scholarly journals Weighted nearest neighbours-based control group selection method for observational studies

PLoS ONE ◽  
2020 ◽  
Vol 15 (7) ◽  
pp. e0236531
Author(s):  
Szabolcs Szekér ◽  
Ágnes Vathy-Fogarassy
Keyword(s):  
Observational Studies ◽  
Group Selection ◽  
Selection Method ◽  
Control Group ◽  
Nearest Neighbours

scholarly journals Optimized Weighted Nearest Neighbours Matching Algorithm for Control Group Selection

Algorithms ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 356
Author(s):  
Szabolcs Szekér ◽  
Ágnes Vathy-Fogarassy
Keyword(s):  
Simulated Annealing ◽  
Group Selection ◽  
Feature Space ◽  
Treated Group ◽  
Control Group ◽  
Case Control Studies ◽  
Optimization Task ◽  
Feature Spaces ◽  
Nearest Neighbours ◽  
Monte Carlo Studies

An essential criterion for the proper implementation of case-control studies is selecting appropriate case and control groups. In this article, a new simulated annealing-based control group selection method is proposed, which solves the problem of selecting individuals in the control group as a distance optimization task. The proposed algorithm pairs the individuals in the n-dimensional feature space by minimizing the weighted distances between them. The weights of the dimensions are based on the odds ratios calculated from the logistic regression model fitted on the variables describing the probability of membership of the treated group. For finding the optimal pairing of the individuals, simulated annealing is utilized. The effectiveness of the newly proposed Weighted Nearest Neighbours Control Group Selection with Simulated Annealing (WNNSA) algorithm is presented by two Monte Carlo studies. Results show that the WNNSA method can outperform the widely applied greedy propensity score matching method in feature spaces where only a few covariates characterize individuals and the covariates can only take a few values.

Overstory treatment and planting season affect survival of replacement tree species in emerald ash borer threatened Fraxinus nigra forests in Minnesota, USA

2015 ◽  
Vol 45 (12) ◽  
pp. 1728-1738 ◽  
Author(s):  
Christopher E. Looney ◽  
Anthony W. D’Amato ◽  
Brian J. Palik ◽  
Robert A. Slesak
Keyword(s):  
Tree Species ◽  
Group Selection ◽  
Survival Rates ◽  
Emerald Ash Borer ◽  
Species Selection ◽  
Ecosystem Functions ◽  
Control Group ◽  
High Survival ◽  
Fraxinus Nigra ◽  
Black Ash

Fraxinus nigra Marsh. (black ash) wetland forests in northern Minnesota, USA, are threatened by the invasive insect, emerald ash borer (Agrilus planipennis Fairmaire (EAB)). A potential management option is promoting regeneration of tree species that are not EAB hosts to maintain ecosystem functions. Using an operational-scale field experiment, we examined the survival of 12 alternative tree species in response to different canopy treatments. We planted the seedlings in 1.6 ha plots assigned to four replicated canopy treatments: untreated control, group selection (0.04 ha gaps, 20% of stand), black ash girdling to emulate EAB-induced mortality, and clearcut. Fall and spring plantings were used to compare the effects of spring ponding. Control (32.9%), group selection (34.5%), and girdling (33.3%) treatments had comparable overall seedling survival. Survival in the clear-cut treatments was significantly lower (22%). Species selection, overstory treatment, and season of planting together resulted in survival rates ranging from 0.08% to 94.1%. Conifer species had low overall rates of survival (10.7%), whereas some species with native ranges not presently overlapping with northern F. nigra forests, e.g., Quercus bicolor Willd. (75.5%), had high survival rates. If growth is light-limited, group selection may be effective in promoting recruitment and supporting a larger variety of species.

The ‘well control’ artefact in case/control studies of specific psychiatric disorders

1989 ◽  
Vol 19 (3) ◽  
pp. 737-742 ◽  
Author(s):  
Sharon Schwartz ◽  
Bruce G. Link
Keyword(s):  
Risk Factor ◽  
Psychiatric Disorders ◽  
Group Selection ◽  
Case Control ◽  
Control Group ◽  
Case Control Studies ◽  
Suggested Approach ◽  
Well Control ◽  
Risk Factor Assessment ◽  
Intuitive Appeal

SynopsisAn appropriate choice of controls in case/control studies of specific psychiatric disorders is crucial for valid risk-factor assessment. One suggested approach to control-group selection, the use of a well control group, is the focus of this paper. While using well controls has intuitive appeal, this paper shows that such a procedure can lead to ambiguous and biased results.

scholarly journals Tree Regeneration Response to the Group Selection Method in Southern Indiana

1997 ◽  
Vol 14 (2) ◽  
pp. 90-94 ◽  
Author(s):  
Dale R. Weigel ◽  
George R. Parker
Keyword(s):  
Group Selection ◽  
Species Group ◽  
Selection Method ◽  
Tree Regeneration ◽  
Average Height ◽  
Yellow Poplar ◽  
The North ◽  
South Central ◽  
Regeneration Response ◽  
Number Of Stems

