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Response of ecosystem intrinsic water use efficiency and gross primary productivity to rising vapor pressure deficit
No full textElevated vapor pressure deficit (VPD) due to drought and warming is well-known to limit canopy stomatal and surface conductance, but the impacts of elevated VPD on ecosystem gross primary productivity (GPP) are less clear. The intrinsic water use efficiency (iWUE), defined as the ratio of carbon (C) assimilation to stomatal conductance, links vegetation C gain and water loss and is a key determinant of how GPP will respond to climate change. While it is well-established that rising atmospheric CO2 increases ecosystem iWUE, historic and future increases in VPD caused by climate change and drought are often neglected when considering trends in ecosystem iWUE. Here, we synthesize long-term observations of C and water fluxes from 28 North American FLUXNET sites, spanning eight vegetation types, to demonstrate that ecosystem iWUE increases consistently with rising VPD regardless of changes in soil moisture. Another way to interpret this result is that GPP decreases less than surface conductance with increasing VPD. We also project how rising VPD will impact iWUE into the future. Results vary substantially from one site to the next; in a majority of sites, future increases in VPD (RCP 8.5, highest emission scenario) are projected to increase iWUE by 5%–15% by 2050, and by 10%–35% by the end of the century. The increases in VPD owing to elevated global temperatures could be responsible for a 0.13% year^−1 increase in ecosystem iWUE in the future. Our results highlight the importance of considering VPD impacts on iWUE independently of CO2 impacts
Psychology and morality of political extremists: evidence from Twitter language analysis of alt-right and Antifa
No full textThe recent rise of the political extremism in Western countries has spurred renewed interest in the psychological and moral appeal of political extremism. Empirical support for the psychological explanation using surveys has been limited by lack of access to extremist groups, while field studies have missed psychological measures and failed to compare extremists with contrast groups. We revisit the debate over the psychological and moral appeal of extremism in the U.S. context by analyzing Twitter data of 10,000 political extremists and comparing their text-based psychological constructs with those of 5000 liberal and 5000 conservative users. The results reveal that extremists show a lower positive emotion and a higher negative emotion than partisan users, but their differences in certainty is not significant. In addition, while left-wing extremists express more language indicative of anxiety than liberals, right-wing extremists express lower anxiety than conservatives. Moreover, our results mostly lend support to Moral Foundations Theory for partisan users and extend it to the political extremists. With the exception of ingroup loyalty, we found evidences supporting the Moral Foundations Theory among left- and right-wing extremists. However, we found no evidence for elevated moral foundations among political extremists
Climate Change Marches as Motivators for Bystander Collective Action
No full textPolitical marches are one of the most public and vocal means of engaging in collective action and can potentially build social movements by increasing the likelihood that bystanders become engaged with the social movement. Here, we conduct a trend study to test the impacts of two back-to-back highly visible large-scale climate change related marches on bystanders, targeting psychological drivers of collective action: efficacy beliefs, perceptions of others’ climate change activism and concerns, impressions of marchers, and behavioral intentions. Participants either completed a survey the day before the March for Science (n = 302) or several days after the People’s Climate March, which occurred a week after the first march (n = 285). Results suggest that the marches were at least partially effective: bystanders’ (a) collective efficacy beliefs and (b) impressions of marchers improved after the march. In contrast, marches were ineffective in increasing perceptions of others’ engagement with concern about climate change. We anticipated that political leaning of bystanders’ news sources would moderate effects of marches. Unexpectedly, collective efficacy beliefs improved among consumers of conservative, but not liberal, news. This unanticipated result is consistent with the notion that conservative news sources dedicated less coverage than liberal news sources to the marches prior to the marches (potentially leading to lower collective efficacy among those who consumed these sources), but that coverage afterwards was more equal across ideological bias of news sources. We also found that the more conservative the news sources consumed by an individual, the more negative impressions they had of marchers, and this relation was strongest among those that indicated, after the marches, that they had heard about the marches. These results on impressions are consistent with the notion that, when marches were covered, conservative news sources portrayed marchers relatively more negatively than liberal news sources. Overall, results suggest that marches can increase the likelihood that bystanders will participate in social movements via changes in psychological drivers of participation and the effects will likely depend upon political leanings of news sources via both whether sources mention the marches and how the sources cover the marches
A computational model of context-dependent encodings during category learning
No full textAlthough current exemplar models of category learning are flexible and can capture how different features are emphasized for different categories, they still lack in the flexibility to adapt to local pressures in category learning, such as the effect of different sequences of study. In this paper we introduce a new model of category learning, the Sequential Attention Theory Model (SAT-M), in which the encoding of each presented item is influenced not only by its category assignment (global context) as in other exemplar models, but also by how its properties relate to the properties of temporally neighboring items (local context). We demonstrate that SAT-M is able to capture the effect of local context and predict not only learning but also learners’ attentional patterns during learning
Congregational involvement in HIV: A qualitative comparative analysis of factors influencing HIV activity among diverse urban congregations
No full textReligious congregations can potentially reach disproportionately affected populations with HIV programming, however, factors that influence congregational involvement in HIV are not well-studied. Utilizing comparative case methods and in-depth qualitative data from a diverse sample of 14 urban congregations, we examine a range of attitudinal, organizational, resource, and demographic factors to systematically identify different case scenarios-i.e., combinations of characteristics-associated with the level and types of HIV activities in which the congregational cases tended to be involved. For example, White or mixed race congregations with active gay constituencies and an African-American congregation with a strong lay HIV champion were among the high HIV involvement case scenarios, compared to African-American congregations with a health emphasis but no lay HIV champion among the medium HIV involvement scenarios, and fundamentalist African-American and Latino congregations among the low HIV involvement scenarios. Two key factors that appeared influential across case scenarios included the existence of lay champions for HIV activities and the general theological orientation of the congregation
