF % neutrophils operating characteristics in patients with and without immunocompromise or neutropenia. This was a single center observational cohort study. Patients were categorized into three groups: (1) patients with neutropenia, (2) patients with underlying immunocompromise, and (3) patients with neither. BAL-level analysis reflected neutropenia and immunocompromise state on day of BAL sampling. Operating characteristics of BALF % neutrophils were calculated using varying thresholds of alveolar neutrophilia. Median [Q1,Q3] are reported for nonparametric data and compared using Mann-Whitney U tests. 688 mechanically ventilated patients had 1736 BAL samples. Among bacterial pneumonia episodes, no difference was found in BALF % neutrophils between patients with underlying immunocompromise and patients with neither neutropenia nor immunocompromise on day of sampling: 82.0% [61.0, 91.0] vs 81.0% [66.0, 91.0], p=0.859. However, when neutropenic on day of sampling, the median BALF % neutrophils was 35.0% [8.8, 67.5] (p<0.001 compared with other categories). In patients with neutropenia, a BALF % neutrophil threshold of 7% had a sensitivity of 90% for excluding bacterial pneumonia. We found that among patients with bacterial pneumonia, BALF % neutrophil was not significantly lower in patients with a broad spectrum of immunocompromised states but was significantly lower when measured during acute neutropenia. We found varying thresholds of BALF % neutrophils across the three groups. Patients with neutropenia who mount even a low percent of alveolar neutrophils should raise concern for bacterial pneumonia.

Enhancing shelf-life and nutritional value of broccoli florets through vacuum impregnation with calcium chloride and ascorbic acid.

The present investigation aimed to enhance the postharvest shelf-life of broccoli using vacuum impregnation (VI). Broccoli florets were impregnated with physiologically active chemicals, i.e. calcium chloride and ascorbic acid. Post-impregnation broccoli florets were packed in three different packaging materials (poly(ethylene terephthalate) punnets, low-density polyethylene pouches and shrink-wrap film) and stored at two temperatures (5 and 25 °C). The effects of impregnation solutions, packaging materials and storage temperature on physicochemical attributes (weight loss, total soluble solids, ascorbic acid, total chlorophylls and carotenoid content), antioxidant and phenolic contents, and shelf life were studied. The changes in the chemical structure post-impregnation and during storage were investigated using Fourier transform infrared (FTIR) spectroscopy. Results showed that impregnated broccoli florets exhibited significantly (P < 0.05) higher levels of biochemical attributes immediately after impregnation. During storage, the physicochemical and antioxidant properties of broccoli florets declined for all the samples. However, the reduction in these properties was significantly (P < 0.05) lower in impregnated florets as compared to untreated control samples. Principal component analysis and FTIR results also indicated a clear difference in the impregnated and control samples. The shelf-life of broccoli florets stored at 25 °C was assessed as 4 and 3 days for impregnated and control samples, respectively; whereas the samples stored at 5 °C had a shelf-life of 12 days for impregnated samples and 5 days for the control samples. The findings of the study elucidate the potential of VI in enhancing the initial quality and shelf-life of broccoli. The deterioration during storage is primarily due to physiological weight loss, a natural loss of water and volatile compounds that occur following harvest due to transpiration and respiration. Excessive transpiration can lead to dehydration, which reduces the quality and shelf-life of the product. © 2024 Society of Chemical Industry.

Bayesian inversion of bacterial physiology and dissolved organic carbon biodegradability on water incubation data

In aquatic ecosystems, dissolved organic carbon (DOC) plays a significant role in the global carbon cycle. Microorganisms mineralize biodegradable DOC, releasing greenhouse gases (carbon dioxide, methane) into the atmosphere. Extensive research has focused on the concentrations and biodegradability of DOC in aquatic systems worldwide. However, little attention has been given to uncertainties regarding the physiological characteristics of heterotrophic bacteria, which are crucial for biogeochemical modeling. In this study, the physiological properties of heterotrophic bacteria and the properties of DOC biodegradability in water are inferred through a Bayesian inversion approach. To achieve this, treated and natural water samples collected from the Seine River basin, were inoculated and incubated in laboratory. During incubation, the concentrations of DOC and heterotrophic bacteria biomass were measured. Then, a multiple Monte Carlo Markov Chains method and the HSB model (High-weight polymers, Substrate, heterotrophic Bacteria) are applied on the water incubation data. The results indicate a higher biodegradable fraction of DOC in natural water compared to treated water and significant variability in the fraction of fast biodegradable DOC within 5 days in both water samples. The significant variability highlights the uncertainties/challenges in the HSB model parameterization. The seven water samples used in the paper serve as a proof of concept. They are from various origins and display the potential of the method to identify parameter values in a large range of values. Because mortality rate of heterotrophic bacteria at 20 ∘C (kd20) showed a remarkable stability at 0.013 h−1, we considered that this parameter can be fixed at this value. The maximum growth rates at 20 ∘C (μmax20) was 0.061 h−1 while optimal growth yield (Y) estimated at 0.34 for treated water and at 0.25 for natural water. All these parameter values are well in accordance with previous determinations.

Does shrimp trawling contribute to the decline in sciaenid stocks?

