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Consider an agent traversing a graph of "gadgets", where each gadget has local state that changes with each traversal by the agent according to specified rules. Prior work has studied the computational complexity of deciding whether the agent can reach a specified location, a problem we call reachability. This paper introduces new goals for the agent, aiming to characterize when the computational complexity of these problems is the same or differs from that of reachability. First we characterize the complexity of universal traversal—where the goal is to traverse every gadget at least once—for DAG gadgets (partially), one-state gadgets, and reversible deterministic gadgets. Then we study the complexity of reconfiguration—where the goal is to bring the system of gadgets to a specified state. We prove many cases PSPACE-complete, and show in some cases that reconfiguration is strictly harder than reachability, while in other cases, reachability is strictly harder than reconfiguration. [ABSTRACT FROM AUTHOR]

We present a new tool for generating cutting planes for NP -hard combinatorial optimisation problems. It is based on the concept of gadgets—small subproblems that are "glued" together to form hard problems—which we borrow from the literature on computational complexity. Using gadgets, we are able to derive huge (exponentially large) new families of strong (and sometimes facet-defining) cutting planes, accompanied by efficient separation algorithms. We illustrate the power of this approach on the asymmetric traveling salesman, stable set and clique partitioning problems. [ABSTRACT FROM AUTHOR]

Mobile and sensor related technologies are significantly revolutionizing the medical and healthcare sectors. In current healthcare systems, gadgets are the prominent way of acquiring medical services. However, the recent technological advancements in smart and ambient environments are offering users new ways to access the healthcare services without using any explicit gadgets. One of the key challenges in such gadget-free environments is performing secure user authentication with the intelligent surroundings. For example, a secure, efficient and user-friendly authentication mechanism is essential for elderly/disabled people or patients in critical conditions requiring medical services. Hence, modern authentication systems should be sophisticated enough to identify such patients without requiring their physical efforts or placing gadgets on them. This paper proposes an anonymous and privacy-preserving biometrics based authentication scheme for such gadget-free healthcare environment. We performed formal security verification of our proposed scheme using CDVT /AD tool and our results indicate that the proposed scheme is secure for such smart and gadget-free environments. We verify that the proposed scheme can resist against various well-known security attacks. Moreover, the proposed system showed better performance as compared with existing biometrics based remote user authentication schemes. [ABSTRACT FROM AUTHOR]

Fundamentally, it is believed that interactions between physical objects are two-body. Perturbative gadgets are one way to break up an effective many-body coupling into pairwise interactions: a Hamiltonian with high interaction strength introduces a low-energy space in which the effective theory appears k-body and approximates a target Hamiltonian to within precision ϵ . One caveat of existing constructions is that the interaction strength generally scales exponentially in the locality of the terms to be approximated. In this work we propose a many-body Hamiltonian construction which introduces only a single separate energy scale of order Θ (1 / N 2 + δ) , for a small parameter δ > 0 , and for N terms in the target Hamiltonian H t = ∑ i = 1 N h i to be simulated: in its low-energy subspace, our constructed system can approximate any such target Hamiltonian H t with norm ratios r = max i , j ∈ { 1 , ... , N } ‖ h i ‖ / ‖ h j ‖ = O (exp (exp (poly N))) to within relative precision O (N - δ) . This comes at the expense of increasing the locality by at most one, and adding an at most poly-sized ancillary system for each coupling; interactions on the ancillary system are geometrically local, and can be translationally invariant. In order to prove this claim, we borrow a technique from high energy physics—where matter fields obtain effective properties (such as mass) from interactions with an exchange particle—and employ a tiling Hamiltonian to discard all cross-terms at higher expansion orders of a Feynman–Dyson series expansion. As an application, we discuss implications for QMA-hardness of the Local Hamiltonian problem, and argue that "almost" translational invariance—defined as arbitrarily small relative variations of the strength of the local terms—is as good as non-translational invariance in many of the constructions used throughout Hamiltonian complexity theory. We furthermore show that the choice of geared limit of many-body systems, where e.g. width and height of a lattice are taken to infinity in a specific relation, can have different complexity-theoretic implications: even for translationally invariant models, changing the geared limit can vary the hardness of finding the ground state energy with respect to a given promise gap from computationally trivial, to QMAEXP-, or even BQEXPSPACE-complete. [ABSTRACT FROM AUTHOR]

