moderate sample size
Recently Published Documents


TOTAL DOCUMENTS

19
(FIVE YEARS 5)

H-INDEX

6
(FIVE YEARS 0)

Author(s):  
Xuesong Zhang ◽  
Baoping Li ◽  
Jing Jiang

Given training data, convolutional dictionary learning (CDL) seeks a translation-invariant sparse representation, which is characterized by a set of convolutional kernels. However, even a small training set with moderate sample size can render the optimization process both computationally challenging and memory starving. Under a biconvex optimization strategy for CDL, we propose to diagonally precondition the system matrices in the filter learning sub-problem that can be solved by the alternating direction method of multipliers (ADMM). This method leads to the substitution of matrix inversion ([Formula: see text] and matrix multiplication ([Formula: see text] involved in ADMM with an element-wise operation ([Formula: see text], which significantly reduces the computational complexity as well as the memory requirement. Numerical experiments validate the performance advantage of the proposed method over the state-of-the-arts. Code is available at https://github.com/baopingli/Efficient-Convolutional-Dictionary-Learning-using-PADMM .


2021 ◽  
Author(s):  
Junya Watanabe

Quantification of the magnitude of covariation plays a major role in the studies of phenotypic integration, for which statistics based on dispersion of eigenvalues of a covariance or correlation matrix—eigenvalue dispersion indices—are commonly used. However, their use has been hindered by a lack of clear understandings on their statistical meaning and sampling properties such as the magnitude of sampling bias and error. This study remedies these issues by investigating properties of these statistics with both analytic and simulation-based approaches. The relative eigenvalue variance of a covariance matrix is known in the statistical literature as a test statistic for sphericity, thus is an appropriate measure of eccentricity of variation. The same of a correlation matrix is exactly equal to the average squared correlation, thus is a clear measure of overall integration. Exact and approximate expressions for the mean and variance of these statistics are analytically derived for the null and arbitrary conditions under multivariate normality, clarifying the effects of sample size N, number of variables p, and parameters on the sampling bias and error. Accuracy of the approximate expressions are evaluated with simulations, confirming that most of them work reasonably well with a moderate sample size (N ≥ 16–64). Importantly, sampling properties of these indices are not adversely affected by high p:N ratio, promising their utility in high-dimensional phenotypic analyses. These statistics can potentially be applied to shape variables and phylogenetically structured data, for which necessary assumptions and modifications are presented.


2021 ◽  
Vol 46 (2) ◽  
pp. E303-E312
Author(s):  
Gabriel Robert ◽  
Elise Bannier ◽  
Magali Comte ◽  
Lea Domain ◽  
Isabelle Corouge ◽  
...  

Background: Major depressive disorder (MDD) is characterized by impaired cortical–subcortical functional connectivity. Apathy adds to functional impairment, but its cerebral basis in MDD remains unknown. Our objective was to describe impairments in functional connectivity during emotional processing in MDD (with varying levels of congruency and attention), and to determine their correlation with apathy. Methods: We used the Variable Attention Affective Task during functional MRI, followed by diffusion-weighted MRI, to assess 55 right-handed women (30 with MDD and 25 healthy controls) between September 2012 and February 2015. We estimated functional connectivity using generalized psychophysiologic interaction and anatomic connectivity with tract-based spatial statistics. We measured apathy using the Apathy Evaluation Scale. Results: We found decreased functional connectivity between the left amygdala and the left anterior cingulate cortex (ACC) during negative stimuli in participants with MDD (t54 = 4.2; p = 0.035, family-wise error [FWE]–corrected). During high-attention stimuli, participants with MDD showed reduced functional connectivity between the right dorsolateral prefrontal cortex (dlPFC) and the right ACC (t54 = 4.06, pFWE = 0.02), but greater functional connectivity between the right dlPFC and the right amygdala (t54 = 3.35, p = 0.048). Apathy was associated with increased functional connectivity between the right dlPFC and the right ACC during high-attention stimuli (t28 = 5.2, p = 0.01) and increased fractional anisotropy in the right posterior cerebellum, the anterior and posterior cingulum and the bilateral internal capsule (all pFWE < 0.05). Limitations: Limitations included a moderate sample size, concomitant antidepressant therapy and no directed connectivity. Conclusion: We found that MDD was associated with impairments in cortical–subcortical functional connectivity during negative stimuli that might alter the recruitment of networks engaged in attention. Apathy-related features suggested networks similar to those observed in degenerative disorders, but possible different mechanisms.


