scholarly journals Performance of multispecies assessment models: insights on the influence of diet data

2019 ◽  
Vol 76 (6) ◽  
pp. 1464-1476 ◽  
Author(s):  
Vanessa Trijoulet ◽  
Gavin Fay ◽  
Kiersten L Curti ◽  
Brian Smith ◽  
Timothy J Miller
Keyword(s):  
Stock Assessment ◽  
Small Sample Size ◽  
Model Fitting ◽  
Model Performance ◽  
Simulated Data ◽  
Small Sample ◽  
Data Availability ◽  
Data Sets ◽  
Age Structured

Abstract Multispecies stock assessment models require predator diet data, e.g. stomach samples. Diet data can be unavailable, sparse, of small sample size, or very noisy. It is unclear if multispecies interactions can be estimated without bias when interactions are weak. Research is needed about how model performance is affected by the availability or quality of diet data and by the method for fitting it. We developed seven age-structured operating models that simulate trophic interactions for two fish species and different scenarios of diet data availability or quality. The simulated data sets were fitted using four statistical catch-at-age models that estimated fishing, predation and residual natural mortality and differed in the way the diet data was fitted. Fitting the models to diet data averaged over time should be avoided since it resulted in estimation bias. Fitting annual diet composition per stomach produced bias estimates due to the occurrence of zeros in the observed proportions and the statistical assumptions for the diet model. Fitting to annual stomach proportions averaged across stomachs led to unbiased results even if the number of stomachs was small, the interactions were weak or some sampled years and ages were missing. These methods should be preferred when fitting multispecies models.

scholarly journals Congenital Micropenis: Aetiology And Management

2021 ◽  
Author(s):  
Marianna Rita Stancampiano ◽  
Kentaro Suzuki ◽  
Stuart O’Toole ◽  
Gianni Russo ◽  
Gen Yamada ◽  
...  
Keyword(s):  
Racial Differences ◽  
Small Sample Size ◽  
Small Sample ◽  
Long Term Outcomes ◽  
Penile Length ◽  
Appearance Quality ◽  
Wide Range ◽  
The Impact

Abstract In the newborn, penile length is determined by a number of androgen dependent and independent factors. The current literature suggests that there are inter-racial differences in stretched penile length in the newborn and although congenital micropenis should be defined as a stretched penile length of less than 2.5SDS of the mean for the corresponding population and gestation, a pragmatic approach would be to evaluate all boys with a stretched penile length below 2 cm, as congenital micropenis can be a marker for a wide range of endocrine conditions. However, it remains unclear as to whether the state of micropenis, itself, is associated with any long-term consequences. There is a lack of systematic studies comparing the impact of different therapeutic options on long-term outcomes, in terms of genital appearance, quality of life and sexual satisfaction. To date, research has been hampered by a small sample size and inclusion of a wide range of heterogeneous diagnoses; for these reasons, condition specific outcomes have been difficult to compare between studies. Lastly, there is a need for a greater collaborative effort in collecting standardized data so that all real-world or experimental interventions performed at an early age can be studied systematically into adulthood.

Effectiveness of Directional Microphones and Noise Reduction Schemes in Hearing Aids: A Systematic Review of the Evidence

2005 ◽  
Vol 16 (07) ◽  
pp. 473-484 ◽  
Author(s):  
Ruth A. Bentler
Keyword(s):  
Systematic Review ◽  
Noise Reduction ◽  
Hearing Aids ◽  
Small Sample Size ◽  
Careful Consideration ◽  
Small Sample ◽  
Experimental Conditions ◽  
Directional Microphones ◽  
Directional Microphone

A systematic review of the literature was undertaken to find evidence of real-world effectiveness of directional microphone and digital noise reduction features in current hearing aids. The evidence was drawn from randomized controlled trials, nonrandomized intervention studies, and descriptive studies. The quality of each study was evaluated for factors such as blinding, power of statistical analyses, and use of psychometrically strong outcome measures. Weaknesses in the identified studies included small sample size, resultant poor power to detect potentially worthwhile differences, and overlapping experimental conditions. Nine studies were identified for directional microphones, and the evidence (albeit weak) supports effectiveness. Two studies were identified for the noise reduction feature, and the evidence was equivocal. For the researcher, such a systematic review should encourage the careful consideration of appropriate methodologies for assessing feature effectiveness. For the clinician, the outcomes reported herein should encourage use of such a systematic review to drive clinical practice.

