ECOSYSTEM METABOLISM OF COASTAL TEXAS STREAMS ACROSS PRECIPITATION REGIMES AND LAND USE GRADIENTS

Anthropogenic pressures of land use and climate change have the potential to impact chemical and biological factors that can affect stream ecosystem function. Ecosystem metabolism (i.e., gross primary production [GPP] and ecosystem respiration [ER]), is a metric of stream ecosystem function as it integrates nutrient and carbon cycling. We estimated daily GPP and ER using high temporal frequency oxygen data from nine Texas coastal streams falling along a precipitation and land use gradient. The most arid stream watershed land use consisted of predominantly shrubs and grasses (55%), whereas the most mesic stream watershed consisted of predominantly agricultural land cover (90%). These coastal streams did not show strong seasonal variations of GPP or ER, as often found in more temperate regions. GPP ranged from 0.3 g O 2 m −2 d −1 to 0.9 g O 2 m −2 d −1 , slightly peaking in the middle of the precipitation and land use gradients. ER ranged from -1.0 g O 2 m −2 d −1 to -4.9 g O 2 m −2 d −1 with no apparent trend along the precipitation or land use gradient. These results suggest local factors, such as light and nutrients, may be driving ecosystem metabolism, rather than broad scale processes

Whole genome sequence analysis reveals the broad distribution of the RtxA type 1 secretion system and four novel putative type 1 secretion systems throughout the Legionella genus.

Type 1 secretion systems (T1SSs) are broadly distributed among bacteria and translocate effectors with diverse function across the bacterial cell membrane. Legionella pneumophila, the species most commonly associated with Legionellosis, encodes a T1SS at the lssXYZABD locus which is responsible for the secretion of the virulence factor RtxA. Many investigations have failed to detect lssD, the gene encoding the membrane fusion protein of the RtxA T1SS, in non-pneumophila Legionella, which has led to the assumption that this system is a virulence factor exclusively possessed by L. pneumophila. Here we discovered RtxA and its associated T1SS in a novel Legionella taurinensis strain, leading us to question whether this system may be more widespread than previously thought. Through a bioinformatic analysis of publicly available data, we classified and determined the distribution of four T1SSs including the RtxA T1SS and four novel T1SSs among diverse Legionella spp. The ABC transporter of the novel Legionella T1SS Legionella repeat protein secretion system shares structural similarity to those of diverse T1SS families, including the alkaline protease T1SS in Pseudomonas aeruginosa. The Legionella bacteriocin (1-3) secretion systems T1SSs are novel putative bacteriocin transporting T1SSs as their ABC transporters include C-39 peptidase domains in their N-terminal regions, with LB2SS and LB3SS likely constituting a nitrile hydratase leader peptide transport T1SSs. The LB1SS is more closely related to the colicin V T1SS in Escherichia coli. Of 45 Legionella spp. whole genomes examined, 19 (42%) were determined to possess lssB and lssD homologs. Of these 19, only 7 (37%) are known pathogens. There was no difference in the proportions of disease associated and non-disease associated species that possessed the RtxA T1SS (p = 0.4), contrary to the current consensus regarding the RtxA T1SS. These results draw into question the nature of RtxA and its T1SS as a singular virulence factor. Future studies should investigate mechanistic explanations for the association of RtxA with virulence

Bayesian Neural Networks for Geothermal Resource Assessment: Prediction with Uncertainty

We consider the application of machine learning to the evaluation of geothermal resource potential. A supervised learning problem is defined where maps of 10 geological and geophysical features within the state of Nevada, USA are used to define geothermal potential across a broad region. We have available a relatively small set of positive training sites (known resources or active power plants) and negative training sites (known drill sites with unsuitable geothermal conditions) and use these to constrain and optimize artificial neural networks for this classification task. The main objective is to predict the geothermal resource potential at unknown sites within a large geographic area where the defining features are known. These predictions could be used to target promising areas for further detailed investigations. We describe the evolution of our work from defining a specific neural network architecture to training and optimization trials. Upon analysis we expose the inevitable problems of model variability and resulting prediction uncertainty. Finally, to address these problems we apply the concept of Bayesian neural networks, a heuristic approach to regularization in network training, and make use of the practical interpretation of the formal uncertainty measures they provide.Comment: 27 pages, 12 figure

