6,449 research outputs found
Atmospheric Chemistry for Astrophysicists: A Self-consistent Formalism and Analytical Solutions for Arbitrary C/O
We present a self-consistent formalism for computing and understanding the
atmospheric chemistry of exoplanets from the viewpoint of an astrophysicist.
Starting from the first law of thermodynamics, we demonstrate that the van't
Hoff equation (which describes the equilibrium constant), Arrhenius equation
(which describes the rate coefficients) and procedures associated with the
Gibbs free energy (minimisation, rescaling) have a common physical and
mathematical origin. We address an ambiguity associated with the equilibrium
constant, which is used to relate the forward and reverse rate coefficients,
and restate its two definitions. By necessity, one of the equilibrium constants
must be dimensionless and equate to an exponential function involving the Gibbs
free energy, while the other is a ratio of rate coefficients and must therefore
possess physical units. We demonstrate that the Arrhenius equation takes on a
functional form that is more general than previously stated without recourse to
tagging on ad hoc functional forms. Finally, we derive analytical models of
chemical systems, in equilibrium, with carbon, hydrogen and oxygen. We include
acetylene and are able to reproduce several key trends, versus temperature and
carbon-to-oxygen ratio, published in the literature. The rich variety of
behavior that mixing ratios exhibit as a function of the carbon-to-oxygen ratio
is merely the outcome of stoichiometric book-keeping and not the direct
consequence of temperature or pressure variations.Comment: Accepted by ApJ. 9 pages, 4 figure
The Misery of Mitra: Considering Criminal Punishment for Computer Crimes
This paper analyzes the policies and philosophy of punishment for computer crimes under the post-Sept. 11th regime. I argue that the judicial discourse represented in Mitra represents a willingness to use the Computer Fraud and Abuse Act to go after defendants that cause trouble with critical infrastructures, the so-called “domestic terrorist.” This is manifested in the levels of punishments for such offenses and calls into question whether the traditional theories of punishment are applicable. I argue that as a policy, it makes good sense but the hazy definitions of terrorism may present problems for its success, and instead an approach that takes into consideration the perpetrators may help facilitate a resolution to this problem. I first give a discussion of the historical background and context to §1030. Next, I discuss the increase in punishment levels in § 1030. I then give a discussion about the pervasiveness of computer-chip technology and apply Mitra. Then, I analyze this in the context of theories of punishment, and discuss and present a solution to this slippery-slope problem
23(B)(2) Class Certification: Choosing an Approach for Certifying Civil Rights Discrimination Class Action Suits
The passage of the 1991 amendments to the Civil Rights Act granted injunctive as well as monetary damages for impermissible discrimination in the workplace. The Act also created a tension with the last revision of the Federal Rules of Civil Procedure in 1966. This revision prohibits the certification of a class under Rule 23(b)(2) if the damages sought are predominantly monetary in nature. On one end of this resulting tension is the desire to protect individuals rights to “opt-out” of a class action suit and maintain future individual actions. On the other end is the desire for judicial economy and the possibility to have sweeping remedies in the form of injunctive or declaratory relief. This tension is not reconcilable at the present and has fueled the growth of a three-way circuit split over what standard should be used to decide the certification of a class action civil rights discrimination suit. I argue that the circuit split has presented some courts to provide a higher burden to alleged victims of civil rights discrimination, in direct frustration of Congress’ legislative intent to compensate victims and give a punitive remedy against large companies that commit civil rights violations. I propose a burden-shifting solution to the circuit split that takes into account the interests of the parties in a class action suit as well as the effects of racial politics. I however advocate an appropriate and ultimate solution that revises the Federal Rule that clearly expresses an approach taking into account this tension
A Comparison of Water Potential and Mechanical Strength of Tip and Base Leaves in Heteromeles arbutifolia
Heteromeles arbutifolia, commonly known as, Hollywood, is a plant that is extremely common in the California Chaparral ecosystem. It was observed that with Hollywood, the leaves grow on the tips of the branches predominantly. However, there are leaves that grow on the base of the branches that appear to be equally as healthy. The purpose of this investigation was to determine whether the leaves that grow at the tips of the branches or at the base of the branches were better suited to benefit the rest of the plant. Our hypothesis was that the leaves at the tips of the branches would be better suited to benefit the rest of the plant due to their better access to sunlight, as the rest of the plant does not overshadow them. We determined which leaves would be better suited to benefit the plant by measuring the water potential and mechanical strength of leaves at the tip and bases of branches on Heteromeles arbutifolia plants across the street from the Pepperdine cross. Samples were collected from Heteromeles arbutifolia specimens that were both in the sun and in the shade. After the results were compared, the plants in the sun showed that leaves at the base were mechanically stronger than those at the tip, while plants in the shade showed leaves at the tip were mechanically stronger. As for water potential, base leaves had higher water potential across the board
