179 research outputs found

    Examining Climate Change Effects on Flowering in Moss Campion

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    Examining the variation in the collection date of herbarium specimens is a common method for studying the phenological effects of climate change on a flowering plant species. We used herbarium data to examine how warming temperatures have affected flowering time in Silene acaulis in the state of Colorado. Silene acaulis, commonly known as moss campion and cushion pink, is an alpine tundra plant. Using ordinal date of collection as a proxy for flowering date and year collected as a proxy for increasing average temperature, a linear regression test found that there was no significant relationship between increasing temperatures and flowering time. Further examination of the herbarium data revealed a pattern of summertime specimen collection for Silene acaulis. As a species that flowers in response to snow melt, the collection pattern indicates that herbarium data is insufficient for assessing the phenological effects of climate change on Silene acaulis. More intensive research on the relationship between snow melt and flowering time is needed to understand the impacts of climate change on Silene acaulis

    Factors Influencing Conservation Knowledge: A Survey of Residents in the United States

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    Basic principles have been established for visitors of national and state parks, but some visitors may be more aware of conservation practices than others. To understand visitor awareness, this study investigated three factors that influence the general public’s understanding of the Leave No Trace (LNT) conservation ethic: natural areas visitation, state of residence, and media consumption. Each of the factors showed statistically significant impacts on awareness of LNT, supporting our hypotheses that this knowledge will increase with a higher frequency of park visits and media consumption, and that region of residence will also impact LNT knowledge

    Investigating the Effects of Climate Change on the Phenology of Achillea millefolium, Aquilegia coerulea, and Penstemon cyanocaulis

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    As the effects of climate change are starting to unearth themselves, the impacts can be observed by tracking the patterns of cyclical natural phenomena also known as phenology, and monitoring how they have changed over time. These cycles are at the crux of making ecosystems viable for their local biodiversity, and understanding the ongoing change allows for further understanding of the ecosystem’s change over time. In this study, we look at the ordinal flowering dates of the Achillea millefolium, Aquilegia coerulea, and Penstemon cyanocaulis over the past century. Our data give insight into how warmer temperatures occurring earlier in the year are changing the cycle of flowering plants in the western United States. This framework encourages more investigation into the changes in plant phenology throughout different regions due to climate change

    A solution to treat mixed-type human datasets from socio-ecological systems

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    Coupled human and natural systems (CHANS) are frequently represented by large datasets with varied data including continuous, ordinal, and categorical variables. Conventional multivariate analyses cannot handle these mixed data types. In this paper, our goal was to show how a clustering method that has not before been applied to understanding the human dimension of CHANS: a Gower dissimilarity matrix with partitioning around medoids (PAM) can be used to treat mixed-type human datasets. A case study of land managers responsible for invasive plant control projects across rivers of the southwestern U.S. was used to characterize managers’ backgrounds and decisions, and project properties through clustering. Results showed that managers could be classified as “federal multitaskers” or as “educated specialists”. Decisions were characterized by being either “quick and active” or “thorough and careful”. Project goals were either comprehensive with ecological goals or more limited in scope. This study shows that clustering with Gower and PAM can simplify the complex human dimension of this system, demonstrating the utility of this approach for systems frequently composed of mixed-type data such as CHANS. This clustering approach can be used to direct scientific recommendations towards homogeneous groups of managers and project types

    A Solution to Treat Mixed-Type Human Datasets from Socio-Ecological Systems

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    Coupled human and natural systems (CHANS) are frequently represented by large datasets with varied data including continuous, ordinal, and categorical variables. Conventional multivariate analyses cannot handle these mixed data types. In this paper, our goal was to show how a clustering method that has not before been applied to understanding the human dimension of CHANS: a Gower dissimilarity matrix with partitioning around medoids (PAM) can be used to treat mixed-type human datasets. A case study of land managers responsible for invasive plant control projects across rivers of the southwestern U.S. was used to characterize managers’ backgrounds and decisions, and project properties through clustering. Results showed that managers could be classified as “federal multitaskers” or as “educated specialists”. Decisions were characterized by being either “quick and active” or “thorough and careful”. Project goals were either comprehensive with ecological goals or more limited in scope. This study shows that clustering with Gower and PAM can simplify the complex human dimension of this system, demonstrating the utility of this approach for systems frequently composed of mixed-type data such as CHANS. This clustering approach can be used to direct scientific recommendations towards homogeneous groups of managers and project types

    Vitrification of human embryos subjected to blastomere biopsy for preimplantation genetic screening produces higher survival and pregnancy rates than slow freezing. J Assist Reprod Genet,

