Cassini's Compositae genera: A nomenclatural and taxonomic assessment

Work on the Global Compositae Checklist has highlighted uncertainties and errors in the nomenclatural parameters of many genera and subgenera described by Henri Cassini. Problems concern rank (subgenus vs. genus); type designation; correct place of valid publication; alternative names; and other miscellaneous issues. An annotated list with correct nomenclatural information for 391 generic names or designations is provided, including types (newly designated here for 17 names) and one new combination (Gyptis tanacetifolia). The current taxonomic disposition of Cassini's genera and the accepted names for the listed typonyms are consistently mentioned. The familiar names Felicia and Chrysopsis, already conserved, are threatened by unlisted earlier synonyms, and currently used Fulcaldea turns out to be illegitimate. Proposals to deal with these problems by conservation are being presented separatel

A study of human-agent collaboration for multi-UAV task allocation in dynamic environments

We consider a setting where a team of humans oversee the coordination of multiple Unmanned Aerial Vehicles (UAVs) to perform a number of search tasks in dynamic environments that may cause the UAVs to drop out. Hence, we develop a set of multi-UAV supervisory control interfaces and a multi-agent coordination algorithm to support human decision making in this setting. To elucidate the resulting interactional issues, we compare manual and mixed-initiative task allocation in both static and dynamic environments in lab studies with 40 participants and observe that our mixed initiative system results in lower workloads and better performance in re-planning tasks than one which only involves manual task allocation. Our analysis points to new insights into the way humans appropriate flexible autonomy

An analysis of effect of local exhaust ventilation on tritium surface contamination in a governmental facility

The objective of this study was to analyze the effectiveness of local exhaust ventilation on tritium surface contamination in a governmental maintenance and repair facility. Samples for this study were drawn from quarterly and suspected contamination swipes over a six year period and analyzed for tritium contamination utilizing a scintillation technique. The dependent variable selected was a measurement which determined whether tritium surface contamination was present. Three models were utilized to help determine the relationships between the independent variables ( location, time, swipe, and test, ) and the dependent variable (tritium surface contamination). Logistical regression was used to analyze radiation contamination. Through this, it was demonstrated that a significant relationship exists between swipe and tritium surface contamination. The evidence also indicates there is a difference between test, pre-local exhaust ventilation and post-local exhaust ventilation, and tritium surface contamination

HAC-ER: a disaster response system based on human-agent collectives

This paper proposes a novel disaster management system called HAC-ER that addresses some of the challenges faced by emergency responders by enabling humans and agents, using state-of-the-art algorithms, to collaboratively plan and carry out tasks in teams referred to as human-agent collectives. In particular, HAC-ER utilises crowdsourcing combined with machine learning to extract situational awareness information from large streams of reports posted by members of the public and trusted organisations. We then show how this information can inform human-agent teams in coordinating multi-UAV deployments as well as task planning for responders on the ground. Finally, HAC-ER incorporates a tool for tracking and analysing the provenance of information shared across the entire system. In summary, this paper describes a prototype system, validated by real-world emergency responders, that combines several state-of-the-art techniques for integrating humans and agents, and illustrates, for the first time, how such an approach can enable more effective disaster response operations

Effect of a Coevolved Parasitic Nematode on Fitness of the Desert Horned Lizard (Phrynosoma platyrhinos)

In the Alvord Desert in Harney County, Oregon, I examined the response of desert horned lizards (Phrynosoma platyrhinos) to a common and abundant gastrointestinal nematode parasite (Skrjabinoptera phrynosoma) transmitted to them through harvester ants (Pogonomyrmex californicus), a principal component of their specialized diet. I examined presumed fitness correlates including foraging, prey choice, energetic endurance, and immune response at varying levels of nematode load in joules/hour while correcting for body size differences in 19 male and 21 female Desert horned lizards in summer 2018. The effects of increasing nematode load were more benign than hypothesized, with the only significant detriments being in reduced energetic endurance and blood immune response. Nematode load was positively correlated with foraging, body condition, and showed a sex-specific influence on prey choice. I posit that male and non-reproductive female desert horned lizards accumulate nematodes with little consequence and may become hyperphagic in order to feed both themselves and their parasites, explaining the enhanced foraging and body condition in more parasitized lizards. I also suggest that reproductive female horned lizards are the cause for the continued relationship, as reproductive females have the obligation to utilize the nematode-transmitting harvester ants to meet their reproductive energy needs, while nematodes have the obligation to be mild enough upon their hosts as to not facilitate mortality during horned lizards’ energetically challenging reproductive season. This study indicates that even nutritionally limited species can support large parasite communities with little fitness costs, and dietary specificity can lead to highly autonomous and stable host-parasite systems

Regular mosaic pattern development: A study of the interplay between lateral inhibition, apoptosis and differential adhesion

