Do We Need Partial Intentions?

Richard Holton has argued that the traditional account of intentions—which only posits the existence of all-out intentions—is inadequate because it fails to accommodate dual-plan cases; ones in which it is rationally permissible for an agent to adopt two competing plans to bring about the same end. Since the consistency norms governing all-out intentions prohibit the adoption of competing intentions, we can only preserve the idea that the agent in a dual-plan case is not being irrational if we attribute to them a pair of partial intentions. I argue that, contrary to initial appearances, (i) Holton has yet to offer us an actual account of partial intentions, and (ii) that the traditional account of intentions already has the resources necessary to accommodate dual-plan cases

Are Desires Beliefs about Normative Reasons?

Analytic Philosophy, EarlyView

A Study of the Effects of Pair Production and Axionlike Particle Oscillations on Very High Energy Gamma Rays from the Crab Pulsar

Pulsars are highly-magnetized rapidly-rotating neutron stars that emit energy throughout the electromagnetic spectrum. Despite decades of study, the emission mechanisms of pulsars are not well understood. New observations at the highest energy end of the spectrum can provide strong constraints on theoretical models of pulsar emission. The strong magnetic fields of pulsar magnetospheres accelerate charged particles to relativistic energies and these particles emit very high energy (VHE; E \u3e 100 GeV) gamma rays. In addition to creating conditions to emit gamma rays, the magnetic fields are powerful enough to attenuate gamma rays through pair production. The attenuation of gamma rays limits the photon energies that may escape the magnetosphere, unless an additional physical process decreases the opacity of the magnetosphere to these photons. The interaction of axions or axionlike particles (ALPs) with magnetic fields is one such process. Some extensions of the Standard Model suggest the existence of axions, which are light pseudoscalar bosons with a two-photon coupling. As a result of this coupling photon-ALP oscillations can occur in the strong fields of a pulsar magnetosphere. For typical parameters of pulsar magnetospheres, VHE photons fall within the strong mixing-regime for oscillations when the axion mass is 10−3 eV \u3c ma \u3c 10 eV and the axion-photon coupling constant is 10−11 \u3c gaγ \u3c 10−6 . Axion-photon oscillations within the inner magnetosphere would decrease its opacity as axions would propagate unimpeded by pair attenuation. In this dissertation, the VHE photon emission and propagation from pulsars is studied in detail. New observations and analysis of the Crab pulsar from the VERITAS experiment are presented which extend the Crab spectrum to higher energies. The magnetospheres of pulsars are simulated using a retarded vacuum dipole solution for the magnetic field. VHE photon emission and propagation is studied using a Monte Carlo method. The emission regions are defined using the slot gap and outer gap models. The effects of pair production and axion-photon mixing are considered and light curves and spectra are produced to illustrate the influence of both processes on the observations of pulsars. For some geometries, VHE photons are heavily attenuated by pair production. Axion-photon mixing is shown to reduce the opacity of pulsar magnetospheres allowing a larger fraction of VHE photons to survive propagation. However, we find that the inclusion of QED effects on the effective photon mass limit the conversion probability over much of the region where strong pair attenuation is expected

The Rational Significance of Desire

My dissertation addresses the question "do desires provide reasons?" I present two independent lines of argument in support of the conclusion that they do not. The first line of argument emerges from the way I circumscribe the concept of a desire. Complications aside, I conceive of a desire as a member of a family of attitudes that have imperative content, understood as content that displays doability-conditions rather than truth-conditions. Moreover, I hold that an attitude may provide reasons only if it has truth-evaluable content. Insofar as desires lack truth-evaluable content, I hold that the content of a desire has the wrong kind of logical structure to provide reasons. My second line of argument claims that even if a desire did have truth-evaluable content, it would not follow that desires provide reasons. This is because a desire has no more rational significance than a guess or coin-flip. My argument relies on what I call the non-substitutability principle, the thesis that (all things being equal) one cannot substitute something that lacks rational significance, relative to some attitude, A, for something that has rational significance, relative to A, and leave the rational standing of A unchanged. For example, one cannot substitute the guess that P (i.e., something that lacks rational significance relative to the belief that P) for the perception that P (i.e., something that is rationally significant relative to the belief that P) without altering the rational standing of the belief. I argue that when the non-substitutability principle is applied to a desire that gives rise to an intention, it turns out that one can always substitute a guess or coin-flip (i.e., something that lacks rational significance relative to the intention) for the desire, without altering the rational standing of the intention. I take this to show that desires are not rationally significant relative to the intentions to which they giv

Analysis of the Crab Nebula and Pulsar

Although the Crab Nebula is well understood, the Very Energetic Radiation Imaging Telescope Array System (VERITAS) still regularly observes the Crab\u27s highest energy emissions. These emissions are used to calibrate the telescopes, further, document the system, and investigate the validity of physical models. Our research this summer is geared to analyze data from 2018-2022 to add to an ongoing research project investigating the long term variability of the Crab Nebula’s emission

An Introduction to the VERITAS Observatory

Located at the base of Mount Hopkins, Arizona, at an elevation of approximately 4200 feet, the Very Energetic Radiation Imaging Telescope Array System (VERITAS) is a ground-based gamma ray observatory containing four Cherenkov telescopes designed to detect very high energy gamma rays with energies ranging from 100GeV to 10TeV using the Imaging Atmospheric Cherenkov Technique. In April 2007, VERITAS began successful operations with all four telescopes. As of today, over 15 years of data has been taken by the VERITAS array, stored in an archive of data, and used for a wide variety of research, publications, PhD theses, and conventions examining some of the most violent and energetic processes in our universe

Method for RNA extraction and transcriptomic analysis of single fungal spores

Transcriptomic analysis of single cells has been increasingly in demand in recent years, thanks to technological and methodological advances as well as growing recognition of the importance of individuals in biological systems. However, the majority of these studies have been performed in mammalian cells, due to their ease of lysis and high RNA content. No single cell transcriptomic analysis has yet been applied to microbial spores, even though it is known that heterogeneity at the phenotype level exists among individual spores. Transcriptomic analysis of single spores is challenging, in part due to the physically robust nature of the spore wall. This precludes the use of methods commonly used for mammalian cells. Here, we describe a simple method for extraction and amplification of transcripts from single fungal conidia (asexual spores), and its application in single-cell transcriptomics studies. The method can also be used for studies of small numbers of fungal conidia, which may be necessary in the case of limited sample availability, low-abundance transcripts or interest in small subpopulations of conidia.• The method allows detection of transcripts from single conidia of Aspergillus niger• The method allows detection of genomic DNA from single conidia of Aspergillus nige