Single-cell transcriptomics allows researchers to investigate complex communities of heterogeneous cells. It can be applied to stem cells and their descendants in order to chart the progression from ...multipotent progenitors to fully differentiated cells. While a variety of statistical and computational methods have been proposed for inferring cell lineages, the problem of accurately characterizing multiple branching lineages remains difficult to solve.
We introduce Slingshot, a novel method for inferring cell lineages and pseudotimes from single-cell gene expression data. In previously published datasets, Slingshot correctly identifies the biological signal for one to three branching trajectories. Additionally, our simulation study shows that Slingshot infers more accurate pseudotimes than other leading methods.
Slingshot is a uniquely robust and flexible tool which combines the highly stable techniques necessary for noisy single-cell data with the ability to identify multiple trajectories. Accurate lineage inference is a critical step in the identification of dynamic temporal gene expression.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The neutral theory of molecular evolution predicts that the amount of neutral polymorphisms within a species will increase proportionally with the census population size (Nc). However, this ...prediction has not been borne out in practice: while the range of Nc spans many orders of magnitude, levels of genetic diversity within species fall in a comparatively narrow range. Although theoretical arguments have invoked the increased efficacy of natural selection in larger populations to explain this discrepancy, few direct empirical tests of this hypothesis have been conducted. In this work, we provide a direct test of this hypothesis using population genomic data from a wide range of taxonomically diverse species. To do this, we relied on the fact that the impact of natural selection on linked neutral diversity depends on the local recombinational environment. In regions of relatively low recombination, selected variants affect more neutral sites through linkage, and the resulting correlation between recombination and polymorphism allows a quantitative assessment of the magnitude of the impact of selection on linked neutral diversity. By comparing whole genome polymorphism data and genetic maps using a coalescent modeling framework, we estimate the degree to which natural selection reduces linked neutral diversity for 40 species of obligately sexual eukaryotes. We then show that the magnitude of the impact of natural selection is positively correlated with Nc, based on body size and species range as proxies for census population size. These results demonstrate that natural selection removes more variation at linked neutral sites in species with large Nc than those with small Nc and provides direct empirical evidence that natural selection constrains levels of neutral genetic diversity across many species. This implies that natural selection may provide an explanation for this longstanding paradox of population genetics.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Our primary objective was to examine prevalence rates of suicide behavior across 6 gender identity groups: female; male; transgender, male to female; transgender, female to male; transgender, not ...exclusively male or female; and questioning. Our secondary objective was to examine variability in the associations between key sociodemographic characteristics and suicide behavior across gender identity groups.
Data from the Profiles of Student Life: Attitudes and Behaviors survey (
= 120 617 adolescents; ages 11-19 years) were used to achieve our objectives. Data were collected over a 36-month period: June 2012 to May 2015. A dichotomized self-reported lifetime suicide attempts (never versus ever) measure was used. Prevalence statistics were compared across gender identity groups, as were the associations between sociodemographic characteristics (ie, age, parents' highest level of education, urbanicity, sexual orientation, and race and/or ethnicity) and suicide behavior.
Nearly 14% of adolescents reported a previous suicide attempt; disparities by gender identity in suicide attempts were found. Female to male adolescents reported the highest rate of attempted suicide (50.8%), followed by adolescents who identified as not exclusively male or female (41.8%), male to female adolescents (29.9%), questioning adolescents (27.9%), female adolescents (17.6%), and male adolescents (9.8%). Identifying as nonheterosexual exacerbated the risk for all adolescents except for those who did not exclusively identify as male or female (ie, nonbinary). For transgender adolescents, no other sociodemographic characteristic was associated with suicide attempts.
Suicide prevention efforts can be enhanced by attending to variability within transgender populations, particularly the heightened risk for female to male and nonbinary transgender adolescents.
The ionospheric conductance is the major quantity that determines the interaction of the magnetosphere with the ionosphere, where the magnetosphere is the large region of space affected by Earth's ...geomagnetic field, and the ionosphere is its electrically conducting inner boundary, lying right on the edge of the atmosphere. Storms and substorms in space dissipate their energy through ionospheric currents, which heat the atmosphere and disrupt satellite orbits. The ionospheric conductance has, heretofore, been estimated using the staticized physics known as electrostatic theory, which finds that it can be computed by integrating the zero-frequency conductivity along the lines of Earth's geomagnetic field. In this work we test this supposition by deriving an electromagnetic solution for collisional plasma, and applying it to obtain a first-ever fully-electromagnetic calculation of ionospheric conductance. We compare the results to the field line integrated conductivity, and find significant differences on all scales investigated. We find short-wavelength, mode-mixing, and wave-admittance effects that were completely unexpected. When this theoretical result is matched with recent observational findings for the scale of the magnetosphere-ionosphere coupling-interaction, there results a situation where small- to intermediate-scale effects really may contribute to global modeling of the Sun-Earth system.
