40 research outputs found
Figure 9: Aspects of ultimate legs during courtship behavior.
The arthropodium is the key innovation of arthropods. Its various modifications are the outcome of multiple evolutionary transformations, and the foundation of nearly endless functional possibilities. In contrast to hexapods, crustaceans, and even chelicerates, the spectrum of evolutionary transformations of myriapod arthropodia is insufficiently documented and rarely scrutinized. Among Myriapoda, Chilopoda (centipedes) are characterized by their venomous forcipulesâevolutionarily transformed walking legs of the first trunk segment. In addition, the posterior end of the centipedesâ body, in particular the ultimate legs, exhibits a remarkable morphological heterogeneity. Not participating in locomotion, they hold a vast functional diversity. In many centipede species, elongation and annulation in combination with an augmentation of sensory structures indicates a functional shift towards a sensory appendage. In other species, thickening, widening and reinforcement with a multitude of cuticular protuberances and glandular systems suggests a role in both attack and defense. Moreover, sexual dimorphic characteristics indicate that centipede ultimate legs play a pivotal role in intraspecific communication, mate finding and courtship behavior. We address ambiguous identifications and designations of podomeres in order to point out controversial aspects of homology and homonymy. We provide a broad summary of descriptions, illustrations, ideas and observations published in past 160 years, and propose that studying centipede ultimate legs is not only essential in itself for filling gaps of knowledge in descriptive morphology, but also provides an opportunity to explore diverse pathways of leg transformations within Myriapoda
The design, implementation, and performance of the LZ calibration systems
LUX-ZEPLIN (LZ) is a tonne-scale experiment searching for direct dark matter interactions and other rare events. It is located at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. The core of the LZ detector is a dual-phase xenon time projection chamber (TPC), designed with the primary goal of detecting Weakly Interacting Massive Particles (WIMPs) via their induced low energy nuclear recoils. Surrounding the TPC, two veto detectors immersed in an ultra-pure water tank enable reducing background events to enhance the discovery potential. Intricate calibration systems are purposely designed to precisely understand the responses of these three detector volumes to various types of particle interactions and to demonstrate LZ's ability to discriminate between signals and backgrounds. In this paper, we present a comprehensive discussion of the key features, requirements, and performance of the LZ calibration systems, which play a crucial role in enabling LZ's WIMP-search and its broad science program. The thorough description of these calibration systems, with an emphasis on their novel aspects, is valuable for future calibration efforts in direct dark matter and other rare-event search experiments
New constraints on ultraheavy dark matter from the LZ experiment
Searches for dark matter with liquid xenon time projection chamber experiments have traditionally focused on the region of the parameter space that is characteristic of weakly interacting massive particles, ranging from a few GeV/c2 to a few TeV/c2. Models of dark matter with a mass much heavier than this are well motivated by early production mechanisms different from the standard thermal freeze-out, but they have generally been less explored experimentally. In this work, we present a reanalysis of the first science run of the LZ experiment, with an exposure of 0.9ââtonneĂyr, to search for ultraheavy particle dark matter. The signal topology consists of multiple energy deposits in the active region of the detector forming a straight line, from which the velocity of the incoming particle can be reconstructed on an event-by-event basis. Zero events with this topology were observed after applying the data selection calibrated on a simulated sample of signal-like events. New experimental constraints are derived, which rule out previously unexplored regions of the dark matter parameter space of spin-independent interactions beyond a mass of 1017ââGeV/c2.
Published by the American Physical Society
2024
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Makerspace for a Relocated STEM Library
A small branch of a large academic library is in the process of moving locations from one area of campus to another. Although the new space is drastically smaller than what they currently have, the librarian wishes to build upon the small maker area that was recently created for the relaxation and enjoyment of the patrons. With the SCAFFOLD makerspace design framework, this new area will be created using the latest research in making and learning, keeping inclusivity at the forefront of all activities. This paper describes the current maker area, what the plans are for the new space, and how that space will be designed using this new SCAFFOLD method. It is hoped that this project can be replicated by any academic librarian wishing to add a small yet useful makerspace while staying within their budget
The Role of Relational Mobility has on Persistence of First Impressions Across Cultures
We are testing to see what role relational mobility, a socioenvironmental variable that determines how easy it is to form new relationships and exit old ones, plays in explaining how persistent first impressions are across cultures. Participants in the US and Japan were exposed to either positive or negative narratives to form an initial impression of a character named John. Then half the participants were presented with additional narratives that contradict the initial impression before completing impression formation measure, followed by a test that measures perceived relational mobility. Greater relational mobility may suggest greater significance of first impressions. Therefore, we hypothesized first impressions, despite later contradictions, will continue to persist in high relationally mobile environments (i.e., US) relative to low relationally mobile environment (i.e., Japan) and that this difference will be mediated by cultural variations in relational mobility scores
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Design, Synthesis, and Anti-leukemic Activity of Stereochemically Defined Constrained Analogs of FTY720 (Gilenya).
FTY720 functions as an immunosuppressant due to its effect on sphingosine-1-phosphate receptors. At doses well above those needed for immunosuppression, FTY720 also has anti-neoplastic actions. Our published work suggests that at least some of FTY720's anti-cancer activity is independent of its effects on S1P receptors and due instead to its ability to induce nutrient transporter down-regulation. Compounds that trigger nutrient transporter loss but lack FTY720's S1P receptor-related, dose-limiting toxicity have the potential to be effective and selective anti-tumor agents. In this study, a series of enantiomerically pure and stereochemically diverse O-substituted benzyl ethers of pyrrolidines was generated and tested for the ability to kill human leukemia cells. The stereochemistry of the hydroxymethyl was found to be a key determinant of compound activity. Moreover, phosphorylation of this group was not required for anti-leukemic activity