Results of Experimental Studies Conducted within the Framework of the SURA-CSES Program in 2018–2023

MEASURING LOTIC ECOSYSTEM RESPONSES TO NUTRIENTS: A Mismatch that Limits the Synthesis and Application of Experimental Studies to Management.

Preventive Nephrology: A Role for the Pediatrician

Interest in and use of experimental and quasi-experimental studies has increased among medical educators. These studies may be focused on a cause and effect relationship if they are rigorously conducted. Put another way; the medical education researcher manipulates or controls the independent variable (cause) in order to evaluate its impact on the dependent variable or outcome (effect). It is difficult to establish a cause and effect relationship in medical education research because the researcher is unable to control all covariables (confounding/intervening variables) that can influence the outcome of the study. Campbell and Stanley described confounding variables as threats to internal and external validity.1 Internal validity refers to the degree to which changes in the outcome(s) (the dependent variable(s)) of the study can be accounted for by the independent variable(s). Factors that may be considered as threats to internal validity are not part of the independent variables in an experimental study, but they can have a significant effect on the dependent variable (s) (outcome). Indeed, these factors may account for the results of the study, not the independent variable (s) (intervention (s)) of interest. External validity is focused on the extent to which the results of the study can be generalised to the target population. Threats to internal and external validity can undermine the quality of a meta-analysis which is grounded in a systematic review of the relevant literature. The methodological quality of experimental studies in medical education research may be in error. Given the possibility of methodological errors in experimental or quasi-experimental studies, authors of meta-analyses should first critically appraise the quality of all relevant studies comprised in the meta-analysis. For further discussion of criteria for experimental and quasi-experimental studies, I refer the interested readers to more extended discussions of quantitative and qualitative methods in medical education research.2,3 Intervention effect One of the criteria for conducting an experimental study is to manipulate the experimental independent variable. By manipulating the independent variable, we mean that the researcher controls the independent or experimental variable to evaluate its impact on the dependent variable (s) (outcome(s)). In medical education research, the experimental variable is typically an education intervention, for instance, the impact of simulation-based education on the development of clinical reasoning or the performance of medical students. The researcher conducting an experimental study manipulates the intervention of interest (e.g., simulation-based training) by administrating it to some students (the experimental group) and not to other students (control group). The control group usually receives a routine intervention, e.g., the usual teaching. After randomly assigning students into two groups, the experimental and the control groups, both groups take a pre-test as a basis for comparison of their performance on the pre-test with a post-test, which is given after the experimental group receives the intervention of interest and the control group receives a routine treatment. Using a measurement instrument, to assess the performance of both groups before and after the intervention and the routine treatment, is a pre-test-post-test control group design. If we assume that the collected data for measuring the performance of students is a continuous measure, we calculate the means and standard deviation of student performance. Using inferential statistics, the researcher is able to determine the impact of the intervention of interest on the performance of students. The fundamental data analysis is to calculate effect size indices, which inform us about the magnitude of the effect of an intervention (e.g., simulation) on particular outcomes (e.g., student performance). The effect size indicates the magnitude of differences in two means, e.g., the difference between interventional and control group means on student performance. Effect sizes indicate whether the differences are important. Effect sizes are essential for conducting meta-analyses. Sometimes the outcomes of studies with experimental designs are dichotomous and meta-analysts use the Odds Ratios (OR) or Risk Ratios (RR). In non-experimental studies, they may use the Pearson correlation coefficient (i.e., Pearson’s r) to show the strength and direction of an effect. The purpose of this introductory guide is to show how a meta-analysis works in the context of medical education research using experimental studies. The purpose of this article is to introduce standards and methods for meta-analysis for experimental studies in order to synthesise data from the primary research studies using meta-analysis and related statistics. This paper does not deal with the primary steps of a meta-analysis, i.e., how to address a problem, how to design a meta-analysis, how to appraise the quality of primary research studies, and how to extract and code data for analysis. Once these steps are completed, the meta-analysis is performed. Interested readers may refer to systematic review texts to conduct a thorough meta-analysis.