How to train a mouse-methodological issues in pre-clinical exercise oncology
No full textWe point at several challenges that current exercise oncology rodent models face, which call their human-relevance into question: the vast majority of pre-clinical studies in exercise oncology treat “physical exercise” as a primitive concept without further analysis or qualification, and their results are based on dosages that no human can endure. The lack of analysis and qualification together with the dosage mismatch conceal the fact that rodents do not run like humans. Consequently, while these pre-clinical studies may yield insights into potential biological mechanisms underlying the systemic effects of physical exercise on cancer, the applicability of this knowledge to preventive interventions in healthy humans and the ability to translate it to practical therapies in the critically ill remain limited. We propose an alternative exercise rodent model that has better chances of meeting these challenges
Repetitive Head Impact Exposure in College Football Following an NCAA Rule Change to Eliminate Two-A-Day Preseason Practices: A Study from the NCAA-DoD CARE Consortium
No full textRepetitive head impact exposure sustained by athletes of contact sports has been hypothesized to be a mechanism for concussion and a possible explanation for the high degree of variability in sport-related concussion biomechanics. In an attempt to limit repetitive head impact exposure during the football preseason, the NCAA eliminated two-a-day practices in 2017, while maintaining the total number of team practice sessions. The objective of this study was to quantify head impact exposure during the preseason and regular season in Division I college football athletes to determine whether the 2017 NCAA ruling decreased head impact exposure. 342 unique athletes from five NCAA Division I Football Bowl Subdivision (FBS) programs were consented and enrolled. Head impacts were recorded using the Head Impact Telemetry (HIT) System during the entire fall preseasons and regular seasons in 2016 and 2017. Despite the elimination of two-a-day practices, the number of preseason contact days increased in 2017, with an increase in average hourly impact exposure (i.e., contact intensity), resulting in a significant increase in total head impact burden (+ 26%) for the 2017 preseason. This finding would indicate that the 2017 NCAA ruling was not effective at reducing the head impact burden during the football preseason. Additionally, athletes sustained a significantly higher number of recorded head impacts per week (+ 40%) during the preseason than the regular season, implicating the preseason as a time of elevated repetitive head impact burden. With increased recognition of a possible association between repetitive head impact exposure and concussion, increased preseason exposure may predispose certain athletes to a higher risk of concussion during the preseason and regular season. Accordingly, efforts at reducing concussion incidence in contact sports should include a reduction in overall head impact exposure
Neural correlates of emotion processing comparing antidepressants and exogenous oxytocin in postpartum depressed women: An exploratory study
No full textDespite common use of antidepressants to treat postpartum depression, little is known about the impact of antidepressant use on postpartum brain activity. Additionally, although oxytocin has been investigated as a potential treatment for postpartum depression, the inter- action between antidepressants and exogenous oxytocin on brain activity is unknown. We explored postpartum depressed women’s neural activation in areas identified as important to emotion and reward processing and potentially, antidepressant response: the amygdala, nucleus accumbens and ventral tegmental area. We conducted a secondary analysis of a functional imaging study of response to sexual, crying infant and smiling infant images in 23 postpartum depressed women with infants under six months (11 women taking antidepres- sants, 12 unmedicated). Participants were randomized to receive a single dose of oxytocin or placebo nasal spray. There was significantly higher amygdala activation to sexual stimuli than either neutral or infant-related stimuli among women taking antidepressants or receiv- ing oxytocin nasal spray. Among unmedicated women receiving placebo, amygdala activa- tion was similar across stimuli types. There were no significant effects of antidepressants nor oxytocin nasal spray on reward area processing (i.e., in the nucleus accumbens or ven- tral tegmental area). Among postpartum women who remain depressed, there may be sig- nificant interactions between the effects of antidepressant use and exogenous oxytocin on neural activity associated with processing emotional information. Observed effect sizes were moderate to large, strongly suggesting the need for further replication with a larger sample
Mammography Social Support for Women Living in a Midwestern City: Toward Screening Promotion via Social Interactions
No full textNotwithstanding recommendations and interventions, the percentage of 50 – 74-year-old U.S. women who reported having had a mammography in the past two years remained below target coverage. Social interactions may influence mammography rates. To measure characteristics of social interactions in a Midwestern city as they relate to social support for mammography received by women older than 40 years of age. A cross-sectional study was conducted in Bloomington, Indiana, sending mail surveys to 3,000 telephone directory addresses selected by simple random sampling. An anonymous, self-administered, closed-ended, questionnaire with eight checklist items (for demographics) and six multipart semantic differential scale items (for social support), derived from validated instruments, was used. Social support for mammography in women who had undergone regular screening was analyzed using chi-square test and logistic regression. Of 450 respondents with valid responses, 91% were white; 47% were older than 80; 92% had good health insurance coverage; and 82% had undergone regular mammography. Healthcare workers provided the highest support, followed by children, siblings, and relatives. Friends, neighbors, and co-workers were least supportive. In social interactions, emotional support was the most prominent, followed by informational, appraisal, and instrumental supports. Having higher income and being married were associated with receiving greater support. Although mammography provides limited benefits after age 74, women older than 80 years of age received the highest support. Identifying the structural and functional characteristics of social interactions is important for: 1) designing interventions that enhance social support, and 2) expanding breast cancer screening via personalized approaches using existing social interactions
