Unequal Sizes Research Articles

Evaluation of Statistical Power in Random Effect Meta Analyses for Correlation Effect Size

In meta-analysis, numerical index is used as an estimate of effect size to describe the results of each study and thereafter these estimates of across studies are combined to obtain summary of results. 
 It should be known that calculations of the power of statistical tests are important in planning research studies and for interpreting situations in which a result has not proven to be statistically significant. Although statistical power is often considered in the design of primary research studies, it is rarely considered in meta-analysis. Despite the importance of statistical power, few studies have been examined the performance of simulated power in meta-analysis. (In this study, calculations of statistical power for statistical tests that are used for unequal sample size on random effects model in meta-analysis using correlation coefficient as effect size were conducted.)
 The power of the test for the overall effect size was calculated by using both analytical method and simulation method. Thus, it was investigated whether there was any difference between the simulation power and analytical power in random effects meta-analysis by using correlation coefficient as an effect size.

P-004 Optimizing Sperm Selection and Reproductive outcomes by Magnetic Cell Sorting (MACS) for Couples with Raised DFI

Abstract Study question For couples with raised sperm DNA Fragmentation (SDF), can sperm processing by MACS help in optimizing reproductive outcomes? Summary answer In couples with raised SDF, sperm processing by MACS seems to have limited role in optimizing reproductive outcomes. What is known already Raised SDF is known to affect the reproductive outcomes of a couple. Interventions that help in optimizing sperm selection process to negate the negative effects of SDF are still elusive and needs further research. Hence, we intend to evaluate the role of MACS to optimize sperm selection and reproductive outcomes in this study. Study design, size, duration This is a retrospective study during 2017-2020. Study group looked at couples with raised SDF>25% and were undergoing MACS(n = 65). Couples with raised SDF and had no MACS (underwent density gradient sperm preparation) was considered as control group (n = 30). All women in this study were<37 years and had atleast one failed IVF cycle. Men with sperm parameters >5m.ml and SDF>25% were considered in the study group. One failed IVF cycle was the indication for SDF testing Participants/materials, setting, methods Women underwent Controlled Ovarian Stimulation (COS) as per clinic’s Standard Operating Procedures (SOP). Semen on the day of oocyte retrieval were subjected to MACS and oocytes were injected with MACS separated sperm by ICSI. Embryos were cultured till the Blastocyst stage and then vitrified. In a frozen embryo transfer (FET) cycle two good grade blastocysts, with100%Survival were transferred. Implantation rates (IR), Miscarriage rates (MR), Multiple Pregnancy Rates (MPR) and Live Birth rates (LBR) were calculated Main results and the role of chance Reproductive Outcomes of MACS and Control groups were as follows: Blastocyst formation rates (BR) - 45.42 % vs 43 % (P = 0.827) IR - 47.1 % vs 42.30 % (p = 0.664) MR - 3.1 % vs 3.33 % (p = 0.95) MPR – 17% Vs 14% (p = 0.712) LBR - 73.8% Vs 56.6 (p = 0.0955) Reproductive outcomes between MACS and control group looked comparable. There was no statistical significance that was noted. Though LBR seemed high with MACS group there was no statistical significance. Double Density gradient for sperm processing also seems to be helping in optimizing sperm section with good quality DNA sperms and seems to offer similar reproductive outcomes. Data from this study doesn’t show encouraging role for MACS as a sperm processing method in men with raised SDF to optimize reproductive outcomes. Role of MACS to optimize sperm selection and Reproductive outcomes still needs further research. Limitations, reasons for caution This study had small sample size and unequal size, retrospective data evaluation and paternal age was not accounted. Wider implications of the findings A well-designed RCT to look for an ideal sperm processing technique, which offers sperms with good DNA quality and optimal reproductive outcomes, is the need of the hour and can shorten the time to conception Trial registration number N/A

O-193 Reproductive outcomes in women with Borderline Ovarian Tumours. Does fertility treatment increase the risk of disease recurrence?

