scholarly journals Towards a pragmatic use of statistics in ecology

2018 ◽  
Author(s):  
Leonardo Castilho ◽  
Paulo Inácio Prado
Keyword(s):  
Stepwise Regression ◽  
Common Ground ◽  
Statistical Hypothesis ◽  
P Value ◽  
Data Set ◽  
Null Hypothesis Testing ◽  
Correct Conclusion ◽  
Correlation Tests ◽  
The Mean

AbstractAlthough null hypothesis testing (NHT) is the primary method for analyzing data in many natural sciences, it has been increasingly criticized. Recently, a new method based on information theory (IT) has become popular and is held by many to be superior for many reasons, not least because is enables researchers to properly assess the strength of the evidence that data provide for competing hypotheses. Many studies have compared IT and NHT in the context of model selection and stepwise regression, but a systematic comparison of the most simple but realistic uses of statistics by ecologists is still lacking. We used computer simulations to compare how both methods perform in four basic test designs (t-test, ANOVA, correlation tests, and multiple linear regression). Performance was measured by the proportion of simulated samples for which each method provided the correct conclusion (power), the proportion of detected effects with a wrong sign (S-error), and the mean ratio of the estimated effect to the true effect (M-error). We also checked if the p-value from significance tests correlated to a measure of strength of evidence, the Akaike weight. In most cases both methods performed equally well. The concordance is explained by the monotonic relationship between p-values and evidence weights in simple designs, which agree with analytic results. Our results show that researchers can agree on the conclusions drawn from a data set even when they are using different statistical approaches. By focusing on the practical consequences of inferences, such a pragmatic view of statistics can promote insightful dialogue among researchers on how to find a common ground from different pieces of evidence. A less dogmatic view of statistical inference can also help to broaden the debate about the role of statistics in science to the entire path that leads from a research hypothesis to a statistical hypothesis.

scholarly journals Towards a pragmatic use of statistics in ecology

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12090
Author(s):  
Leonardo Braga Castilho ◽  
Paulo Inácio Prado
Keyword(s):  
Stepwise Regression ◽  
Common Ground ◽  
Statistical Hypothesis ◽  
Data Set ◽  
Akaike Weight ◽  
Null Hypothesis Testing ◽  
Correct Conclusion ◽  
Correlation Tests ◽  
The Mean

Although null hypothesis testing (NHT) is the primary method for analyzing data in many natural sciences, it has been increasingly criticized. Recently, approaches based on information theory (IT) have become popular and were held by many to be superior because it enables researchers to properly assess the strength of the evidence that data provide for competing hypotheses. Many studies have compared IT and NHT in the context of model selection and stepwise regression, but a systematic comparison of the most basic uses of statistics by ecologists is still lacking. We used computer simulations to compare how both approaches perform in four basic test designs (t-test, ANOVA, correlation tests, and multiple linear regression). Performance was measured by the proportion of simulated samples for which each method provided the correct conclusion (power), the proportion of detected effects with a wrong sign (S-error), and the mean ratio of the estimated effect to the true effect (M-error). We also checked if the p-value from significance tests correlated to a measure of strength of evidence, the Akaike weight. In general both methods performed equally well. The concordance is explained by the monotonic relationship between p-values and evidence weights in simple designs, which agree with analytic results. Our results show that researchers can agree on the conclusions drawn from a data set even when they are using different statistical approaches. By focusing on the practical consequences of inferences, such a pragmatic view of statistics can promote insightful dialogue among researchers on how to find a common ground from different pieces of evidence. A less dogmatic view of statistical inference can also help to broaden the debate about the role of statistics in science to the entire path that leads from a research hypothesis to a statistical hypothesis.

