566 research outputs found

    Plastron properties of a superhydrophobic surface

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    Most insects and spiders drown when submerged during flooding or tidal inundation, but some are able to survive and others can remain submerged indefinitely without harm. Many achieve this by natural adaptations to their surface morphology to trap films of air, creating plastrons which fix the water-vapor interface and provide an incompressible oxygen-carbon dioxide exchange surface. Here the authors demonstrate how the surface of an extremely water-repellent foam mimics this mechanism of underwater respiration and allows direct extraction of oxygen from aerated water. The biomimetic principle demonstrated can be applied to a wide variety of man-made superhydrophobic materials

    (How Much) Does a Private WAN Improve Cloud Performance?

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    The buildout of private Wide Area Networks (WANs) by cloud providers allows providers to extend their network to more locations and establish direct connectivity with end user Internet Service Providers (ISPs). Tenants of the cloud providers benefit from this proximity to users, which is supposed to provide improved performance by bypassing the public Internet. However, the performance impact of private WANs is not widely understood. To isolate the impact of a private WAN, we measure from globally distributed vantage points to a large cloud provider, comparing performance when using its worldwide WAN and when forcing traffic to instead use the public Internet. The benefits are not universal. While 40% of our vantage points saw improved performance when using the WAN, half of our vantage points did not see significant performance improvement, and 10% had better performance over the public Internet. We find that the benefits of the private WAN tend to improve with client-to-server distance, but that the benefits (or drawbacks) to a particular vantage point depend on specifics of its geographic and network connectivity

    Under what conditions does bureaucracy matter in the making of global public policies?

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    First published: 16 November 2022This study investigates how configurations of bureaucratic autonomy, policy complexity and political contestation allow international public administrations (IPAs) to influence policymaking within international organizations. A fuzzy-set Qualitative Comparative Analysis of 17 policy decisions in four organizations (FAO, WHO, ILO, UNESCO) shows that all IPAs studied can be influential in favorable contexts. When policies are both contested and complex, even IPAs lacking autonomy can influence policy. If either complexity or contestation is absent, however, it is the variant of autonomy of will that helps the IPA exploit procedural strategies of influence. Low autonomy of will, among other factors, explains why IPAs cannot exert influence. Conversely, the variant of autonomy of action appears largely irrelevant. The study provides new insights into the role of bureaucracy beyond the state, exemplifying how research of bureaucratic influence can yield more systematic results in various empirical settings

    The New Mexico State University Satellite (NMSUSat) Mission

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    The New Mexico State University Satellite (NMSUSat) is part of the University Nanosat 3 program managed by the Air Force Research Laboratory and it is being developed at New Mexico State University. The planned Science Mission for the satellite is to perform Near Ultra Violet emission intensity measurements of the earth\u27s upper atmosphere over the night side of the earth. The Engineering Mission is to demonstrate techniques for distributed data relaying over the Internet and to conduct an energy storage experiment to assess the operational characteristics of double layer capacitors. The Educational Mission of the program to assist in the further development of the aerospace engineering concentration area in the College of Engineering and to develop multi-disciplinary capstone and design classes for students in engineering departments, computer science, and the engineering physics program. This paper will discuss the preliminary design for the satellite components and how the mission segments will be worked among the participating departments at New Mexico State University

    Topography and instability of monolayers near domain boundaries

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    We theoretically study the topography of a biphasic surfactant monolayer in the vicinity of domain boundaries. The differing elastic properties of the two phases generally lead to a nonflat topography of ``mesas'', where domains of one phase are elevated with respect to the other phase. The mesas are steep but low, having heights of up to 10 nm. As the monolayer is laterally compressed, the mesas develop overhangs and eventually become unstable at a surface tension of about K(dc)^2 (dc being the difference in spontaneous curvature and K a bending modulus). In addition, the boundary is found to undergo a topography-induced rippling instability upon compression, if its line tension is smaller than about K(dc). The effect of diffuse boundaries on these features and the topographic behavior near a critical point are also examined. We discuss the relevance of our findings to several experimental observations related to surfactant monolayers: (i) small topographic features recently found near domain boundaries; (ii) folding behavior observed in mixed phospholipid monolayers and model lung surfactants; (iii) roughening of domain boundaries seen under lateral compression; (iv) the absence of biphasic structures in tensionless surfactant films.Comment: 17 pages, 9 figures, using RevTeX and epsf, submitted to Phys Rev

    Different genes interact with particulate matter and tobacco smoke exposure in affecting lung function decline in the general population