Glazed ceramics have not typically been sampled for organic residue analysis because the glaze is not porous; therefore, it is commonly believed that these ceramics cannot absorb substances. Although this is partially true, the aim of this paper is to demonstrate that the glaze may exhibit imperfections due to the production process or the use of ceramics and that these imperfections allow the ceramic matrix to trap residues of the food contained in the vessels. The absorption of organic residues in glazed ceramics is demonstrated by analyses of modern vessels experimentally enriched with wine and vegetable oils (olive and lentisk oils) and archaeological vessels obtained from post-medieval Florence (Italy) and medieval Pla d'Almatà (Balaguer, Lleida, Spain). The analyses were conducted using gas chromatography-mass spectrometry following different extraction protocols aimed at identifying lipids and wine residues preserved in the ceramic vessels. Images of the glazed ceramic coating were recorded using an optical microscope and a scanning electron microscope to verify the presence of imperfections. In addition to providing information about the use of the studied vessels, the obtained results demonstrate how glazed ceramics can be studied to recover information regarding ceramic use and dietary practices in medieval and post-medieval periods when glazed wares were very common. [ABSTRACT FROM AUTHOR]

In the abstract Tile Assembly Model (aTAM), the phenomenon of cooperation occurs when the attachment of a new tile to a growing assembly requires it to bind to more than one tile already in the assembly. Often referred to as 'temperature-2' systems, those which employ cooperation are known to be quite powerful (i.e. they are computationally universal and can build an enormous variety of shapes and structures). Conversely, aTAM systems which do not enforce cooperative behavior, a.k.a. 'temperature-1' systems, are conjectured to be relatively very weak, likely to be unable to perform complex computations or algorithmically direct the process of self-assembly. Nonetheless, a variety of models based on slight modifications to the aTAM have been developed in which temperature-1 systems are in fact capable of Turing universal computation through a restricted notion of cooperation. Despite that power, though, several of those models have previously been proven to be unable to perform or simulate the stronger form of cooperation exhibited by temperature-2 aTAM systems. In this paper, we first prove that another model in which temperature-1 systems are computationally universal, namely the restricted glue TAM (rgTAM) in which tiles are allowed to have edges which exhibit repulsive forces, is also unable to simulate the strongly cooperative behavior of the temperature-2 aTAM. We then show that by combining the properties of two such models, the Dupled Tile Assembly Model (DTAM) and the rgTAM into the DrgTAM, we derive a model which is actually more powerful at temperature-1 than the aTAM at temperature-2. Specifically, the DrgTAM, at temperature-1, can simulate any aTAM system of any temperature, and it also contains systems which cannot be simulated by any system in the aTAM. [ABSTRACT FROM AUTHOR]

Differential equations of motion of a boomerang can be integrated numerically given its aerodynamic and inertial properties and initial conditions. We use the dynamic model and experimental aerodynamic data of a typical boomerang in still air studied by Hess (Boomerangs, aerodynamics and motion. PhD thesis, University of Groningen, ). The trajectory size and shape are well-defined functions of five initial conditions. Beginning with a nominal guessed set, an iterative search finds release conditions that result in exact return. The distance to the point on the trajectory closest to the desired return point and its gradient with respect to the release conditions are calculated. Release conditions are then modified iteratively using Newton's method to decrease the miss distance. Exact return conditions are presented for constant values of initial angle of attack and advance ratio. A variant of the algorithm calculates release conditions that ensure return at 'turnaround' where the speed is lowest and thus catching is easiest. Although in general the set of exact return release conditions is five dimensional, it is thin in the sense that certain variables must lie in a fairly narrow range. Some initial conditions are more easily modified than others, accounting for the not-inconsiderable skill required to achieve exact return in practice. A discussion is also included of the stable asymptotic helical attractor approached by the boomerang after turnaround. [ABSTRACT FROM AUTHOR]

Efficient planning for LNG berths used by modern generation vessels needs a high level and accumulation of experiences. The planning process should cover the main components for the handling berth as berthing dolphins, mooring dolphins, berthing platform and suitable type of fenders. The planning and design should cover studying all the design forces that affect these items, including the hidden capacities. This efficient planning should cover two international standards. The first is the British standard (BS) and the second one is the (OCIMF, Oil Companies International Marine Forum) international standards for the petroleum companies forum. Applying the specifications for these two standards together, the efficient planning for LNG berths can be obtained. This research deals with that planning details in a simplified procedure, which is easy to follow. [ABSTRACT FROM AUTHOR]