This study uniquely examined the effects on self, cognition, anxiety, and physiology when iPhone users are unable to answer their iPhone while performing cognitive tasks. A 2 x 2 within‐subjects ...experiment was conducted. Participants (N = 40 iPhone users) completed 2 word search puzzles. Among the key findings from this study were that when iPhone users were unable to answer their ringing iPhone during a word search puzzle, heart rate and blood pressure increased, self‐reported feelings of anxiety and unpleasantness increased, and self‐reported extended self and cognition decreased. These findings suggest that negative psychological and physiological outcomes are associated with iPhone separation and the inability to answer one's ringing iPhone during cognitive tasks. Implications of these findings are discussed.
Found in a diverse set of viral populations, defective interfering particles are parasitic variants that are unable to replicate on their own yet rise to relatively high frequencies. Their presence ...is associated with a loss of population fitness, both through the depletion of key cellular resources and the stimulation of innate immunity. For influenza A virus, these particles contain large internal deletions in the genomic segments which encode components of the heterotrimeric polymerase. Using a library-based approach, we comprehensively profile the growth and replication of defective influenza species, demonstrating that they possess an advantage during genome replication, and that exclusion during population expansion reshapes population composition in a manner consistent with their final, observed, distribution in natural populations. We find that an innate immune response is not linked to the size of a deletion; however, replication of defective segments can enhance their immunostimulatory properties. Overall, our results address several key questions in defective influenza A virus biology, and the methods we have developed to answer those questions may be broadly applied to other defective viruses.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Research confirms that the mental health burdens following community-wide disasters are extensive, with pervasive impacts noted in individuals and families. It is clear that child disaster outcomes ...are worst among children of highly distressed caregivers, or those caregivers who experience their own negative mental health outcomes from the disaster. The current study used path analysis to examine concurrent patterns of parents’ (n = 420) experience from a national sample during the early months of the U.S. COVID-19 pandemic. The results of a multi-group path analysis, organized by parent gender, indicate good fit to the data X
2
(10) = 159.04, p < .01. Results indicate significant linkages between parents’ caregiver burden, mental health, and perceptions of children’s stress; these in turn are significantly linked to child-parent closeness and conflict, indicating possible spillover effects for depressed parents and compensatory effects for anxious parents. The impact of millions of families sheltering in place during the COVID-19 pandemic for an undefined period of time may lead to unprecedented impacts on individuals’ mental health with unknown impacts on child-parent relationships. These impacts may be heightened for families whose caregivers experience increased mental health symptoms, as was the case for fathers in the current sample.
Abstract
This study incorporated the dual-motivational theory with psychological reactance theory to investigate the cognitive and emotional responses that unfold when audience members encounter a ...freedom-threatening message and experience psychological reactance. A total of 100 college-aged, daily e-cigarette users were purposively recruited and randomly assigned to view four, 30-second anti-vaping public service announcements (PSAs) in random presentation featuring either dogmatic or suggestive language. As expected, daily e-cigarette users in the dogmatic anti-vaping PSA condition self-reported greater unpleasantness, freedom threat, psychological reactance, and behavioral intentions to use e-cigarettes than daily e-cigarette users in the suggestive anti-vaping PSA condition. Daily e-cigarette users in the dogmatic anti-vaping PSA condition also had greater defensive motivational reactivity during message exposure as indicated by greater corrugator muscle activation, skin conductivity levels, and less heart rate deceleration than daily e-cigarette users in the suggestive anti-vaping PSA condition. Taken together, this study provides substantial evidence of the psychophysiological and defensive nature of psychological reactance theory.
Abstract
Methods for jointly estimating both the size-specific relative retention and absolute retention (retention probability) of two experimental trawl gears are considered. One approach would be ...to undertake comparative fishing of both gears, from which their comparative catchability can be estimated directly. If comparative catchability can be corrected for differing sampling effort and fishing efficiency of the two gears, then relative retention can be estimated. Furthermore, if a suitable functional form of the absolute retention curve is assumed, then estimates of absolute retention can potentially be obtained. However, these estimated retention curves are seen to have extremely large statistical variability and will not be useful in practice. On the other hand, if the gears are each fished with a non-selective control, then absolute retention can be directly estimated, from which estimates of relative retention can immediately be obtained. However, these estimates of relative retention have greater variability than would be obtained by comparative fishing with the same level of sampling effort. It is shown that a hybrid selectivity design that includes both comparative fishing of the experimental trawls and fishing with a non-selective control provides a more balanced approach. An extensive simulation study is conducted using scenarios based on recently published work on selectivity experiments targeting cod (Gadus Morhua) and hoki/blue grenadier (Macruronus novaezelandiae).
Abstract This study examined associations among depression, suicidal behaviors, and bullying and victimization experiences in 1491 high school students using data from the 2009 Youth Risk Behavior ...Survey. Results demonstrated that depression mediated the association between bullying/victimization and suicide attempts, but differently for males and females. Specifically, depression mediated the link between traditional victimization and suicide attempts similarly across gender, whereas depression mediated the link between cyber victimization and suicide attempts only for females. Similarly, depression mediated the link between traditional bullying and suicide attempts for females only. Depression did not mediate the link between cyberbullying and suicide attempts for either gender. Implications of the findings are discussed, including the importance of greater detection of depression among students involved in bullying, and the need for a suicide prevention and intervention component in anti-bullying programs. Findings suggest that bullying prevention efforts be extended from middle school students to include high school students.
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