Evaluation of Transient Elastography in Prediction Of De novo Recurrence of Hepatocellular Carcinoma after Radiofrequency Ablation

QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Nadia abdelaty Abdelkader ◽  
Moustafa Hamed Abdelaleem ◽  
Mohammed El-Gharib Abo El- maaty ◽  
Heba Ismail Aly ◽  
Sayed Ahmed Sayed
Keyword(s):  
Hepatocellular Carcinoma ◽  
Radiofrequency Ablation ◽  
Transient Elastography ◽  
P Value ◽  
Hepatic Decompensation ◽  
Non Invasive ◽  
Prediction Of Mortality ◽  
The Mean ◽  
One Year

Abstract Background Hepatocellular carcinoma (HCC) is the sixth most common malignancy worldwide and it is also a common cause of death in patients with chronic liver disease. The curative treatment options for HCC that are currently available are surgical resection, liver transplantation and radiofrequency ablation .Despite progressive improvements in the efficacy of RFA, the survival of patients with HCC who undergo RFA remains disappointing, mainly due to frequent intrahepatic recurrence of HCC after RFA. Aim of the work To evaluate the role of transient elastography (as an indirect indicator to degree of liver fibrosis) in prediction of denovo recurrence of hepatocellular carcinoma after radiofrequency ablation in hepatitis C related hepatocellular carcinoma .And to compare between transient elastography and other non invasive fibrosis indices in prediction of denovo recurrence of hepatocellular carcinoma after radiofrequency ablation hepatitis C related hepatocellular carcinoma Patients and methods This prospective cohrt study was conducted on hepatocellular carcinoma patient, who underwent radiofrequency ablation in Tropical Medicine Department in Eldemerdash and Ain Shams Specialized Hospital, HCC clinic Ain Shams University Hospitals, Cairo, Egypt between march, 2017 and May, 2019. Data of the patient, who underwent radiofrequency ablation during the study period, were reviewed and the patients who fulfilled the inclusion criteria were enrolled into this study. The patients who fulfilled the inclusion criteria and underwent radiofrequency ablation were followed up for 12 months. Results TE revealed 28 patients with F4 and only 2 patients with F3, the mean measurement of liver stiffness was (22.45 ± 10.36) KPa. There was a significant negative correlation between LS and denovo recurrence of HCC (mean of LS in patients with complete response was 17.19 ± 3.32 and the mean of LS in patient with denovo recurrence was 36,94 ± 5.93,with the The best cut off value ≥24.65 (p value < 0.001)). There was no significant correlation between CDC, FIB4, API scores and denovo recurrence of HCC. Also it was found that the LS was significantly associated with prediction of manifestation of hepatic decompensation after RFA (means of LS in patient without manifestation decompensation after RFA (p value <0.001) .Regarding prediction of mortality, LS at cut off value > 42 .75 (p value = 0,031) was significantly associated with prediction of mortality after one year of RFA. As regard serum non invasive fibrosis indices our results showed correlation between FIB4 score and hepatic decompensation after one year of intervention (the mean of FIB4 score in patients ascites and jaundice was 6.05 ± 4.71 (p value = 0.05) ).Therewas no statistically significant correlation between CDS and API with hepatic decompensation after RFA .As regard role of serum non invasive fibrosis indices in prediction of mortality after RFA, FIB4 score, CDS and API were statistically non significant. Conclusion Our data suggest that LS measurement is a useful predictor of HCC de novorecurrence overall survival and possibility of hepatic decompensation after RFA

scholarly journals Role of Chemical Biomarkers in Prediction of Intra-Amniotic Infection in Cases with Preterm Premature Rupture of Membrane, Observational Study

2019 ◽  
Vol 3 (2) ◽  
Keyword(s):  
Interleukin 6 ◽  
Mean Value ◽  
Maternal Serum ◽  
P Value ◽  
Subclinical Infection ◽  
Premature Rupture ◽  
Cutoff Value ◽  
The Mean ◽  
Sensitivity Specificity