The Baihetan Hydropower Station reservoir area began impoundment in 2021, triggering the reactivation of ancient landslides and the formation of new ones. This not only caused direct landslide disasters but also significantly increased the likelihood of secondary surge wave disasters. This study takes the Wangjiashan (WJS) landslide in the Baihetan reservoir area as an example and conducts large-scale three-dimensional physical model experiments. Based on the results of the physical model experiments, numerical simulation is used as a comparative verification tool. The results show that the numerical simulation method effectively reproduces the formation and propagation process of the WJS landslide-induced surge waves observed in the physical experiments. At the impoundment water level of 825 m, the surge waves generated by the WJS landslide pose potential threats to the Xiangbiling (XBL) residential area. In this study, the numerical simulation based on computational fluid dynamics confirmed the actual propagation forms of the surge waves, aligning well with the results of the physical experiments at a microscopic scale. However, at a macroscopic scale, there is some discrepancy between the numerical simulation results and the physical experiment outcomes, with a maximum error of 25%, primarily stemming from the three-dimensional numerical source model. This study emphasizes the critical role of physical model experiments in understanding and mitigating surge wave disasters in China. Furthermore, physical experiments remain crucial for accurate disaster prediction and mitigation strategies. The theories and methods used in this study will provide important references for future research related to landslide disasters in reservoir areas.

Background: Hypertensive patients have difficulties in controlling blood pressure (BP), resulting in high mortality rates. There is a growing number of lab and human studies investigating the effects of photobiomodulation (PBM) therapy on hypertension. This motivated the current work to systematically assess existing literature and group evidence on the utility of PBM in BP management. Methods: A systematic review with meta-analysis was performed on randomized clinical trials (RCTs) and experimental animal studies assessing PBM treatments in hypertensive patients/animals. Five primary databases were assessed by two reviewers. Descriptive and quantitative analyses were performed separately for clinical and experimental studies. Results: A total of 197 articles were screened that identified four RCTs and five experimental studies for final inclusion. The clinical trials noted that PBM treatments reduced systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR), but with very low certainty. Experimental lab studies corroborated that PBM treatments reduced SBP, DBP, and mean arterial pressure (MAP) while increasing nitric oxide levels, again with very low certainty. Overall, RCTs had a high risk of bias, and experimental studies had an unclear risk of bias. Conclusions: PBM treatments have the potential to be an adjunct therapy for the treatment of hypertension, with studies showing a possible reduction in SBP, DBP, MAP, and HR, but the evidence is of very low certainty, coming from RCTs with a high risk of bias and experimental studies with an unclear risk of bias. The current evidence needs to be significantly improved with rigorous, well-designed experimental and clinical studies.

To analyze why numerous acute stroke treatments were successful in the laboratory but failed in large clinical trials. We searched all phase 3 trials of medical treatments for acute ischemic stroke and corresponding early clinical and experimental studies. We compared the overall efficacy and assessed the impact of publication bias and study design on the efficacy. Furthermore, we estimated power and true report probability of experimental studies. We identified 50 phase 3 trials with 46,008 subjects, 75 early clinical trials with 12,391 subjects, and 209 experimental studies with >7,141 subjects. Three (6%) phase 3, 24 (32%) early clinical, and 143 (69.08%) experimental studies were positive. The mean treatment effect was 0.76 (95% confidence interval [CI] = 0.70-0.83) in experimental studies, 0.87 (95% CI = 0.71-1.06) in early clinical trials, and 1.00 (95% CI = 0.95-1.06) in phase 3 trials. Funnel plot asymmetry and trim-and-fill revealed a clear publication bias in experimental studies and early clinical trials. Study design and adherence to quality criteria had a considerable impact on estimated effect sizes. The mean power of experimental studies was 17%. Assuming a bias of 30% and pre-study odds of 0.5 to 0.7, this leads to a true report probability of <50%. Pivotal study design differences between experimental studies and clinical trials, including different primary end points and time to treatment, publication bias, neglected quality criteria and low power, contribute to the stepwise efficacy decline of stroke treatments from experimental studies to phase 3 clinical trials. Even under conservative estimates, less than half of published positive experimental stroke studies are truly positive. ANN NEUROL 2020;87:40-51.

Background: In spite of several successful experimental studies, neuroprotective drugs have always failed in large clinical trials. We aimed to determine the efficacy decline of neuroprotectants from animal studies to early phase and phase III clinical trials. Moreover, we aimed to identify study characteristics of experimental studies and clinical trials, which contribute to the efficacy decline of neuroprotective drugs. Methods: We identified all phase III clinical trials and corresponding experimental studies and early clinical trials of neuroprotective drugs for ischemic stroke. The overall efficacy of neuroprotective drugs in experimental studies, early phase and phase III clinical trials was determined by means of a meta-analysis. We performed power analyses and estimated the publication bias in experimental studies and clinical trials. Stratified meta-analyses will be performed to identify study characteristics (e.g. randomization, blinded outcome assessment, time to treatment) which influence the results of experimental studies and clinical trials. Results: We identified 47 phase III trials, 190 corresponding experimental studies and 66 corresponding early clinical trials. Seventy-seven percent of experimental studies and 39,4% of early clinical trials reported a positive result in at least one treatment arm. By contrast, there was only one positive phase III trial, which was followed by a larger negative trial. Funnel plot asymmetry revealed a major publication bias in experimental studies. The mean power of experimental studies was 47,3%. Conclusion: Our study illustrates the efficacy decline from experimental studies to phase III clinical trials. Publication bias and low power inflate the efficacy of neuroprotective drugs in experimental stroke studies.