Discovery and Early Evolution of ASASSN-19bt, the First TDE Detected by TESS

We present the discovery and early evolution of ASASSN-19bt, a tidal disruption event (TDE) discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN) at a distance of $d\simeq115$ Mpc and the first TDE to be detected by TESS. As the TDE is located in the TESS Continuous Viewing Zone, our dataset includes 30-minute cadence observations starting on 2018 July 25, and we precisely measure that the TDE begins to brighten $\sim8.3$ days before its discovery. Our dataset also includes 18 epochs of Swift UVOT and XRT observations, 2 epochs of XMM-Newton observations, 13 spectroscopic observations, and ground data from the Las Cumbres Observatory telescope network, spanning from 32 days before peak through 37 days after peak. ASASSN-19bt thus has the most detailed pre-peak dataset for any TDE. The TESS light curve indicates that the transient began to brighten on 2019 January 21.6 and that for the first 15 days its rise was consistent with a flux $\propto t^2$ power-law model. The optical/UV emission is well-fit by a blackbody SED, and ASASSN-19bt exhibits an early spike in its luminosity and temperature roughly 32 rest-frame days before peak and spanning up to 14 days that has not been seen in other TDEs, possibly because UV observations were not triggered early enough to detect it. It peaked on 2019 March 04.9 at a luminosity of $L\simeq1.3\times10^{44}$ ergs s$^{-1}$ and radiated $E\simeq3.2\times10^{50}$ ergs during the 41-day rise to peak. X-ray observations after peak indicate a softening of the hard X-ray emission prior to peak, reminiscent of the hard/soft states in X-ray binaries.Comment: 23 pages, 14 figures, 5 tables. A machine-readable table containing the host-subtracted photometry presented in this manuscript is included as an ancillary fil

Rapid mechanosensitive migration and dispersal of newly divided mesenchymal cells aid their recruitment into dermal condensates

Embryonic mesenchymal cells are dispersed within an extracellular matrix but can coalesce to form condensates with key developmental roles. Cells within condensates undergo fate and morphological changes and induce cell fate changes in nearby epithelia to produce structures including hair follicles, feathers, or intestinal villi. Here, by imaging mouse and chicken embryonic skin, we find that mesenchymal cells undergo much of their dispersal in early interphase, in a stereotyped process of displacement driven by 3 hours of rapid and persistent migration followed by a long period of low motility. The cell division plane and the elevated migration speed and persistence of newly born mesenchymal cells are mechanosensitive, aligning with tissue tension, and are reliant on active WNT secretion. This behaviour disperses mesenchymal cells and allows daughters of recent divisions to travel long distances to enter dermal condensates, demonstrating an unanticipated effect of cell cycle subphase on core mesenchymal behaviour

Path to Success: Development of the Pharmacist Through the Continuum of Pharmacy School and Beyond

Objective: To explore the processes and opportunities provided in the co-curriculum of the Wegmans School of Pharmacy (WSoP) that contribute to the development of successful pharmacy graduates. Methods: Pharmacy career preparation begins at orientation with workshops on emotional intelligence, leadership, and the APhA Career Pathway Evaluation Program. During the P1 through P4 years, the optional Student Development Workshop Series (SDW) offers seminars for students on a variety of topics including time management, exam taking strategies/anxiety management, learning styles, personal “brand” creation, CV/portfolio development, and interview soft skills. All students may participate in the annual WSoP Career Day, which offers networking and career opportunities, including post-graduate training options. During the P4 year, there is opportunity for a structured Residency/Fellowship Preparation Program (RPP). Additionally, local pharmacy residents/fellows participate in a Residency Teaching/Learning Curriculum Program (TLC) to develop academic teaching and precepting skills. Results: The SDW program has been successful and well attended with greater than 90% of students finding the topics relevant to their post-graduate success. After the RPP, ASHP residency match results in the 2016 class yielded an improvement from previous years, with 76 % of applied students and 94% of ranked students matching programs in Phase 1. Of the TLC participants, 90% documented an improvement in multiple types of teaching skills. Implications: Based on data and student/faculty input, career development is reassessed and improved continuously at WSoP. In the near future, a method for tracking graduates will be designed to further monitor the impact of programs on student success

Ballooning Instability in Polar Caps of Accreting Neutron Stars

We assess the stability of Kruskal-Schwarzschild (magnetic Rayleigh-Taylor) type modes for accreted matter on the surface of a neutron star confined by a strong (>= 1.E12 G) magnetic field. Employing the energy principle to analyze the stability of short-wavelength ballooning modes, we find that line-tying to the neutron star crust stabilizes these modes until the overpressure at the top of the neutron star crust exceeds the magnetic pressure by a factor ~ 8(a/h), where a and h are respectively the lateral extent of the accretion region and the density scale height. The most unstable modes are localized within a density scale height above the crust. We calculate the amount of mass that can be accumulated at the polar cap before the onset of instability.Comment: 8 pages, 2 figures, accepted for publication by ApJ, uses AASTEX 5.0 and emulateapj5.sty (included

