Unconstrained Astrometric Orbits for Hipparcos Stars with Stochastic Solutions

A considerable number of astrometric binaries whose positions on the sky do not obey the standard model of mean position, parallax and linear proper motion, were observed by the Hipparcos satellite. Some of them remain non-discovered, and their observational data have not been properly processed with the more adequate astrometric model that includes nonlinear orbital motion. We develop an automated algorithm based on "genetic optimization", to solve the orbital fitting problem with no prior information about the orbital elements is available (from, e.g., spectroscopic data or radial velocity monitoring). We test this method on Hipparcos stars with known orbital solutions in the catalog, and further apply it to stars with stochastic solutions, which may be unresolved binaries. At a confidence level of 99%, orbital fits are obtained for 65 stars, most of which have not been known as binary. A few of the new probable binaries with A-type primaries with periods 444-2015 d are chemically peculiar stars, including Ap and \lambda Boo type. The anomalous spectra of these stars are explained as admixture of the light from the unresolved, sufficiently bright and massive companions. We estimate the apparent orbits of four stars which have been identified as members of the 300 Myr-old UMa kinematic group. Another four new nearby binaries may include low-mass M-type or brown dwarf companions. Similar astrometric models and algorithms can be used for binary stars and planet hosts observed by SIM PlanetQuest and Gaia

Standard and retrial queueing systems: a comparative analysis

We describe main models and results of a new branch of the queueing theory, theory of retrial queues, which is characterized by the following basic assumption: a customer who cannot get service (due to finite capacity of the system, balking, impatience, etc.)leaves the service area, but after some random delay returns to the system again. Emphasis is done on comparison with standard queues with waiting line and queues with losses. We give a survey of main results for both single server M/G/1 type and multiserver M/M/c type retrial queues and discuss similarities and differences between the retrial queues and their standard counterparts. We demonstrate that although retrial queues are closely connected with these standard queueing models they, however, ossess unique distinguished features. We also mention some open problems.We describe main models and results of a new branch of the queueing theory, theory of retrial queues, which is characterized by the following basic assumption: a customer who cannot get service (due to finite capacity of the system, balking, impatience, etc.)leaves the service area, but after some random delay returns to the system again. Emphasis is done on comparison with standard queues with waiting line and queues with losses. We give a survey of main results for both single server M/G/1 type and multiserver M/M/c type retrial queues and discuss similarities and differences between the retrial queues and their standard counterparts. We demonstrate that although retrial queues are closely connected with these standard queueing models they, however, ossess unique distinguished features. We also mention some open problems

Topical clobetasol for the treatment of toxic epidermal necrolysis: study protocol for a randomized controlled trial.

BackgroundToxic epidermal necrolysis (TEN) is a rare systemic allergic drug eruption with high patient mortality. Currently, no established treatments have been shown to be effective for TEN beyond supportive care. Prior studies of systemic corticosteroids have yielded conflicting data, with some showing a possible benefit and others reporting in increased mortality. However, topical steroids have shown promise for treatment of ocular sequelae of TEN, such as scarring and vision loss. We have designed a randomized controlled trial to evaluate topical clobetasol for treatment of the epidermal manifestations of TEN. In addition, we propose genetic studies to characterize the TEN transcriptome and alterations in cutaneous gene expression that might occur following topical steroid treatment.Methods/designThis split-body randomized, double-blind, placebo-controlled Phase IIa proof-of-concept trial will evaluate the safety and efficacy of once-daily topical clobetasol applied to the skin of patients with TEN. This multicenter trial will recruit a total of 15 patients between the ages of 12 and 85 from the University of California Davis Medical Center and Shriners Hospital for Children inpatient burn units. Designated treatment areas on opposite sides of the body will be treated with blinded clobetasol 0.05% ointment or control petrolatum ointment daily for 14 days. On day 3 of therapy, a biopsy will be taken from the treated area for genetic studies. The primary study aims will be to establish the safety of topical clobetasol treatment and determine the time to cessation of skin detachment for the control and clobetasol-treated areas. Secondary endpoints will evaluate efficacy using parameters such as time to 90% re-epithelialization and percentage of affected skin at 0, 3, 6, 9, 12 and 15 days. Genomic DNA and RNA will be obtained from biopsy samples, to characterize the TEN transcriptome and identify changes in gene expression after topical steroid treatment.DiscussionTopical steroids have shown promise for treating ocular complications of TEN, but to date have not been evaluated for cutaneous manifestations of the disease. This trial will investigate clinical and molecular outcomes of topical clobetasol application and hopefully provide insight into the disease pathophysiology.Trial registrationClinicalTrials.gov NCT02319616. https://clinicaltrials.gov/ct2/show/NCT02351037