Abstract Tree regeneration response following the use of the group selection method was studied within 36 group openings on the Naval Surface Warfare Center, Crane Division in south central Indiana. Two different aspects and three time periods since cutting were examined. The objectives were to determine whether aspect, age, species group, location within the opening, or their interactions had any influence on the number of stems or average height of the tree regeneration. Among openings up to 20 yr since cutting, yellow-poplar and dogwood were most abundant for stems greater than 2.5 cm diameter at breast height (dbh), and dogwood and cherry-ash-walnut were most abundant for stems less than 2.5 cm dbh. The location×species group interaction also influenced the number of stems greater than 2.5 cm dbh. Stems less than 2.5 cm dbh were influenced by the age×species group and aspect×species group interactions. The north aspect and the oldest openings contained the most stems per hectare less than 2.5 cm dbh. The interaction of age and species group influenced average height for stems greater than or equal to 2.5 cm dbh. Average height increased with age for stems greater than or equal to 2.5 cm dbh. North. J. Appl. For. 14(2):90-94.

A Method of Selecting Acupoints for Acupuncture Treatment of Peripheral Facial Paralysis by Thermography

2007 ◽  
Vol 35 (06) ◽  
pp. 967-975 ◽  
Author(s):  
Dong Zhang
Keyword(s):  
Facial Paralysis ◽  
Acupuncture Treatment ◽  
Test Group ◽  
Selection Method ◽  
Utilization Rate ◽  
Control Group ◽  
Peripheral Facial Paralysis ◽  
Significant Difference ◽  
The Face ◽  
Healthy Side

The purpose of this study is to select acupoints for acupuncture treatment of peripheral facial paralysis according to the temperature on the face of the patient detected by thermogram, to determine an objective acupoint selection method for acupuncture treatment. In the test group of 60 cases of facial paralysis, the infrared thermogram on the face was detected at the first visit, and then acupuncture was given at the acupoints on the affected side with a temperature difference of over 0.5°C from the healthy side for one therapeutic course, and in each successive course the acupoints were re-determined according to the results of thermogram examination and were administrated till the end of the total therapeutic course, and 120 cases of the control group were treated with acupuncture at conventionally selected acupoints. The results showed that the cured and basically cured rate was 90.0% (54 cases) in the test group and 77.5% (93 cases) in the control group with a significant difference between the two groups ( p < 0.05); and the total sessions of acupuncture were less and the course of treatment was shorter in the test group than those in the control group (both p < 0.001). The utilization rate of the acupoints selected by facial thermogram in the test group was in order of Dicang (ST 4, 92.3%), Yingxiang (LI 20, 90.6%), Taiyang (EX-HN 5, 85.5%), Yangbai (GB 14, 76.6%), Quanliao (SI 18, 72.3%), and so on. In conclusion, acupuncture at the acupoints selected by thermogram for treatment of facial paralysis in the cured rate, the therapeutic course and sessions of acupuncture is significantly superior to acupuncture at the conventionally selected acupoints, and the thermogram-aided acupoint selection method is beneficial to objectivity and modernization of acupoint selection for acupuncture and moxibustion treatments.

scholarly journals A Case-Control Investigation of Adenomyosis: Impact of Control Group Selection on Risk Factor Strength

2011 ◽  
Vol 21 (2) ◽  
pp. 160-164 ◽  
Author(s):  
Britton Trabert ◽  
Noel S. Weiss ◽  
Carole B. Rudra ◽  
Delia Scholes ◽  
Victoria L. Holt
Keyword(s):  
Risk Factor ◽  
Group Selection ◽  
Case Control ◽  
Control Group

scholarly journals INDIRECT SELECTION OF FEMALE TROUT AS A SELECTION METHOD TO INCREASE THEIR PRODUCTIVITY AND RESISTANCE

2020 ◽  
pp. 180-186
Author(s):  
I.N. Agleev ◽  
◽  
А.V. Bushov ◽  
Keyword(s):  
Live Weight ◽  
Indirect Selection ◽  
Selection Method ◽  
The Body ◽  
Oxygen Absorption ◽  
Control Group ◽  
Head Region ◽  
Functional Features ◽  
Experimental Group ◽  
Selection Of

The scientific work considers the selection method of selection in a herd of producers of rainbow trout Kamloops, taking into account values of positive correlation of some morphometric characteristics and degree of development of their reproductive products, as well as the features of natural protective functions of their body at the age of three. It is established that the somatic structure and, development of postorbital region largely determine the functional features of trout, as well as their reproductive qualities. In the indirect selection of three-year-old breeders, taking into account morphometry and correlation, females with a size of postorbital head region greater than 55 mm exceeded by 29.2% the live weight and by 40.4% the weight of trout caviar with a length of this head region less than 55 mm. When comparing the resistance of two experimental groups of three-year-old breeder flock, certain differences in immune proteins and hemoglobin content in blood were revealed. Note that in the selected group of fish, a large degree of saturation of red blood cells with hemoglobin is observed, which indicates increased share of oxygen absorption by the body, as well as the intensity of redox processes of metabolism. Indicators of serum proteins of trout in experimental groups vary ambiguously. So in the experimental group, producers had an average total protein in blood of 63.26 g / l, which is significantly 17.5% more than in the blood of fish in the control group. This can be explained by the relationship of the globulins with the immune status of fish of experimental group and its resistance by raising the level of globulin fraction, a high amount of Ig M` protein (by 42.9%) in the blood of trout in the experimental group suggests more aggressive immune system in these fish to viral, invasive and other infections, indicating improved adaptability of selected herds.

