Non-homogeneous Groups Research Articles

Detection of differential item functioning with latent class analysis: PISA 2018 mathematical literacy test

The purpose of this research is to determine whether PISA 2018 mathematical literacy test items show a differential item functioning across countries. For this purpose, only the items in booklet number three were examined using the MIMIC method with Latent Class Analysis (LCA) approach. PISA 2018 tests are mostly developed in English. Therefore, in DIF analyses, the reference group is the UK, while the focal groups consist of the other countries examined in the research (Türkiye, Finland, Japan, and the USA). According to the results, of the 23 test items, statistically significant DIF was observed in eight items in the UK-Türkiye sample, in seven items in the UK-Finland sample, in eleven items in the UK-Japan sample, and in three items in the UK-USA sample. It is seen that the effect and size of DIF in non-homogeneous groups differ between groups and these effects can be examined in more detail with the LCA method.

Caudal epidural steroid injection versus transforaminal ESI for unilateral S1 radiculopathy: a prospective, randomized trial.

Epidural steroid injections are frequently performed to manage radicular symptoms. Most research investigating the effectiveness of different routes of epidural injections were conducted with non-homogeneous groups. In this study our aim was to investigate the efficacy of caudal versus transforaminal approaches in patients with unilateral S1 radiculopathy secondary to a paracentral L5-S1 disc herniation. Prospective, randomized clinical trial. A university hospital pain management center. The study was conducted between January 2022 and February 2023. Patients with unilateral S1 radiculopathy were randomly divided into two groups: the caudal epidural steroid injection (CESI) and the transforaminal epidural steroid injection (TFESI) group. Severity of pain and disability were assessed with Numeric Rating Scale (NRS-11) and Oswestry Disability Index (ODI) at baseline, 3 weeks, and 3 months after treatment. Fifty percent or more improvement in NRS-11 was defined as treatment success. Fluoroscopy time and doses of exposed radiation were also recorded. A total of 60 patients were included in the final analysis (n = 30 for each group). Significant improvement in pain and disability scores was observed at 3rd week and 3rd month compared to baseline (P < .001). Treatment success rate at 3rd month was 77% for the CESI group and 73% for the TFESI group without any significant difference between the groups (P = .766). CESI is equally effective as TFESI in the management of S1 radiculopathy due to a paracentral L5-S1 disc herniation. Both approaches can reduce pain and disability, while CESI requires shorter fluoroscopy time and less radiation exposure.

Single-port transumbilical pediatric cholecystectomy: any benefits for the patient?

To compare the perioperative results of single-port laparoscopic cholecystectomy (SPLC) with those of laparoscopic cholecystectomy (LC), and to analyze whether there were any differences between both techniques in our patients. A retrospective, observational analysis was carried out in non-homogeneous groups of patients under 15 years of age undergoing LC and SPLC over a 6-year period. LC was conducted using four ports, while SPLC was performed through an umbilical incision using a wound retractor to which a surgical glove was coupled for the insertion of 3 ports and instruments curved as required. 15 clinical, surgical, and economic variables were compared by means of a univariate and bivariate analysis. 11 patients underwent surgery - 5 through SPLC and 6 through LC. No significant differences were found in terms of mean operating time (SPLC: 144 minutes vs. LC: 139, P= 0.855) or hospital stay, but a slight increase in hospital cost was noted (SPLC: 1,160 € vs. LC: 1,177 €). The cost of LC was 1,322 € vs. 1,367 € for SPLC, with a premium of 44.30 € owing to the use of the wound retractor. None of the patients had perioperative complications, and all of them felt the cosmetic result was excellent. In our limited experience, the differences between SPLC and LC do not clearly support one or the other. SPLC could provide patients with a better cosmetic result and allow surgeons to improve their skills. However, we believe cholecystectomy is not the most adequate procedure to start a career in single-port laparoscopy because potential complications may be severe.

