Mechanisms underlying the production of carapace vibrations and associated waterborne sounds in the American lobster, Homarus americanus

American lobsters produce carapace vibrations, which also lead to waterborne acoustic signals, by simultaneously contracting the antagonistic remotor and promotor muscles located at the base of the second antenna. These vibrations have a mean frequency of 183.1 Hz (range 87–261 Hz), range in duration from 68 to 1720 ms (mean 277.1 ms) and lead to waterborne sounds of similar frequencies. Lobsters most often produce these signals using only one pair of muscles at a time and alternate between the muscles of the left and right antennae when making a series of vibrations. Occasionally, they vibrate their carapace by simultaneously contracting both sets of muscles. While the remotor muscle is required for producing carapace vibrations, the promotor appears to play a secondary role. Electrical stimulation of the remotor, but not the promotor, results in the production of vibrations, while lesions of the remotor, but not promotor, eliminate the ability of lobsters to vibrate their carapace. Lobsters of all sizes and both sexes produce these signals when startled, grasped or threatened. However, at this time, the behavioral significance of vibration and/or sound production by American lobsters is not known

The degradation of alzak by short wavelength ultraviolet radiation

The changes in reflectance of thermal aluminum coating samples exposed to different irradiating utraviolet wavelengths are discussed. It is shown that the coating is damaged faster and further by 180 to 210 in radiation than by Lyman alpha radiation. On an equivalent incident energy basis, Lyman alpha does less damage than 180 to 210 nm radiation. Above 300 nm no degradation is observed for long exposures and below 300 nm increasing degradation with decreasing wavelength is found. It is concluded that Lyman alpha radiation need not be included in laboratory testing of this thermal coating for spacecraft structures

Solar absorptance and thermal emittance of some common spacecraft thermal-control coatings

Solar absorptance and thermal emittance of spacecraft materials are critical parameters in determining spacecraft temperature control. Because thickness, surface preparation, coatings formulation, manufacturing techniques, etc. affect these parameters, it is usually necessary to measure the absorptance and emittance of materials before they are used. Absorptance and emittance data for many common types of thermal control coatings, are together with some sample spectral data curves of absorptance. In some cases for which ultraviolet and particle radiation data are available, the degraded absorptance and emittance values are also listed

Information literacy and regimes of truth: continuity and disruption

Introduction. This study sought to understand how academic librarians perceived the information literacy programmes that they provided, what this might mean for democratic practices in a society and how this work was linked to a regime of truth. Method. Eighteen librarians who provide information literacy programmes and services in university libraries in Sydney, Australia, participated in semi-structured interviews. Analysis. Through a thematic analysis using a priori and open coding, the factors the librarians consider important in their work were identified, including changes to the ways they implement information literacy programmes and services, and how these linked to regimes of truth. Results. There was a strong emphasis on the authority of information and the development of critical thinking, although in some universities, the responsibility for information literacy programmes is devolving to study skills support staff. Some librarians stressed the importance of ensuring that academics understood the government policy changes in the valuing of scholarly output. Conclusions. Although all librarians noted changes in the university and in their work, their focus on the authority of information and the ways it is established suggest that, while changes to the regime of truth may be apparent, a regime of post-truth is not yet emerging

NECAP: NASA's Energy-Cost Analysis Program. Part 2: Engineering manual

Each segment of NECAP is described, and the algorithms that were programmed into each subroutine are presented. For part 1, see

NECAP: NASA's Energy-Cost Analysis Program. Part 1: User's manual

The NECAP is a sophisticated building design and energy analysis tool which has embodied within it all of the latest ASHRAE state-of-the-art techniques for performing thermal load calculation and energy usage predictions. It is a set of six individual computer programs which include: response factor program, data verification program, thermal load analysis program, variable temperature program, system and equipment simulation program, and owning and operating cost program. Each segment of NECAP is described, and instructions are set forth for preparing the required input data and for interpreting the resulting reports

Human in the Loop Integrated Life Support Systems Ground Testing

Human exploration missions beyond low earth orbit will be long duration with abort scenarios of days to months. This necessitates provisioning the crew with all the things they will need to sustain themselves while carrying out mission objectives. Systems engineering and integration is critical to the point where extensive integrated testing of life support systems on the ground is required to identify and mitigate risks. Ground test facilities (human-rated altitude chambers) at the Johnson Space Center are being readied to integrate all the systems for a mission along with a human test crew. The relevant environment will include deep space habitat human accommodations, sealed atmosphere capable of 14.7 to 8 psi total pressure and 21 to 32% oxygen concentration, life support systems (food, air, and water), communications, crew accommodations, medical, EVA, tools, etc. Testing periods will approximate those of the expected missions (such as a near Earth asteroid, Earth-Moon L2 or L1, the moon, Mars). This type of integrated testing is needed for research and technology development as well as later during the mission design, development, test, and evaluation (DDT&E) phases of an approved program. Testing will evolve to be carried out at the mission level fly the mission on the ground . Mission testing will also serve to inform the public and provide the opportunity for active participation by international, industrial and academic partners

