Measuring Performance of a Weedy Species (Nicotania glauca) vs. a Native Species (Venegasia Carpesioides) on the Pepperdine Campus

This study investigated four different mechanisms of growth performance of a native chaparral species, Venegasia carpesioides, and a weedy species, Nicotiana glauca. The research group hypothesized that one or more of the following variables would be higher for the weedy species than the native species: photosynthetic rate, conductance, fluorescence, and electron transport rate (ETR). This hypothesis was formulated in order to provide a plausible explanation for why weedy species often outcompete native species when grown in proximity to each other, especially in a chaparral environment experiencing drought conditions. This hypothesis was tested by obtaining two groups of each species and testing these variables using a LI-6400XT gas exchange system. The results obtained showed that the photosynthetic rate, fluorescence, and ETR were higher for the native plant species than for the weedy plant species; a Student t-Test showing statistically significant differences between those values, while there was no statistically significant difference for conductance between the two species. Using Nicotiana glauca and Venegasia carpesioides as model specimens, the results did not support our hypothesis that weedy plant species outcompete native plant species by one of the four mechanistic variables measured

Contribution of time of day and the circadian clock to the heat stress responsive transcriptome in Arabidopsis.

In Arabidopsis, a large subset of heat responsive genes exhibits diurnal or circadian oscillations. However, to what extent the dimension of time and/or the circadian clock contribute to heat stress responses remains largely unknown. To determine the direct contribution of time of day and/or the clock to differential heat stress responses, we probed wild-type and mutants of the circadian clock genes CCA1, LHY, PRR7, and PRR9 following exposure to heat (37 °C) and moderate cold (10 °C) in the early morning (ZT1) and afternoon (ZT6). Thousands of genes were differentially expressed in response to temperature, time of day, and/or the clock mutation. Approximately 30% more genes were differentially expressed in the afternoon compared to the morning, and heat stress significantly perturbed the transcriptome. Of the DEGs (~3000) specifically responsive to heat stress, ~70% showed time of day (ZT1 or ZT6) occurrence of the transcriptional response. For the DEGs (~1400) that are shared between ZT1 and ZT6, we observed changes to the magnitude of the transcriptional response. In addition, ~2% of all DEGs showed differential responses to temperature stress in the clock mutants. The findings in this study highlight a significant role for time of day in the heat stress responsive transcriptome, and the clock through CCA1 and LHY, appears to have a more profound role than PRR7 and PRR9 in modulating heat stress responses during the day. Our results emphasize the importance of considering the dimension of time in studies on abiotic stress responses in Arabidopsis

Regional Invasive Species & Climate Change Management Challenge: Double Trouble. Understanding risks from invasive species + climate change

Individually, invasive species and climate change are major threats to global ecosystems. Together they create new challenges for effective management. Before we can design management strategies to respond to this double trouble, we need to understand how these two forms of global change interact

Clock-Controlled and Cold-Induced CYCLING DOF FACTOR6 Alters Growth and Development in Arabidopsis

The circadian clock represents a critical regulatory network, which allows plants to anticipate environmental changes as inputs and promote plant survival by regulating various physiological outputs. Here, we examine the function of the clock-regulated transcription factor, CYCLING DOF FACTOR 6 (CDF6), during cold stress in Arabidopsis thaliana. We found that the clock gates CDF6 transcript accumulation in the vasculature during cold stress. CDF6 mis-expression results in an altered flowering phenotype during both ambient and cold stress. A genome-wide transcriptome analysis links CDF6 to genes associated with flowering and seed germination during cold and ambient temperatures, respectively. Analysis of key floral regulators indicates that CDF6 alters flowering during cold stress by repressing photoperiodic flowering components, FLOWERING LOCUS T (FT), CONSTANS (CO), and BROTHER OF FT (BFT). Gene ontology enrichment further suggests that CDF6 regulates circadian and developmental-associated genes. These results provide insights into how the clock-controlled CDF6 modulates plant development during moderate cold stress

Translational invasion ecology: bridging research and practice to address one of the greatest threats to biodiversity