Abstract Study question Does fertility treatment (FT) increase the risk of recurrence of Borderline Ovarian Tumours (BOTs)? Summary answer There is a significant association between recurrence of BOTs and exposure to FT (p = 0.025). What is known already The association between pregnancy or controlled ovarian stimulation (COS) and risk of recurrence of BOTs is a controversial topic of interest amongst clinicians and women undergoing treatment. Some studies report a risk of non- invasive relapse following ovarian stimulation between 19.4-23%, whereas earlier case-control studies have shown no significant association.It is important to consider that most studies are limited by their retrospective analysis, with an emphasis on the incidence of primary BOTs following exposure to FT. Whereby, data regarding the risk of disease recurrence following spontaneous pregnancy (SP) or COS specifically, remains sparse. Study design, size, duration A retrospective cohort of women who underwent fertility sparing surgery (FSS) for the management of BOTs between the 1st January 2004 and 31st December 2020 at Imperial College Healthcare NHS Trust, with prospective follow up of reproductive outcomes and recurrence of disease following surgery. Participants/materials, setting, methods Subgroup analysis included a control group of all women not exposed to FT or SP and a non-control group of those who achieved either SP or underwent FT following FSS for the management of BOTs. The recurrence rate of BOTs was determined within each subgroup. Main results and the role of chance 90 women underwent FSS for BOTs. Subgroup analysis confirmed 38.9% (35/90) were in the control group, 50% (45/90) in the non-control and 11.1% (10/90) lost to follow up. In the non-control group, 35.6% (16/45) achieved SP only and 64.4% (29/45) underwent FT. FT included COS for oocyte cryopreservation only (24.4%; 11/45), intracytoplasmic sperm insemination (ICSI) ± fresh or frozen embryo transfer (24.4%; 11/45) and those who underwent COS but also achieved SP without returning to their cryopreserved gametes (15.5%; 7/45). Within the non-control group, 75.6% (34/45) of women conceived, with a livebirth rate per pregnancy of 58.7% (27/46). The recurrence rate in the control and non-control groups were 20% (7/35) and 22.2% (10/45) respectively (p = 0.025) and 24.1% (7/29) following FT. Recurrence rates were 18.8% (3/16) after SP only, 0% (0/11) following oocyte cryopreservation only, 18.2% (2/11) ICSI ± embryo transfer and 71.4% (5/7) in those who underwent COS and achieved a SP. All recurrence of disease presented as serous BOTs. Within the FT group, logistic regression analysis demonstrated no significant predictors of disease recurrence. A combination of SP and FT is significantly associated with recurrence when compared to the following groups: control (p = 0.000), SP only (p = 0.001) and COS only (p = 0.015). Limitations, reasons for caution Due to the partial retrospective nature of the study, certain clinical information was not adequately documented and the subgroups compared were of unequal sample size, whilst overall sample size is also considered low. There was also a lack of control for confounders which may affect disease recurrence. Wider implications of the findings Despite the risk of recurrence of BOTs associated with FT, cases are often non invasive and successfully managed with further FSS with excellent prognosis. This evidence should be used to counsel women of reproductive age to ensure they can fulfil their reproductive aspirations, despite a diagnosis of BOT. Trial registration number NA

P-005 Optimizing Sperm Selection and Reproductive outcomes by Microfluidics for Couples with Raised DFI