‘There is no sincerer love than the love of food’ (George Bernard Shaw, 1903): The meaning of food and its uses in prison subculture

2018 ◽  
Vol 16 (2) ◽  
pp. 127-146 ◽  
Author(s):  
Tomer Einat ◽  
Moran Davidian
Keyword(s):  
Small Sample Size ◽  
Food Products ◽  
Analysis Data ◽  
Small Sample ◽  
Structured Interviews ◽  
Maximum Security ◽  
Maximum Security Prison ◽  
The Social ◽  
Bernard Shaw

This study examines the ways in which the prison service handles food and analyses the uses and meanings of food in prison subculture. Using semi-structured interviews and content analysis, data were collected and analysed from 20 ex-prisoners who were incarcerated in maximum-security prison facilities for a period of three years or more. Our main findings are that, according to the interviewees’ testimonies, (a) the Israel Prison Service (IPS) makes manipulative and abusive use of food in order to perpetuate its power; and (b) food serves as a means to determine the relationship between prisoners and staff, govern social status or rejection in the prison subculture, or pass the time. We have four main conclusions. First, the IPS nutrition policy differentiates and discriminates among prisoners and clearly violates the basic human rights of prisoners, thus suggesting an abuse of power. Second, the IPS’s use of food as a tool for punishing or rewarding introduces and perpetuates inequalities and encourages the illegal prison trade in food and food products. Third, cooking in prison, especially in light of its illegality, constitutes a symbolic expression of resistance to the institution and a meaningful way of coping with boredom. Lastly, food and its possession in prison serve as very powerful tools for constructing and perpetuating exploitation and unequal power relations among prisoners. Although the study suffers from two limitations – the validity of the adolescents’ responses and the small sample size – its findings lead us to propose that an improvement in the food products that are accessible to prisoners and permission to cook in their cells are inexpensive and legitimate means of bettering both the prisoners’ quality of life and the social atmosphere in prison.

An initial validation of a new quality of life measure for adults with intellectual disability: The Mini-MANS-LD

2018 ◽  
Vol 24 (2) ◽  
pp. 177-193
Author(s):  
Roman Raczka ◽  
Kate Theodore ◽  
Janice Williams
Keyword(s):  
Quality Of Life ◽  
Intellectual Disability ◽  
Small Sample Size ◽  
Initial Study ◽  
Small Sample ◽  
Self Report ◽  
Life Measure ◽  
Acceptable Internal Consistency ◽  
Report Measure

There is an appropriate increasing focus on the need to ensure the voices of people with intellectual disability are captured as part of assessing individuals’ quality of life; however, there remains a lack of a consensus on ways to achieve this. This article describes the development of a self-report measure of quality of life for people with intellectual disability, the ‘Mini-MANS-LD’, based on the concepts of Maslow’s hierarchy of needs. Following use with 33 individuals with intellectual disability, the Mini-MANS-LD was found to have acceptable psychometric properties, including moderate congruent validity and acceptable internal consistency. Administrators’ feedback suggested good acceptability and feasibility, and the measure was relatively quick to administer, easy to use and acceptable to service users. Despite a small sample size, this initial study suggests that the Mini-MANS-LD may present a conceptually relevant, feasible and acceptable self-report measure of quality of life for people with intellectual disability.

scholarly journals Partial Least Square Analyses of Landscape and Surface Water Biota Associations in the Savannah River Basin

ISRN Ecology ◽  
2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Maliha S. Nash ◽  
Deborah J. Chaloud
Keyword(s):  
Surface Water ◽  
Small Sample Size ◽  
Surface Water Quality ◽  
Spatial Location ◽  
Small Sample ◽  
Partial Least Square ◽  
Least Square ◽  
Data Sets ◽  
Savannah River ◽  
Remotely Sensed Data

Ecologists are often faced with problem of small sample size, correlated and large number of predictors, and high noise-to-signal relationships. This necessitates excluding important variables from the model when applying standard multiple or multivariate regression analyses. In this paper, we present the results of applying PLS to explore relationships among biotic indicators of surface water quality and landscape conditions accounting for the above problems. Available field sampling and remotely sensed data sets for the Savannah Basin are used. We were able to develop models and compare results for the whole basin and for each ecoregion (Blue Ridge, Piedmont, and Coastal Plain) in spite of the data constraints. The amount of variability in surface water biota explained by each model reflects the scale, spatial location, and the composition of contributing landscape metrics. The landscape-biota model developed for the whole basin using PLS explains 43% and 80% of the variation in water biota and landscape data sets, respectively. Models developed for each of the three ecoregions indicate dominance of landscape variables which reflect the geophysical characteristics of that ecoregion.