Effective natural resource management and policy is contingent on information generated by research. Conversely, the applicability of research depends on whether it is responsive to the needs and constraints of resource managers and policy makers. However, many scientific fields including invasion ecology suffer from a disconnect between research and practice. Despite strong socio-political imperatives, evidenced by extensive funding dedicated to addressing invasive species, the pairing of invasion ecology with stakeholder needs to support effective management and policy is lacking. As a potential solution, we propose translational invasion ecology (TIE). As an extension of translational ecology, as a framework to increase collaboration among scientists, practitioners, and policy makers to reduce negative impacts of invasive species. As an extension of translational ecology, TIE is an approach that embodies an intentional and inclusive process in which researchers, stakeholders, and decision makers collaborate to develop and implement ecological research via joint consideration of the ecological, sociological, economic, and/or political contexts in order to improve invasive species management. TIE ideally results in improved outcomes as well as shared benefits between researchers and managers. We delineate the steps of our proposed TIE approach and describe successful examples of ongoing TIE projects from the US and internationally. We suggest practical ways to begin incorporating TIE into research and management practices, including supporting boundary-spanning organizations and activities, expanding networks, sharing translational experiences, and measuring outcomes. We find that there is a need for strengthened boundary spanning, as well as funding and recognition for advancing translational approaches. As climate change and globalization exacerbate invasive species impacts, TIE provides a promising approach to generate actionable ecological research while improving outcomes of invasive species management and policy decisions

The NEOWISE-Discovered Comet Population and the CO+CO_2 production rates

The 163 comets observed during the WISE/NEOWISE prime mission represent the largest infrared survey to date of comets, providing constraints on dust, nucleus size, and CO + CO_2 production. We present detailed analyses of the WISE/NEOWISE comet discoveries, and discuss observations of the active comets showing 4.6 μm band excess. We find a possible relation between dust and CO + CO_2 production, as well as possible differences in the sizes of long and short period comet nuclei

Cell size is a determinant of stem cell potential during aging

Stem cells are remarkably small. Whether small size is important for stem cell function is unknown. We find that hematopoietic stem cells (HSCs) enlarge under conditions known to decrease stem cell function. This decreased fitness of large HSCs is due to reduced proliferation and was accompanied by altered metabolism. Preventing HSC enlargement or reducing large HSCs in size averts the loss of stem cell potential under conditions causing stem cell exhaustion. Last, we show that murine and human HSCs enlarge during aging. Preventing this age-dependent enlargement improves HSC function. We conclude that small cell size is important for stem cell function in vivo and propose that stem cell enlargement contributes to their functional decline during aging.Peer reviewe

Strategies Utilized to Prevent and Control SARS-CoV-2 Transmission in Two Congregate, Psychiatric Healthcare Settings During the Pandemic

BACKGROUND: The COVID-19 pandemic has had a substantial effect on the delivery of psychiatric healthcare. Inpatient psychiatric healthcare facilities have experienced outbreaks of COVID-19, making these areas particularly vulnerable. METHODS: Our facility used a multidisciplinary approach to implement enhanced infection prevention and control (IPC) interventions in our psychiatric healthcare areas. RESULTS: In a sixteen-month period during the COVID-19 pandemic, our two facilities provided >29,000 patient days of care to 1,807 patients and identified only forty-seven COVID-19 positive psychiatric health inpatients (47/1,807, or 2.6%). We identified the majority of these cases by testing all patients at admission, preventing subsequent outbreaks. Twenty-one psychiatric healthcare personnel were identified as COVID+ during the same period, with 90% linked to an exposure other than a known positive case at work. DISCUSSION: The IPC interventions we implemented provided multiple layers of safety for our patients and our staff. Ultimately, this resulted in low SARS-CoV-2 infection rates within our facilities. CONCLUSIONS: Psychiatric healthcare facilities are uniquely vulnerable to COVID-19 outbreaks because they are congregate units that promote therapeutic interactions in shared spaces. IPC interventions used in acute medical care settings can also work effectively in psychiatric healthcare, but often require modifications to ensure staff and patient safety