Robust mixture regression modeling based on the normal mean-variance mixture distributions

Mixture regression models (MRMs) are widely used to capture the heterogeneity of relationships between the response variable and one or more predictors coming from several non-homogeneous groups. Since the conventional MRMs are quite sensitive to departures from normality caused by extra skewness and possible heavy tails, various extensions built on more flexible distributions have been put forward in the last decade. The class of normal mean-variance mixture (NMVM) distributions that arise from scaling both the mean and variance of a normal random variable with a common mixing distribution encompasses many prominent (symmetric or asymmetrical) distributions as special cases. A unified approach to robustifying MRMs is proposed by considering the class of NMVM distributions for component errors. An expectation conditional maximization either (ECME) algorithm, which incorporates membership indicators and the latent scaling variables as the missing data, is developed for carrying out maximum likelihood (ML) estimation of model parameters. Four simulation studies are conducted to examine the finite-sample property of ML estimators and the robustness of the proposed model against outliers for contaminated and noisy data. The usefulness and superiority of our methodology are demonstrated through applications to two real datasets.

Laparoscopic Single-Port versus Mini-Laparoscopic Hysterectomy: An International Study

Objectives: Laparoendoscopic single-site surgery (LESS) and mini-laparoscopic surgery (Mini-LPS) have been performed with comparable results to conventional laparoscopy. However, there are few data on the comparison between them. Our main objective was to compare LESS and Mini-LPS in terms of surgical time, postoperative pain, and hospital stay in patients who underwent hysterectomy for benign pathology. Design: It is a retrospective international multicentric study carried out in 5 centers including 2 Spanish and 3 Italian. Methods: Data from patients who underwent hysterectomy for benign pathology between January 1, 2010, and December 31, 2015, were reviewed. We collected the clinical-pathological characteristics of the patients and the perioperative results. The main variables of the study were surgical time, the switch to oral analgesia, and the hospital stay. The two comparison groups in the study included patients undergoing hysterectomy for benign pathology by LESS or by Mini-LPS. The decision to perform the type of procedure was left to the discretion of the surgeon, based primarily on the surgical skills and experience of the center. All data were collected retrospectively by an online encrypted platform. Results: 161 patients were included in the study. 104 (64.6%) patients underwent LESS hysterectomy and 57 (35.4%) Mini-LPS. Median surgical time was significantly longer in the LESS group when compared to the Mini-LPS group (120 vs. 75 min, respectively; p < 0.001). Moreover, longer median hospital stay was observed in the LESS group compared to Mini-LPS (48 vs. 36 h, respectively; p < 0.001). Conversion of the technique to conventional LPS was performed in 4 (2.5%) patients, all of them in the Mini-LPS group (p = 0.015). Limitations: It is a retrospective study with the biases that this implies. Furthermore, some variables have been incompletely registered in the database, which implies loss of information. This is a nonrandomized study since the decision to intervene with one or another technique was made by the surgeon, which generated 2 nonhomogeneous groups in terms of the number of patients. On the other hand, all the patients who underwent Mini-LPS hysterectomy belonged to the same center, which may have made these results center dependent. Conclusions: Significant shorter surgical time and shorter hospital stay were observed in patients undergoing Mini-LPS hysterectomy compared to LESS technique; however, intraoperative complications related to instrumentation flaws were higher in the mini-LPS group that required conversion to standard laparoscopy in all cases. Both ultra-minimally invasive techniques seem safe to perform hysterectomies for benign pathology and emphasize the importance in surgical training to adapt them to our current practice.

Wet and dry periods in the state of Alagoas (Northeast Brazil) via Standardized Precipitation Index