Introduction: Early recognition of subclinical intra-amniotic infection before development of clinical Chorioamnionitis dramatically improve neonatal outcome before affection of fetal neurological function. Objective: this study was conducted to evaluate the role of procalcitonin and interleukin-6 in early prediction of intrauterine infection in pregnant women with premature rupture of membranes. Methods: This observational prospective cohort study was conducted on 100 pregnant women with preterm premature rupture of membrane (PPROM), Patients were divided into 2 groups: Group I: with normal CRP and WBCs level. Group2: with subclinical infection which was detected by elevated WBCs count >15,000 c/mm3 and / or positive CRP. This group was divided into two groups (Group (II) and Group (III) according to development of Chorioamnionitis. follow up of these patients was done to detect the cutoff value of procalcitonin and interleukin-6 as a predictive indicator of clinical intra-amniotic infection in patients with premature rupture of membrane. Results: This study showed that the mean value of maternal serum PCT concentration was higher in patients with clinical infection than its concentration in patients without infection or with subclinical infection with P-value 0.0001 which is highly significant between the studied cases and with cutoff value was >0.67ng/ml, sensitivity, specificity, PPV, NPV was 88.7%, 42.9%, 79.7% and 60% respectively and the mean value of maternal serum IL-6 concentration was also higher in patients with clinical infection than its concentration in patients without infection or with subclinical infection with P-value 0.001which is highly significant between the studied cases and with cutoff value was >11.1pg/ ml, sensitivity, specificity, PPV, NPV was 67.9%, 61.9%, 81.8% and 43.3% respectively. Conclusion: maternal serum procalcitonin is a good predictor of clinical intra-amniotic infection with good sensitivity, specificity, PPV, NPV which is nearly good as CRP which is better than serum interleukin-6 regarding sensitivity

scholarly journals Serum Neutrophil Gelatinase-Associated Lipocalin Levels In Early Detection Of Contrast-Induced Nephropathy

2016 ◽  
Vol 39 (3) ◽  
pp. 88 ◽  
Author(s):  
Murat Muratoglu ◽  
Cemil Kavalci ◽  
Elif Kilicli ◽  
Meliha Findik ◽  
Afşin Emre Kayipmaz ◽  
...  
Keyword(s):  
Early Detection ◽  
P Value ◽  
Ngal Level ◽  
Contrast Induced Nephropathy ◽  
Sodium Potassium ◽  
Neutrophil Gelatinase Associated Lipocalin ◽  
The Mean ◽  
Neutrophil Gelatinase ◽  
Over Time

Purpose: The purpose of this study was to investigate the role of serum neutrophil gelatinase-associated lipocalin (NGAL) levels in the early detection of contrast-induced nephropathy (CIN). Methods: This prospective study enrolled 74 patients undergoing abdominal tomography with contrast (1 November 2014 - 28 February 2015). Demographic properties (age and sex), symptoms and CT examination results were analysed. Sodium, potassium, urea, creatinine and NGAL levels were measured at 0th, 6th, and 72nd hours. P value < 0.05 was considered statistically significant. Results: CIN developed in 16.2% of the study patients. The mean age was significantly higher in the patients who developed CIN (p0.05). Urea levels did not differ significantly between the groups at 0th and 6th hours (p>0.05) but was significantly higher in the patients with CIN at 72nd hour (p0.05). Creatinine level was not significantly different between the groups (p>0.05) but increased significantly over time (p>0.05). There were no significant differences between the groups with respect to NGAL levels at 0th and 72nd hours (p>0.05) whereas the group with CIN had a significantly higher NGAL level at 6th hour (p

scholarly journals ROLE OF GINKGO BILOBA IN TINNITUS BASED ON TINNITUS HANDICAP INVENTORY

2021 ◽  
Vol Volume 9 (upjohns/volume9/Issue2) ◽  
pp. 32-36
Author(s):  
Monica Manhas
Keyword(s):  
Informed Consent ◽  
Ginkgo Biloba ◽  
Ethics Committee ◽  
P Value ◽  
Inclusion Criteria ◽  
Tinnitus Handicap Inventory ◽  
Institutional Ethics ◽  
The Mean ◽  
Pre Treatment