<p>Abstract</p> <p>Background</p> <p>A significant body of literature is devoted to modeling developmental mechanisms that create patterns within groups of initially equivalent embryonic cells. Although it is clear that these mechanisms do not function in isolation, the timing of and interactions between these mechanisms during embryogenesis is not well known. In this work, a computational approach was taken to understand how lateral inhibition, differential adhesion and programmed cell death can interact to create a mosaic pattern of biologically realistic primary and secondary cells, such as that formed by sensory (primary) and supporting (secondary) cells of the developing chick inner ear epithelium.</p> <p>Results</p> <p>Four different models that interlaced cellular patterning mechanisms in a variety of ways were examined and their output compared to the mosaic of sensory and supporting cells that develops in the chick inner ear sensory epithelium. The results show that: 1) no single patterning mechanism can create a 2-dimensional mosaic pattern of the regularity seen in the chick inner ear; 2) cell death was essential to generate the most regular mosaics, even through extensive cell death has not been reported for the developing basilar papilla; 3) a model that includes an iterative loop of lateral inhibition, programmed cell death and cell rearrangements driven by differential adhesion created mosaics of primary and secondary cells that are more regular than the basilar papilla; 4) this same model was much more robust to changes in homo- and heterotypic cell-cell adhesive differences than models that considered either fewer patterning mechanisms or single rather than iterative use of each mechanism.</p> <p>Conclusion</p> <p>Patterning the embryo requires collaboration between multiple mechanisms that operate iteratively. Interlacing these mechanisms into feedback loops not only refines the output patterns, but also increases the robustness of patterning to varying initial cell states.</p

Muscle damage and inflammation after eccentric exercise: can the repeated bout effect be removed?

The current consensus in exercise physiology is that the repeated bout effect always appears after few eccentric exercise sessions. This is the first attempt to challenge this tenet, by exploiting specificity in muscle plasticity. More specifically, we examined whether the opposing adaptations in muscle induced after concentric and eccentric exercise can attenuate and/or remove the repeated bout effect. Seventeen young men were randomly assigned into one of the following groups: (1) the alternating eccentric-concentric exercise group; and (2) the eccentric-only exercise group. Both groups performed 8 weeks of resistance exercise using the knee extensors of both legs on an isokinetic dynamometer. The alternating eccentric-concentric exercise group performed an alternating exercise protocol, switching between eccentric-only and concentric-only exercise every 4 weeks, while the eccentric-only group performed eccentric exercise. Evaluation of muscle damage using physiological (isometric torque, delayed onset muscle soreness, and range of movement) and biochemical (creatine kinase) markers and inflammation (C-reactive protein) was performed at weeks 1, 5, and 10. Baseline isometric peak torque was also evaluated at week 14 after another cycle (4 weeks) of alternating or eccentric-only exercise training. In the alternating eccentric-concentric exercise group, the concentric exercise training performed prior to eccentric exercise reduced dramatically the repeated bout effect by reversing muscle back to its unaccustomed state. On the contrary, the eccentric-only exercise group exhibited a typical manifestation of the repeated bout effect. Interestingly, muscle strength was elevated similarly for both alternating and eccentric-only exercise groups after 13 weeks of training. The alternating eccentric-concentric exercise scheme, implemented in the present study, has for the first time successfully overcame the repeated bout effect. The similarity in muscle strength measurements following the two protocols is against the notion that inflammation plays an important role in exercise-induced adaptations in muscle

Muscle cell derived angiopoietin-1 contributes to both myogenesis and angiogenesis in the ischemic environment

Recent strategies to treat peripheral arterial disease (PAD) have focused on stem cell based therapies, which are believed to result in local secretion of vascular growth factors. Little is known, however, about the role of ischemic endogenous cells in this context. We hypothesized that ischemic muscle cells (MC) are capable of secreting growth factors that act as potent effectors of the local cellular regenerative environment. Both muscle and endothelial cells (ECs) were subjected to experimental ischemia, and conditioned medium (CM) from each was collected and analyzed to assess myogenic and/or angiogenic potential. In muscle progenitors, mRNA expression of VEGF and its cognate receptors (Nrp1, Flt, Flk) was present and decreased during myotube formation in vitro, and EC CM or VEGF increased myoblast proliferation. Angiopoietin-1 (Ang-1), Tie1, and Tie2 mRNA increased during MC differentiation in vitro. Exogenous Ang-1 enhanced myogenic (MyoD and Myogenin) mRNA in differentiating myoblasts and increased myosin heavy chain protein. Myotube formation was enhanced by MC CM and inhibited by EC CM. Ang-1 protein was present in CM from MCs isolated from both the genetically ischemia-susceptible BALB/c and ischemia-resistant C57BL/6 mouse strains, and chimeric Tie2 receptor trapping in situ ablated Ang-1's myogenic effects in vitro. Ang-1 or MC CM enhanced myotube formation in a mixed isolate of muscle progenitors as well as a myoblast co-culture with pluripotent mesenchymal cells (10T1/2) and this effect was abrogated by viral expression of the extracellular domain of Tie2 (AdsTie2). Furthermore, mesh/tube formation by HUVECs was enhanced by Ang-1 or MC CM and abrogated by Tie2 chimeric receptor trapping. Our results demonstrate the ability of muscle and endothelial cell-derived vascular growth factors, particularly Ang-1, to serve as multi-functional stimuli regulating crosstalk between blood vessels and muscle cells during regeneration from ischemic myopathy