Trawling is widely used to exploit shrimp resources worldwide and is considered a highly destructive fishing method due to the high by-catch and discard rates. By-catch levels in shrimp trawling are reported to be 5–10 times the target catch, especially in the subtropics and tropics. This study assesses the status of sciaenids landed by mechanized shrimp trawls (single day operated), off Hendala, Sri Lanka. Catch data and samples were collected at the Hendala fish landing site (6°59'25.5"N 79°52'27.9"E) by making biweekly field visits from January to December 2021. On each sampling day, 50–60 % of operating shrimp trawlers were randomly sampled, and by-catch samples (n = 3) of ∼2 kg each were collected to identify the taxonomic status of sciaenids and their composition. The size at first sexual maturity (Lm) and population parameters of dominant species in the catches were also assessed. Of the estimated total annual by-catch of 19.67 tons, the Sciaenidae family accounted for 31 %. Fourteen sciaenid species belonging to 7 genera including Johnius (Johnieops) dussumieri, a new record for Sri Lanka, were reported in this study. Otolithes ruber (27 %) made the highest contribution followed by Kathala axillaris (21 %), Johnius belangerii (15 %), Johnius macropterus (15 %), and Johnius borneensis (10 %). The Lm (cm) of 3 dominant species, O. ruber, J. belangerii and K. axillaris was estimated as 20.6, 13.8 and 11.0, respectively. Immature individuals of 85.5 %, 73.4 %, and 39.1 % respectively, were caught before reaching their first maturity. Estimates of population parameters suggested that non-target species like O. ruber, J. belangerii and K. axillaris are showing signs of over-exploitation. Management measures such as gear modification and introduction of by-catch-reducing devices as well as awareness programmes will be helpful to sustain the livelihood of fishers while protecting aquatic biodiversity and ecological sustainability.

Intensive short-term sampling with long-term consequences: characterizing pollutant transport with implications for developing monitoring.

Riverine sampling of pollutants is commonly used to understand pollutants' transport pathways, relationships with hydrology, and overall presence in a waterbody. However, temporal gaps between sample collection introduce errors to these efforts, and guidance prescribing sampling frequency remains sparse. The magnitude of error often depends on a contaminant's transport mechanisms and local hydrologic conditions, making the creation of comprehensive sampling guidance difficult. This study analyzed a unique dataset that measured 18 analytes, including pesticides, nutrients, and pathogens, in three Iowa rivers for 90 consecutive days (May 4-August 1, 2000). This dataset provided a novel opportunity to relate pollutants to local hydrology and quantify errors associated with recurring sampling. Pesticide concentrations followed the spring flush phenomenon, where values were greatest during high streamflow in May and June but often depleted by July. Fecal coliform and total phosphorus (TP) also coincided with high flow, but unlike pesticides, their concentrations never diminished. Nitrate exhibited more complex behavior; concentrations were diluted during high flows and then increased as streamflow receded. Autocorrelations were significant for nitrate and atrazine in larger rivers but negligible for fecal coliform and TP. Loads were calculated for four pollutants with minimal non-detects (atrazine, fecal coliform, nitrate, and TP). We simulated intermittent sampling by selecting evenly spaced subsets of measured values to estimate loads, which were compared to the loads calculated using every daily sample to quantify error. This method typically overestimated nitrate loads but underestimated other pollutants, and errors often decreased in larger watersheds. Nitrate generally had the lowest error, while fecal coliform had the highest. We used these results to approximate the sampling frequency needed to bind errors within a certain threshold.

Effect of DASH vs. Mediterranean diet on metabolic syndrome and cardiometabolic profile in adults with high normal blood pressure or grade 1 hypertension: the DASH-MedDiet randomized controlled trial

Abstract Background Lifestyle interventions are recommended as the first-line treatment to control metabolic syndrome components and improve cardiometabolic profile. However, studies directly comparing the effects of the Dietary Approaches to Stop Hypertension (DASH) vs. the Mediterranean diet (MedDiet) on metabolic syndrome prevalence and cardiometabolic risk factors are currently lacking. Purpose We aimed to assess the effects of a 3-month intensive dietary intervention implementing salt restriction either alone or on top of the DASH and MedDiet compared to no/ minimal intervention on metabolic syndrome prevalence and cardiometabolic profile in never drug-treated adults with high normal blood pressure (BP) or grade 1 hypertension. Methods We randomly assigned individuals to the control group (CG, n = 60), salt restriction group (SRG, n = 60), DASH diet with salt restriction group (DDG, n = 60), or MedDiet with salt restriction group (MDG, n = 60). All patients were followed monthly for 3 months in individual sessions coordinated by the clinical dietician. For the patients of all four study groups, the goal was to maintain the initial body weight unchanged. Patients in the CG received general advice on dietary principles for BP control. For the patients in all three intervention groups, the goal was to limit sodium intake to 2,000 mg/ day (equivalent to 5,0g salt/ day). In addition, patients in the DDG and the MDG received an individualized dietary plan with six daily sample menus to facilitate the adoption of the assigned dietary pattern. Anthropometric indices, dietary intake, office BP, and fasting blood samples were evaluated pre- and post-intervention. Results According to the intention-to-treat analysis, at 3 months post-intervention, the DDG and the MDG had lower odds ratio (OR) (95% CI) of metabolic syndrome [0.29 (0.12, 0.72), and 0.15 (0.06, 0.41), respectively] compared to the CG. Moreover, the MDG had lower odds of elevated BP levels compared to both the DDG and the SRG [0.08 (0.03, 0.19), and 0.13 (0.05, 0.34), respectively], and lower odds of metabolic syndrome compared to the SRG [0.25 (0.09, 0.67)]. In addition, the DDG and the MDG had lower odds of elevated fasting glucose compared to both the CG and the SRG, whereas the study groups did not differ regarding the odds of elevated waist circumference, elevated triglycerides, and reduced HDL- cholesterol. Regarding cardiometabolic indices, total and LDL-cholesterol, fasting glucose, HbA1c, and systolic/ diastolic BP were reduced in all three intervention groups compared to the CG. Conclusions On a background of salt restriction, the MedDiet was superior in BP reduction, but the DASH and MedDiet reduced the prevalence of metabolic syndrome to the same extent.