1,243 research outputs found

    Precision Assessment of the HPLC Phytoplankton Pigment Dataset Analyzed by NASA to Quantify Global Variability in Support of Ocean Color Remote Sensing

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    The ability to generate chlorophyll a (Chl a) assessments from ocean color orbital sensors, such as VIIRS and MODIS, that satisfy the requirements to be climate-quality data record (CDR) quality is contingent in part on the quality of the in situ ground or sea truth observations that serve as datasets for vicarious calibration and algorithm validation activities. NASA has a mandate to collect, analyze, and distribute in situ data of the highest possible quality with documented uncertainties and in keeping with established performance metrics. Using a dataset of over 18,000 HPLC phytoplankton pigment samples representing water collected in all major ocean basins analyzed a central laboratory (Field Support Group (FSG) of the Ocean Ecology Laboratory (OEL) at NASA Goddard Space Flight Center (GSFC)), we performed an assessment of the global precision among sample replicates of Chl a as well as major accessory pigments. We investigated the impacts of filtration volume, water basin, collection technique, pigment concentration, and different filtration volumes for replicate filters on replicate filter precision, as well as investigating any pigment-specific differences. Our results quantify sample variability with the goal of understanding any systemic biases or biogeographic influences

    Improving Quantitative Laboratory Analysis of Phycobiliproteins to Provide High Quality Validation Data for Ocean Color Remote Sensing Algorithm

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    Identification and characterization of phytoplankton communities and their physiology is a primary aim of NASA's PACE satellite mission. The concentration and composition of phytoplankton pigments modulate the spectral distribution of light emanating from the ocean, which is measured by ocean color satellites, and thus provide critical information on phytoplankton community composition and physiological parameters. One diagnostic class of pigments not routinely well-characterized is the phycobiliproteins (PBPs), and NASA has a requirement to collect and distribute high quality in situ data in support of data product validation activities for ocean color missions. Phycobiliproteins are light-harvesting proteins that are the predominant photosynthetic pigments in some classes of phytoplankton including cyanobacteria, such as Synechococcus, Trichodesmium, and Microcystis. With the advance of hyperspectral ocean color sensors such as on PACE (expected to launch in late 2022), it is essential that we implement routine analysis of PBPs that satisfies several considerations: reproducible, high extraction efficiency for a variety of environments, and Suitable for large scale analysis. Published techniques for PBP analysis vary in recommendations for: collection, extraction, disruption mode, and analysis; evidence suggests the variation in results may depend at least in part on the species and even strain(s) of interest. Experiments that tested variations in these parameters have drawn very different conclusions regarding extraction efficiency and reproducibility. Cyanobacteria are more difficult to extract than other PBP-containing algae such as cryptophytes, but can be important primary producers. We used a cryptophyte (Rhodomonas salina) and cyanobacterium (Synechococcus sp.) to compare extraction efficiencies of water samples concentrated via centrifugation to filtered samples using two different extraction buffers (phosphate and asolectin-CHAPS). Samples were analyzed on a fluorometer configured for PC and PE detection. The results have important implications for collection and storage of samples for routine analysis; some previous studies (although not all) have suggested that filtered samples have a much lower extraction efficiency than whole water samples

    Nutrient Addition Effects on Phytoplankton Communities in the Amazon River Plume

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    The types and abundance of phytoplankton is largely controlled by availability of sunlight and bioavailable nutrients. Phytoplankton require essential nutrients including nitrate, phosphate, and silicate to grow, so understanding the role of these macronutrients in limiting the growth phytoplankton communitiesand the way this may differ depending on community compositionis key to understanding the controls on phytoplankton biomass and community structure. We aimed to explore how the availability of these nutrients affects the health and composition of phytoplankton communities by conducting a series of nutrient amendment experiments (NAEs) with samples from the Western Tropical North Atlantic, which is heavily influenced by the nutrient-rich, low salinity waters of the Amazon River Plume. These experiments, conducted at five locations in and around the plume, provide greater resolution and further our understanding about the ways nutrients affect communities in dynamic coastal regions

    Interpersonal problems of the nonprofit workforce: Evaluating the wounded healer as the reason for high turnover

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    The research goal was to identify a potential explanation for the high levels of turnover in nonprofit organizations. First, nonprofit employees’ levels of Adverse Childhood Experiences (ACEs) were evaluated and found to be significantly higher than for for-profit and government employees. This phenomenon could speak to a self-selection bias whereas wounded healers are drawn into the helping fields because of some perceived personal benefit they gain or because they might feel they can offer something more given their experiences. Having higher ACEs has been linked to job instability, and could be a contributing factor in the sector\u27s turnover rates. Nonprofit employees’ levels of interpersonal problems were also examined using the IIP-32 and it was found they had lower levels than the general population

