Water wave transmission by an array of floating disks

An experimental validation of theoretical models of transmission of regular water waves by large arrays of floating disks is presented. The experiments are conducted in a wave basin. The models are based on combined potential-flow and thin-plate theories, and the assumption of linear motions. A low-concentration array, in which disks are separated by approximately a disk diameter in equilibrium, and a high-concentration array, in which adjacent disks are almost touching in equilibrium, are used for the experiments. The proportion of incident wave energy transmitted by the disks is presented as a function of wave period, and for different wave amplitudes. Results indicate that the models predict wave energy transmission accurately for small-amplitude waves and low-concentration arrays. Discrepancies for large-amplitude waves and high-concentration arrays are attributed to wave overwash of the disks and collisions between disks. Validation of model predictions of rigid-body motions of a solitary disk are also presented

Pluto's Light Curve in 1933-1934

We are reporting on a new accurate photographic light curve of Pluto for 1933-1934 when the heliocentric distance was 40 AU. We used 43 B-band and V-band images of Pluto on 32 plates taken on 15 nights from 19 March 1933 to 10 March 1934. Most of these plates were taken with the Mount Wilson 60" and 100" telescopes, but 7 of the plates (now at the Harvard College Observatory) were taken with the 12" and 16" Metcalf doublets at Oak Ridge. The plates were measured with an iris diaphragm photometer, which has an average one-sigma photometric error on these plates of 0.08 mag as measured by the repeatability of constant comparison stars. The modern B and V magnitudes for the comparison stars were measured with the Lowell Observatory Hall 1.1-m telescope. The magnitudes in the plate's photographic system were converted to the Johnson B- and V-system after correction with color terms, even though they are small in size. We find that the average B-band mean opposition magnitude of Pluto in 1933-1934 was 15.73 +- 0.01, and we see a roughly sinusoidal modulation on the rotational period (6.38 days) with a peak-to-peak amplitude of 0.11 +- 0.03 mag. With this, we show that Pluto darkened by 5% from 1933-1934 to 1953-1955. This darkening from 1933-1934 to 1953-1955 cannot be due to changing viewing geometry (as both epochs had identical sub-Earth latitudes), so our observations must record a real albedo change over the southern hemisphere. The later darkening trend from 1954 to the 1980s has been explained by changing viewing geometry (as more of the darker northern hemisphere comes into view). Thus, we now have strong evidence for albedo changes on the surface of Pluto, and these are most easily explained by the systematic sublimation of frosts from the sunward pole that led to a drop in the mean surface albedo.Comment: Icarus in press, 24 page

The Origins of the Service State: On the Ironies of Intervention

This essay discusses the growth of the interventionist service state in the United States since the 1890s. It indicates how the exhaustion of the national entrepreneurial capitalist model necessitated state management of the economy, society and culture in order to consolidate the emergence of a transnational monopoly capitalist mode of economic growth. These bureaucratic interventions, however, from the 1930s through the 1970s dangerously eroded the continuing reproduction of civil society. Hence, the new social movements of the 1960s and 1970s are discussed as popular efforts to countervail the bureaucratic logic of monopoly capital and the service state. The new social movements\u27 focus on popular participation, community-building and political empowerment, in turn, might provide the organizational basis for creating new democratic economic, political and social alternatives to the over-administered consumer society constructed by the service state and transnational capital during the 20th century

A risky challenge for intransitive preferences

Philosophers have spent a great deal of time debating whether intransitive preferences can be rational. I present a risky decision that poses a challenge for the defender of intransitivity. The defender of intransitivity faces a trilemma and must either: (i) reject the rationality of intransitive preferences, (ii) deny State-wise Dominance, or (iii) accept the bizarre verdict that you can be required to pay to relabel the tickets of a fair lottery. If we take the first horn, then we have a synchronic refutation of intransitivity, an improvement on widely criticized diachronic arguments. I sketch possible responses that may rescue intransitivity and argue that each response is possible but generates an explanatory debt. I conclude by showing how the challenge here clarifies the foundations of decision theory without transitivity, conditional on some explanatory debt being payable

Deception as forgery: The role of reference information in honesty and deceit

Using concepts derived from cybernetics, self-presentation theory, and research on human self-regulation, I develop a cybernetic perspective of deception and self-presentation. In this perspective, human communication, both honest and deceptive, is controlled by feedback mechanisms. I report two studies designed to test the basic prediction derived from the cybernetic framework that deceivers are able to better emulate truth-tellers when they have access to relevant reference information about the way truth-tellers behave. Each study manipulated liars\u27 and truth-tellers\u27 access to reference information in a different manner. In Study 1, some participants viewed video recordings of people being interviewed in a manner highly similar to the way the participants would be imminently interviewed. I hypothesized that the exemplar videos would equip liars with reference information that would enable to them to \u27counterfeit\u27 a truth-teller\u27s behavior. In Study 2, some participants engaged in activities analogous to the task about which they were to be interviewed. Of those who completed the analogous activities, some were interviewed about those activities, and some were not. I hypothesized that liars who completed the analogous activities and were interviewed about them would gain reference information from their own behavior and be better able to counterfeit truthful responses. The results of Study 1 partially supported the hypotheses. The results of Study 2 failed to support the hypotheses, possibly because processes more complex than expected were at work. Implications of the results are discussed in relation to the cybernetic framework of self-presentation and deception