Abstract Study question For couples with raised sperm DNA Fragmentation (SDF), can sperm processing by Microfluidics help optimize reproductive outcomes? Summary answer In couples with raised SDF, sperm processing by Microfluidics seems to have limited role in optimizing reproductive outcomes What is known already Raised SDF is known to affect the reproductive outcomes for a couple. As the interventions which help optimize sperm selection process in order to negate the harmful effects of SDF are still vague, further research in this area is warranted. Hence, we aim to assess the role of Microfluidics as an intervention to optimize sperm selection and reproductive outcomes in this study. Study design, size, duration This is a retrospective study during 2016-2020. Study group(n = 38) looked at couples with raised SDF>25% and who underwent Microfluidics. The control group(n = 30) were couples with raised SDF with no Microfluidics. (Underwent density gradient sperm preparation). Women in this study were <37 years and had at least one failed IVF cycle. Men who had sperm parameters >5m/ml and SDF >25% were considered in the study group. One failed IVF cycle was the indication for SDF testing. Participants/materials, setting, methods Women underwent Controlled Ovarian Stimulation (COS) as per clinic’s Standard Operating Procedure(SOP). Semen on the day of oocyte retrieval were subjected to Microfluidics and oocytes were injected with Microfluidics separated sperm by ICSI. Embryos were cultured till Blastocyst stage and then vitrified. In a frozen embryo transfer (FET) cycle, two good grade blastocysts with 100% survival were transferred. Implantation rates (IR), Miscarriage rates (MR), Multiple Pregnancy Rates (MPR) and Live Birth rates (LBR) were calculated. Main results and the role of chance Reproductive Outcomes of Microfluidics and Control groups were as follows: Blastocyst formation rates (BR) - 46 % vs 43 % (P = 0.806) IR - 47.7 % vs 42.30 % (p = 0.659) MR – 7.8 % vs 3.33 % (p = 0.438) MPR – 18.4 % Vs 16.6 % (p = 0.847) LBR – 63.14 % Vs 56.6 % (p = 0.587) The reproductive outcomes between Microfluidics and Control group seemed comparable. No statistical significance was noted between both groups. Although LBR seemed to be higher with the Microfluidics (study) group, there was no statistical significance. Double Density gradient for sperm processing also seems to be helping in optimizing sperm selection with good quality DNA sperms, hence resulting in similar reproductive outcomes. Data from this study seems to indicate that the role of Microfluidics as an intervention for sperm selection, in men with raised SDF, to optimize reproductive outcomes is limited. Role of Microfluidics to optimize sperm selection and Reproductive outcomes needs more widespread research. Limitations, reasons for caution This study has a small and unequal sample size, retrospective data evaluation and paternal age was not taken into consideration. Wider implications of the findings A non-invasive method for couples with raised SDF which can provide sperms with good quality DNA in order to optimize reproductive outcomes and improve the probability of conception is crucial. Trial registration number N/A

P-232 The developmental potential of human embryos with subtypes of multinucleation in cleavage stages

Abstract Study question Does subtypes of multinucleation in cleavage stage affect the developmental and implantation potential of human embryos? Summary answer Different subtypes of multinucleation presented diverse effects on morphokinetic abnormality and blastocyst rate, but achieved comparable implantation rate with blastocysts transfer. What is known already Time-lapse images reveals many abnormal events in early embryonic development. Blastomere multinucleation (MN) has the highest incidence, thus attracts extensive attention. More and more studies have been conducted on the generation mechanism, reproductive potential and utilization value of multinucleation embryos, but the impact of different subtypes of MN on embryo developmental potential, morphokinetics and clinical outcomes have not been well identified. Study design, size, duration Using a time-lapse incubator (EmbryoScope plus), we retrospectively explored the associations between the subtypes of MN with morphokinetic parameters, blastocyst rate and clinical pregnancy. This study assessed 4416 embryos, including 628 MN embryos from single embryo transfers after 1521 ICSI cycles conducted in Reproductive Medical Center of the First Affiliated Hospital of Hainan Medical University between October 2019 and October 2021. Participants/materials, setting, methods ubtypes of MN, morphokinetic parameters, blastocyst rate, preimplantation genetic testing for aneuploidy (PGT-A) result and clinical pregnancy were studied retrospectively. The quantitative variables were expressed as mean SD and were compared by means of Student two-sample t test. The categoric variables were expressed as frequency and percentage and were compared between groups by means of Pearson chi-square test or Fisher exact test. Main results and the role of chance The rate of MN was the highest (14.22%) among abnormal events. The blastocyst rate of MN embryos was significantly reduced (52.48%). The blastocyst rate of MN at 2-cell stage was significantly higher than that at 4-cell stage, but there was no significant difference in euploid rate and implantation rate with single blastocyst transfer. We chose embryos with only one blastomere multinucleation (MN-1) at 2-cell stage to analyze the effect of subtypes of MN, including two equal size nuclei (Bi-), two unequal size nuclei (micro-), more than two equal nuclei (poly-) and more than two unequal nuclei (cluster-), on developmental and implantation potential of human embryos. There were significant morphokinetic delay and reduced blastocyst rate in cluster-nucleation and poly-nucleation groups, but they could achieve competence implantation rate after blastocyst transfer. It was interesting that when we separately analyze the MN embryos which could survive to blastocyst, the morphokinetic data didn’t show significant delay in micro-nucleation group, only the cleavage time to the 3-cell stage was significant longer in Bi-nucleation group, and the time of pronuclear fading and cleavage time to the 2-cell stage were significant longer in poly-nucleation group. Limitations, reasons for caution The population size was relatively small and the current study is restricted by its retrospective nature and absence of live birth information. Wider implications of the findings It would be interesting to explore, prospectively in multi-clinics, whether these subtypes of multinucleation embryos equal to non-multinucleation embryos with blastocyst transfer. Further studies are needed, notably to explore the underline "self-repair" mechanism of Blastomere multinucleation. Trial registration number 0