A debate about implementing immersive technology for higher education: Pre-study examining the usability of virtual reality for lectures

2020 ◽  
Vol 39 (4) ◽  
pp. 565-571
Author(s):  
Matej Hopp ◽  
Sandra Pfiel ◽  
René Mario Schuster ◽  
Florian Tiefenbacher ◽  
Michael Reiner
Keyword(s):  
Applied Sciences ◽  
Higher Education ◽  
Virtual Reality ◽  
Response Rate ◽  
Small Sample Size ◽  
Theoretical Background ◽  
Small Sample ◽  
Advanced Technologies ◽  
University Of Applied Sciences

BACKGROUND: As the COVID-pandemic has shown, the need for innovative (digitalized) solutions is in high demand across almost every field of interest. The implementation of advanced technologies in higher education provides an intriguing opportunity to expand its scope by reaching new audiences as well as ensuring a high quality of learning outcome. OBJECTIVE: In this article we tried to examine if virtual reality can be a suitable option by placing lectures into a virtual setup. METHODS: First, we explored the theoretical background if and how virtual reality has been adapted for usage in higher education. We then asked five lecturers from the IMC University of Applied Sciences Krems to test a virtual environment (Mozilla Hubs) and evaluate the platform for their teaching purposes. RESULTS: Among one of the results was, that 80 percent would recommend using the platform for lectures to their colleagues. Due to the small sample size the findings need to be further evaluated. CONCLUSIONS: In the foreseeable future virtual reality will become a valuable teaching assistance in higher education. Findings show that the response rate when training with virtual reality applications is much higher than to common studying methods.

Evaluating evidence for alternative natural mortality and process error assumptions using a state-space, age-structured assessment model

2018 ◽  
Vol 75 (5) ◽  
pp. 691-703 ◽  
Author(s):  
Timothy J. Miller ◽  
Saang-Yoon Hyun
Keyword(s):  
State Space ◽  
Gulf Of Maine ◽  
Model Performance ◽  
Simulated Data ◽  
State Space Models ◽  
Assessment Model ◽  
Biomass Estimation ◽  
Natural Mortality ◽  
Space Age ◽  
Age Structured

State-space models explicitly separate uncertainty associated with unobserved, time-varying parameters from that which arises from sampling the population. The statistical aspects of formal state-space models are appealing and these models are becoming more widely used for assessments. However, treating natural mortality as known and constant across ages continues to be common practice. We developed a state-space, age-structured assessment model that allowed different assumptions for natural mortality and the degree of temporal stochasticity in abundance. We fit a suite of models where natural mortality was either age-invariant or an allometric function of mass and interannual transitions of abundance were deterministic or stochastic to observations on Gulf of Maine – Georges Bank Acadian redfish (Sebastes fasciatus). We found that allowing stochasticity in the interannual transition in abundance was important and estimating age-invariant natural mortality was sufficient. A simulation study showed low bias in annual biomass estimation when the estimation and simulation model matched and the Akaike imformation criterion accurately measured relative model performance, but it was important to allow simulated data sets to include the stochasticity in interannual transitions of abundance-at-age.

Simulation of the estimation of ageing bias inside an integrated assessment of canary rockfish using age estimates from a bomb radiocarbon study

2007 ◽  
Vol 58 (10) ◽  
pp. 905 ◽  
Author(s):  
Ian J. Stewart ◽  
Kevin R. Piner
Keyword(s):  
Functional Form ◽  
Stock Assessment ◽  
Small Sample Size ◽  
Small Sample ◽  
Assessment Model ◽  
Bomb Radiocarbon ◽  
Interval Width ◽  
Functional Forms ◽  
Age Model ◽  
Spawning Biomass

The stock of canary rockfish off the west coast of the continental US is currently assessed using an integrated statistical catch-at-age model. The functional form of an ageing bias detected in production ageing (large numbers of ages read for use in stock assessment) from a bomb radiocarbon study with small sample size (n = 16) was estimated externally and used to adjust the age data in the most recent stock assessment. Using simulation methods, the present study evaluated whether integrating the estimation of the ageing bias inside the assessment model would (1) influence the uncertainty in assessment results and (2) improve our ability to differentiate between competing functional forms (linear, linear with intercept and jointed) for specifying the ageing bias. Internal estimation of the ageing bias relationship increased the approximate 95% confidence interval width about the spawning biomass estimate by 1–10% depending on the functional form assumed. The assessment model was not able to reliably distinguish between all competing functional forms of the ageing bias tested, even with increased radiocarbon sample sizes. However, significant under-ageing at the youngest ages was found to be inconsistent with other sources of data in the assessment model. The question of ageing bias form remains important because it had moderate effects on estimates of spawning biomass and assessment model uncertainty.