ABSTRACT AIMS AND OBJECTIVES To evaluate whether there is role of Ginkgo biloba in treatment of tinnitus or not, using Tinnitus Handicap Inventory MATERIAL METHODS: The present prospective study, after approval by Institutional Ethics Committee, was conducted in Department of ENT, GMC Jammu from January 2019 to January 2020 on 90 patients with primary complaint of tinnitus. Inclusion criteria- Age: 20 years or above, Duration of tinnitus > 3 months. Informed consent was taken and all patients were asked to complete the THI-Tinnitus Handicap Inventory. All patients were given 50mg of Ginkgo biloba standardized extract LI 1370 (containing 25% flavonoids, 3% ginkgolides and 5% bilobalides). Patients were advised to take three tablets daily for 12 weeks. RESULTS The mean pre-treatment THI score was 43.6 and mean post-treatment THI score (at 12 weeks) was 39.4; the mean change in THI score was 4.2, the result being statistically insignificant (p-value= 0.43). Out of 90 patients, 51 reported unchanged severity of tinnitus, 27 patients reported improvement in severity of tinnitus and 12 patients reported worsening of condition. CONCLUSION According to our study, Ginkgo biloba has no significant therapeutic role in tinnitus. However, the aetiology of tinnitus is multifactorial and Ginkgo biloba could benefit patients with ischemic aetiology. KEYWORDS Ginkgo, biloba, handicap, inventory, tinnitus

scholarly journals Pharmacometabolomics of Bronchodilator Response in Asthma and the Role of Age-Metabolite Interactions

Metabolites ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 179 ◽  
Author(s):  
Rachel S. Kelly ◽  
Joanne E. Sordillo ◽  
Sharon M. Lutz ◽  
Lydiana Avila ◽  
Manuel Soto-Quiros ◽  
...  
Keyword(s):  
Asthma Management ◽  
Management Program ◽  
P Value ◽  
Bronchodilator Response ◽  
Age Related ◽  
Children With Asthma ◽  
The Mean ◽  
Interaction With Age ◽  
Effect Of Age

The role of metabolism in modifying age-related differential responses to asthma medications is insufficiently understood. The objective of this study was to determine the role of the metabolome in modifying the effect of age on bronchodilator response (BDR) in individuals with asthma. We used longitudinal measures of BDR and plasma metabolomic profiling in 565 children with asthma from the Childhood Asthma Management Program (CAMP) to identify age by metabolite interactions on BDR. The mean ages at the three studied time-points across 16 years of follow-up in CAMP were 8.8, 12.8, and 16.8 years; the mean BDRs were 11%, 9% and 8%, respectively. Of 501 identified metabolites, 39 (7.8%) demonstrated a significant interaction with age on BDR (p-value < 0.05). We were able to validate two significant interactions in 320 children with asthma from the Genetics of Asthma in Costa Rica Study; 2-hydroxyglutarate, a compound involved in butanoate metabolism (interaction; CAMP: β = −0.004, p = 1.8 × 10−4; GACRS: β = −0.015, p = 0.018), and a cholesterol ester; CE C18:1 (CAMP: β = 0.005, p = 0.006; GACRS: β = 0.023, p = 0.041) Five additional metabolites had a p-value < 0.1 in GACRS, including Gammaminobutyric acid (GABA), C16:0 CE, C20:4 CE, C18.0 CE and ribothymidine. These findings suggest Cholesterol esters and GABA may modify the estimated effect of age on bronchodilator response.

227 CALRETICULIN, A 60-kDa PROTEIN, PREVENTS POLYSPERMY IN ZONA PELLUCIDA-FREE PIG OCYTES

2013 ◽  
Vol 25 (1) ◽  
pp. 261
Author(s):  
R. Romar ◽  
C. Soriano-Úbeda ◽  
M. D. Saavedra ◽  
J. Gadea ◽  
M. Avilés ◽  
...  
Keyword(s):  
Zona Pellucida ◽  
Calcium Binding ◽  
Statistical Significance ◽  
P Value ◽  
Oocyte Activation ◽  
Cortical Granules ◽  
Chaperone Protein ◽  
The Mean