6 Background 6 Objectives 6 Selection criteria 6 Search strategy 7 Data collection and analysis 7 Main results 7 Authors’ conclusions 7

High sodium intake is a cause of elevated blood pressure in adults. In children and adolescents, less evidence is available and findings are equivocal. We systematically reviewed the evidence from experimental and observational studies on the association between sodium intake and blood pressure in children and adolescents. A systematic search of the Medline, Embase, CINAHL and CENTRAL databases up to March 2017 was conducted and supplemented by a manual search of bibliographies and unpublished studies. Experimental and observational studies involving children or adolescents between 0 and 18 years of age were included. Random-effects meta-analyses were performed by pooling data across all studies, separately for experimental and observational studies, and restricting to studies with sodium intake and blood pressure measurement methods of high quality. Subgroup meta-analyses, sensitivity analyses and meta-regressions were conducted to investigate sources of heterogeneity and confounding. The dose-response relationship was also investigated. Of the 6572 publications identified, 85 studies (14 experimental; 71 observational, including 60 cross-sectional, 6 cohort and 5 case-control studies) with 58531 participants were included. In experimental studies, sodium reduction interventions decreased systolic blood pressure by 0.6 mm Hg [95% confidence interval (CI): 0.5, 0.8] and diastolic blood pressure by 1.2 mm Hg (95% CI: 0.4, 1.9). The meta-analysis of 18 experimental and observational studies (including 3406 participants) with sodium intake and blood pressure measurement methods of high quality showed that, for every additional gram of sodium intake per day, systolic blood pressure increased by 0.8 mm Hg (95% CI: 0.4, 1.3) and diastolic blood pressure by 0.7 mm Hg (95% CI: 0.0, 1.4). The association was stronger among children with overweight and with low potassium intake. A quasi-linear relationship was found between sodium intake and blood pressure. Sodium intake is positively associated with blood pressure in children and adolescents, with consistent findings in experimental and observational studies. Since blood pressure tracks across the life course, our findings support the reduction of sodium intake during childhood and adolescence to lower blood pressure and prevent the development of hypertension.

Functional morphology," in its broadest sense, is simply the study of relationships between biological form and its functions."Function" can include many different aspects of an organism's biological adaptations, but in this context, and as most often used in physical anthropology, I will concentrate on mechanical function.There is a very long history of interest in the mechanical significance of anatomical variation (Galilei, 1638).Engineering principles were applied to the human skeleton by anatomists and orthopedic surgeons in the 1800s, most famously by Wolff (1892), whose name became associated with the concept of bone functional adaptation (i.e., "Wolff's Law"), despite many problems with the original formulation of the concept (Ruff, Holt, & Trinkaus, 2006).Comparative anatomists and anthropologists were aware of this work (Keith, 1918;Morton, 1924).However, the actual application of mechanical principles to the interpretation of extant and fossil humans and other primates was relatively rare during the early history of physical anthropology.Today, functional morphological studies make up a significant and expanding component of research in our field, due to many conceptual and technical advances over the past 100 years, particularly during the past 50 years.In this article, I review these developments, focusing in particular on the role of the AJPA as an outlet for encouraging and presenting new research in this area.