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    BACKGROUND: Oxidative stress related genes modify the effects of ambient air pollution or tobacco smoking on lung function decline. The impact of interactions might be substantial, but previous studies mostly focused on main effects of single genes. OBJECTIVES: We studied the interaction of both exposures with a broad set of oxidative-stress related candidate genes and pathways on lung function decline and contrasted interactions between exposures. METHODS: For 12679 single nucleotide polymorphisms (SNPs), change in forced expiratory volume in one second (FEV(1)), FEV(1) over forced vital capacity (FEV(1)/FVC), and mean forced expiratory flow between 25 and 75% of the FVC (FEF(25-75)) was regressed on interval exposure to particulate matter >10 microm in diameter (PM10) or packyears smoked (a), additive SNP effects (b), and interaction terms between (a) and (b) in 669 adults with GWAS data. Interaction p-values for 152 genes and 14 pathways were calculated by the adaptive rank truncation product (ARTP) method, and compared between exposures. Interaction effect sizes were contrasted for the strongest SNPs of nominally significant genes (p(interaction)>0.05). Replication was attempted for SNPs with MAF<10% in 3320 SAPALDIA participants without GWAS. RESULTS: On the SNP-level, rs2035268 in gene SNCA accelerated FEV(1)/FVC decline by 3.8% (p(interaction) = 2.5x10(-6)), and rs12190800 in PARK2 attenuated FEV1 decline by 95.1 ml p(interaction) = 9.7x10(-8)) over 11 years, while interacting with PM10. Genes and pathways nominally interacting with PM10 and packyears exposure differed substantially. Gene CRISP2 presented a significant interaction with PM10 (p(interaction) = 3.0x10(-4)) on FEV(1)/FVC decline. Pathway interactions were weak. Replications for the strongest SNPs in PARK2 and CRISP2 were not successful. CONCLUSIONS: Consistent with a stratified response to increasing oxidative stress, different genes and pathways potentially mediate PM10 and tobac smoke effects on lung function decline. Ignoring environmental exposures would miss these patterns, but achieving sufficient sample size and comparability across study samples is challengin

    Mesenteric panniculitis of the sigmoid colon: a case report and review of the literature

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    <p>Abstract</p> <p>Introduction</p> <p>Mesenteric panniculitis of the sigmoid colon is a rare occurrence in surgical practice. The aim of this article is to present a case of mesenteric panniculitis of the sigmoid colon and a short review of the literature.</p> <p>Case presentation</p> <p>We reviewed the hospital record of a 63-year-old man who presented with a palpable mass in the left abdomen and clinical signs of a partial bowel obstruction. The pre-operative impression was a possible cancer of the sigmoid colon. A laparotomy was performed through a midline incision. The mesentery was found to be markedly thickened, constricted and puckered. The normal architecture of the adipose tissue had been lost and replaced with an irregular nodular mass. The microscopic pathologic sections demonstrated a chronic reactive inflammatory process with an exuberant proliferation of fibroblasts and fibrocytes. The adipose tissue contained scattered areas of steatonecrosis with foci of lipid-laden macrophages, lymphocytes and plasma cells. The sigmoid colon and its mesocolon were resected. The postoperative course was uneventful and the patient was discharged in good condition, and followed up for the next two years.</p> <p>Conclusion</p> <p>Mesenteric panniculitis of sigmoid is an extremely rare entity of unknown origin in which the normal architecture of the mesentery is replaced by fibrosis, necrosis and calcification. On gross examination the alterations may be mistaken for a neoplastic process. A frozen section may be necessary for confirmation of the diagnosis. When the advanced inflammatory changes became irreversible and bowel obstruction occurs, resection may be indicated.</p

    Genome-wide association and HLA fine-mapping studies identify risk loci and genetic pathways underlying allergic rhinitis

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    Allergic rhinitis is the most common clinical presentation of allergy, affecting 400 million people worldwide, with increasing incidence in westernized countries1,2. To elucidate the genetic architecture and understand the underlying disease mechanisms, we carried out a meta-analysis of allergic rhinitis in 59,762 cases and 152,358 controls of European ancestry and identified a total of 41 risk loci for allergic rhinitis, including 20 loci not previously associated with allergic rhinitis, which were confirmed in a replication phase of 60,720 cases and 618,527 controls. Functional annotation implicated genes involved in various immune pathways, and fine mapping of the HLA region suggested amino acid variants important for antigen binding. We further performed genome-wide association study (GWAS) analyses of allergic sensitization against inhalant allergens and nonallergic rhinitis, which suggested shared genetic mechanisms across rhinitis-related traits. Future studies of the identified loci and genes might identify novel targets for treatment and prevention of allergic rhinitis
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