Pancreatic metastasis of malignant melanoma presenting as a tumor occluding the main pancreatic duct

Metastasis to the pancreas is rare, especially for malignant melanoma. In these scarce cases, tumors normally present in the parenchyma of the pancreas. A 70-year-old woman was referred to our hospital for an asymptomatic pancreatic tumor detected by contrast-enhanced computed tomography (CE-CT). She had undergone a pneumonectomy for primary malignant melanoma (MM) of the lung approximately 3years prior and was receiving nivolumab for recurrent intrapulmonary metastasis. CE-CT revealed a hypo-vascular lesion occluding the main pancreatic duct (MPD) which was consequently dilated. On magnetic resonance imaging, the MPD lesion had high signal intensity on T1-weighted and diffusion-weighted images. Contrast-enhanced endoscopic ultrasonography revealed that the low echoic tumor had heterogenous enhancement in the early phase. Endoscopic retrograde pancreatography (ERP) was performed for evaluation of tumor area and histological diagnosis. A contrast agent defected lesion was observed in the dilated MPD from the pancreas body to tail suggesting the tumor totally occluded the MPD. Biopsy was performed and the specimens obtained from the defect lesion were black in color. Histopathological examination of the black specimens revealed substantial growth of tumor cells with eosinophilic cytoplasm and unequal nuclei size. The tumor cells had a brownish pigmentation of melanin. From these findings, the tumor was diagnosed as pancreatic metastasis of MM. The patient underwent chemotherapy with ipilimumab and nivolumab. The final diagnosis was pancreatic metastasis of MM occurring as a tumor occluding the MPD. ERP was useful for histological diagnosis and could be useful for future cases.

Division behaviours and their effects on pre-implantation development of pig embryos.

The quality of pre-implantation embryos could affect developmental efficiency after embryo transfer. However, the assessment of pre-implantation embryos was unsatisfactory, especially in pig embryos to date. Therefore, this study was designed to investigate available and applicable parameters that indicate developmental potential and quality of porcine pre-implantation embryos produced by handmade cloning (HMC), and parthenogenetic activation without zona pellucida (PAZF) and with zona pellucida (PAZI). Firstly, a common division behaviour was detected, that is the formation of uneven division with two unequal size blastomeres (UD 2-cell), especially in HMC embryos; then, the proportion of UD 2-cell was found to be significantly higher than that of even division with equal size blastomeres (ED 2-cell) (72.56 ± 4.56 vs. 24.57 ± 1.92). The formation of UD 2-cell might be due to the spindle migration along the long axis in 1-cell stage, and the cleavage furrow was not formed in the centre of cytoplasm. In the two sister blastomeres of UD 2-cell, uneven distribution of organelles (mitochondria and lipid droplet) was observed with lower proportion in the smaller one (p<.05). Although no difference in blastocyst rate was observed between UD and ED 2-cell embryos, the cell number per blastocyst from UD 2-cell embryos was lower than that from ED 2-cell embryos (44.15 ± 2.05 vs. 51.55 ± 1.83). Besides, because of non-synchronized division of each blastomere, the following three cleavage routes were observed in all HMC/PAZF/PAZI embryos: T1 (2-cell → 3-cell → 4-cell → ≥5-cell → morula → blastocyst), T2 (2-cell → 3-cell → 4-cell → morula → blastocyst) and T3 (2-cell → 3-cell/4-cell → morula → blastocyst). Therefore, in pig in vitro-produced embryos, division behaviours of uneven volume of cytoplasm and non-synchronized cell cycles were observed at the early embryonic developmental stage, which might be another potential factor to evaluate embryonic development.

