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Ecology and Evolution Jan 2016Body size is a fundamental functional trait that can be used to forecast individuals' responses to environmental change and their contribution to ecosystem functioning....
Body size is a fundamental functional trait that can be used to forecast individuals' responses to environmental change and their contribution to ecosystem functioning. However, information on the mean and variation of size distributions often confound one another when relating body size to aggregate functioning. Given that size-based metrics are used as indicators of ecosystem status, it is important to identify the specific aspects of size distributions that mediate ecosystem functioning. Our goal was to simultaneously account for the mean, variance, and shape of size distributions when relating body size to aggregate ecosystem functioning. We take advantage of habitat-specific differences in size distributions to estimate nutrient recycling by a non-native crayfish using mean-field and variance-incorporating approaches. Crayfishes often substantially influence ecosystem functioning through their omnivorous role in aquatic food webs. As predicted from Jensen's inequality, considering only the mean body size of crayfish overestimated aggregate effects on ecosystem functioning. This bias declined with mean body size such that mean-field and variance-incorporating estimates of ecosystem functioning were similar for samples at mean body sizes >7.5 g. At low mean body size, mean-field bias in ecosystem functioning mismatch predictions from Jensen's inequality, likely because of the increasing skewness of the size distribution. Our findings support the prediction that variance around the mean can alter the relationship between body size and ecosystem functioning, especially at low mean body size. However, methods to account for mean-field bias performed poorly in samples with highly skewed distributions, indicating that changes in the shape of the distribution, in addition to the variance, may confound mean-based estimates of ecosystem functioning. Given that many biological functions scale allometrically, explicitly defining and experimentally or statistically isolating the effects of the mean, variance, and shape of size distributions is necessary to begin generalizing relationships between animal body size and ecosystem functioning.
PubMed: 26811781
DOI: 10.1002/ece3.1852 -
Platelets 2015
Topics: Endocarditis; Female; Humans; Male; Mean Platelet Volume; Platelet Count
PubMed: 24617309
DOI: 10.3109/09537104.2014.887200 -
Toxics Apr 2022This study provides baseline information on the concentrations of antibiotics in influent and effluent from two wastewater treatment plants in regular operation in the...
This study provides baseline information on the concentrations of antibiotics in influent and effluent from two wastewater treatment plants in regular operation in the State of Kuwait. Wastewater samples were collected from the influent and effluent streams of two WWTPs, over four sampling campaigns and analyzed for a broad range of antibiotics. The mean influent concentrations of sulfamethoxazole, ciprofloxacin, clarithromycin, and cefalexin were 852 ng/L, 672 ng/L, 592 ng/L), and 491 ng/L, respectively, at Umm Al Hayman WWTP. At the Kabd WWTP, the influent concentration of clarithromycin was highest with a mean of 949 ng/L, followed by ciprofloxacin (mean, 865 ng/L), cefalexin (mean, 598 ng/L), and sulfamethoxazole (mean, 520 ng/L). The dominant compounds in the effluent from Umm Al Hayman were sulfamethoxazole (mean, 212 ng/L), ciprofloxacin (mean, 153 ng/L), ofloxacin (mean, 120 ng/L), dimetridazole (mean, 96 ng/L), and metronidazole (mean, 93 ng/L). Whereas, at the Kabd WWTP, the dominant compounds were sulfamethoxazole (mean, 338 ng/L), dimetridazole (mean, 274 ng/L), cefalexin (mean, 213 ng/L), ciprofloxacin (mean, 192 ng/L), and clarithromycin (189 ng/L). The mean influent concentrations of all compounds were higher than those measured in the effluents. The concentrations of antibiotic compounds were not significantly different between the two WWTPs (p > 0.05). The removal efficiencies of the various antibiotics over the four sampling campaigns for the Kabd and Umm Hayman WWTPs ranged between 10.87 and 99.75% and also showed that they were variable and were compound dependent. The data clearly show that the concentrations of antibiotics measured in the influents of both WWTPs were highest in samples collected during the winter-summer (September samples) transition followed by the concentrations measured during the winter-summer (March samples) transition period. This is possibly linked to the increased prescription of these medications to treat infectious diseases and flu prevalent in Kuwait during these periods. This study provides the first reported concentrations of antibiotics in the dissolved aqueous influents and effluents of WWTPs in Kuwait. Additional studies are required to evaluate the environmental impact that antibiotic residues may cause since treated wastewater is used in irrigation, and often there are instances when untreated wastewater is discharged directly into the marine environment.
