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2021 ◽  
Vol 6 ◽  
Author(s):  
Séverin Lions ◽  
Carlos Monsalve ◽  
Pablo Dartnell ◽  
María Inés Godoy ◽  
Nora Córdova ◽  
...  

Middle bias has been reported for responses to multiple-choice test items used in educational assessment. It has been claimed that this response bias probably occurs because test developers tend to place correct responses among middle options, tests thus presenting a middle-biased distribution of answer keys. However, this response bias could be driven by strong distractors being more frequently located among middle options. In this study, the frequency of responses to a Chilean national examination used to rank students wanting to access higher education was used to categorize distractors based on attractiveness level. The distribution of different distractor types (best distractor, non-functioning distractors…) was analyzed across 110 tests of 80 five-option items administered to assess several disciplines in five consecutive years. Results showed that the strongest distractors were more frequently found among middle options, most commonly at option C. In contrast, the weakest distractors were more frequently found at the last option (E). This pattern did not substantially vary across disciplines or years. Supplementary analyses revealed that a similar position bias for distractors could be observed in tests administered in countries other than Chile. Thus, the location of different types of distractors might provide an alternative explanation for the middle bias reported in literature for tests’ responses. Implications for test developers, test takers, and researchers in the field are discussed.


2021 ◽  
Author(s):  
Noah Tjiang ◽  
Hans Zempel

Abstract Loss of neuronal polarity and missorting of the axonal microtubule-associated protein TAU are hallmarks of Alzheimer’s disease (AD) and related tauopathies. Impairment of mitochondrial function is causative for various neurogenetic mitochondriopathies, but the role of mitochondria in tauopathies and in axonal TAU-sorting is still unclear. The axon initial segment (AIS) is vital for maintaining neuronal polarity and proper sorting of TAU. Here, we aimed to investigate the role of mitochondria in the AIS regarding the maintenance of TAU polarity. Using global mitochondria impairment, but also live-cell-imaging and photoactivation methods, we specifically tracked and selectively impaired mitochondria in the AIS in primary mouse and human iPSC-derived neurons, and measured the subsequent missorting of TAU. We observed that global application of mitochondrial toxins efficiently induced tauopathy-like missorting, indicating involvement of mitochondria in TAU polarity. Mitochondria show a biased distribution within the AIS, with a proximal cluster and relative absence in the central AIS. The mitochondria of this cluster are largely immobile and only sparsely participate in axonal mitochondria-trafficking. Locally constricted impairment of only the AIS-mitochondria-cluster leads to detectable increases of somatic TAU, reminiscent of AD-like TAU-missorting. Here, we provide first evidence that the mitochondrial distribution within the proximal axon is biased towards the proximal AIS and that proper function of this newly described mitochondrial cluster may be essential for the maintenance of TAU neuronal polarity. This strengthens the role of mitochondrial impairment as an upstream event and therapeutic target in the pathological cascade leading to TAU missorting and consequent neuronal dysfunction.


2021 ◽  
Vol 912 (2) ◽  
pp. L24
Author(s):  
Rieko Momose ◽  
Kazuhiro Shimasaku ◽  
Kentaro Nagamine ◽  
Ikkoh Shimizu ◽  
Nobunari Kashikawa ◽  
...  
Keyword(s):  

Author(s):  
Rashid A. Ganaie ◽  
V. Rajagopalan

In this Paper, we have introduced a new version of new quasi lindley distribution known as the length-biased weighted new quasi lindley distribution (LBWNQLD). Length biased distribution is a special case of weighted distribution. The different structural properties of the newly proposed distribution are derived and the model parameters are estimated by using the method of maximum likelihood estimation and also the Fisher’s information matrix have been discussed. Finally, applications to real life two data sets are presented for illustration.


Viruses ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1270 ◽  
Author(s):  
Léo Blanca ◽  
Eugène Christo-Foroux ◽  
Sofia Rigou ◽  
Matthieu Legendre

Marseilleviridae members are large dsDNA viruses with icosahedral particles 250 nm in diameter infecting Acanthamoeba. Their 340 to 390 kb genomes encode 450 to 550 protein-coding genes. Since the discovery of marseillevirus (the prototype of the family) in 2009, several strains were isolated from various locations, among which 13 are now fully sequenced. This allows the organization of their genomes to be deciphered through comparative genomics. Here, we first experimentally demonstrate that the Marseilleviridae genomes are circular. We then acknowledge a strong bias in sequence conservation, revealing two distinct genomic regions. One gathers most Marseilleviridae paralogs and has undergone genomic rearrangements, while the other, enriched in core genes, exhibits the opposite pattern. Most of the genes whose protein products compose the viral particles are located in the conserved region. They are also strongly biased toward a late gene expression pattern. We finally discuss the potential advantages of Marseilleviridae having a circular genome, and the possible link between the biased distribution of their genes and the transcription as well as DNA replication mechanisms that remain to be characterized.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Masumi Hasegawa ◽  
Toshiaki Hosaka ◽  
Keiichi Kojima ◽  
Yosuke Nishimura ◽  
Yu Nakajima ◽  
...  