Analytical pyrolysis with thermally assisted hydrolysis and methylation was employed to investigate ancient ointments collected from Spanish vessels coming from the sixteenth century pharmacies. The ointments were reproduced on the basis of historical recipes and characterization was made in comparison with real samples. Characteristic markers indicate the presence of beeswax, of animal and plant lipids, and of natural resins. Analyses of old samples are consistent with the modern reproductions and with the analysis of raw materials. Multivariate data analysis was used to discriminate between the different types of lipidic materials, also in connection with their relative amount in the samples. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Nine black powders found in Pompeii houses in three different types of bronze vessels (cylindrical theca atramentaria, unguentaries, and aryballoi) were characterized in order to assess a correspondence between the composition and the type of vessel and, possibly, to verify if these powders were inks or not. For the compositional characterization, a multi-analytical approach was adopted, which involved the use of scanning electron microscopy-energy dispersive X-ray, Fourier-transformed infrared spectroscopy, Raman, X-ray diffraction, electron paramagnetic resonance spectroscopy, thermogravimetric analysis, gas chromatography coupled with mass spectrometry (GC/MS), and pyrolysis GC/MS. Powders contained in cylindrical theca atramentaria form a homogeneous group, and their organic and inorganic compositions suggest that they were writing inks, while powders contained in unguentaries and aryballoi could have had several different uses, including writing inks and cosmetics. Furthermore, the composition profile of the powders found in cylindrical cases shows that, at 79 ad, in Pompeii, carbon-based inks were still used for writing, and iron gall inks had not been introduced yet. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

part of monitoring the exposure of the Ghanaian public to natural radioactivity, radioactivity concentrations in titanium enamel frits use for coating, spraying and decorating steel bowls were investigated. Samples collected from Ghana Utensil Manufacturing Company in Ghana were analyzed using γ-ray spectrometry with a high purity germanium detector. The samples were found to contain an average absorbed dose rate of 509.38 nGy h, while an average annual effective dose was calculated to be 2.50 mSv. [ABSTRACT FROM AUTHOR]

After the appearance of agriculture and subsequent increasing population densities and agricultural intensification, some mobile hunters, foragers, and part-time horticulturalists often obtained ceramic vessels from nearby villages. Mobile groups are firmly embedded within regional patterns of interaction and exchange. Certain regional interaction patterns encourage use of vessels made by a sedentary neighbor, and the factors that would discourage it are less significant than previously believed. The vessels made by neighboring agriculturalists may often be as well suited to the tasks and settlement pattern of mobile groups as vessels made by the mobile groups themselves. Given the probable frequency with which mobile groups discarded ceramics made by a neighboring group, archaeologists should consider this scenario when interpreting ceramic frequencies in remote small sites, where some ceramics may be far from the villages in which they were apparently made. Using an archaeological case study from the Western Papaguería of the US Southwest, I propose using vessel techno-function, along with other data, to place individual sites within a broader settlement system. The settlement system, rather than diagnostic ceramic types, may be most useful for assigning these sites to particular cultural traditions and for understanding patterns of landscape use. [ABSTRACT FROM AUTHOR]

Abstract  Six models for determining air temperatures for thermal comfort of people using sleeping bags were reviewed. These models were based on distinctive metabolic rates and mean skin temperatures. All model predictions of air temperatures are low when the insulation values of the sleeping bag are high. Nevertheless, prediction variations are greatest for the sleeping bags with high insulation values, and there is a high risk of hypothermia if an inappropriate sleeping bag is chosen for the intended conditions of use. There is, therefore, a pressing need to validate the models by wear trial and determine which one best reflects ordinary consumer needs. [ABSTRACT FROM AUTHOR]

The article presents information on the effect of stationary hemodynamic flows in an elastic vessel with friction. It is stated that the behavior of solution depends on the state of equation. The state equations are divided into 2 classes, first class reveals that subsonic flows with a given flow rate is limited within a finite length of the vessel and the second class reveals that subsonic flows exist in a vessel of an arbitrary length.

Using an RC model, the behavior of a TAM high-performance calorimeter (Thermometric AB, Sweden) equipped with a flow-mixing insertion vessel using independent pumps for each reactant is studied. The model shows a reliable sensitivity behavior for mixtures realized inside the cell. The model behavior is compared with experimental measurements. [ABSTRACT FROM AUTHOR]

The form of English white ball-clay pipebowls can be used to determine accurate mean dates for historical contexts. Using previously established bowl sedations and typologies on the well-dated material assemblage uncovered at the site of the 1607 James Fort at Jamestown Island, Virginia, a newly developed calculation proves to be a reliable technique of assessing chronology. Determining the pipebowl mean date involves identifying the shape of each bowl, counting the number of examples of each morphological type, and then completing a series of simple arithmetic calculations. The pipebowl-dating device correlates well with other archaeological lines of evidence. On average, pipebowl mean dates are within seven years of mean dates established by other factors. This method regularly outperforms established pipestem-based mean-data measures. [ABSTRACT FROM AUTHOR]

The variation of the flow-rate of a fluid flowing out of a prefilled cylindrical vessel through sinkholes with a diameter less than 0.1 of the vessel diameter has been studied experimentally. The study was carried out in both the presence and the absence of a vortex funnel around the sinkhole. In these experiments the vessel was filled in such a way that a funnel was formed only when a disk immersed in the fluid was rotated before the sinkhole was opened. The time dependence of the flow-rate is found for various initial heights and rates of artificial swirl. Four different outflow stages were detected. It is shown that for certain flow parameters there is a time interval on which the fluid flow-rate is independent of the column height. A critical rotation velocity W0* below which ( W0 < W0*) an intense funnel is not formed is found. A limiting curve approached by all the flow-rate curves in the final stage of outflow is obtained. [ABSTRACT FROM AUTHOR]