PubMed: 35448435
DOI: 10.3390/toxics10040174 -
Intensive Care Medicine Jan 1998It has been recently shown that there is a match between dicrotic notch and mean pulmonary artery (PA) pressures in spontaneously breathing patients studied by means of...
OBJECTIVE
It has been recently shown that there is a match between dicrotic notch and mean pulmonary artery (PA) pressures in spontaneously breathing patients studied by means of high-fidelity pressure catheters. The aim of the study was to analyze the relation between mean PA pressure and PA pressure at the incisura by using a Swan-Ganz catheter in critically ill, mechanically ventilated patients.
MEASUREMENTS AND RESULTS
Fluid-filled PA pressures were obtained over four ventilatory cycles in 32 consecutive, mechanically ventilated patients in the intensive care unit. We measured mean PA pressure and dicrotic notch pressure. We also calculated the widely used approximation of mean PA pressure (mean PAPapprox = diastolic + 1/3 pulse pressure). Cardiac output was measured in triplicate by using the thermodilution technique. Dicrotic notch was clearly identified in 30 of 32 patients. Mean PA pressure (32.1 +/- 10.2 mm Hg) and PA dicrotic notch pressure (31.8 +/- 10.4 mm Hg) were linearly related (r = 0.989, p < 0.001). Agreement between dicrotic notch and mean PA pressures was suggested (mean difference +/- SD = -0.3 +/- 1.5 mm Hg). Similar agreement was found between mean PAPapprox and mean PA pressure (mean difference +/- SD = -0.7 +/- 0.8 mm Hg; p = 0.20).
CONCLUSION
By using a Swan-Ganz catheter we found that dicrotic notch pressure equalled mean PA pressure in the critically ill, mechanically ventilated patients studied. This indicated that right-sided ejection was completed at a PA pressure equal to mean PA pressure in these patients.
Topics: Aged; Blood Pressure; Catheterization, Swan-Ganz; Critical Illness; Female; Hemodynamics; Humans; Male; Middle Aged; Pulmonary Artery; Respiration, Artificial
PubMed: 9503226
DOI: 10.1007/s001340050519 -
Journal of Children's Orthopaedics Jun 2020Treatment of moderate to severe stable slipped capital femoral epiphysis (SCFE) remains a challenging problem. Open reduction by modified Dunn procedure carries a... (Review)
Review
PURPOSE
Treatment of moderate to severe stable slipped capital femoral epiphysis (SCFE) remains a challenging problem. Open reduction by modified Dunn procedure carries a considerable risk of osteonecrosis (ON). Imhauser osteotomy is capable of realigning the deformity without the risk of ON, but the remaining metaphyseal bump is implicated with significant chondro-labral lesions and accelerated osteoarthritis. We conducted this study to evaluate the efficacy and safety of Imhauser osteotomy combined with osteochondroplasty (OCP) through the surgical hip dislocation (SHD) approach.
METHODS
A prospective series of 23 patients with moderate-severe stable SCFE underwent Imhauser osteotomy and OCP through SHD. The mean age was 14.4 years (13 to 20) and the mean follow-up period was 45 months (24 to 66). The outcome measures included clinical and radiological parameters and Harris hip score (HHS) was used as a functional score.
RESULTS
The mean HHS improved significantly from 65.39 to 93.3. The limb length discrepancy improved by a mean of 1.72 cm. The mean flexion and abduction arcs showed a significant improvement (mean increase of 37.5° and 18.5°, respectively). The mean internal rotation demonstrated the most significant improvement (mean increase of 38.5°). All the radiographic parameters improved significantly; including anterior and lateral slip angles (mean improvement 37.52° and 44.37°, respectively). The mean alpha angle decreased by 39.19°. The articulo-trochanteric distance significantly increased to a mean of 23.26 mm. No cases of ON or chondrolysis were identified.
