2,273 research outputs found
A Comparison of Fish Communities in Southwestern Lake Ontario Tributaries From One Century Ago
I evaluated a study performed by Albert Hazen Wright between 1902 and 1904, on the Tributaries of Lake Ontario in Monroe County, NY. I extracted data from Wright\u27s original graphical analysis, and analyzed these data with Canonical Correspondence Analysis (CCA), to assess the value of these data for use as historical benchmarks for future studies on the same tributaries. Wright identified 52 species of fish within his distribution diagrams, eight of the species were rare species and were not analyzed with the CCA. Of the 44 remaining species analyzed, 37 matched very well between Wright\u27s interpretations of his data, and the results of my analysis. Six species were a partial match, and one, the Tessellated Darter (Etheostoma olmstedi), was considered a subspecies and was not interpreted by Wright. Overall, Wright\u27s interpretations matched well with my analysis of his data, and corresponded well with current understandings of the species x species and species x habitat relationships within a stream continuum from more recent studies. Wright\u27s data set and interpretations proved to be accurate, and a valuable historical reference. I then examined these same tributaries for current fish populations, using a point-transect methodology and a combination of haul seine and dip nets to sample each macro-habitat (pool, riffle, run) present at each site. I found a total of 34 species of fish, three fewer than Wright\u27s 37 species, within the same segments of these streams. Of the 34 species I found, eight were species Wright did not find. Introductions of native and non-native invasive species appeared to greatly influence the habitat associations of some species. I found that the habitat parameters river mile, depth, width and vegetation, had the greatest influence on fish distribution
'A Metamorphosed Language': Tracing Language Attitudes Towards Lubumbashi Swahili and French in the DRC
Language attitudes in Lubumbashi, and particularly towards Lubumbashi Swahili and French, are not only indicative of positive, negative, and ambivalent feelings towards vocabulary or syntax, but of larger socio-historical and current developments, too. These attitudes, however, have not been explicitly researched. This paper seeks to begin filling that void, examining three intertwined hypotheses grounded in the language attitudes seen across Sub-Saharan Africa: (1) languages have historically been regarded ambivalently, and will continue to be held in such regard, but also that; (2) Lubumbashi Swahili has become an indispensable tool for survival in the city and that; (3) French remains an important tool for social mobility. Building off the limited scholarship on historic attitudes, my fieldwork conducted in Lubumbashi in July 2022 confirms these hypotheses, giving a fuller indication of how locals and settlers felt and continue to feel about languages as they relate to the now modernised society of Lubumbashi
Microfascism in the 21st Century: Finding a Way Forward through Deleuze’s Immanent Theory of Desire
This paper takes a critical examination at selected works by 20th century philosophers Gilles Deleuze and Félix Guattari. I argue that, far from arcane, distant, inaccessible concepts, the selected Marxist ideas presented in their immanent critiques provide priceless insight into how fascism, in all forms, permeates every stretch of society. Understanding how these events occur, called micro- and macro-fascism, and how they are mediated through our beliefs and desires, can allow for us to resist transcendent theories of desire and modes and politics, and towards a mode of immanence, one that is always critiquing itself, and always resisting fascism
The Lyot Project Direct Imaging Survey of Substellar Companions: Statistical Analysis and Information from Nondetections
The Lyot project used an optimized Lyot coronagraph with Extreme Adaptive
Optics at the 3.63m Advanced Electro-Optical System telescope (AEOS) to observe
86 stars from 2004 to 2007. In this paper we give an overview of the survey
results and a statistical analysis of the observed nondetections around 58 of
our targets to place constraints on the population of substellar companions to
nearby stars. The observations did not detect any companion in the substellar
regime. Since null results can be as important as detections, we analyzed each
observation to determine the characteristics of the companions that can be
ruled out. For this purpose we use a Monte Carlo approach to produce artificial
companions, and determine their detectability by comparison with the
sensitivity curve for each star. All the non-detection results are combined
using a Bayesian approach and we provide upper limits on the population of
giant exoplanets and brown dwarfs for this sample of stars. Our nondetections
confirm the rarity of brown dwarfs around solar-like stars and we constrain the
frequency of massive substellar companions (M>40Mjup) at orbital separation
between and 10 and 50 AU to be <20%.Comment: 32 pages, 11 figures, 2 tables. Published in the Astrophysical
Journa
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Cointegration: A tool for Ecosystem-Based Conservation and Management of Fisheries
Species within marine ecosystems are known to be interconnected. This is
a result of many factors including predation and competition for resources.