The state of Alagoas has its economic base directed to agriculture, and the knowledge of wet and dry periods is fundamental for the success of agricultural enterprises. The objective was to define the wet and dry periods in the state of Alagoas via multivariate analysis applied to the Standardized Precipitation Index (SPI). Monthly rainfall data for 20 weather stations from 1960 to 2016 were used, with fault filling via imputation. Moreover, Cluster analysis (CA) was applied to the time series (definition of homogeneous regions) and SPI-12 (annual) - (determination of dry and wet spell periods). The annual accumulated rainfall showed two distinct periods: 1960 to 1990 (P1) and 1990 to 2016 (P2), according to Pettitt test. Both periods alternate according to the phases of La Niña and Neutral (rainy years) and El Niño (dry years). In the monthly rainfall, only the Eastern part of Alagoas increased the rainy months during long time series. In tested connection methods, the average connection, also known as cophenetic correlation coefficient (CCC = 0.8760), represented homogeneous groups of rainfall, featuring two regions: one on the coast (G1) and another hinterland and arid (G2); and two non-homogeneous groups (NA) in the state. The annual SPI helped identify dry and wet periods, regardless of El Niño-Southern Oscillation (ENSO) categorization. The SPI-12 categories show high annual and decadal variability in the groups, except for the extremely dry and wet categories. There is greater variability in dry and wet periods near the coast than hinterland of the state.

Clinical Efficacy and Safety Profile of Anterior Thalamic Stimulation for Intractable Epilepsy.

Deep brain stimulation of the anterior nucleus of the thalamus (ANT DBS) is a neuromodulation therapy for patients with refractory partial seizures. The ANT is the structure of a limbic system with abundant neuronal connections to temporal and frontal brain regions that participate in seizure propagation circuitry. We have performed a literature search regarding the clinical efficacy of ANT DBS. We discuss the surgical technique of the implantation of DBS electrodes with special attention paid to the targeting methods of the ANT. Moreover, we present in detail the clinical efficacy of ANT DBS, with a special emphasis on the stimulation parameters, a stimulation mode, and polarity. We also report all adverse events and present the current limitations of ANT DBS. In general, the safety profile of DBS in intractable epilepsy patients is good, with a low rate of surgery, hardware-related, and stimulation-induced adverse events. No significant cognitive declines or worsening of depressive symptoms was noted. At long-term follow-up, the quality-of-life scores have improved. The limitations of ANT DBS studies include a limited number of patients treated and mostly open-label designs with only one double-blind, randomized multicenter trial. Most studies do not report the etiology of intractable epilepsy or they include nonhomogeneous groups of patients affected by intractable epilepsy. There are no guidelines for setting initial stimulation parameters. All the variables mentioned may have a profound impact on the final outcome. ANT DBS appears to be a safe and efficacious treatment, particularly in patients with refractory partial seizures (three-quarters of patients gained at least 50% seizure reduction after 5 years). ANT DBS reduces most effectively the seizures originating in the temporal and frontal lobes. The published results of ANT DBS highlight promise and hope for patients with intractable epilepsy.

The first-member heuristic: Group members labeled "first" influence judgment and treatment of groups.

People often make judgments about a group (e.g., immigrants from a specific country) based on information about a single group member. Seven studies (N = 1,929) tested the hypothesis that people will expect the performance of an arbitrarily ordered group to match that of the group member in the first position of a sequence more closely than that of group members in other positions. This greater perceived diagnosticity of the first member will in turn affect how people treat the group. This pattern of judgment and treatment of groups, labeled the "first-member heuristic," generalized across various performance contexts (e.g., gymnastic routine, relay race, and job performance), and regardless of whether the focal member performed poorly or well (Studies 1-3). Consistent with the notion that first members are deemed most informative, participants were more likely to turn to the member in the first (vs. other) position to learn about the group (Study 4). Further, through their disproportionate influence on the expected performance of other group members, first members' performances also influenced participants' support for policies that would benefit or hurt a group (Study 5) and their likelihood to join a group (Study 6). Finally, perceived group homogeneity moderated the first-member heuristic, such that it attenuated for nonhomogeneous groups (Study 7). (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Is it necessary to be afraid of vitamin B12 deficiency during metformin treatment?