Author(s):  
Alberto Frigerio ◽  
Lucia Ballerini ◽  
Maria Del C. Valdés Hernández

This review systematically explored structural, functional, and metabolic features of the cisgender brain compared with the transgender brain before hormonal treatment and the heterosexual brain compared to the homosexual brain from the analysis of the neuroimaging literature up to 2018, and identified and discussed subsequent studies published up to March 2021. Our main aim was to help identifying neuroradiological brain features that have been related to human sexuality to contribute to the understanding of the biological elements involved in gender identity and sexual orientation. We analyze 39 studies on gender identity and 24 on sexual orientation. Our results suggest that some neuroanatomical, neurophysiological, and neurometabolic features in transgender individuals resemble those of their experienced gender despite the majority resembling those from their natal sex. In homosexual individuals the majority resemble those of their same sex heterosexual population rather than their opposite sex heterosexual population. However, it is always difficult to interpret findings with non-invasive neuroimaging. Given the gross nature of these measures, it is possible that more differences too subtle to measure with available tools yet contributing to gender identity and sexual orientation could be found. Conflicting results contributed to the difficulty of identifying specific brain features which consistently differ between cisgender and transgender or between heterosexual and homosexual groups. The small number of studies, the small-to-moderate sample size of each study, and the heterogeneity of the investigations made it impossible to meta-analyze all the data extracted. Further studies are necessary to increase the understanding of the neurological substrates of human sexuality.


2021 ◽  
Vol 19 (2) ◽  
pp. 179-191
Author(s):  
Mwita Sospeter ◽  
Theresia J Shavega ◽  
Cosmas Mnyanyi

Social emotions are frequently experienced in every individual in the daily life including adolescents’ secondary school students. The mult-social emotional changes such as aggressive and happiness among adolescents influences students coping with learning at school. The purpose of this study was to develop social emotional model for coping with learning among adolescent secondary school students. Specifically the study attempted to answer the extent social emotional model is effective in improving students coping with learning. The study adapted collaborative action research design in which a total of 244 adolescent secondary school students responded to questionnaires and focus group discussion. The effectiveness of the developed social emotional model for student coping with learning was reported by students through the questionnaires. It was found that the aspects incorporated in the model improved practices in learning outcomes to both teachers and students in coping with learning. It was found that, Teachers used guidance and counseling, action oriented activities such as role play, encouraging play and exploration as the strategies to foster active engagement among adolescent secondary school students towards learning adjustment. Furthermore, the study revealed positive significant because the data in the model summary shows that the value of r=.351 indicates that one item for adolescent secondary school students coping with learning increased for about 35.1% with 77.5% standard error of the estimated predictor value. Although this study was conducted in Tanzania employing moderate sample size from which the data was gathered with the help of collaboration action research design. The findings provide guidelines for further replicate research on social emotion behaviours and academic performance in education elsewhere.


2020 ◽  
Vol 75 (3) ◽  
pp. 455-476
Author(s):  
Kertész Csaba ◽  
F. Földi Rita ◽  
Honbolygó Ferenc

A ritmikai és a nyelvi, illetve olvasási képességek közötti kapcsolatot a gyakorlati megfi gyeléseken túl számos kutatás eredménye látszik alátámasztani, ugyanakkor a magyar anyanyelvű gyerekeket vizsgáló munkák száma ez idáig csekély. 39 tipikus első osztályos (6–7 éves) tanuló vizsgálatára került sor a tanév kezdetekor egy digitális, gyermekek számára kialakított ritmikai szinkronizációt és spontán motoros tempót mérő teszt, valamint egy ritmusreprodukciós feladatsor segítségével. A tanév végén felmértük a gyerekeket a fonológiai tudatosság, valamint a szóolvasás területein. Az olvasás színvonala és a fonológiai tudatosság is szignifi káns kapcsolatot mutatott a szinkronizációs és a spontán tempó feladat több mutatójával, ugyanakkor a ritmusreprodukciós feladat nem rendelkezett hasonló prediktív erővel. Bár a minta nagysága messzemenő következtetések levonására nem alkalmas, az eredmények egy irányba mutatnak a külföldi szakirodalomban találhatókkal, és azonkívül, hogy további vizsgálatok szükségességét jelzik, felhívják a fi gyelmet a korai ritmikai fejlesztés fontosságára. A growing body of research supports the link between rhythmic abilities and the development of language and reading, while investigations carried out with Hungarian speaking children are sparse. The rhythmic abilities of 39 typically developing, 6-7 year old, Hungarian native-speaking children were assessed at the beginning of their fi rst school year in three domains: rhythm reproduction, tapping to a regular musical beat, and unpaced tapping, using a digital test suitable for their age. At the end of the school year, children completed tests of phonological awareness and reading abilities. Both showed signifi cant correlation with several indicators of the tapping tasks. Surprisingly however, rhythm reproduction did not predict either of them. Although the moderate sample size of our present study does not allow far-reaching conclusions, our fi ndings are congruent with previous literature, and in addition to the need for further research, stresses the importance of early rhythmic activities.