CONCLUSION
Combined Imhauser osteotomy and OCP through the surgical dislocation approach provide a comprehensive and safe management of moderate to severe stable SCFE.
LEVEL OF EVIDENCE
IV.
PubMed: 32582386
DOI: 10.1302/1863-2548.14.200021 -
The Cochrane Database of Systematic... Aug 2012Tubal sterilization by hysteroscopy involves inserting a foreign body in both fallopian tubes. Over a three-month period, the tubal lumen is occluded by tissue growth... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Tubal sterilization by hysteroscopy involves inserting a foreign body in both fallopian tubes. Over a three-month period, the tubal lumen is occluded by tissue growth stimulated by the insert. Tubal sterilization by hysteroscopy has advantages over laparoscopy or mini-laparotomy, including the avoidance of abdominal incisions and the convenience of performing the procedure in an office-based setting. Pain, an important determinant of procedure acceptability, can be a concern when tubal sterilization is performed in the office.
OBJECTIVES
To review all randomized controlled trials that evaluated interventions to decrease pain during tubal sterilization by hysteroscopy.
SEARCH METHODS
From January to March 2011, we searched the computerized databases of MEDLINE, POPLINE, CENTRAL, EMBASE, LILACS, and CINAHL for relevant trials. We searched for current trials via Clinicaltrials.gov. We also examined the reference lists of pertinent articles and wrote to known investigators for information about other published or unpublished trials.
SELECTION CRITERIA
We included all randomized controlled trials that evaluated pain management at the time of sterilization by hysteroscopy. The intervention could be compared to another intervention or placebo.
DATA COLLECTION AND ANALYSIS
Initial data were extracted by one review author. A second review author verified all extracted data. Whenever possible, the analysis was conducted with all women randomized and in the original assigned groups. Data were analyzed using RevMan software. Pain was measured using either a 10-cm or 100-point visual analog scale (VAS). When pain was measured at multiple points during the procedure, the overall pain score was considered the primary treatment effect. If this was not measured, a summation of all pain scores for the procedure was considered to be the primary treatment effect. For continuous variables, the mean difference with 95% confidence interval was computed.
MAIN RESULTS
Two trials met the inclusion criteria. The total number of participants was 167. Using a 10-cm VAS to measure pain, no significant difference emerged in overall pain for the entire procedure between women who received a paracervical block with lidocaine versus normal saline (mean difference -0.77; 95% CI -2.67 to 1.13). No significant difference in pain score was noted at the time of injection of study solution to the anterior lip of the cervix (mean difference -0.6; 95% CI -1.3 to 0.1), placement of the device in the tubal ostia (mean difference -0.60; 95% CI -1.8 to 0.7), and postprocedure pain (mean difference 0.2; 95% CI -0.8 to 1.2). Procedure time (mean difference -0.2 minutes; 95% CI -2.2 to 1.8 minutes) and successful bilateral placement (OR 1.0; 95% CI 0.19 to 5.28) was not significantly different between groups. During certain portions of the procedure, such as placement of the tenaculum (mean difference -2.03; 95% CI -2.88 to -1.18), administration of the paracervical block (mean difference -1.92; 95% CI -2.84 to -1.00), and passage of the hysteroscope through the external (mean difference -2.31; 95% CI -3.30 to -1.32) and internal os (mean difference -2.31; 95% CI -3.39 to -1.23), use of paracervical block with lidocaine resulted in lower pain scores.Using a 600-point scale calculated by adding 100-point VAS scores from six different portions of the procedure, no significant difference emerged in overall pain between women who received intravenous conscious sedation versus oral analgesia (mean difference -23.00; CI -62.02 to 16.02). Using a 100-point VAS, no significant difference emerged at the time of speculum insertion (mean difference 4.0; 95% CI -4.0 to 12.0), cervical injection of lidocaine (mean difference -1.8; 95% CI -10.0 to 6.4), insertion of the hysteroscope (mean difference -8.7; 95% CI -19.7 to 2.3), placement of the first device (mean difference -4.4; 95% CI -15.8 to 7.0), and removal of the hysteroscope (mean difference 0.9; 95% CI -3.9 to 5.7). Procedure time (mean difference -0.2 minutes; 95% CI -2.0 to 1.6 minutes) and time in the recovery area (mean difference 3.6 minutes; 95% CI -11.3 to 18.5 minutes) was not different between groups. However, women who received intravenous conscious sedation had lower pain scores at the time of insertion of the second tubal device compared to women who received oral analgesia (mean difference -12.60; CI -23.98 to -1.22).