Psilocybin prevents symptoms of hyperarousal and enhances novel object recognition in rats exposed to the single prolonged stress paradigm

Pharmacotherapy for stress-related psychological disorders remains inadequate. Patients who are treated with conventional pharmacological agents frequently report negligeable symptom reduction, and, in most cases, less than 50% experience full remission. Clearly, there is a need for additional pharmaceutical research into both established and novel approaches to alleviate these conditions. Over the past several years, there has been a renewed interest in the use of psychedelics to aid in the treatment of psychological disorders. Several studies have reported promising results in patients with major depression, anxiety disorders, and post-traumatic stress disorder (PTSD) following treatment with psychedelic agents such as lysergic acid diethylamide (LSD), 3,4-methylenedioxymethamphetamine (MDMA), ayahuasca, ketamine, and psilocybin. However, the precise behavioral and neurobiological mechanisms for these effects remain unclear. Thus, we aimed to develop an animal model of PTSD that involved prophylactic treatment with psilocybin, a 5-HT2A agonist, that could be used to further understand the mechanisms underlying the benefit of psychedelic substances in treating these disorders. Adult male and female Sprague-Dawley rats were subjected to the single prolonged stress (SPS) paradigm, including 2 hours of physical restraint, 15 minutes of forced swim, and ether vapor exposure until loss of consciousness. Five minutes following ether-induced loss of consciousness, the rats were intraperitoneally injected with vehicle (0.9% saline) or psilocybin (1 mg/kg). One week later, the rats underwent a battery of behavioral tests, including the elevated plus maze (EPM), startle response assessment, open field testing, and novel object recognition (NOR) testing. No effects of SPS or psilocybin were observed for EPM behavior. SPS led to enhanced startle responses in males, but not females, which was prevented by psilocybin. SPS also increased locomotor activity in the open field in males, but not females, and this effect was not prevented by psilocybin. SPS had no impact on NOR memory in males, but enhanced memory in females. Interestingly, psilocybin administration, alone or in combination with SPS, enhanced NOR memory in males only. These findings support a complex interaction between the administration of psilocybin and the prevention of stress-induced behavioral sequelae that depends on both sex and the type of behavioral task

Low-dose psilocybin enhances novel object recognition but not inhibitory avoidance in adult rats

Given the recently renewed interest in using psychedelics to aid in the treatment of psychological disorders, we aimed to examine the impact of psilocybin, a 5-HT2A agonist, on learning and memory in rodents. Previous work has demonstrated that psilocybin and other 5-HT2A agonists can enhance fear conditioning, fear extinction, and novel object recognition (NOR). Thus, we predicted that low doses of psilocybin would enhance inhibitory avoidance (IA) and NOR memory. In the first experiment, adult male and female Sprague-Dawley rats underwent step-through IA training (involving 0.45, 0.65, or 1 mA scrambled footshock) and were injected intraperitoneally (i.p.) with vehicle (0.9% saline) or psilocybin (1 mg/kg) immediately afterward. Rats were tested for their IA memory two days later. In the second experiment, adult male and female Sprague-Dawley rats were acclimated to an open field apparatus for 5 minutes on Day 1. The next day, the rats were given i.p. injections of vehicle or psilocybin (0.1 mg/kg) 10 minutes before undergoing NOR training, during which they were exposed to two replicas of an identical object for 3 minutes. On Day 3, one of the objects from NOR training was exchanged for a novel object; rats were exposed to this novel object and a new replica of the object from Day 2 (i.e., familiar object) for 5 minutes. The results showed that psilocybin had no significant impact on IA memory but enhanced novel object recognition memory in both males and females. The differential impact of psilocybin on IA memory and novel object recognition could be explained by the different doses of psilocybin or the different times of drug administration used for each task. Alternatively, they may suggest that psilocybin exerts distinct effects on different types of learning

Synthetic biology: Building the language for a new science brick by metaphorical brick

Changes in the biosciences and their relations to society over the last decades provide a unique opportunity to examine whether or not such changes leave traces in the language we use to talk about them. In this article we examine metaphors used in English-speaking press coverage to conceptualize a new type of (interdisciplinary) bioscience: synthetic biology. Findings show that three central metaphors were used between 2008 and May 2010. They exploit social and cultural knowledge about books, computers and engines and are linked to knowledge of three revolutions in science and society (the printing, information and industrial revolutions). These three central metaphors are connected to each other through the concepts of reading/writing, designing and mass production and they focus on science as a revolutionary process rather than on the end results or products of science. Overall, we observed the use of a complex bricolage of mixed metaphors and chains of metaphors that root synthetic biology in historical events and achievements, while at the same time extolling its promises for the future. © 2011 Copyright Taylor and Francis Group, LLC