Despite this, many fisheries are still managed using a single species
framework. This paper uses cointegration analysis to quantify the
relationship between different fish species. Cointegration is a method for
examining how time series variables that are integrated (e.g., I(0) or long
memory fractional) and move together. Using data from Northern
Anchovy, Pacific Sardines, and Albacore Tuna off the California coast, a
vector error correction model is estimated which shows a statistically
significant relationship between anchovy and tuna harvests. Results suggest
financial gains from accounting for external effects between these two
fisheries and provide an economic justification for ecosystem based
management.Keywords: Environmental, Ecological and Economic Considerations in the Conservation and Management of Forage Fish, Fisheries Economics, Fishery Managemen
Development of a Coherent Doppler Lidar for Precision Maneuvering and Landing of Space Vehicles
A coherent Doppler lidar has been developed to address NASAs need for a high-performance, compact, and cost-effective velocity and altitude sensor onboard its landing vehicles. Future robotic and manned missions to planetary bodies require precise ground-relative velocity vector and altitude data to execute complex descent maneuvers and safe, soft landing at a pre-designated site. This lidar sensor, referred to as a Navigation Doppler Lidar, meets the required performance of landing missions while complying with vehicle size, mass, and power constraints. Operating from over five kilometers altitude, the lidar obtains velocity and range precision measurements with 2 cm/sec and 2 meters, respectively, dominated by the vehicle motion. After a series of flight tests onboard helicopters and rocket-powered free-flyer vehicles, the Navigation Doppler Lidar is now being ruggedized for future missions to various destinations in the solar system
Distribution and Ecology of Invasive Ants
This project examines exactly how invasive specific types of ants are, and what effect that has on the ecosystem. To do so, most of the research must be compiled for the first time, as there is a lack of knowledge and research on this subject. Through former research, Tillberg finds that there are invasive pavement ants in Oregon state parks, but due to a lack of research on the species, their impact is unknown. The research will follow a paired design, comparing similar areas with and without pavement ants, to discover what differences this invasive species has on habitats
Distribution and Ecology of Invasive Ants
This project examines exactly how invasive specific types of ants are, and what effect that has on the ecosystem. To do so, most of the research must be compiled for the first time, as there is a lack of knowledge and research on this subject. Through former research, Tillberg finds that there are invasive pavement ants in Oregon state parks, but due to a lack of research on the species, their impact is unknown. The research will follow a paired design, comparing similar areas with and without pavement ants, to discover what differences this invasive species has on habitats
An RNA-sequencing transcriptome of the rodent Schwann cell response to peripheral nerve injury.
BACKGROUND
The important contribution of glia to mechanisms of injury and repair of the nervous system is increasingly recognized. In stark contrast to the central nervous system (CNS), the peripheral nervous system (PNS) has a remarkable capacity for regeneration after injury. Schwann cells are recognized as key contributors to PNS regeneration, but the molecular underpinnings of the Schwann cell response to injury and how they interact with the inflammatory response remain incompletely understood.
METHODS
We completed bulk RNA-sequencing of Schwann cells purified acutely using immunopanning from the naïve and injured rodent sciatic nerve at 3, 5, and 7 days post-injury. We used qRT-PCR and in situ hybridization to assess cell purity and probe dataset integrity. Finally, we used bioinformatic analysis to probe Schwann cell-specific injury-induced modulation of cellular pathways.
RESULTS
Our data confirm Schwann cell purity and validate RNAseq dataset integrity. Bioinformatic analysis identifies discrete modules of genes that follow distinct patterns of regulation in the 1st days after injury and their corresponding molecular pathways. These findings enable improved differentiation of myeloid and glial components of neuroinflammation after peripheral nerve injury and highlight novel molecular aspects of the Schwann cell injury response such as acute downregulation of the AGE/RAGE pathway and of secreted molecules Sparcl1 and Sema5a.
CONCLUSIONS
We provide a helpful resource for further deciphering the Schwann cell injury response and a depth of transcriptional data that can complement the findings of recent single cell sequencing approaches. As more data become available on the response of CNS glia to injury, we anticipate that this dataset will provide a valuable platform for understanding key differences in the PNS and CNS glial responses to injury and for designing approaches to ameliorate CNS regeneration
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