Food Preservation within Multi-Echelon Supply Chain Considering Single Setup and Multi-Deliveries of Unequal Lot Size

Intricacy of the supply chains for deteriorating products, involving multiple retailers with unequal lot sizes and multiple deliveries is simplified in this article by optimizing the replenishment cycle, investment in preservation technology, and number of deliveries. This study proposes a multi-tier supply chain model consisting of a single manufacturer and multiple retailers. A single-setup multiple deliveries (SSMD) policy is adopted considering the synchronized cycle time of manufacturers with that of retailers and the delivery of unequal lot size for each retailer. Preservation technology is used at retailers to minimize the effects of deterioration in a way that the magnitude of decrease in deterioration reduces for additional investment in preservation technology. A centralized supply chain model is proposed by defining a nonlinear mathematical model for maximizing total profit through an analytical optimization technique and an algorithm. Numerical experiments are exhibited to validate the applications of the provided model. The results exhibit that the proposed preservation policy increases the product’s lifetime and the total profit by reducing the number of shipments/transportation and increasing the lot size. The SSMD policy helps to reduce the preservation cost and increase the total profit. Some managerial insights are provided for the decision makers for applying the proposed model.

A modified single-stage sampling procedure for heteroscedasticity analysis of means with unbalanced design

The analysis of means (ANOM) is a method that can compare the mean of each treatment with the overall mean. As one-way ANOVA, the conventional ANOM is not robust under unequal variances. We applied two inference procedures, single-stage and modified single-stage sampling, to solve heteroscedastic analysis of means (HANOM) under unbalanced design. Using proposed weighted average across groups, the influence of the unknown mean and variance are both eliminated. To validate the stability of HANOM under several scenarios of unequal variances and sample sizes, simulation studies of empirical type I error rate are conducted to test the quality of procedures. A real application is provided for illustrating these two procedures clearly. In addition, we build an user-friendly interface to show the results of the HANOM by using Shiny package in R software.

Efficiently handling high‐dimensional data from multifactorial designs with unequal group sizes using Rebalanced ASCA (RASCA)

AbstractA novel chemometric approach is proposed to analyze high‐dimensional data from unbalanced designs of experiments. It combines a rebalancing strategy based on averages with the ASCA method under the name Rebalanced ASCA (RASCA). The ability of RASCA to handle unbalanced designs was compared with standard ASCA, as well as state‐of‐the‐art methods, such as ASCA+ and WE‐ASCA. For that purpose, a controlled framework was designed to provide a systematic comparison of the various approaches. It included two real datasets obtained from initially balanced designs, which were gradually unbalanced by removing observations belonging to specific combinations of factor levels. The results illustrate that all methods considered led to identical solutions when the initial balanced design was kept. Nevertheless, increasing differences appeared when the design was gradually unbalanced. The proposed benchmark showed that RASCA and ASCA+ provided overall similar results for all effects with high agreement with the balanced solutions in comparison to classical ASCA and WE‐ASCA. RASCA was found to be a suitable chemometric tool to tackle unbalanced designs by ensuring unbiased parameter estimators with the added benefit of producing rigorously orthogonal effect matrices, thus facilitating interpretation.

Isolation and confinement due to the COVID-19 pandemic: Lessons for human spaceflight

BackgroundAstronauts live and work in isolated, confined, extreme (ICE) environments that create both high stress and the need for high performance. The COVID-19 pandemic created ICE-like conditions across the globe by confining people to their homes under the ever-present threat of disease. Our goal is to understand the impact of prior experience in ICE on coping, using the pandemic as a pseudo space analog environment. MethodsWe administered a survey three times with 7 days between administrations. A total of 82 participants completed all three survey sessions, and these participants were divided into three groups for analysis. The first group is those with prior experience in an ICE environment (n = 17; 7F/10 M), the second is those aged 30–55 with a master's or doctoral degree and without prior experience (n = 22; 10F/12 M), and the third is the general population (n = 43; 27F/16 M). Linear mixed models were used for statistical analysis of the results, given the unequal sample sizes. ResultsThe experienced group did not show healthier mental health scores than the astronaut-like group, but both groups displayed higher scores than the general population. However, work productivity scores for the experienced group were higher on average than the other two groups. DiscussionResults suggest that prior experience in ICE may improve the capability to maintain productivity—corresponding to the idea of resilience. However, experience may not improve mental health maintenance, suggesting that other approaches are needed to prepare astronauts for the mental health stressors of long-duration exploration missions.