After gamete membrane fusion or artificial oocyte activation, cortical granules undergo exocytosis and the released content modifies the zona pellucida (ZP), preventing polyspermy. Calreticulin (CRT), a calcium-binding highly conserved protein of 60 kDa, is contained in cortical granules from hamster eggs (Muñoz-Gotera et al. 2001 Mol. Reprod. Dev. 60), and we recently showed it is exocytosed from chemically activated ZP-free pig oocytes (Romar et al. 2012 Reprod. Fertil. Dev. 24). When pig ZP-enclosed oocytes were incubated with CRT, monospermy was not improved (Romar et al. 2011, Maternal communication with gametes and embryo, p. 72), suggesting that the likely role of CRT in preventing polyspermy might be carried out at the oolemma level. Our objective was to evaluate whether CRT prevents polyspermy in pig ZP-free oocytes by treating the cells with this protein before being inseminated. In vitro-matured cumulus–oocyte complexes (44 h, NCSU-37 medium) were decumulated and ZP was digested with Tyrode’s acid. The ZP-free oocytes were incubated for 30 min in TALP medium supplemented with 0, 100, 1000, and 5000 pg of CRT (ab91577, Abcam, Cambridge, MA, USA) per oocyte. After washing, ZP-free oocytes were inseminated (25 000 sperm mL–1) and gametes were co-cultured for 18 h. Putative zygotes were fixed and stained with Hoechst 33342 to analyse the fertilization results. Four replicates with 30 to 35 oocytes per group were done, and results were analysed by one-way ANOVA. A P-value ≤0.05 was taken to denote statistical significance. Incubation with CRT did not affect penetration rates that were similar among groups (77.12 ± 3.88 and 72.73 ± 4.07, respectively, for the 0- and 5000-pg CRT groups). However, the mean number of sperm per penetrated oocyte decreased from 3.01 ± 0.28 (0-pg group) to 2.07 ± 0.16 (5000-pg group), and monospermy rate increased from 30.77 ± 4.87 (0-pg group) to 52.27 ± 5.36 (5000-pg group; P ≤ 0.05). Incubation with CRT did not affect the number of sperm attached to oolemma, which was similar among all groups (11.45 ± 1.16 v. 10.75 ± 1.17, respectively, for 0 and 5000 pg of CRT). These preliminary data suggest that CRT, a protein exocytosed after oocyte activation, participates in the membrane block to polyspermy in pigs. Future studies to describe the exact mechanism of action of this chaperone protein are necessary. Supported by MEC and FEDER (AGL2009-12512-C02-01).

scholarly journals Role of Optical Coherence Tomography Angiography in Following-up Choroidal Neovascular Membranes during the Course of Aflibercept Therapy

2021 ◽  
pp. 89-96
Author(s):  
Ahmad R. Ziada ◽  
Mostafa Abd El Latif Abo El Einen ◽  
Hamdy Abd El Azim El Koumy ◽  
El Said Ibraheem El Dessouky
Keyword(s):  
Choroidal Neovascularization ◽  
Optical Coherence Tomography Angiography ◽  
University Hospital ◽  
P Value ◽  
Interventional Study ◽  
Flow Area ◽  
Corrected Visual Acuity ◽  
The Mean ◽  
Automated Software

Aims: To evaluate the mean area of choroidal neovascularization (CNV) and the flow area within the CNV and determine their value in monitoring the effect of aflibercept therapy. Study Design: prospective, interventional study. Place and Duration of Study: Tanta University Hospital in the period between March 2017 and March 2019. Methodology: OCT angiography images were obtained using the AngioVue (Optovue Inc., CA, USA). For quantitative analysis of the mean area of CNV and the flow area within the CNV, the CNV was manually delineated with the help of the manufacturer’s automated software, and the parameters of interest were automatically calculated and generated. Results: The study included forty eyes of 40 patients, 14 females and 26 males, the mean age of patients was 69 ± 5 years. The mean baseline best-corrected visual acuity (BCVA) was 51.29 ± 14.80 ETDRS letters, which significantly increased to 63.41 ± 5.03 at week 36; p-value < 0.05. The mean area of choroidal neovascularization decreased significantly from baseline (2.72 ± 4.29 mm2) to week 36 (1.53 ± 1.07 mm2); p-value < 0.05. The the flow area within the measured CNV decreased significantly from baseline (2.28 ± 2.08 mm2) to week 36 (0.91 ± 0.63 mm2); p-value < 0.05. Conclusion: The mean area of CNV and the flow area within the measured CNV are valuable biomarkers for following up CNV during treatment with aflibercept.

scholarly journals A study on mean platelet volume in ischemic cerebrovascular stroke