Summary Three-spined sticklebacks in natural lacustrine populations are often infected with plerocercoids of the indirectly transmitted pseudophyllidean cestode Schistocephalus solidus. Field studies typically show infections to be associated with reduced host condition, gonadogenesis and energy reserves, though infection phenotypes can vary considerably both between and within host populations. Experimental infection studies allow the impact of infections on hosts to be studied under a variety of rearing conditions, and so can be used to determine the environmental component of infection phenotypes. Here, we review recent laboratory studies undertaken by our group, examining the growth and condition of experimentally infected fish reared under conditions that differed in terms of absolute ration, temporal pattern of feeding and level of competition between fish. We compare infection phenotypes generated in our experimental studies with those of fish sampled in field based studies. Experimental studies in which infected fish were reared under competition for limited food resources, or were fed a restricted diet, generated infection phenotypes that most closely resembled those found in the majority of natural populations. When access to food was unrestricted, however, infected fish were able to sustain high growth rates and lay down energy reserves. If experimental studies are to be used to understand the impact of infection under natural conditions, husbandry protocols that closely match field conditions must be designed. We suggest that a full understanding of the impact of parasites on their hosts can only be gained by integrating controlled laboratory experiments with detailed field studies. The stickleback‐Schistocephalus system is ideally suited to examining these questions, and we provide several suggestions for future research.

Experimental and numerical studies have been conducted on the effects of bed roughness elements such as cubic and T-section elements that are regularly half-channel arrayed on one side of the river on turbulent flow characteristics and bed erosion downstream of the roughness elements. The experimental study has been done for two types of bed roughness elements (cubic and T-section shape) to study the effect of these elements on the velocity profile downstream the elements with respect to different water flow discharges and water depths. A comparison between the cubic and T-section artificial bed roughness showed that the velocity profile downstream the T-section increased in smooth side from the river and decrease in the rough side from it compared with the case when a cubic artificial bed roughness is used. By comparing the results for the element shapes, it can be notices that the T-section bed roughness element more effective compared to cubic shape for both sides of the channel. The numerical method has been done using Computational Fluid Dynamic (CFD) method. A validation for the CFD model with the experimental study have been carried out for a specific flow discharge and water depth. The results indicated that the velocity distribution profiles downstream the bed roughness elements in both sides shown very good agreement for manning coefficients between the numerical and experimental studies. The range of errors between the experimental and numerical study have been calculated using Root Mean Square Error (RMSE) approach, which is found that the RMSE is approximately equal to 1 in case of cubic bed roughness and the RMSE is about 1.5 in case of T-section bed roughness for both smooth and rough sides. Furthermore, the influence of the velocity profile and the bed erosion downstream of the T-section element under the effect of tides have been investigated using the CFD method, which is commonly happened in Shat al-Arab south of Iraq. The results show that the tide of the flow has a reverse effect on the velocity profiles for both sides. Since the velocity profile downstream of bed roughness region increase in the rough side and decrease in the smooth side compared with the normal flow of the river.

Physiotherapists use a small number of behaviour change techniques when promoting physical activity: A systematic review comparing experimental and observational studies

The use of experimental research methods can be of great benefit to researchers who want to gain more insight into causal relationships in leadership processes. In this chapter, we first explain which experimental paradigms and methods are often used by leadership researchers (e.g., vignette studies, laboratory experiments, field experiments, group experiments) and we provide some examples. Subsequently, we address some unique strengths of these experimental methods. Some specific points we discuss are related to issues of internal validity/testing causal explanations, the opportunity of studying specific underlying processes in isolation, testing possible interventions, testing complex models, and the relatively low time investment needed to conduct some types of experimental research. Notably, experimental methods also have potential pitfalls and we discuss those as well by pointing to the pervasive use of student samples, a general lack of psychological realism/external validity, the use of low-impact manipulations of high-impact situations, and the use of short-term approaches to long-term phenomena. Finally, we present a look to the future of leadership research, highlighting recent developments in experimental leadership methods and pointing out opportunities for further development and refinement of these methods.

The research aims to determine the effectiveness of the experimental and demonstration methods in improving the observation skills of physical objects in terms of gender differences. Experimental research uses a 2x2 factorial design, with a population of class X MAN students in Kutowinangun. Sampling using cluster random sampling with class X-IPA1 (experimental group) and class X-IPA2 (control group). The instrument for collecting data on object observation skills equipped with rubric has fulfilled the validity and reliability requirements. The results showed that (1) there was a difference in effectiveness between the experimental and demonstration methods for enhancing physics object observation skills. The Fhitung for the experimental group was 32.41&gt; when compared to the Fhitung for the demonstration group by 23.93. Based on the components of the input, process, and output, and the results of statistical tests, the learning process using the experimental method is more effective than the demonstration method. (2) Male students who use the experimental method with a mean value of 46.12 are more effective against increasing physical object observation skills than female students who use the experimental method with a mean value of 36.45. (3) Female students who use the demonstration method with a mean value of 42.27 are more effective against increasing physical object observation skills compared to male students who use a demonstration method with a mean value of 37.00