A mesoscopic model for microscale hydrodynamics and interfacial phenomena: Slip, films, and contact angle hysteresis

We present a model based on the lattice Boltzmann equation that is suitable for the simulation of dynamic wetting. The model is capable of exhibiting fundamental interfacial phenomena such as weak adsorption of fluid on the solid substrate and the presence of a thin surface film within which a disjoining pressure acts. Dynamics in this surface film, tightly coupled with hydrodynamics in the fluid bulk, determine macroscopic properties of primary interest: the hydrodynamic slip; the equilibrium contact angle; and the static and dynamic hysteresis of the contact angles. The pseudo- potentials employed for fluid-solid interactions are composed of a repulsive core and an attractive tail that can be independently adjusted. This enables effective modification of the functional form of the disjoining pressure so that one can vary the static and dynamic hysteresis on surfaces that exhibit the same equilibrium contact angle. The modeled solid-fluid interface is diffuse, represented by a wall probability function which ultimately controls the momentum exchange between solid and fluid phases. This approach allows us to effectively vary the slip length for a given wettability (i.e. the static contact angle) of the solid substrate

The prevalence of rheumatic diseases in central Greece: a population survey

<p>Abstract</p> <p>Background</p> <p>Rheumatic diseases are a major health and financial burden for societies. The prevalence of rheumatic diseases may change over time, and therefore, we sought to estimate the prevalence of rheumatic diseases in an adult population of central Greece.</p> <p>Methods</p> <p>In this prospective cross-sectional population survey, a random sample of adult population was drawn from poll catalogues of a region in central Greece. A postal questionnaire was sent to 3,528 people for the presence of any rheumatic disease. All positive cases were further confirmed by clinical examination using the American College of Rheumatoloy criteria. Multiple regression analysis was used to assess risk factors for rheumatic diseases.</p> <p>Results</p> <p>The response rate was 48.3% (1,705 answers). Four hundred and twenty individuals (24.6%) had a rheumatic disease. The prevalence of rheumatoid arthritis was 0.58% (95% confidence interval [CI], 0.32-0.87), of psoriatic arthritis was 0.35% (95% CI, 0.33-1.13), of ankylosing spondylitis was 0.29% (95% CI, 0.28-0.94), of primary Sjögren's syndrome was 0.23% (95% CI, 0.22-0.75) and of systemic lupus erythematosus was 0.11% (95% CI, 0.11-0.37). One individual had systemic sclerosis (prevalence, 0.058%), 1 individual had dermatomyositis (prevalence, 0.058%; 95% CI, 0.05-0.18), 2 individuals had vasculitis (prevalence 0.11%; 95% CI, 0.11-0.37), 81 individuals had gout (prevalence, 4.75%; 95% CI, 4.41-5.13), and 304 individuals had osteoarthritis (OA) (prevalence 17.82%; 95% CI, 16.50-19.34). Gout was associated with male gender, diabetes mellitus, and hypertension, and OA was associated with age, female gender, and hypertension.</p> <p>Conclusions</p> <p>Rheumatic diseases are common in central Greece, affecting nearly a quarter of adult population. OA and gout are the most common joint disorders.</p

The genetic history of the Southern Arc: a bridge between West Asia and Europe

By sequencing 727 ancient individuals from the Southern Arc (Anatolia and its neighbors in Southeastern Europe and West Asia) over 10,000 years, we contextualize its Chalcolithic period and Bronze Age (about 5000 to 1000 BCE), when extensive gene flow entangled it with the Eurasian steppe. Two streams of migration transmitted Caucasus and Anatolian/Levantine ancestry northward, and the Yamnaya pastoralists, formed on the steppe, then spread southward into the Balkans and across the Caucasus into Armenia, where they left numerous patrilineal descendants. Anatolia was transformed by intra–West Asian gene flow, with negligible impact of the later Yamnaya migrations. This contrasts with all other regions where Indo-European languages were spoken, suggesting that the homeland of the Indo-Anatolian language family was in West Asia, with only secondary dispersals of non-Anatolian Indo-Europeans from the steppe

Knits: Switch-based connection hand-off

Abstract—This paper describes a mechanism allowing nodes to hand-off active connections by utilizing connection splicing at an edge-switch serving as a gateway to a server cluster. The mechanism is primarily intended to be used as part of a content aware request distribution strategy. Our approach uses an extended form of network address translation which maps inbound connection information (ie. address, port, and sequence number) to a separate outbound connection. A key difference in our approach is that while the switch performs network address translation and TCP splicing, the actual hand-off is triggered by the back-end nodes. This relieves the switch of performing any application layer responsibilities. Nodes may hand-off connections by first initiating a new connection to the destination and then sending a message to the gateway which splices the two connections together. The gateway modifies subsequent packet headers in order to create a transparent hand-off. This mechanism requires no modification to the operating system on the servers or the clients and supports HTTP/1.1 persistent connections and pipelined requests. To test our design, we implemented a soft-switch using Linux Netfilter which includes the extended network address translation. We provide some preliminary performance analysis and make recommendations for future work. I

Aggressive prefetching: an idea whose time has come

Abstract I/O prefetching serves to hide the latency of slow pe-ripheral devices. Traditional OS-level prefetching strategies have tended to be conservative, fetching only thosedata that are very likely to be needed according to some simple heuristic, and only just in time for them to ar-rive before the first access. More aggressive policies, which might speculate more about which data to fetch, or fetch them earlier in time, have typically not beenconsidered a prudent use of computational, memory, or bandwidth resources. We argue, however, that techno-logical trends and emerging system design goals have dramatically reduced the potential costs and dramati-cally increased the potential benefits of highly aggressive prefetching policies. We propose that memory management be redesigned to embrace such policies. 1 Introduction Prefetching, also known as prepaging or read-ahead, hasbeen standard practice in operating systems for more than thirty years. It complements traditional cachingpolicies, such as LRU, by hiding or reducing the latency of access to non-cached data. Its goal is to predict futuredata accesses and make data available in memory before they are requested. A common debate about prefetching concerns how ag-gressive it should be. Prefetching aggressiveness ma