Author(s):  
Arjun Bhattacharya ◽  
Alina M Hamilton ◽  
Helena Furberg ◽  
Eugene Pietzak ◽  
Mark P Purdue ◽  
...  

Abstract The NanoString RNA counting assay for formalin-fixed paraffin embedded samples is unique in its sensitivity, technical reproducibility and robustness for analysis of clinical and archival samples. While commercial normalization methods are provided by NanoString, they are not optimal for all settings, particularly when samples exhibit strong technical or biological variation or where housekeeping genes have variable performance across the cohort. Here, we develop and evaluate a more comprehensive normalization procedure for NanoString data with steps for quality control, selection of housekeeping targets, normalization and iterative data visualization and biological validation. The approach was evaluated using a large cohort ($N=\kern0.5em 1649$) from the Carolina Breast Cancer Study, two cohorts of moderate sample size ($N=359$ and$130$) and a small published dataset ($N=12$). The iterative process developed here eliminates technical variation (e.g. from different study phases or sites) more reliably than the three other methods, including NanoString’s commercial package, without diminishing biological variation, especially in long-term longitudinal multiphase or multisite cohorts. We also find that probe sets validated for nCounter, such as the PAM50 gene signature, are impervious to batch issues. This work emphasizes that systematic quality control, normalization and visualization of NanoString nCounter data are an imperative component of study design that influences results in downstream analyses.


Author(s):  
Arjun Bhattacharya ◽  
Alina M. Hamilton ◽  
Helena Furberg ◽  
Eugene Pietzak ◽  
Mark P. Purdue ◽  
...  

ABSTRACTThe NanoString RNA counting assay for formalin-fixed paraffin embedded samples is unique in its sensitivity, technical reproducibility, and robustness for analysis of clinical and archival samples. While commercial normalization methods are provided by NanoString, they are not optimal for all settings, particularly when samples exhibit strong technical or biological variation or where housekeeping genes have variable performance across the cohort. Here, we develop and evaluate a more comprehensive normalization procedure for NanoString data with steps for quality control, selection of housekeeping targets, normalization, and iterative data visualization and biological validation. The approach was evaluated using a large cohort (N = 1,649) from the Carolina Breast Cancer Study, two cohorts of moderate sample size (N = 359 and 130), and a small published dataset (N = 12). The iterative process developed here eliminates technical variation (e.g. from different study phases or sites) more reliably than the three other methods, including NanoString’s commercial package, without diminishing biological variation, especially in long-term longitudinal multi-phase or multi-site cohorts. We also find that probe sets validated for nCounter, such as the PAM50 gene signature, are impervious to batch issues. This work emphasizes that systematic quality control, normalization, and visualization of NanoString nCounter data is an imperative component of study design that influences results in downstream analyses.


Science ◽  
2020 ◽  
Vol 367 (6477) ◽  
pp. 569-573 ◽  
Author(s):  
S. Gulsuner ◽  
D. J. Stein ◽  
E. S. Susser ◽  
G. Sibeko ◽  
A. Pretorius ◽  
...  

Africa, the ancestral home of all modern humans, is the most informative continent for understanding the human genome and its contribution to complex disease. To better understand the genetics of schizophrenia, we studied the illness in the Xhosa population of South Africa, recruiting 909 cases and 917 age-, gender-, and residence-matched controls. Individuals with schizophrenia were significantly more likely than controls to harbor private, severely damaging mutations in genes that are critical to synaptic function, including neural circuitry mediated by the neurotransmitters glutamine, γ-aminobutyric acid, and dopamine. Schizophrenia is genetically highly heterogeneous, involving severe ultrarare mutations in genes that are critical to synaptic plasticity. The depth of genetic variation in Africa revealed this relationship with a moderate sample size and informed our understanding of the genetics of schizophrenia worldwide.


2020 ◽  
Author(s):  
Matt Williams ◽  
Bruce A Jaftha

Despite segments of scepticism, the majority of the general public in most countries believe that climate change is occurring and caused by human activities. Behavioural changes by individuals can reduce greenhouse gas emissions to at least some extent, but a range of psychological and economic barriers can prevent individuals from taking action. A survey of New Zealanders by Aitken, Chapman and McClure (2011) reported that belief in human influence on climate change and the risks of climate change were positively correlated with the probability of taking action on climate change. Conversely, perceptions of powerlessness and the commons dilemma were negatively related to the probability of taking action. Feeling powerless was associated with placing less importance on climate change as an influence on actions. Although Aitken et al’s study has been influential, it was exploratory in nature, had a moderate sample size, was not preregistered, and has not previously been replicated. In this study we report a preregistered replication with a sample of 352 Australians. We were able to reproduce each of the key findings stated above.


Sign in / Sign up

Export Citation Format

Share Document