AUTHORS' CONCLUSIONS
The available literature is insufficient to determine the appropriate analgesia or anesthesia for sterilization by hysteroscopy. Compared to paracervical block with normal saline, paracervical block with lidocaine reduced pain during some portions of the procedure. Intravenous sedation resulted in lower pain scores during insertion of the second tubal device. However, neither paracervical block with lidocaine nor conscious sedation significantly reduced overall pain scores for sterilization by hysteroscopy.
Topics: Anesthetics, Local; Female; Humans; Hysteroscopy; Lidocaine; Pain Management; Pain Measurement; Sterilization, Tubal
PubMed: 22895987
DOI: 10.1002/14651858.CD009251.pub2 -
American Journal of Hematology 1980The International Committee for Standardization in Hematology recommended three methods for calculating objectively the mean platelet survival time, ie, weighted mean of...
The International Committee for Standardization in Hematology recommended three methods for calculating objectively the mean platelet survival time, ie, weighted mean of linear estimate and logarithmic estimate, truncated exponential model, and gamma model. For determining which method is better, data of the survival study were fitted to each of three methods, as well as the Paulus polynomial and exponential polynomial models, and the mean survival time and the mean square error were compared. Mean survival obtained by each method was always longest in healthy controls and shortest in ITP. In 3rd degree of polynomial estimate and 2nd and 3rd degrees of logarithmic estimate, several cases showed practically outlying mean survival time of more than 12 days. In healthy controls, highest mean square error was observed in 1st degree logarithmic estimate, and in cases with short mean survival time the highest one was obtained in 1st degree polynomial estimate. Mean square error in ITP pre- and postsplenectomy and in aplastic anemia was smallest in the gamma model. Among nine methods recommended by the International Committee for Standardization in Hematology and by Dr. Paulus, the gamma model so far provides the best method for calculating the mean survival time of 51Cr-platelets.
Topics: Blood Platelets; Cell Survival; Humans; Mathematics; Models, Biological
PubMed: 7416159
DOI: 10.1002/ajh.2830080306 -
Journal of Insurance Medicine (New... 2006To explain the impact of the 10% annual increase in mortality rate in the life tables from about age 45 to 90 years on mean expected mortality rate in any follow-up (FU)...
OBJECTIVE
To explain the impact of the 10% annual increase in mortality rate in the life tables from about age 45 to 90 years on mean expected mortality rate in any follow-up (FU) group with a wide age range. Use of the mean age to enter a life table invariably underestimates the true mean expected mortality rate in small age groups with an age range of 5 to 10 years. As a result, when mean age and standard deviation (SD) are the only age characteristic given for the cohort reported in a FU study, the mean age must be adjusted upward to enter the life table to obtain a valid mean expected mortality rate of the entire cohort.
METHOD
The 1989-91 Decennial US Life Table is used to illustrate the variation of expected annual rate, q', with age, x. The magnitude of the error in mean q' introduced by failure to adjust mean age to obtain mean q' is illustrated in examples of both cardiovascular and cancer FU studies. Other tabular analytical data are also presented.
RESULTS
From the 1989-91 US Life Tables for the white population, it is shown that the mean increase in annual mortality rate between ages 45 and 90 years has been found to be 9.36 +/- 0.79% per year for males and 9.94 +/- 1.13 for females. For age groups with a narrow range (10 years or less), a mean age can be used to estimate an accurate mean q'. But if the range exceeds about 15 years, as it does in most groups of patients in a FU study, a tabular q; obtained by entering the life table with the mean age is underestimated and is lower than the actual mean q'. The magnitude of the error increases with the magnitude of the range or SD. Examples are given of the magnitude of the error in one group as patients with coronary heart disease and in another group with cancer. Summary data on the magnitude of the error are also given for multiple groups in each category.