scholarly journals Randomized Controlled Trial of Strain-Specific Probiotic Formulation (Renadyl) in Dialysis Patients

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ranganathan Natarajan ◽  
Bohdan Pechenyak ◽  
Usha Vyas ◽  
Pari Ranganathan ◽  
Alan Weinberg ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Statistical Power ◽  
Small Sample Size ◽  
Controlled Trial ◽  
Statistical Significance ◽  
Venous Blood ◽  
Small Sample ◽  
Uremic Toxin ◽  
Double Blind

Background. Primary goal of this randomized, double-blind, placebo-controlled crossover study of Renadyl in end-stage renal disease patients was to assess the safety and efficacy of Renadyl measured through improvement in quality of life or reduction in levels of known uremic toxins. Secondary goal was to investigate the effects on several biomarkers of inflammation and oxidative stress.Methods. Two 2-month treatment periods separated by 2-month washout and crossover, with physical examinations, venous blood testing, and quality of life questionnaires completed at each visit. Data were analyzed with SAS V9.2.Results. 22 subjects (79%) completed the study. Observed trends were as follows (none reaching statistical significance): decline in WBC count(-0.51×109/L,P=0.057)and reductions in levels of C-reactive protein(-8.61 mg/L,P=0.071)and total indoxyl glucuronide(-0.11 mg%,P=0.058). No statistically significant changes were observed in other uremic toxin levels or measures of QOL.Conclusions. Renadyl appeared to be safe to administer to ESRD patients on hemodialysis. Stability in QOL assessment is an encouraging result for a patient cohort in such advanced stage of kidney disease. Efficacy could not be confirmed definitively, primarily due to small sample size and low statistical power—further studies are warranted.

scholarly journals Experience of Using an App in HIV Patients Older Than 60 Years: Pilot Program (Preprint)

2018 ◽  
Author(s):  
Julián Olalla ◽  
Jose María García de Lomas ◽  
Efrén Márquez ◽  
Francisco Jesús González ◽  
Alfonso Del Arco ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Physical Activity ◽  
Hiv Infection ◽  
New Technologies ◽  
Small Sample Size ◽  
Mobile App ◽  
Small Sample ◽  
Control Group

BACKGROUND New technologies can promote knowledge of HIV infection among patients suffering from this disease. Older patients with HIV infection represent an increasingly large group that could benefit from the use of specific apps. OBJECTIVE The aim of the study was to observe the acceptability and use of a mobile app on HIV infection in patients at least 60 years old and offer them the possibility of anonymously establishing contact with their peers. METHODS A series of clinical and psychosocial parameters were studied in 30 HIV-infected patients of over 60 years. The patients must be at least 60 years old, with a follow-up in the outpatient clinic for at least 1 year and without pathologies that limit his or her life expectancy to less than a year. They must know how to read and write. To be part of the group assigned to the app, they had to have their own smartphone and confirm that they were connected to the internet from that device. Overall, 15 of them were randomized to use an app and 15 were in the control group. All tests were repeated after 6 months. RESULTS The median age of patients was 66.5 years. Among them, 29 patients had an undetectable viral load at baseline. The median number of comorbid diseases was 2. Overall, 11 of them lived with their partners and 19 lived alone. They spent an average of 5 hours a day sitting down, and 56% (17/30) of them referred high physical activity. They scored 4 out of 5 for general quality of life perception. Moreover, 80% (24/30) presented high adherence to their treatment, and the average number of concomitant medications was 5. In the 6-min walking test, they covered a distance of 400 meters, and 3 of them desaturated during the test. The 15 patients made frequent use of the app, with 2407 sessions and an average of 7 min and 56 seconds time of use with a total of 13,143 screen views. During the 6 months of the trial, 3 non-AIDS events took place. There were no significant modifications to body mass index, blood pressure measurements, lipid profile, or immuno-virology information data. There were no differences in the questionnaire scores for perception of quality of life, confessed physical activity, or antiretroviral treatment (ART) and non-ART treatment adherence. CONCLUSIONS Significant differences between studied parameters were not objectified in these patients, possibly because this trial has significant limitations, such as a small sample size and only a brief follow-up period. However, patients did use the app frequently, making this a possible intervention to be proposed in future subsequent studies.

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