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    Abstract Purpose Cryopreservation of blastocysts, especially those subjected to the trauma due to blastomere biopsy for the purposes of pre-implantation genetic screening (PGS), requires significant optimization. Laboratory and clinical outcomes were compared to determine the effect of two different cryopreservation techniques on the development of human pre-implantation embryos that underwent blastomere biopsy and blastocoel drainage prior to cryopreservation. Design Retrospective clinical study. Patient(s) Women who requested cryotransfer of supernumerary blastocysts were analyzed by FISH. Results The main outcome measures were post-thaw survival (SR), pregnancy (PR), and implantation (IR). The SR of slowly frozen blastocysts was 83% compared to 97% for vitrified blastocysts. In 160 cases where biopsied embryos were cryotransferred, the results for slowly frozen versus vitrified blastocysts were: SR (71% vs. 95%), PR (23% vs. 37%), and IR (26% vs. 36%, P<0.05), respectively. Conclusion The results revealed that vitrified blastocysts provided higher SR, PR and IR as compared to slowly frozen counterparts

    Vegetation response to invasive Tamarix control in southwestern U.S. rivers: a collaborative study including 416 sites

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    Most studies assessing vegetation response following control of invasive Tamarix trees along southwestern U.S. rivers have been small in scale (e.g., river reach), or at a regional scale but with poor spatial-temporal replication, and most have not included testing the effects of a now widely used biological control. We monitored plant composition following Tamarix control along hydrologic, soil, and climatic gradients in 244 treated and 172 reference sites across six U.S. states. This represents the largest comprehensive assessment to date on the vegetation response to the four most common Tamarix control treatments. Biocontrol by a defoliating beetle (treatment 1) reduced the abundance of Tamarix less than active removal by mechanically using hand and chain-saws (2), heavy machinery (3) or burning (4). Tamarix abundance also decreased with lower temperatures, higher precipitation, and follow-up treatments for Tamarix resprouting. Native cover generally increased over time in active Tamarix removal sites, however, the increases observed were small and was not consistently increased by active revegetation. Overall, native cover was correlated to permanent stream flow, lower grazing pressure, lower soil salinity and temperatures, and higher precipitation. Species diversity also increased where Tamarix was removed. However, Tamarix treatments, especially those generating the highest disturbance (burning and heavy machinery), also often promoted secondary invasions of exotic forbs. The abundance of hydrophytic species was much lower in treated than in reference sites, suggesting that management of southwestern U.S. rivers has focused too much on weed control, overlooking restoration of fluvial processes that provide habitat for hydrophytic and floodplain vegetation. These results can help inform future management of Tamarix-infested rivers to restore hydrogeomorphic processes, increase native biodiversity and reduce abundance of noxious species

    Gender and Racial Disparity Among Liver Transplantation Professionals: Report of a Global Survey.

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    Equality, diversity, and inclusion (EDI) are fundamental principles. Little is known about the pattern of practice and perceptions of EDI among liver transplant (LT) providers. International Liver Transplant Society (ILTS) EDI Committee survey around topics related to discrimination, mentorship, and gender. Answers were collected and analyzed anonymously. Worldwide female leadership was also queried via publicly available data. The survey was e-mailed to 1312 ILTS members, 199 responses (40.7% female) were collected from 38 countries (15.2% response rate). Almost half were surgeons (45.7%), 27.6% hepatologists and 26.6% anesthetists. Among 856 LT programs worldwide, 8.2% of leadership positions were held by females, and 22% of division chiefs were female across all specialties. Sixty-eight of respondents (34.7%) reported some form of discrimination during training or at their current position, presumably related to gender/sexual orientation (20.6%), race/country of origin (25.2%) and others (7.1%). Less than half (43.7%) received mentorship when discrimination occurred. An association between female responses and discrimination, differences in compensation, and job promotion was observed. This survey reveals alarmingly high rate of experience with racial and gender disparity, lack of mentorship, and very low rates of female leadership in the LT field and calls to action to equity and inclusion

    A Quantitative Systems Pharmacology perspective on the importance of parameter identifiability

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    There is an inherent tension in Quantitative Systems Pharmacology (QSP) between the need to incorporate mathematical descriptions of complex physiology and drug targets with the necessity of developing robust, predictive and well-constrained models. In addition to this there is no "gold standard" for model development and assessment in QSP. Moreover, there can be confusion over terminology such as model and parameter identifiability; complex and simple models; virtual populations; and other concepts, which leads to potential miscommunication and misapplication of methodologies within modelling communities, both the QSP community and related disciplines. This perspective article highlights the pros and cons of using simple (often identifiable) vs. complex (more physiologically detailed but often non-identifiable) models, as well as aspects of parameter identifiability, sensitivity and inference methodologies for model development and analysis. The paper distills the central themes of the issue of identifiability and optimal model size and discusses open challenges
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