OA29 Clinical outcomes up to week 48 of filgotinib treatment in an ongoing long-term extension trial of RA patients with inadequate response to methotrexate initially treated with filgotinib or adalimumab during the Phase 3 Parent Trial

Abstract Background/Aims The preferential Janus kinase (JAK)-1 inhibitor filgotinib (FIL) is approved for treatment of moderately to severely active RA in Europe and Japan. We assessed efficacy and safety of FIL in patients (pts) with inadequate response to MTX (MTX-IR) who completed a Phase 3 trial (NCT02889796) and went on to enroll in a long-term extension (LTE; NCT03025308). Methods Pts who completed the parent study (PS) on study drug were eligible to enter the LTE. LTE data cutoff was June 1, 2020, and safety data are reported to that date, with median exposure 2.2 years. Efficacy data to W48 are reported for 4 treatment groups (all with background MTX): pts who received FIL 200mg (FIL200) or FIL 100mg (FIL100) in the PS and continued their dose in LTE (FIL200/FIL200, FIL100/FIL100) and ADA pts who were re-randomized, double blind, to FIL200 or FIL100 for LTE (ADA/FIL200, ADA/FIL100). ACR20/50/70 response rates, DAS28[CRP] ≤3.2 and &amp;lt;2.6, and CDAI ≤10 and ≤2.8 are reported. Exposure-adjusted incidence rates (EAIR)/100 pt-years of exposure of treatment-emergent adverse events (TEAEs) and AEs of special interest (AESIs) are summarized. Results As of June 1, 2020, 522/571 (91%) FIL200/FIL200, 502/570 (88%) FIL100/FIL100, 118/128 (92%) ADA/FIL200, and 115/130 (89%) ADA/FIL100 pts were still on study drug. LTE baseline (BL) disease characteristics were similar between groups: mean duration of RA was approximately 8.7 years; DAS28(CRP) was 2.55 and mean MTX dosage was 15.0 mg/week. Proportions of pts achieving ACR20/50/70, DAS28(CRP) ≤3.2, &amp;lt;2.6, and CDAI ≤10, ≤2.8 were maintained in all 4 LTE groups through W48. Numerically greater proportions of pts met response criteria at W48 in the FIL200 groups vs FIL100, regardless of PS treatment. TEAEs, serious AEs, and AEs Grade ≥3 were largely comparable between groups and lowest in ADA/FIL100 pts. There were 3 deaths in each PS FIL group and 2 in each PS ADA group; EAIRs for deaths were lower for FIL/FIL groups compared with ADA/FIL groups. Opportunistic infections occurred only in FIL/FIL pts (2 in each group). Nonmelanoma skin cancer (NMSC; n = 5) occurred only in FIL/FIL groups, and malignancies excluding NMSC occurred in all groups except ADA/FIL100. Conclusion During the LTE through W48, response rates were maintained for FIL/FIL and ADA/FIL pts. Though there were differences between LTE groups, safety was largely comparable and consistent with that observed in the PS and in previously reported results of safety data from 7 trials: rates of AESIs were low, and all confidence intervals were overlapping. Limitation: the LTE was not formally randomized for comparison between FIL/FIL and ADA/FIL treatment groups, the groups were of unequal size, and the switch from ADA to FIL for LTE was by design, rather than based on disease activity. Disclosure B. Combe: Consultancies; AbbVie; Eli Lilly &amp; Co.; Gilead Sciences, Inc.; Janssen; Pfizer; Roche-Chugai; and Sanofi. Member of speakers’ bureau; for BMS; Eli Lilly &amp; Co.; Gilead Sciences, Inc.; MSD; Pfizer; Roche- Chugai; and UCB. Grants/research support; Novartis, Pfizer, and Roche-Chugai. Y. Tanaka: Consultancies; Eli Lilly, Daiichi- Sankyo, Taisho, Ayumi, Sanofi, GSK, Abbvie. Member of speakers’ bureau; Daiichi- Sankyo, Eli Lilly, Novartis, YL Biologics, Bristol-Myers, Eisai, Chugai, Abbvie, Astellas, Pfizer, Sanofi, Asahi-kasei, GSK, Mitsubishi-Tanabe, Gilead, Janssen. Grants/research support; Abbvie, Mitsubishi-Tanabe, Chugai, Asahi-Kasei, Eisai, Takeda, Daiichi-Sankyo. P. Emery: Consultancies; AbbVie, BMS, Celltrion, Gilead, Lilly, Novartis, Roche, Samsung, and Sandoz. Grants/research support; AbbVie, BMS, Lilly, and Samsung. A. Pechonkina: Shareholder/stock ownership; employee and shareholder in Gilead Sciences, Inc. A. Kuo: Shareholder/stock ownership; employee and shareholder in Gilead Sciences, Inc. Q. Gong: Shareholder/stock ownership; employee and shareholder in Gilead Sciences, Inc. K. Van Beneden: Shareholder/stock ownership; employee of and shareholder in Galapagos, NV. V. Rajendran: Shareholder/stock ownership; employee of and shareholder in Galapagos, NV. H. Schulze-Koops: Consultancies; from AbbVie, Amgen, BMS, Celgene, Celltrion, Chugai, Gilead, Janssen, Eli Lilly and Company, Merck Sharp &amp; Dohme, Novartis- Sandoz, Pfizer, Roche, Sanofi. Grants/research support; AbbVie and Novartis.