Metformin, a biguanide derivative, is the most frequently used antihyperglycaemic agent in the world. Various adverse effects can occur during the drug therapy. One of them is vitamin B12 deficiency, which may be either asymptomatic (biochemical) or may lead to neurological and/or haematological disorders. Causal diagnosis of these disorders is hampered due to the fact that nervous system symptoms are similar to neurological complications developing over the course of diabetes mellitus. It is estimated that 5.8 to 33% of metformin treated patients have a low (below the reference level) serum vitamin B12 concentration. The interrelation between vitamin B12 deficiency and metformin usage has been known for decades and over that time many studies have been carried out to assess the issue. Unfortunately, these studies were mainly observational, retrospective and performed on nonhomogeneous groups of patients. Recently a meta-analysis of studies concerning only diabetic patients was performed and it demonstrated the existence of a relationship between metformin treatment and vitamin B12 deficiency. Nevertheless, further well-designed, large-scale, randomized studies performed on a homogenous group of patients and employing homogenous criteria for diagnosing vitamin B12 deficiency are necessary in order to decide whether serum vitamin B12 concentration should be routinely checked among metformin treated patients.

Intention to Purchase Alcohol by Adults in the Country in Transition: the Effects of Health Consciousness, Self-efficacy and Religion Importance

The major trend in modern societies is towards encouragement of the reduction of alcohol use; however, this is not always in line with the various contexts and occasions. Individual factors may present rather non-homogeneous groups that often exert totally opposite influence on the intention to purchase alcohol. This research aims to examine the phenomenon of adult intention to purchase alcohol in Lithuania as a country in transition influenced by an individual’s health-consciousness, self-efficacy and religion importance. The nature of these factors is very different; their essence may lie in a rather individualistic concern about personal health, or can be linked with rather distant, but strong personal beliefs, priorities or lifestyles. Therefore, this research aimed to explore these effects. A total of 487 completed questionnaires were collected to perform the research. The findings reveal that health consciousness and religion importance have a significant influence on alcohol purchase intention among adults. However, self-efficacy proved to be of low influence.

Loudness range of a choir based on choir size and voice range profiles of individuals

The size of a choir is based on many factors, including availability of singers, size of the performance hall, economics of practice and performance, and the desired ensemble sound. It is generally assumed that a large choir has a greater dynamic range than a small choir. It is also generally assumed that a choir with well-trained singers can produce a greater dynamic range. A theoretical study is presented here that combines sound pressure level and loudness of homogeneous and non-homogeneous groups of singers to produce an overall sound level profile of a choir. Internal constraints are self-to-other ratio and individual voice range profiles of choir members. Results indicate that the dynamic range of a choir is determined mostly by the dynamic range of individuals with wide ranges, assuming that inhomogeneity is allowed. Choir size makes little difference. Singers with small dynamic ranges have little effect on choir dynamics unless louder voices are selectively turned off in pianissimo passages.

The effect of bariatric surgery on echocardiographic indices: a review of the literature

Obesity is the new epidemic and is associated with an increased risk of diastolic and systolic heart failure. Effective treatment options with drastic results such as bariatric surgery have raised interest in the possible reversal of some of the cardiovascular sequelae. Many studies have assessed individually the effect of weight loss on specific echocardiographic indices, mostly employing nonhomogeneous groups. The purpose of this narrative review is to summarise the effect of bariatric surgery on echocardiographic indices of biventricular function and to help in the understanding of the expected echocardiographic changes in bariatric patients after weight-loss surgery.

Gene expression profiles of progressive pancreatic endocrine tumours and their liver metastases reveal potential novel markers and therapeutic targets