From an Embodied Understanding to Ethical Considerations during Creative Practice

This paper discusses material-based creative processes in the context of higher education. The focus is on the ethical aspects related to material considerations during the iterative phases of personal projects. We explore how personal feelings and an embodied understanding of the material world influence decisions on how and why we engage with different materials during creative processes. Recent trends in material-based research aim to explore the relationships between humans and materials, examining them as equal members in research and thus challenging the top-down perception of materials as mere resources for human needs. However, this kind of approach to research and material-based creative practices requires ethical considerations that reach not only the human but also the non-human world. In this paper, we open this discussion by examining design students’ creative processes, which unfold an understanding of ethics in relation to non-humans. We build on data consisting of documentation, reflections and outcomes derived from the creative processes of four MA-level students and discuss a number of complementing ethical guidelines for art, culture and earth systems. The paper uses ‘ethically disturbing moments’ as an analytical tool for looking into students’ material choices in their creative processes. The four selected processes open up a personal connection to materials that results in ethical considerations during the creative practice and thus reveal the need for discussing material-focused ethics in the context of craft, design and art education. Personal aspects related to materials are discussed as embodied understanding and are seen to affect the ethics of engaging with materials

Ammonia and salinity tolerance of Penaeus monodon across eight breeding families

© 2016 Chen et al. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Ammonia nitrogen and salinity tolerance of Penaeus monodon from eight selected breeding families were evaluated at the concentration of 67.65 mg L−1 ammonia-N and reducing salinity from 15 to 0 ‰. The final survival of family A (88.67 ± 9.81 %) was highest, and the final survival of family B was lowest (24.33 ± 14.01 %) after the ammonia tolerance test. Upon completing the sudden drop salinity test from 15 to 0 ‰, the highest survival was observed in family B (98.00 ± 1.73 %), and the lowest survival was found in family H (18.00 ± 1.73 %). Family A showed the strongest ability to tolerate ammonia stress, and family B showed the strongest tolerance to low salinity. This study suggests that the tolerance of salinity and ammonia nitrogen varied between breeding families. Results from the present study provide useful information towards selective breeding in shrimp in aquaculture for environmental tolerance

Length–weight relationship and condition factor of giant tiger shrimp, Penaeus monodon (Fabricius, 1798) from four breeding families

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Background: Length–weight relationships and condition factors of giant tiger shrimp Penaeus monodon (Fabricius, 1798) from four breeding families (family S: South China seas family, family A: African family, family SA: ♂ South China seas family × ♀ Africa family, family AS: ♂ Africa family × ♀ South China seas family) were evaluated in this study. Findings and conclusion: Length–weight relationships can be expressed as W = 0.0239BL2.789 (R2 = 0.8977) in family S, W = 0.0206BL2.9107 (R2 = 0.9107) in family A, W = 0.0211BL2.831 (R2 = 0.8869) in family SA, and W = 0.0249BL2.781 (R2 = 0.9159) in family AS. The growth of P. monodon from four breeding families follows a negative allometric trend. Fulton’s body condition factor (K) was not significantly different in males, while in females, the highest K (3.07) was observed in family AS, and the lowest K was found in family A (1.88). Results from the present study indicate that the cross group family AS (♂ Africa family × ♀ South China seas family) has obvious heterosis in females. This may suggest that the direction of further breeding of P. monodon, should be conducted by using Africa family as male parent, and South China seas family as female parent. Results from the present study will provide valuable information on selective breeding in P. monodon. Methodology used in the present study can also be applied in other similar species

Raman signature and phonon dispersion of atomically thin boron nitride

Raman spectroscopy has become an essential technique to characterize and investigate graphene and many other two-dimensional materials. However, there is still a lack of consensus on the Raman signature and phonon dispersion of atomically thin boron nitride (BN), which has many unique properties distinct from graphene. Such a knowledge gap greatly affects the understanding of the basic physical and chemical properties of atomically thin BN as well as the use of Raman spectroscopy to study these nanomaterials. Here, we use both experiment and simulation to reveal the intrinsic Raman signature of monolayer and few-layer BN. We find experimentally that atomically thin BN without interaction with a substrate has a G band frequency similar to that of bulk hexagonal BN (hBN), but strain induced by the substrate can cause a pronounced Raman shift. This is in excellent agreement with our first-principles density functional theory (DFT) calculations at two levels of theory, including van der Waals dispersion forces (opt-vdW) and a fraction of the exact exchange from Hartree–Fock (HF) theory through the hybrid HSE06 functional. Both calculations demonstrate that the intrinsic E2g mode of BN does not depend sensibly on the number of layers. Our simulations also suggest the importance of the exact exchange mixing parameter in calculating the vibrational modes in BN, as it determines the fraction of HF exchange included in the DFT calculations