1,526 research outputs found
Dual Band Electrodes in Generator-Collector Mode: Simultaneous Measurement of Two Species
A computational model for the simulation of a double band collector-generator
experiment is applied to the situation where two electrochemical reactions
occur concurrently. It is shown that chronoamperometric measurements can be
used to take advantage of differences in diffusion coefficients to measure the
concentrations of both electroactive species simultaneously, by measuring the
time at which the collection efficiency reaches a specific value. The
separation of the electrodes is shown to not affect the sensitivity of the
method (in terms of percentage changes in the measured time to reach the
specified collection efficiency), but wider gaps can provide a greater range of
(larger) absolute values of this characteristic time. It is also shown that
measuring the time taken to reach smaller collection efficiencies can allow for
the detection of smaller amounts of whichever species diffuses faster. The case
of a system containing both ascorbic acid and opamine in water is used to
exemplify the method, and it is shown that mole fractions of ascorbic acid
between 0.055 and 0.96 can, in principle, be accurately measured.Comment: 34 pages, 8 figure
Snowmass Early Career: The Key Initiatives Organization
In April 2020, the 2019 and 2020 American Physical Society's Division of
Particles and Fields (APS DPF) Early Career Executive Committee (ECEC) members
were tasked with organizing the formation of a representative body for
High-Energy Physics (HEP) early career members for the Snowmass process by the
DPF Executive Committee. Here, we outline the structure we developed and the
process we followed to help provide context and guidance for future early
career Snowmass efforts. Our organization was composed of a cross-frontier
branch with committees on Inreach, Diversity Equity and Inclusion, Survey, and
Long Term Organizational Planning; in addition to the Frontier Coordination
branch, formed by committees responsible for liaising with each Frontier.
Throughout this document, the authors reflect on the triumphs and pitfalls of a
program created from nothing over a very short period of time, by people with
good intentions, who had no prior experience in building such an organization.
Through this exercise of reflecting, we sometimes find that we would recommend
a different path to our future selves. Insomuch as there are things to find
fault with, it is in the robustness of the systems we built and refined.Comment: contribution to Snowmass 2021, 16 pages, 0 figure
Molecular characterization of firefly nuptial gifts: a multi-omics approach sheds light on postcopulatory sexual selection
Postcopulatory sexual selection is recognized as a key driver of reproductive trait evolution, including the machinery required to produce endogenous nuptial gifts. Despite the importance of such gifts, the molecular composition of the non-gametic components of male ejaculates and their interactions with female reproductive tracts remain poorly understood. During mating, male Photinus fireflies transfer to females a spermatophore gift manufactured by multiple reproductive glands. Here we combined transcriptomics of both male and female reproductive glands with proteomics and metabolomics to better understand the synthesis, composition and fate of the spermatophore in the common Eastern firefly, Photinus pyralis. Our transcriptome of male glands revealed up-regulation of proteases that may enhance male fertilization success and activate female immune response. Using bottom-up proteomics we identified 208 functionally annotated proteins that males transfer to the female in their spermatophore. Targeted metabolomic analysis also provided the first evidence that Photinus nuptial gifts contain lucibufagin, a firefly defensive toxin. The reproductive tracts of female fireflies showed increased gene expression for several proteases that may be involved in egg production. This study offers new insights into the molecular composition of male spermatophores, and extends our understanding of how nuptial gifts may mediate postcopulatory interactions between the sexes.Tuft University. Faculty Research Fund (FRAC (S.M.L.)Arnold and Mabel Beckman Foundation. Beckman Young InvestigatorPew Scholars Program in the Biomedical SciencesSearle Scholars Progra
Differences in signal contrast and camouflage among different colour variations of a stomatopod crustacean, Neogonodactylus oerstedii
Animal colouration is often a trade-off between background matching for camouflage from predators, and conspicuousness for communication with con- or heterospecifics. Stomatopods are marine crustaceans known to use colour signals during courtship and contests, while their overall body colouration may provide camouflage. However, we have little understanding of how stomatopods perceive these signals in their environment or whether overall body coloration does provide camouflage from predators. Neogonodactylus oerstedii assess meral spot colour during contests, and meral spot colour varies depending on local habitat. By calculating quantum catch for N. oerstedii’s 12 photoreceptors associated with chromatic vision, we found that variation in meral spot total reflectance does not function to increase signal contrast in the local habitat. Neogonodactylus oerstedii also show between-habitat variation in dorsal body colouration. We used visual models to predict a trichromatic fish predator’s perception of these colour variations. Our results suggest that sandy and green stomatopods are camouflaged from a typical fish predator in rubble fields and seagrass beds, respectively. To our knowledge, this is the first study to investigate signal contrast and camouflage in a stomatopod. These results provide new insight into the function and evolution of colouration in a species with a complex visual system
The Dark Side of the Light Show: Predators of Fireflies in the Great Smoky Mountains
In the Great Smoky Mountains of East Tennessee, the Light Show is a popular seasonal attraction created by thousands of courting male Photinus carolinus fireflies (Coleoptera: Lampyridae) that flash in synchrony to locate females. This study was undertaken to provide a temporal snapshot of whether invertebrate predators are active within these dense and conspicuous firefly breeding aggregations. In addition, we examined whether female Photuris fireflies, which are specialist predators on other fireflies, show any feeding preferences within the diverse local firefly fauna. A field survey revealed a surprisingly diverse suite of generalist insectivores feeding on fireflies within P. carolinus breeding aggregations. In addition, laboratory studies revealed major differences in prey consumption rates when Photuris predators were given access to several lampyrid taxa. This suite of generalist and specialist predators appears to create a complex selective landscape that is predicted to be a powerful force shaping the evolution of firefly defenses
Using RNA sequencing to characterize female reproductive genes between Z and E Strains of European Corn Borer moth (Ostrinia nubilalis)
Lifestyle and personal wellness in particle physics research activities
Finding a balance between professional responsibilities and personal
priorities is a great challenge of contemporary life and particularly within
the HEPAC community. Failure to achieve a proper balance often leads to
different degrees of mental and physical issues and affects work performance.
In this paper, we discuss some of the main causes that lead to the imbalance
between work and personal life in our academic field. We present some
recommendations in order to establish mechanisms to create a healthier and more
equitable work environment, for the different members of our community at the
different levels of their careers
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