The intrinsic nature of tumour behaviour (stable vs progressive) and the presence of liver metastases are key factors in determining the outcome of patients with a pancreatic endocrine tumour (PET). Previous expression profile analyses of PETs were limited to non-homogeneous groups or to primary lesions only. The aim of this study was to investigate the gene expression profiles of a more uniform series of sporadic, non-functioning (NF) PETs with progressive disease and, for the first time, their liver metastases, on the Affymetrix human genome U133A and B GeneChip set. Thirteen NF PET samples (eight primaries and five liver metastases) from ten patients with progressive, metastatic disease, three cell lines (BON, QGP and CM) and four purified islet samples were analysed. The same samples were employed for confirmation of candidate gene expression by means of quantitative RT-PCR, while a further 37 PET and 15 carcinoid samples were analysed by immunohistochemistry. Analysis of genes differentially expressed between islets and primaries and metastases revealed 667 up- and 223 down-regulated genes, most of which have not previously been observed in PETs, and whose gene ontology molecular function has been detailed. Overexpression of bridging integrator 1 (BIN1) and protein Z dependent protease inhibitor (SERPINA10) which may represent useful biomarkers, and of lymphocyte specific protein tyrosine kinase (LCK) and bone marrow stromal cell antigen (BST2) which could be used as therapeutic targets, has been validated. When primary tumours were compared with metastatic lesions, no significantly differentially expressed genes were found, in accord with cluster analysis which revealed a striking similarity between primary and metastatic lesions, with the cell lines clustering separately. We have provided a comprehensive list of differentially expressed genes in a uniform set of aggressive NF PETs. A number of dysregulated genes deserve further in-depth study as potentially promising candidates for new diagnostic and treatment strategies. The analysis of liver metastases revealed a previously unknown high level of similarity with the primary lesions.

Simulating the dynamics of collective behavior in nonhomogeneous groups

Simulating the dynamics of collective behavior in nonhomogeneous groups

Neuromotor Development of Preterm Infants Through the First Year of Life

Physical and occupational therapists monitor the development of preterm infants graduating form neonatal intensive care units and frequently use the neuromotor development of fullterm infants as the criterion against which normality is judged. Despite the methodological problems of comparison on non-homogeneous groups, poor matching, inadequate measurement tools, and expectancy bias, the literature suggests that preterm infants develop differently from full term infants. Neither the extent nor reasons for differences and suggestions for future research are proposed. Knowledge of the variability of preterm infant neuromotor behavior should be useful to pediatric therapists aiming to identify those infants who truly are developing abnormally.

Social choice axioms for fuzzy set aggregation

The problem of aggregating n fuzzy sets F 1, F 2,.., F n on a set ω is viewed as one of merging the opinions of n individuals (e.g. experts) that rate objects belonging to ω. This approach contrasts with the pure set-theoretic point of view, and leads to interpreting already known axioms underlying fuzzy connectives in a way different from that of multiple criteria aggregation. Various natural properties of a voting procedure, including the ones proposed by Arrow are expressed in the fuzzy set setting. A number of conditions limiting the choice of fuzzy set operations are proposed and classified according to whether they are imperative, mainly technical, or facultative. Families of solutions are obtained that include those proposed in earlier works. The case of non-homogeneous groups is briefly examined. Lastly the application of the voting paradigm to the management of antagonistic local decision rules in knowledge-based systems is outlined.

Cardiopulmonary parameters in severe multiple injury

INTRODUCTION FAST evacuation with modern rescue systems, early volume replacement and ventilatory support have changed the classical patterns of traumatic shock in multiply injured patients. Therefore the severity of shock is often underestimated and its treatment may often be characterized as being too little and too late. The improvement of the rescue systems and aggressive management of shock have decreased the immediate mortality, but patients now die with respiratory failure, sepsis or multiple organ failure, 1 to 3 weeks after injury (Schweiberer and Saur, 1974; Schmit-Neuerburg, 1974). The mortality rate still continues to be reported at 40 to 60 per cent. In a few clinical studies an attempt has been made with comprehensive monitoring to define physiological parameters which are correlated with outcome to help to understand the responsible aetiological factors (Hardaway, 1968; Shubin et al., 1974; Zimmermann et al., 1971; Shoemaker, 1976). These studies, however, have been of limited value because they include non-homogeneous groups of patients or series where intensive monitoring has been delayed following injury. To avoid these defects and to define significant physiological factors contributing to mortality, we have intensively studied all severely injured patients cared for at the Trauma Unit at Hannover Medical School, Germany. This regional emergency system is organized to provide centralized injury care within a radius of 100kin for a population of 2000000. All patients studied sustained blunt injuries, all were intensively monitored commencing within 1 hour of injury, all were cared for by a small group of accident surgeons, and all underwent similar resuscitative and therapeutic regimes.