Parametric estimation of location and scale parameters based on ranked set sampling with unequal set sizes

Ranked set sampling with unequal set sizes (RSSU) are some of the important variants of ranked set sampling with equal set sizes (RSS). The sets that arise naturally in many applications are typically of different set sizes. One may prefer to use the largest sets available naturally along with the smaller sets rather than an attempt to form artificial equal-sized sets. This article develops maximum likelihood estimators for the location-scale family of distributions based on ranked set sampling with unequal set sizes (RSSU). The closed form expressions for MLE under RSSU do not exist, we have proved the existence of MLE for location and scale parameters for some standard distributions for RSSU data. It is proved that MLE based on MedRSSU are more efficient than their counterparts based on SRS for some standard distributions for location-scale parameters. It is also shown that asymptotic efficiencies of the MLE based on MedRSSU are considerably better than those of the estimators based on RSS with the same number of observations. A simulation study is conducted to compare the performances of the MLE’s from RSS and MedRSSU with the corresponding SRS estimators when the underlying distributions are normal and logistic.

Revisiting variable-foreperiod effects: evaluating the repetition priming account.

A warning signal preceding an imperative stimulus by a certain foreperiod can accelerate responses (foreperiod effect). When foreperiod is varied within a block, the foreperiod effect on reaction time (RT) is modulated by both the current and the prior foreperiods. Using a non-aging foreperiod distribution in a simple-reaction task, Capizzi et al. (Cognition, 134, 39-49, 2015) found equal sequential effects for different foreperiods, which they credited to repetition priming. The multiple-trace theory of Los et al. (Frontiers in Psychology, 5, Article 1058, 2014) attributes the slope of the foreperiod-RT function to the foreperiod distribution. We conducted three experiments that examined these predicted relations. Experiment 1 tested Capizzi et al.’s prediction in a choice-reaction task and found an increasing foreperiod-RT function but a larger sequential effect at the shorter foreperiod. Experiment 2 used two distinct short foreperiods with the same foreperiod distribution and found a decreasing foreperiod-RT function. By increasing the difference between the foreperiods used in Experiment 2, Experiment 3 yielded a larger sequential effect overall. The experiments provide evidence that, with a non-aging foreperiod distribution, the variable-foreperiod paradigm yields unequal sequential-effect sizes at the different foreperiods, consistent with the multiple-trace theory but contrary to Capizzi et al.’s repetition-priming account. The foreperiod-RT functions are similar to those of the fixed-foreperiod paradigm, which is not predicted by the multiple trace theory.

Alternative shipment policies compared for an international supply chain model with stochastic exchange rate, carbon emission and imperfect quality items

Researchers have recently developed a model for international supply chains for transferring lots in equal-sized batches, taking environmental concerns into account. This scheme incorporated stochastic behaviour of the exchange rate between the vendor's and buyer's currencies as part of the process for making optimal decisions on the supply chain. They demonstrated that their model leads to a decrease in the total cost. However, a lower total cost can be achieved by synchronizing the integrated production flow through generalization of the batch transfer method used to deliver the lot. Furthermore, there seems to be a better fit from a new data set for comparing two currencies. With these developments in mind, we suggest an alternative model, considering transferring batches of unequal sizes, transfer costs that may be fixed or variable, and with an eye on environmental issues. Numerical experiments are presented to demonstrate the proposed model and solution method. These numerical experiments show the value of this integrated approach in the combined determination of optimal policies for production and shipment. Suggestions for further research are given in the conclusion.