    Charcot foot reconstruction with combined internal and external fixation: case report

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    Charcot neuroarthropathy is a destructive and often-limb threatening process that can affect patients with peripheral neuropathy of any etiology. Early recognition and appropriate management is crucial to prevention of catastrophic outcomes. Delayed diagnosis and subsequent pedal collapse often preclude successful conservative management of these deformities and necessitate surgical intervention for limb salvage. We review the current literature on surgical reconstruction of Charcot neuroarthropathy and present a case report of foot reconstruction with combined internal and external fixation methods

    Mindsets of Health and Healthy Eating Intentions

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    Across two studies, we examined the relation between mindsets of health, expectancy-value and eating intentions. We also explored if relations are stronger for African Americans compared to White Americans. In Study 1, we conducted a correlational study (N= 158) to examine initial relations among constructs. In Study 2, we employed an experimental design (N = 205), and randomly assigned participants to either a growth mindset or a fixed mindset of health condition. In both studies, we measured participants’ mindsets of health, expectancy-value beliefs, healthy eating intentions, past eating habits and demographics. In Study 1, stronger growth mindsets of health predicted healthier eating intentions. Expectancy-value beliefs, namely, the extent to which individuals value healthy eating habits and expect to be able to manage their eating, mediated this relation. In Study 2, we successfully manipulated mindsets of health and individuals in the growth mindset condition reported healthier eating intentions, compared to those in the fixed mindset condition. Expectancy-value beliefs again mediated this link. Race only moderated the relation in Study 1, such that effects of growth mindsets on outcomes (i.e., eating intentions and expectancy-value beliefs) are stronger for African Americans compared to White Americans. Study 1 provided initial evidence of a relationship between stronger growth mindsets of health and healthier beliefs and intentions. Study 2 offered experimental evidence. We discuss theoretical and practical implications

    The Parthenon, April 26, 2012

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    The Parthenon, Marshall University’s student newspaper, is published by students Monday through Friday during the regular semester and weekly Thursday during the summer. The editorial staff is responsible for the news and the editorial content

    Gender comprehension and vowel production: Are they related?

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    Spanish gender divides nouns into two predictable morphological classes, most frequently marked by word-final unstressed /a o/ vowels.[1] These vowels undergo mergers and centralization in heritage Spanish-English speakers (HSs).[2,3] Unlike monolingual children, who learn gender early using noun phonology4, HSs make gender errors into adulthood.[5,6] Gender aids sentence processing: monolinguals show anticipatory effects on nouns when the determiner expresses gender, but results for bilinguals are complex.[7,8] Are bilingual effects in syntactic processing (i.e. no anticipation from the gender-marked determiner) in HSs predicted from vowel reduction? Two existing corpus studies [6,9] do not establish a clear link. Our study tests the hypothesis that HSs’ patterns of word final vowel realization may trigger systemic changes in gender marking in bilinguals.[10] We tested Heritage speakers born in the US/Canada or immigrated before adolescence (n=17), and adult Spanish-speaking immigrants (ASI; n=19) who emigrated to Canada later. A naming task determined speakers’ familiarity with the experimental stimuli and provided data for acoustic analyses of unstressed /a e o/ final vowels (F1-F2 formants, 243 tokens per participant). An eye-tracking task, implemented in a Tobii Pro Fusion system at 120 Hz, presented three images with an unspliced audio prompt; stimuli were controlled for gender, animacy, noun morphology, and determiner (def/possess), counterbalanced across participants. Proportion of gaze fixations to target were extracted in two windows to test retrieval advantage in W1 (noun onset to offset; effect of determiner) and W2 (offset+300ms, effect of noun ending). A linear mixed effects model with determiner and group as independent variables revealed that, during W1, ASIs have a higher proportion of looks to target than HSs in trials with the definite determiner. By W2, group and determiners were significant, with HSs showing fewer fixations to target than controls. Thus, HSs’ performance does not indicate an anticipatory effect but suggests a facilitatory effect (i.e., eye movements as the identity of the noun unfolds). ASIs’ performance is consistent with their vowel production which does not show overlap. These findings might be consistent with the view that morphology and dispersion in the vocalic space may interact in shaping the gender agreement system in heritage bilinguals. References [1] Clegg, J. H. (2011). A frequency-based analysis of the norms for Spanish noun gender. Hispania, 94(2), 303-319. [2] Menke, M. (2010). Examination of the Spanish vowels produced by Spanish-English bilingual children. Southwest Journal of Linguistics, 28(2), 98-135. [3] Mazzaro, N., Colantoni, L., & Cuza, A. (2016). Age effects and the discrimination of consonantal and vocalic contrasts in heritage and native Spanish. In C. Tortora, M. den Dikken, I. Montoya, & T. O’Neill (Eds.), Romance Linguistics 2013: Selected papers of the 43th Linguistic Symposium on Romance Languages (LSRL), New York, 17-19 April, 2013 (pp. 277-300). John Benjamins. [4] Culberston, J., Jarvinen, H., Heggarty, F., and Smith, K. (2019). Children’s sensitivity to phonological and semantic cues during noun class learning evidence for a phonological bias. Language 95: 268–93. [5] Montrul, S., & Potowski, K. (2007). Command of gender agreement in school-age Spanish-English bilingual children. International Journal of Bilingualism, 11(3), 301-328. https://doi.org/10.1177/13670069070110030301 [6] PĂ©rez-Leroux, A. T., LĂłpez, Y. Á., Barreto, M., Cuza, A., Marinescu, I., Yang, J., & Colantoni, L. (2023). The Phonetic and Morphosyntactic Dimensions of Grammatical Gender in Spanish Heritage Language Acquisition, Heritage Language Journal, 20(1), 1-37. doi: https://doi.org/10.1163/15507076-bja10017 [7] Baron, A., Connell, K. and Griffin, ZM. (2022). Grammatical Gender in Spoken Word Recognition in School-Age Spanish-English Bilingual Children. Frontiers in Psychology 13: 788076. doi: 10.3389/fpsyg.2022.788076 [8] Lew-Williams, C., and Fernald, A. (2007). Young children learning Spanish make rapid use of grammatical gender in spoken word recognition. Psychological Science, 18, 193–198. [9] Colantoni, L., R. MartĂ­nez, N. Mazzaro, A. T. PĂ©rez-Leroux, and N. Rinaldi. (2020). A Phonetic Account of Spanish-English Bilinguals’ Divergence with Agreement. Languages, 5(4), 58. https://doi.org/10.3390/languages5040058 [10] Scontras, Gregory, Zuzanna Fuchs, and Maria Polinsky. (2015). Heritage language and linguistic theory. Frontiers in Psychology 6: 15–45