2018 ◽  
Vol 5 (2) ◽  
pp. 316 ◽  
Author(s):  
Vitan Patel ◽  
Mahendra Parmar ◽  
Kinjal Shah ◽  
Rishikesh Joshi
Keyword(s):  
Ischemic Stroke ◽  
Mean Platelet Volume ◽  
Multivariate Regression ◽  
Multivariate Regression Analysis ◽  
Clinical Severity ◽  
P Value ◽  
Platelet Volume ◽  
The Mean ◽  
Cerebrovascular Stroke

Background: Ischemic Cerebrovascular stroke is one of the largest cause of death and disability. It is usually caused by thrombosis or thromboembolic phenomena. Large platelets are more reactive, produce more prothrombotic factors and aggregate more easily, and can be a major risk factor/indicator for stroke. While the Mean Platelet Volume (MPV) has been studied in detail in cases of IHD, very few studies have been done in stroke, and none in India – prompting this study. We aim to determine whether an association exists between MPV and incidence/severity of stroke.Methods: The study was carried out among fifty patients with an acute ischemic stroke. Clinical severity was assessed using Modified Rankin‘s scale. MPV was measured using an automated analyzer. Fifty controls were recruited and analysed.Results: MPV has got a statistically significant correlation with Ischemic stroke with a p value of < 0.0001. Average MPV in cases was 9.78+1.25 fl vs. controls who average 8.30+1.14 fl. We did not find a statistically significant correlation between clinical severity of stroke and MPV (P = 0.550).Conclusions: This study has shown an elevation of MPV in acute phase of Ischemic stroke. Within this relationship and adjusting for other significant variables in multivariate regression analysis, it can be stated that an increase in MPV is independently associated with stroke. Further research is required into the role of platelet volume in stroke pathology, outcome, and, most importantly, in individuals at risk for stroke. 

scholarly journals Role of Perineal Length Estimation in The Prediction of Maternal and Fetal Outcomes

2020 ◽  
Vol 2 (1) ◽  
pp. 11
Author(s):  
Sabah R. H. Ahmed ◽  
Hala A. Ali
Keyword(s):  
Cesarean Section ◽  
Apgar Score ◽  
Normal Vaginal Delivery ◽  
P Value ◽  
Fetal Outcomes ◽  
Second Stage Of Labor ◽  
Second Stage ◽  
Significant Difference ◽  
The Mean

Context: Female perineum is a significant part of females because perineal tears and episiotomy habitually happen in childbirth with first-time deliveries. Aim: This study aimed to explore the role of perineal length (PL) estimation in the prediction of maternal and fetal outcomes. Methods: A prospective cohort observational design used to collect data from the Department of Obstetrics and Gynecology, Laboring room, Kafrelsheikh General Hospital, Kafrelsheikh City, Egypt. A purposive sample of 139 parturient women recruited during the period from the first of December 2018 to the end of August 2019. Six tools used to conduct this study. Maternal and newborn characteristics questionnaire, disposable standardized paper tape for measuring PL in centimeters, a standardized scale for measuring maternal height by meters, and body weight in kilograms to calculate Body Mass Index (BMI) (k/m2), REEDA scale, partograph for labor process and Apgar score. Results: There were statistically significant differences regarding the mean age, previous episiotomy and cesarean section of both studied groups (PL less than or equal to 4 cm and more than 4 cm) at p-value <0.001. Out of 139 parturient women, the two groups of PL less than or more than 4 cm had 16.7% versus 56.9%, respectively had normal vaginal delivery, with a statistically significant difference between both groups, while 46.7% versus 6.3% respectively had an episiotomy. However, the mean duration of the second stage of labor had statistically significant differences between both studied groups, with 116.7 ± 44.3 versus 85.1 ± 42.0, respectively. Additionally; Mean birth weight/grams, cephalohematoma, caput succedaneum, and mean APGAR score after 5 minutes had a statistically significant difference between the two groups. Conclusions: Short perineum accompanied by increased duration of the second stage of labor. Cesarean section delivery and perineal trauma are associated with primigravida with short perineum. Regarding the mean APGAR score after 5 minutes, there were statistically significant differences between both studied groups. Maternity and newborn health nursing need to improve the illustration of the risk factors that can lead to undesirable consequences

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