scholarly journals Gut Microbiota Dysbiosis in Human Hypertension: A Systematic Review of Observational Studies

2021 ◽  
Vol 8 ◽  
Author(s):  
Yang Guo ◽  
Xiaosu Li ◽  
Zhijian Wang ◽  
Bo Yu
Keyword(s):  
Systematic Review ◽  
Gut Microbiota ◽  
Observational Studies ◽  
Short Chain Fatty Acids ◽  
Microbial Interactions ◽  
Control Group ◽  
Microbial Structure ◽  
Phosphotransferase System ◽  
Human Hypertension ◽  
Gut Microbiota Dysbiosis

Introduction: Hypertension is one of the major risk factors to human health and human studies on association between gut microbiota and hypertension or blood pressure have received increased attention. In the present study, we aim to evaluate gut microbiota dysbiosis in human hypertension using a method of systematic review.Methods: PubMed, EMBASE, and Web of Science databases were searched until March 2021 to identify eligible articles. Additional articles were also identified by searching specific authors in this field. Inclusion criteria were observational studies based on stool samples with hypertension group and control group. Newcastle-Ottawa quality assessment scale (NOS) was used to assess the quality of the included studies. PROSPERO registration number: CRD42020212219.Results: A total of 17 studies enrolling 9,085 participants were included. Fifteen of the enrolled studies showed good quality and two studies showed fair quality based on NOS. We found alpha diversity in hypertension decreased significantly and microbial structure can be separated compared with control groups. Gut microbiota of hypertension showed depletion of short chain fatty acids (SCFAs) producers and over-growth of some Proteobacteria and Bacteroidetes members. Up-regulation of lipopolysaccharide biosynthesis, phosphotransferase system, ABC transporters, etc. and down-regulation of some amino acid metabolism, etc. in hypertension were reported. Fecal SCFAs levels increased and plasma SCFAs levels decreased in hypertension. Stronger microbial interactions in hypertension were seen.Conclusion: In conclusion, gut microbiota dysbiosis was observed in hypertension, including decreased diversity, altered microbial structure, compositional change of taxa, alterations of microbial function, nutritional and immunological factors, and microbial interactions. Poor absorption and high excretion of SCFAs may play an important role in the pathogenesis of hypertension. These findings may provide insights into etiology study and new microbial-based therapies of hypertension.Systematic Review Registration: PROSPERO database, identifier CRD42020212219.

scholarly journals Beneficial and Harmful Outcomes of Tocilizumab in Severe COVID-19: A Systematic Review and Meta-Analysis

2020 ◽  
Author(s):  
Manuel Rubio-Rivas ◽  
Jose M. Mora-Lujan ◽  
Abelardo Montero ◽  
Narcis A. Homs ◽  
Jordi Rello ◽  
...  
Keyword(s):  
Systematic Review ◽  
Observational Studies ◽  
Data Extraction ◽  
Meta Analysis ◽  
Standard Of Care ◽  
Control Group ◽  
Efficacy And Safety ◽  
Icu Mortality ◽  
Secondary Infections ◽  
Randomized Control

Objectives: Pending for randomized control trials, the use of tocilizumab (TCZ) in COVID-19 remains controversial. We performed a systematic review and meta-analysis to investigate the effect on clinical outcomes of TCZ to treat severe COVID-19. Methods: From 1 January to 21 August 2020, we searched PubMed (via MEDLINE), Scopus, and medRxiv repository databases for observational studies in any language reporting efficacy and safety of TCZ use in hospitalized adults with COVID-19. Independent and dually data extraction and quality assessment were performed. Results: Of 57 eligible studies, 27 controlled and 30 not. The overall included patients were 8,128: 4,021 treated with TCZ, in addition to standard of care (SOC), and 4,107 only receiving SOC. The pooled mortality was lower in the TCZ-group, with a relative risk (RR) of 0.73 (95%CI 0.57-0.93; p=0.010). TCZ-treated patients were transferred to the intensive care unit (ICU) in a higher proportion, but ICU mortality was lower than in the control group. Conversely, a higher proportion of TCZ-treated patients developed secondary infections after TCZ use. Conclusions: TCZ seems beneficial in preventing in-hospital mortality in severe, non-critically ill COVID-19 patients. However, patients receiving TCZ appear to be at higher risk for secondary infections, especially those admitted to ICU.

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