    Invisible men: space, race, and housing in African American literature

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    “Invisible Men: Space, Race, and Housing in African American Literature” uses an archive of novels written roughly between 1940 and 2000, American Sociology, the philosophy of phenomenology, and ethnography to argue that representations of housing in African American literature form part of a negative discourse that relegates space to forever being racialized but that this discourse is interestingly contradicted by my chosen texts’ very mediation of housing. Problematizing, as examples, the conflict between discriminatory and liberating spaces in Native Son (1940), the narrator’s underground refuge in Invisible Man (1952), and the class and Levinasian boundaries of responsibility in Linden Hills (1985)—among more—my dissertation posits the question, what does it mean for space to be raced in a body of literature simultaneously concerned with contesting the stigma of race, and with it, delimiting structures of subjecthood? If one attempts to separate the conversation about race from the built environment it censures (i.e., slum housing), what is left? My dissertation emphasizes a focus on African American men because, as my dissertation title alludes, they constitute a present absence in the representational fields within literary and ethnographic texts about housing. Pointedly, a large number of representations of housing inequities in African American Literary Studies and American Sociology demonize black men, and yet, beyond Bigger Thomas in Native Son and the Black Panther Party’s work in public housing in the 1970s, the narratives of black men in relationship to housing justice is startlingly undertheorized. My project contributes to both disciplinary fields by addressing the configuration of urban crises seemingly dependent on the high visibility and yet discursive silence of low-income African American men. I examine black men’s intimate and political uses of space through novels, participant-observation, interviews, and photographs to argue that the ways in which black men construct and negotiate housing as shelter are both universal and uniquely transgressive. My efforts are intended to move the literary discussion of ghetto space away from the binary of this space being perceived as either culturally productive (e.g., via the blues and hip hop) or socially destructive (e.g., as geographies of violence and poverty). Extending my textual readings to qualitative research (which I do in the final chapter) continues the complicated relationship between sociology and black literature in order to widen the picture of African American masculinity that we see in groundbreaking studies such as American Project (2000) and The Dignity of Everyday Resistance (2004). Additionally, my project can be viewed in conversation with feminist and queer studies of domestic fiction. If the domestic is “a site where massive negotiations between often competing ideological pressures are undertaken and then processed into viable, even pleasurable, experiences of [or I would add, resistance to] domestication,” then “Invisible Men” locates black male figures both inside and outside resistance narratives of family, uplift, and the state exactly through their counter uses of the domestic sphere of housing and their agential understanding of that use. This is an overt exploration of the dialectic between space as racialized and race as spatialized, ultimately with the goal of promoting the acceptance of abject space like public housing as a universal place to call home
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