Pair interactions between viscous drops in a viscoelastic matrix in free shear: Transition from passing to tumbling trajectories

Shear-induced pair interactions between viscous drops suspended in a viscoelastic matrix are numerically investigated examining the effects of elasticity and drop deformability on their post-collision trajectory. Two different trajectory types are identified depending on the Weissenberg number Wi and capillary number Ca. Drops suspended in a Newtonian matrix (Wi = 0.0) show a passing trajectory where drops slide past each other and separate in the stream-wise direction. However, when increasing the Weissenberg number above a critical value, a tumbling/doublet trajectory is observed where two drops rotate around the midpoint of the line joining their centers, as was also seen previously for rigid particles. The tumbling trajectory is explained by investigating the flow around a single drop in shear. Elasticity generates a larger region of spiraling streamlines around a drop, which, during a pair interaction, traps the second drop giving rise to the tumbling pair. Decreasing deformability (lower Ca) and increasing viscoelasticity (higher Wi) favor a tumbling trajectory. With simulations sweeping the parameter space, we obtain a phase plot of the two different trajectories as functions of Ca and Wi. Treating the tension along the curved streamlines due to the non-zero first normal stress difference in the viscoelastic medium as an enhancement to the interfacial tension, we have developed an approximate force balance model for the zone of spiraling streamlines. It qualitatively captures the observed scaling of the critical Ca and Wi values at the phase boundary. The effects of unequal size, initial configuration, and non-unity viscosity ratio are briefly investigated.

General Construction of Efficient Circular Weakly Balanced Repeated Measurements Designs

Weakly balanced repeated measurements designs (RMDs) are used to balance out residual effects where minimal balanced RMDs cannot be obtained. RMDs are equally important in periods of both equal and unequal sizes. There should be a general procedure to construct these designs. In this article, some generators are developed for the general construction of efficient minimal circular weakly balanced RMDs.

Methodological Challenges for Cross-cultural Research in Sport Psychology: A Review

This review investigates methodological challenges in conducting cross-cultural studies in sport psychology. Over the last few decades, there has been an increase in the number of studies to incorporate culture and cultural identities in research and interventions in this field. As sport grows more transnational and multicultural, the need to explore better research methods and the challenges in conducting these cross-cultural sport psychology studies emerges. For this review, we examined studies that were published between January 1985 and July 2021, written in English, and focused on cross-cultural studies in the field of sport psychology. The literature search was conducted in EBSCO (e.g., MEDLINE, APA PsychARTICLES, Academic Search Ultimate, and ERIC), Sciencedirect, Researchgate, Springer link and Wiley Online library databases. A total of 18 articles matched the inclusion criteria and were selected. The study observed that quantitative approach was the most often used methodology in the studies due to popularity and easy administration. Qualitative and mixed (quantitative and qualitative) approaches are now gradually being used by researchers to overcome the cultural insensitivity in the quantitative research, although these studies are scarce and need to be highlighted more. We discussed research designs formulated by researchers in their quantitative and qualitative studies and methodological challenges they encountered, such as sample representativeness, small and unequal sample sizes, gender inequality, and comparing different kinds of sports across countries. Therefore, this review addressed the gap in the literature and paved the way for future research studies.

Minimal Circular Nearly Strongly Balanced Repeated Measurements Designs in Unequal Period Sizes

In this article, some series are developed to generate circular nearly strongly balanced repeated measurements designs in periods of three different sizes when p3 (smallest period size) = 2 through method of cyclic shifts (Rule II). These designs with varied period sizes have diversified applications, e.g. medicine, pharmacology, animal sciences and psychology. These designs are mainly used to balance the first order residual effect. Our proposed designs possessat least 98% efficiency of separability, therefore these designs are highly efficient to estimate the residual effects and direct effects independently.

Single-stage sampling procedure for heteroscedasticity in multiple comparisons with a control

Given k (≥2) independent and normally distributed populations with unknown means and unknown (and possibly unequal) variances, we used the single-stage sampling procedure for multiple comparison with a control to the problem of unequal sample sizes. A simulation of the family-wise error type I was conducted to validate the quality of the procedure and a numerical example was provided for illustrating this procedure. We provided a user-friendly interface by R shiny to obtain the critical values for the practitioners.