A large aggregation of self-fragmenting mushroom corals in the Arabian/Persian Gulf

[No abstract available]The Arabian/Persian Gulf is a relatively shallow, semi‐enclosed sea at high tropical latitudes, surrounded by desert land with limited water exchange, high salinities, and extreme annual fluctuations of surface temperatures (Sheppard et al. 1992). These conditions restrict the Gulf's marine biodiversity, as demonstrated by the mushroom coral family Fungiidae (Scleractinia). In the Gulf, this family has only been known to be represented by the free‐living (unattached) species, Cycloseris curvata (Hoeksema, 1989), which is considered uncommon (Riegl et al. 2012), whereas this coral family consists of 52 described species in the entire tropical Indo‐Pacific, 40 of which are unattached (Benzoni et al. 2012).This publication was made possible by NPRP awards [NPRP 7-1129-1-201 and NPRP 8-952-1-186] from the Qatar National Research Fund (a member of the Qatar Foundation) and by the Qatar Museums Authority through the project �Research on Qatar�s geological history and present-day biodiversity� granted to Naturalis Biodiversity Center. The statements made herein are solely the responsibility of the authors. The whip coral species (Fig. 1) was identified by L. P. van Ofwegen. We thank the reviewer and editor for their constructive comments.Scopu

The Influence of Macroscale Stress Concentrations on the Near-Resonant Thermomechanics of Mock Energetic Materials

The characterization of particulate composite energetic materials, both with and without stress concentration, is currently of great interest to the defense community. This work seeks to further characterize the self-heating effect of composite energetic plates, particularly around regions of high stress, when subjected to harmonic excitation near resonance. Mock energetic plates with macroscale stress concentrations are prepared in various compositions based on the PBXN-109 formulation, and are tested near the first resonant frequency using an electrodynamic shaker. The resulting mechanical and thermal responses are recorded using a laser Doppler vibrometer and an infrared camera, respectively. Upon comparison between the regions of heightened strain and stress, a strong correlation was found between the respective areas of heightened response. Additionally, the effect of the type of stress concentration on the resulting levels of stress and strain is discussed. This characterization will aid the defense community in their mission to better understand particulate composite energetic materials

High-pressure structural investigation of several zircon-type orthovanadates

Room temperature angle-dispersive x-ray diffraction measurements on zircon-type EuVO4, LuVO4, and ScVO4 were performed up to 27 GPa. In the three compounds we found evidence of a pressure-induced structural phase transformation from zircon to a scheelite-type structure. The onset of the transition is near 8 GPa, but the transition is sluggish and the low- and high-pressure phases coexist in a pressure range of about 10 GPa. In EuVO4 and LuVO4 a second transition to a M-fergusonite-type phase was found near 21 GPa. The equations of state for the zircon and scheelite phases are also determined. Among the three studied compounds, we found that ScVO4 is less compressible than EuVO4 and LuVO4, being the most incompressible orthovanadate studied to date. The sequence of structural transitions and compressibilities are discussed in comparison with other zircon-type oxides.Comment: 34 pages, 2 Tables, 11 Figure

The Influence of Thermal Conditions on the Thermomechanics of Particulate-Composite, Mock Explosive Samples under Near-Resonant Excitation

Vapor detection is one of the most effective ways to find hidden plastic-bonded explosives in the field today. In recent years, it has been demonstrated that providing near-resonant vibratory excitation to explosives dramatically increases their vapor pressure, allowing for easier detection. Unfortunately, there currently exists a limited understanding of the thermomechanics of energetic material. This study seeks to help fill this technical void by exploring the thermomechanics of mock plastic-bonded explosives using direct mechanical excitation with varying thermal conditions. Using two different ambient thermal boundary conditions (insulated geometric boundaries and boundaries with free convection), a 7 by 10 by 0.5 HTPB/Ammonium Chloride particulate-composite plate was tested by fixing it to an electrodynamic shaker and vibrating the sample at low frequencies (under 1000 Hz). Vibratory and thermal data was collected using a Polytec scanning laser Doppler vibrometer and a FLIR infrared camera. It was determined that insulating boundary conditions, allow the mock energetic material temperature to increase significantly as compared to the convective boundaries under near-resonant excitation. Future work will investigate alternate thermal boundary and initial conditions, as well as alternate mock energetic materials

A Parametric Finite-Element Model for Evaluating Segmented Mirrors with Discrete, Edgewise Connectivity

Since future astrophysics missions require space telescopes with apertures of at least 10 meters, there is a need for on-orbit assembly methods that decouple the size of the primary mirror from the choice of launch vehicle. One option is to connect the segments edgewise using mechanisms analogous to damped springs. To evaluate the feasibility of this approach, a parametric ANSYS model that calculates the mode shapes, natural frequencies, and disturbance response of such a mirror, as well as of the equivalent monolithic mirror, has been developed. This model constructs a mirror using rings of hexagonal segments that are either connected continuously along the edges (to form a monolith) or at discrete locations corresponding to the mechanism locations (to form a segmented mirror). As an example, this paper presents the case of a mirror whose segments are connected edgewise by mechanisms analogous to a set of four collocated single-degree-of-freedom damped springs. The results of a set of parameter studies suggest that such mechanisms can be used to create a 15-m segmented mirror that behaves similarly to a monolith, although fully predicting the segmented mirror performance would require incorporating measured mechanism properties into the model. Keywords: segmented mirror, edgewise connectivity, space telescop