Abstract Microbial rhodopsin is a photoreceptor protein found in various bacteria and archaea, and it is considered to be a light-utilization device unique to heterotrophs. Recent studies have shown that several cyanobacterial genomes also include genes that encode rhodopsins, indicating that these auxiliary light-utilizing proteins may have evolved within photoautotroph lineages. To explore this possibility, we performed a large-scale genomic survey to clarify the distribution of rhodopsin and its phylogeny. Our surveys revealed a novel rhodopsin clade, cyanorhodopsin (CyR), that is unique to cyanobacteria. Genomic analysis revealed that rhodopsin genes show a habitat-biased distribution in cyanobacterial taxa, and that the CyR clade is composed exclusively of non-marine cyanobacterial strains. Functional analysis using a heterologous expression system revealed that CyRs function as light-driven outward H+ pumps. Examination of the photochemical properties and crystal structure (2.65 Å resolution) of a representative CyR protein, N2098R from Calothrix sp. NIES-2098, revealed that the structure of the protein is very similar to that of other rhodopsins such as bacteriorhodopsin, but that its retinal configuration and spectroscopic characteristics (absorption maximum and photocycle) are distinct from those of bacteriorhodopsin. These results suggest that the CyR clade proteins evolved together with chlorophyll-based photosynthesis systems and may have been optimized for the cyanobacterial environment.


2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Nao Sasano ◽  
Yoichi Katsumata ◽  
Hiroki Nakata

Abstract Background The mechanisms underlying the relative age effect (RAE), a biased distribution of birth dates, in sport events have been investigated for more than two decades. The present study comprised an historical analysis involving the most recent quarter-century (1993–2018) on RAEs among Japanese male professional athletes (soccer, baseball, basketball, and volleyball) to clarify how the RAEs changed over time. Methods Birth data were obtained from 7805 Japanese male professional athletes registered in 1993, 2001, 2010, and 2018. The athletes were divided into four groups based on their month of birth: quartiles Q1 (April–June), Q2 (July–September), Q3 (October–December), and Q4 (January–March of the following year). In addition, based on the data in 1993 for soccer and baseball and in 2010 for basketball and volleyball, the expected numbers of players were calculated in 2001, 2010, and 2018 for soccer and baseball, and 2018 for basketball and volleyball. Results Significant RAEs were observed among soccer and baseball players in 1993, 2001, 2010, and 2018, and strong tendencies of RAEs were found among basketball and volleyball players in 2010 and 2018. The magnitudes of the RAEs in soccer, baseball, and volleyball decreased over time, but not in basketball. Conclusion The exact reasons for the decreasing or unchanging RAEs among these professional players remain unclear, but socio-cultural factors, such as low birthrates and the popularity of sports in Japan, might be related to the changing RAEs.


2020 ◽  
Author(s):  
Nao Sasano ◽  
Yoichi Katsumata ◽  
Hiroki Nakata

Abstract Background: The mechanisms underlying the relative age effect (RAE), a biased distribution of birth dates, in sport events have been investigated for more than two decades. The present study comprised an historical analysis involving the most recent quarter-century (1993-2018) on RAEs among Japanese male professional athletes (soccer, baseball, basketball, and volleyball) to clarify how the RAEs changed over time.Methods: Birth data were obtained from 7,805 Japanese male professional athletes registered in 1993, 2001, 2010, and 2018. The athletes were divided into four groups based on their month of birth: quartiles Q1 (April–June), Q2 (July–September), Q3 (October–December), and Q4 (January–March of the following year). In addition, based on the data in 1993 for soccer and baseball and in 2010 for basketball and volleyball, the expected numbers of players were calculated in 2001, 2010, and 2018 for soccer and baseball, and 2018 for basketball and volleyball.Results: Significant RAEs were observed among soccer and baseball players in 1993, 2001, 2010, and 2018, and strong tendencies of RAEs were found among basketball and volleyball players in 2010 and 2018. The magnitudes of the RAEs in soccer, baseball, and volleyball decreased over time, but not in basketball.Conclusion: The exact reasons for the decreasing or unchanging RAEs among these professional players remains unclear, but socio-culture factors, such as low birthrates and the popularity of sports in Japan, might be related to the changing RAEs.


2020 ◽  
Author(s):  
Nao Sasano ◽  
Yoichi Katsumata ◽  
Hiroki Nakata

Abstract Background: The mechanisms underlying the relative age effect (RAE), a biased distribution of birth dates, in sport events have been investigated for more than two decades. The present study comprised an historical analysis involving the most recent quarter-century (1993-2018) on RAEs among Japanese male professional athletes (soccer, baseball, basketball, and volleyball) to clarify how the RAEs changed over time. Methods: Birth data were obtained from 7,805 Japanese male professional athletes registered in 1993, 2001, 2010, and 2018. The athletes were divided into four groups based on their month of birth: quartiles Q1 (April–June), Q2 (July–September), Q3 (October–December), and Q4 (January–March of the following year). In addition, based on the data in 1993 for soccer and baseball and in 2010 for basketball and volleyball, the expected numbers of players were calculated in 2001, 2010, and 2018 for soccer and baseball, and 2018 for basketball and volleyball. Results: Significant RAEs were observed among soccer and baseball players in 1993, 2001, 2010, and 2018, and strong tendencies of RAEs were found among basketball and volleyball players in 2010 and 2018. The magnitudes of the RAEs in soccer, baseball, and volleyball decreased over time, but not in basketball. Conclusion: The exact reasons for the decreasing or unchanging RAEs among these professional players remains unclear, but socio-culture factors, such as low birthrates and the popularity of sports in Japan, might be related to the changing RAEs.


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