CONCLUSION
Recommendations are made on how to adjust the mean age, when possible, to provide a more accurate q', when data by separate age groups are not available.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Child; Female; Humans; Life Tables; Male; Middle Aged; Mortality; United States
PubMed: 16845842
DOI: No ID Found -
Pathology, Research and Practice Aug 2020Endometrial ablation for abnormal uterine bleeding is used as a less invasive alternative to hysterectomy, however, in cases of treatment failure hysterectomy may be...
BACKGROUND
Endometrial ablation for abnormal uterine bleeding is used as a less invasive alternative to hysterectomy, however, in cases of treatment failure hysterectomy may be finally performed. The histologic changes in these post-treatment uteri are not well-described.
OBJECTIVE
To describe the histological findings in post-endometrial ablation uteri.
STUDY DESIGN
During a ten-year period, 321 patients were treated with endometrial ablation. Twenty-five patients (7.8%), 10 treated with NovaSure® and 15 treated with ThermaChoice® endometrial ablation were finally subjected to hysterectomy mostly due to persistent uterine bleeding. Histologic features of these hysterectomies are described.
RESULTS
The patients' age ranged from 33 to 73 years (mean 44.5) and 34-53 (mean 42) for the NovaSure® and ThermaChoice® group, respectively. The time from endometrial ablation to hysterectomy was 2-24 months (mean 8.8) and 2-60 months (mean 23.2) for the two groups, respectively (p = 0.01). Hysterectomies performed later (mean 22 months) showed no fibrosis (p = 0.04) compared with those performed earlier (mean 5 months). Endometrial lining was found more frequently in hysterectomies performed later (mean 13 months) than those performed earlier (mean 2 months, p = 0.0004). Abundant necrotic tissue of myometrial origin was found in 28% of the cases, but it was not associated with the time of hysterectomy (p = 0.2). A zonation effect and vascular changes also seen. Granulomatous reaction was not found. Ten patients (40%) harbored adenomyosis and another three (12%) extensive leiomyomas/diffuse leiomyomatosis.
CONCLUSION
Necrosis, fibrosis and vascular changes are found during the first year of post-thermal uterine effect. Hysterectomies performed later show less prominent changes and almost normal endometrial lining. Adenomyosis is found in an important part of post-endometrial ablation hysterectomies.
Topics: Adult; Aged; Endometrial Ablation Techniques; Female; Humans; Hysterectomy; Middle Aged; Radiofrequency Ablation; Retrospective Studies; Treatment Failure; Uterine Hemorrhage; Uterus
PubMed: 32475645
DOI: 10.1016/j.prp.2020.152992 -
Risk Analysis : An Official Publication... Jun 1998Since substantial bias can result from assigning some type of mean exposure to a group, risk assessments based on epidemiological data should avoid the grouping of data... (Comparative Study)
Comparative Study
Since substantial bias can result from assigning some type of mean exposure to a group, risk assessments based on epidemiological data should avoid the grouping of data whenever possible. However, ungrouped data are frequently unavailable, and the question arises as to whether an arithmetic or geometric mean is the most appropriate summary measure of exposure. It is argued in this paper that one should use the type of mean for which the total risk that would result if every member of the population was exposed to the mean level is as close as possible to the actual total population risk. Using this criterion an arithmetic mean is always preferred over a geometric mean whenever the dose response is convex. In each of several data sets examined in this paper for which the dose response was not convex, an arithmetic mean was still preferred based on this criterion.
Topics: Data Interpretation, Statistical; Dose-Response Relationship, Drug; Epidemiologic Methods; Humans; Mathematics; No-Observed-Adverse-Effect Level; Risk Assessment
PubMed: 9664725
DOI: 10.1111/j.1539-6924.1998.tb01296.x