A Flux-Pinning Mechanism for Segment Assembly and Alignment

Currently, the most compelling astrophysics questions include how planets and the first stars formed and whether there are protostellar disks that contain large organic molecules. Although answering these questions requires space telescopes with apertures of at least 10 meters, such large primaries are challenging to construct by scaling up previous designs; the limited capacity of a launch vehicle bounds the maximum diameter of a monolithic primary, and beyond a certain size, deployable telescopes cannot fit in current launch vehicle fairings. One potential solution is connecting the primary mirror segments edgewise using flux-pinning mechanisms, which are analogous to non-contacting damped springs. In the baseline design, a flux-pinning mechanism consists of a magnet and a superconductor separated by a predetermined gap, with the damping adjusted by placing aluminum near the interface. Since flux pinning is possible only when the superconductor is cooled below a critical temperature, flux-pinning mechanisms are uniquely suited for cryogenic space telescopes. By placing these mechanisms along the edges of the mirror segments, a primary can be built up over time. Since flux pinning requires no mechanical deployments, the assembly process could be robotic or use some other non-contacting scheme. Advantages of this approach include scalability and passive stability

An Integral Kernel for Weakly Pseudoconvex Domains

A new explicit construction of Cauchy-Fantappi\'e kernels is introduced for an arbitrary weakly pseudoconvex domain with smooth boundary. While not holomorphic in the parameter, the new kernel reflects the complex geometry and the Levi form of the boundary. Some estimates are obtained for the corresponding integral operator, which provide evidence that this kernel and related constructions give useful new tools for complex analysis on this general class of domains

Endocrine changes related to dog domestication: Comparing urinary cortisol and oxytocin in hand-raised, pack-living dogs and wolves

Dogs are exceptionally well adapted to life close to humans, and alterations in their endocrine system during the domestication process may be an underlying mechanism. In particular, it has been suggested that low circulating cortisol concentrations in conjunction with simultaneously high oxytocin concentrations may have resulted in dogs' increased docility (‘selection for tameness’ hypothesis) and heightened propensity to interact and form relationships with humans (‘hypersociability’ hypothesis) compared to wolves. To investigate this, we analyzed cortisol and oxytocin metabolite concentrations from urine samples of hand-raised, pack-living domestic dogs and their non-domestic relatives, grey wolves. Based on the hypotheses outlined above, we predicted lower cortisol but higher oxytocin concentrations in dogs than wolves. In contrast to our prediction, we found higher cortisol concentrations in dogs than wolves. However, oxytocin concentrations were higher in dogs compared to wolves although the effect was relatively small. Indeed, male dogs had the highest oxytocin concentrations while female dogs' oxytocin concentrations were comparable to wolves'. Feeding status, reproductive phase, and conspecific social interactions also significantly affected cortisol and oxytocin concentrations. Furthermore, we compared two methods of correcting for variable water content of urine samples. We discuss our results in light of physiological and behavioral changes during domestication and highlight the importance of accounting for confounding variables in future studies

Life experience rather than domestication accounts for dogs’ increased oxytocin release during social contact with humans

Dogs’ increased human-directed sociability compared to wolves may be the result of increased oxytocin system activity and decreased stress responses, but comparative studies accounting for life experience are lacking. We compared hand-raised, pack-living wolves’ and dogs’ behavior and hormone concentrations after interacting with a closely bonded and a familiar human. Both preferred the bonded partner, but dogs showed less variability in human-directed sociability than wolves. Physical contact was not associated with oxytocin but correlated positively with glucocorticoids in the pack-living animals when the human was not bonded. To clarify the role of life experience, we tested pet dogs and found that oxytocin concentrations correlated positively with physical contact with their owners, while glucocorticoids remained unaffected. Results show that, given similar experiences, wolf-dog differences in human-directed sociability and associated hormones are subtle and indicate that factors related to life as a pet dog rather than domestication account for oxytocin release during human–dog interactions

Environmental representativity in marine protected area networks over large and partly unexplored seascapes

Converting assemblages of marine protected areas (MPAs) into functional MPA networks requires political will, multidisciplinary information, coordinated action and time. We developed a new framework to assist planning environmental representativity in a network across the marine space of Portugal, responding to a political commitment to protect 14% of its area by 2020. An aggregate conservation value was estimated for each of the 27 habitats identified, from intertidal waters to the deep sea. This value was based on expert-judgment scoring for environmental properties and features relevant for conservation, chosen to reflect the strategic objectives of the network, thus providing an objective link between conservation commitments and habitat representativity in space. Additionally, habitats' vulnerability to existing anthropogenic pressures and sensitivity to climate change were also scored. The area coverage of each habitat in Portugal and within existing MPAs (regionally and nationally) was assigned to a scale of five orders of magnitude (from 10%) to assess rarity and existing representation. Aggregate conservation value per habitat was negatively correlated with area coverage, positively correlated with vulnerability and was not correlated with sensitivity. The proposed framework offers a multi-dimensional support tool for MPA network development, in particular regarding the prioritization of new habitats to protect, when the goal is to achieve specific targets while ensuring representativity across large areas and complex habitat mosaics. It requires less information and computation effort in comparison to more quantitative approaches, while still providing an objective instrument to scrutinize progress on the implementation of politically set conservation targets.Agência financiadora Número do subsídio Oceanic Observatory of Madeira M1420-01-0145-FEDER-000001-OOM national funds through FCT UID/BIA/00329/2013 UID/Multi/04326/2013 Fundacao para a Ciencia e a Tecnologia SFRH/BPD/95334/2013 CESAM - FCT/MEC through national funds UID/AMB/50017 - POCI-01-0145-FEDER-007638 FEDER FCT SFRH/BPD/94320/2013 MARE - UID/MAR/04292/2019 EU through the Cohesion Fund POSEUR-03-2215-FC-000046 POSEUR-03-2215-FC-000047 FCT national funds ECO/28687/2017info:eu-repo/semantics/publishedVersio