Sum index and difference index of graphs

Let $G$ be a nonempty simple graph with a vertex set $V(G)$ and an edge set $E(G)$. For every injective vertex labeling $f:V(G)\to\mathbb{Z}$, there are two induced edge labelings, namely $f^+:E(G)\to\mathbb{Z}$ defined by $f^+(uv)=f(u)+f(v)$, and $f^-:E(G)\to\mathbb{Z}$ defined by $f^-(uv)=|f(u)-f(v)|$. The sum index and the difference index are the minimum cardinalities of the ranges of $f^+$ and $f^-$, respectively. We provide upper and lower bounds on the sum index and difference index, and determine the sum index and difference index of various families of graphs. We also provide an interesting conjecture relating the sum index and the difference index of graphs

An Observational Diagnostic for Ultraluminous X-Ray Sources

We consider observational tests for the nature of Ultraluminous X-ray sources (ULXs). These must distinguish between thermal-timescale mass transfer on to stellar-mass black holes leading to anisotropic X-ray emission, and accretion on to intermediate-mass black holes. We suggest that long-term transient behavior via the thermal-viscous disk instability could discriminate between these two possibilities for ULXs in regions of young stellar populations. Thermal-timescale mass transfer generally produces stable disks and persistent X-ray emission. In contrast, mass transfer from massive stars to black holes produces unstable disks and thus transient behavior, provided that the black hole mass exceeds some minimum value. This minimum mass depends primarily on the donor mass and evolutionary state. We show that it exceeds 50 solar masses for a large fraction (greater than 90%) of the mass-transfer lifetime for the most likely donors in young clusters. Thus if long-term monitoring reveals a large transient fraction among ULXs in a young stellar population, these systems would be good candidates for intermediate-mass black holes in a statistical sense; information about the donor star is needed to make this identification secure in any individual case. A transient ULX population would imply a much larger population of quiescent systems of the same type.Comment: 4 pages, 2 figure, ApJ Letters, in press (correct figure 2 included in this version

Effects of Preexisting Psychotropic Medication Use on a Cohort of Patients with Ischemic Stroke Outcome

Background: Several studies investigated the use of selective serotonin reuptake inhibitors (SSRI) after ischemic stroke to improve motor recovery. However, little is known about the effects of preexisting psychotropic medication use (PPMU), such as antidepressants, on a long-term ischemic stroke functional disability. Objective: We sought to determine the prevalence of PPMU and whether PPMU relates to the long-term clinical outcome in a cohort of patients presenting with acute ischemic strokes. Methods: We retrospectively analyzed 323 consecutive patients who presented with an acute ischemic stroke in a single institution between January 2015 and December 2017. Baseline characteristics, functional disability as measured by the modified Rankin Scale (mRS), and major adverse cardiovascular complications (MACE) within 365 days were recorded. The comparison groups included a control group of ischemic stroke patients who were not on psychotropic medications before and after the index ischemic stroke and a second group of poststroke psychotropic medication use (PoMU), which consisted of patients started on psychotropic medication during the index admission. Results: The prevalence of PPMU in the studied cohort was 21.4% (69/323). There was a greater proportion of females in the PPMU than in the comparison groups (P \u3c 0.001), while vascular risk factors were similar in all groups, except for an increased presence of posterior circulation infarcts in the PPMU (37.4% vs. 18.8%, P \u3c 0.001). Among the patients with available 1-year follow-up data (n = 246), we noted significantly greater improvement in stroke deficits, measured by National Institute of Health Stroke Scale (NIHSS) between PPMU and PoMU vs. control (3 (0-7) versus 1 (0-4), P = 0.041). The 1-year mRS was worse in PPMU and PoMU compared to the control group (2 (IQ 1-3) vs. 2 (IQ 0-3) vs. 1 (IQ 0-2), respectively, P = 0.013), but delta mRS reflecting the degree of mRS improvement showed no significant difference between any PMU and control patients (P = 0.76). There was no statistically significant difference in MACE. Conclusion: PPMU in ischemic stroke is common; it can be beneficial in ischemic stroke in the long-term clinical outcome and is not associated with increased risks of MACE