Spatiotemporal Variability in the Macroinvertebrate Community of a Small Coastal California Stream, Little Creek, Davenport, California

Macroinvertebrate community structure was characterized along the channel gradient of a headwater stream in a coast redwood forest on Cal Poly’s Swanton Pacific Ranch in Davenport, California. The significance of physical habitat characteristics in describing macroinvertebrate assemblage structure was assessed in an effort to create a framework to better understand the expected biological response to riparian canopy manipulation. Seven study reaches were established in 2015. These study reaches were evenly spaced throughout the Little Creek watershed, an approximately 4.8 km2 drainage characterized by steep inner-gorge areas and dense riparian vegetation. Macroinvertebrate samples were collected seasonally (i.e., spring, summer, and fall) during 2015 and 2016 using the Reachwide Benthos procedure described by the Surface Water Ambient Monitoring Program’s bioassessment protocol and all captured organisms were identified at family level taxonomic resolution. Non-metric multidimensional scaling (NMDS) and Analysis of Variance (ANOVA) procedures were performed to describe longitudinal patterns in community composition and determine the significance of collected environmental variables as predictors of community structure. The majority of taxa collected belonged to the orders Ephemeroptera, Plecoptera, Trichoptera, and Diptera. Macroinvertebrate density and biomass were significantly associated with study reach, with relatively depauperate macroinvertebrate assemblages occurring in the upper study reaches and significantly larger, more diverse assemblages in the lower study reaches. Significantly higher density and biomass was observed during the summer sample period across all sites. A clear site level separation was observed at the South Fork study reaches where significantly higher abundances of Diptera taxa colonized the primarily bedrock channel at those sites. The most diverse and pollution-intolerant assemblages were observed in riffle habitat types. Stream shading and solar radiation were not significantly associated with any macroinvertebrate community metric examined, making it difficult to predict instream response to a riparian canopy manipulation. However, trophic interactions that influence secondary production in the study reaches could be inferred based on temporal patterns in feeding guild composition; the relative abundance of shredder taxa coincided with seasonal detrital inputs indicating that food webs largely depended on allochthonous energy sources. Therefore, there is significant opportunity for further investigation of energy production and utilization in the study reaches to guide riparian canopy management practices toward enhancing key trophic interactions. This study provides an extensive and novel biological baseline for macroinvertebrate communities in Little Creek

Effects of Presenting Normative Alcohol Data on Perceptions of College Drinking Behavior

Alcohol abuse, often in the form of binge drinking, is a problem that every college campus faces. Many researchers suggest that students believe that their peers drink more alcohol than is actually true, and use such a perception as a justification to drink more alcohol than should be consumed (Perkins, Haines, & Rice, 2005). The purpose of this study is to understand whether presenting normative information on drinking behavior among college students in two different ways (focus on heavy drinking or focus on abstinence) has an effect on the perceptions of drinking behavior

Fostering a Fourth Democratic Wave: A Playbook for Countering the Authoriarian Threat

Fostering a Fourth Democratic Wave is a joint project between the Atlantic Council and the International Center on Nonviolent Conflict (ICNC), aimed at catalyzing support for nonviolent pro-democracy movements fighting against authoritarian rule. The project recognizes that civil resistance movements—using tactics such as strikes, boycotts, civil disobedience, and a range of other nonviolent tactics—are one of the most powerful forces for democracy worldwide and therefore central to reversing the last seventeen years of democratic recession

Refinement 0f animal experimentation techniques

The implementation of the «3 R» rule (Replace – Reduce – Refine) is a major component of the animal experimentation. Originally presented or perceived as a contribution to ethical values and animal welfare, it is also highly synergic with the studies’ scientific objectives. This paper aims at illustrating the «R» of «Refinement» i.e. the optimisation of studies, focusing on its technical aspects.La mise en application de la règle des « 3 R » (Replace - Reduce - Refine) est une composante essentielle de l'expérimentation animale. Initialement présentée ou perçue comme une contribution aux valeurs éthiques et au respect de l'animal, elle apparaît également comme fortement synergique avec les objectifs scientifiques des études. Cet article vise à illustrer le R de « Refinement», c'est-à-dire l'optimisation des études, en étant focalisé sur ses aspects techniques

Fraternity as “Enabling Environment:” Does Membership Lead to Gambling Problems?

Researchers have suggested that fraternity membership is the most reliable predictor of gambling and gambling problems on campus. The purpose of this study was to determine if problematic gambling could be linked to specific aspects of fraternity membership. Though the null hypothesis (no enabling environment) failed to be rejected, descriptive analysis confirms that moderate rates of problem gambling are exhibited by subsets of fraternity members (officers, younger members, those who live with other members). Further, predictive analysis revealed that gambling online and betting on skill games, such as golf or pool, increased the likelihood of problem gambling among fraternity members. Recommendations included a discussion of initiatives at another campus, as well as action steps for developing education and awareness programs

Counting hidden neural networks

We apply combinatorial tools, including P´olya’s theorem, to enumerate all possible networks for which (1) the network contains distinguishable input and output nodes as well as partially distinguishable intermediate nodes; (2) all connections are directed and for each pair of nodes, there are at most two connections, that is, at most one connection per direction; (3) input nodes send connections but don’t receive any, while output nodes receive connections but don’t send any; (4) every intermediate node receives a path from an input node and sends a path to at least one output node; and (5) input nodes don’t send direct connections to output nodes. We first obtain the generating function for the number of such networks, and then use it to obtain precise estimates for the number of networks. Finally, we develop a computer algorithm that allows us to generate these networks. This work could become useful in the field of neuroscience, in which the problem of deciphering the structure of hidden networks is of the utmost importance, since there are several instances in which the activity of input and output neurons can be directly measured, while no direct access to the intermediate network is possible. Our results can also be used to count the number of finite automata in which each cell plays a relevant role

Long-term effects of satellite megaconstellations on the debris environment in low earth orbit

This thesis examines the potential long-term impacts of satellite megaconstellations in Low Earth Orbit, with a focus on how post-mission disposal rates for megaconstellations will affect their contributions to orbital debris over the next 150 years. A new, medium-fidelity simulation for modeling orbital debris is developed and described, and several test cases are run with SpaceX’s Starlink megaconstellation and varying success rates for post-mission disposal. In cases where Starlink’s post-mission disposal rate is insufficient to prevent debris growth, varying amounts of active debris removal are explored as a potential mitigation measure. It is shown that LEO debris levels will grow at almost double their baseline rate if Starlink meets only the minimum regulatory requirements for post-mission disposal, and even relatively high rates of active debris removal cannot always return the LEO environment to its non-megaconstellation baseline. Still, the potential exists to minimize the debris-generating effects of large megaconstellations like Starlink if post-mission disposal rates of 95% or better can be achieved

Car harm:A global review of automobility’s harm to people and the environment

Despite the widespread harm caused by cars and automobility, governments, corporations, and individuals continue to facilitate it by expanding roads, manufacturing larger vehicles, and subsidising parking, electric cars, and resource extraction. This literature review synthesises the negative consequences of automobility, or car harm, which we have grouped into four categories: violence, ill health, social injustice, and environmental damage. We find that, since their invention, cars and automobility have killed 60–80 million people and injured at least 2 billion. Currently, 1 in 34 deaths are caused by automobility. Cars have exacerbated social inequities and damaged ecosystems in every global region, including in remote car-free places. While some people benefit from automobility, nearly everyone—whether or not they drive—is harmed by it. Slowing automobility’s violence and pollution will be impracticable without the replacement of policies that encourage car harm with policies that reduce it. To that end, the paper briefly summarises interventions that are ready for implementation