Unanticipated differences between α- and γ-diaminobutyric acid-linked hairpin polyamide-alkylator conjugates
Hairpin polyamide–chlorambucil conjugates containing an {alpha}-diaminobutyric acid ({alpha}-DABA) turn moiety are compared to their constitutional isomers containing the well-characterized {gamma}-DABA turn. Although the DNA-binding properties of unconjugated polyamides are similar, the {alpha}-DABA conjugates display increased alkylation specificity and decreased rate of reaction. Treatment of a human colon carcinoma cell line with {alpha}-DABA versus {gamma}-DABA hairpin conjugates shows only slight differences in toxicities while producing similar effects on cell morphology and G2/M stage cell cycle arrest. However, striking differences in animal toxicity between the two classes are observed. Although mice treated with an {alpha}-DABA hairpin polyamide do not differ significantly from control mice, the analogous {gamma}-DABA hairpin is lethal. This dramatic difference from a subtle structural change would not have been predicted
When Causal Intervention Meets Adversarial Examples and Image Masking for Deep Neural Networks
Discovering and exploiting the causality in deep neural networks (DNNs) are
crucial challenges for understanding and reasoning causal effects (CE) on an
explainable visual model. "Intervention" has been widely used for recognizing a
causal relation ontologically. In this paper, we propose a causal inference
framework for visual reasoning via do-calculus. To study the intervention
effects on pixel-level features for causal reasoning, we introduce pixel-wise
masking and adversarial perturbation. In our framework, CE is calculated using
features in a latent space and perturbed prediction from a DNN-based model. We
further provide the first look into the characteristics of discovered CE of
adversarially perturbed images generated by gradient-based methods
\footnote{~~https://github.com/jjaacckkyy63/Causal-Intervention-AE-wAdvImg}.
Experimental results show that CE is a competitive and robust index for
understanding DNNs when compared with conventional methods such as
class-activation mappings (CAMs) on the Chest X-Ray-14 dataset for
human-interpretable feature(s) (e.g., symptom) reasoning. Moreover, CE holds
promises for detecting adversarial examples as it possesses distinct
characteristics in the presence of adversarial perturbations.Comment: Noted our camera-ready version has changed the title. "When Causal
Intervention Meets Adversarial Examples and Image Masking for Deep Neural
Networks" as the v3 official paper title in IEEE Proceeding. Please use it in
your formal reference. Accepted at IEEE ICIP 2019. Pytorch code has released
on https://github.com/jjaacckkyy63/Causal-Intervention-AE-wAdvIm
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Latanoprost with high precision, piezo-print microdose delivery for IOP lowering: clinical results of the PG21 study of 0.4 µg daily microdose.
Background:Topical high-precision piezo-print delivery of microdoses of latanoprost achieved significant IOP reduction consistent with the eyedropper effect but with a 75% reduced exposure to drugs and preservatives. Prostaglandin analogs are a mainstay glaucoma therapy. However, conventional eyedroppers deliver 30-50 µL drops that greatly exceed the physiologic 7-µL ocular tear film capacity. Eyedropper overdosing floods the eye with excess drug compounds and preservatives, resulting in ocular surface toxicity, periorbitopathy, and other well-characterized ocular side effects. Piezoelectric high-precision microdosing provides targeted delivery that can reduce exposure to both drug and preservatives compared to conventional eyedropper delivery, with the potential to deliver similar biologic effect. Methods:Both eyes (N=60) of 30 healthy volunteers received single 8-µL microdoses of 0.005% latanoprost (0.4 µg; µRx-latanoprost) on the morning of Days 1 and 2 using a high-precision, piezo-print horizontal delivery system. Diurnal IOP was measured before and 2 days after microdosing. Main efficacy outcomes were diurnal IOP change after µRx-latanoprost microdosing and accurate microdosing success rates, and the primary safety outcome was adverse event (AE) incidence. Results:µRx-latanoprost reduced baseline IOP by 26% and 30% at 1 and 2 days postadministration, respectively. Successful topical dosing was achieved in 100% of technician-assisted deliveries. All patients successfully self-administered microdoses after receiving training. Microdose administration was well tolerated and did not result in any AEs. Conclusion:Microdosing of 0.4 µg of µRx-latanoprost achieved significant IOP reduction. Lower ocular exposure with topical prostaglandin analog microdosing can enable new therapeutic opportunities for optimizing glaucoma treatment. Microdosing may also be beneficial in reducing ocular side effects associated with excessive drug product and preservatives often used to treat chronic ocular diseases such as glaucoma
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