Rational risk‐aversion: good things come to those who weight

No existing normative decision theory adequately handles risk. Expected Utility Theory is overly restrictive in prohibiting a range of reasonable preferences. And theories designed to accommodate such preferences (for example, Buchak's (2013) Risk-Weighted Expected Utility Theory) violate the Betweenness axiom, which requires that you are indifferent to randomizing over two options between which you are already indifferent. Betweenness has been overlooked by philosophers, and we argue that it is a compelling normative constraint. Furthermore, neither Expected nor Risk-Weighted Expected Utility Theory allow for stakes-sensitive risk-attitudes—they require that risk matters in the same way whether you are gambling for loose change or millions of dollars. We provide a novel normative interpretation of Weighted-Linear Utility Theory that solves all of these problems

Electromyographical Analysis of Lower Extremity Muscle Activation During Variations of the Loaded Step-Up Exercise

The loaded step-up exercise allows strength and conditioning practitioners to incorporate a unilateral resistance for athletes while performing extension at the hip, knee, and plantar flexion at the ankle. This study evaluated the activation of the biceps femoris (BF), gluteus maximus (GMx), gluteus medius (GMe), rectus femoris, semitendinosus (ST), vastus lateralis, and vastus medialis during 4 variations of the step-up exercise to assess the specific muscle training stimulus of each exercise variation. The exercises included the step-up, crossover step-up, diagonal step-up, and lateral step-up. Fifteen women who regularly engaged in lower body resistance training performed the 4 exercises with 6 repetition maximum loads on a 45.72-cm (18-in.) plyometric box. Data were collected with a telemetered electromyography (EMG) system, and root mean square values were calculated for EMG data for eccentric and concentric phases. Results of a repeated-measures analysis of variance revealed a variety of differences in muscle activation between the exercises (

Combating drug resistance - Comparison of the antibiotic effect of Hydrastis canadensis extract and pure Berberine via Minimum Inhibitory Concentration assay

Herbal medicines are a melee of complex organic chemicals, making it difficult to ascertain their direct mechanism of action. In contrast to mainstream pharmaceuticals, it is argued that herbal medicines are effective because of multiple constituents working synergistically. The complexity of herbal medicines may give them advantages over simpler pharmaceuticals in combating antibiotic resistant microbes, but these advantages can be difficult to quantitate. Popular literature frequently espouses the healing properties of herbal medicines, but many of these claims are not scientifically supported. Many gains could be realized in public health and medicine if more research was aimed at validating / disproving commonly used remedies. “Home remedies” though scientifically unsupported may still be viable treatments for certain diseases. Goldenseal (Hydrastis canadesis) is commonly used as an herbal therapy to treat bacterial infections, particularly of the upper respiratory tract. In an attempt to provide an organized investigation of weakly supported remedies, this research shows that extracts from Goldenseal have a greater antibiotic effect than the alkaloid berberine, which is thought to be its primary active compound. Minimal Inhibitory Concentration assays were performed with Staphylococcus aureusand found that the MIC of Goldenseal extract is over 15 times lower than the MIC of pure berberine. The increased bactericidal effect of the Goldenseal extract suggests synergistic effects with other compounds in the extract. Elucidation of the synergistic elements of Goldenseal extract and their mechanisms of action would be useful in creating novel methods of decreasing bacterial resistance to antibiotics

FIPS: An R Package for Biomathematical Modelling of Human Fatigue Related Impairment

In many workplace contexts, accurate predictions of a human’s fatigue state can drastically improve system safety. Biomathematical models of fatigue (BMMs) are a family of dynamic phenomenological models that predict the neurobehavioural outcomes of fatigue (e.g., sleepiness, performance impairment) based on sleep/wake history (Dawson, Darwent, & Roach, 2017). However, to-date there are no open source implementations of BMMs, and this presents a significant barrier to their broadscale adoption by researchers and industry practitioners. FIPS is an open source R package (R Core Team, 2020) to facilitate BMM research and simulation. FIPS has implementations of several published bio-mathematical models and includes functions for easily manipulating sleep history data into the required data structures. FIPS also includes default plot and summary methods to aid model interpretation. Model objects follow tidy data conventions (Wickham, 2014), enabling FIPS to be integrated into existing research workflows of R users