This interdisciplinary study focuses on a specific type of Roman coarse ware that was widely distributed in Bavaria, Austria and northern Italy during the 1st half of the 1st century AD. Various physical methods were applied to study the provenance of this characteristic marble tempered blackware and to assess its production techniques. The blackware found in large numbers on the Auerberg and at other sites in southern Germany can be identified as imported from East Tyrol, Austria. [ABSTRACT FROM AUTHOR]

A set of standard surveillance programs for monitoring the design life of reactor pressure vessels (up to 40 years of operation) has been analyzed. In view of the improved test methods and embrittlement evaluation procedures, the necessity has been shown of introducing modifications in the present surveillance programs aiming at a more precise reactor pressure vessel integrity evaluation facing a possible service life of 60 years. Service life predictions are performed for reactor pressure vessels, based on the available surveillance data, reconstituted Charpy specimens, and Master Curve testing. [ABSTRACT FROM AUTHOR]

The High Pressure Asher (HPA-S) was adapted with a Teflon liner for pressurized wet digestion in open vessels. The autoclave was partly filled with water containing 5% (vol/vol) hydrogen peroxide. The digestion vessels dipped partly into the water or were arranged on top of the water by means of a special rack made of titanium or PTFE-coated stainless steel. The HPA-S was closed and pressurized with nitrogen up to 100 bars. The maximum digestion temperature was 250 °C for PFA vessels and 270 °C for quartz vessels. Digestion vessels made of quartz or PFA-Teflon with volumes between 1.5 mL (auto sampler cups) and 50 mL were tested. The maximum sample amount for quartz vessels was 0.5–1.5 g and for PFA vessels 0.2–0.5 g, depending on the material. Higher sample intake may lead to fast reactions with losses of digestion solution. The samples were digested with 5 mL HNO3 or with 2 mL HNO3+6 mL H2O+2 mL H2O2. The total digestion time was 90–120 min and 30 min for cooling down to room temperature. Auto sampler cups made of PFA were used as digestion vessels for GFAAS. Sample material (50 mg) was digested with 0.2 mL HNO3+0.5 mL H2O+0.2 mL H2O2. The analytical data of nine certified reference materials are also within the confidential intervals for volatile elements like mercury, selenium and arsenic. No cross contamination between the digestion vessels could be observed. Due to the high gas pressure, the diffusion rate of volatile species is low and losses of elements by volatilisation could be observed only with diluted nitric acid and vessels with large cross section. In addition, cocoa, walnuts, nicotinic acid, pumpkin seeds, lubrication oil, straw, polyethylene and coal were digested and the TOC values measured. The residual carbon content came to 0.2–10% depending on the sample matrix and amount. [ABSTRACT FROM AUTHOR]

We have used 31P NMR (MAS) and IR spectroscopy and also chemical analysis to show that when Si- and Ti,Si-MCM-41 mesoporous molecular sieves are treated with phosphorus oxychloride, surface-anchored silicophosphate and titanophosphate compounds are formed of the type ≡(Si—O)x—{PO(OH)3-x} and ≡(Ti—O)x—{PO(OH)3-x} (x = 1, 2), and also compounds with the structure of titanium hydrophosphate and pyrophosphate. [ABSTRACT FROM AUTHOR]

A study by SEM/EDX and spectrophotometry in the visible region attempting to assess the stability of new resin-bound mortars used for casting replicas of marble historic fountains is presented in this paper. Different accelerating tests such as thermal ageing, UV light ageing, ageing in an SO2 pollutant chamber, freezing cycles ageing, salt crystallisation ageing, natural ageing and biological attack have been applied to a series of test specimens prepared with polyester-, epoxy- and gel-coat-bound mortars. Examination of morphology, measurement of chemical composition and chromatic coordinates before and after ageing treatments establish the higher stability and resistance properties of these resin-bound mortars by comparison to those from the natural marbles. [ABSTRACT FROM AUTHOR]

Archaeologists generally argue that early (ca. 11,000–8000 B.P. populations on the North American Great Plains moved over very large areas, relying on sophisticated, biface-based flaked stone technology and on extensive resharpening and recycling of tools to cope with unpredictable access to raw material sources. This paper reviews the development of this reconstruction and considers the degree to which data from assemblages of Paleoindian flaked stone tools support it. Published information implies that patterns of raw material use vary greatly over the Plains, that bifaces were not the centerpiece of Paleoindian technology, that there are no published efforts to document an unusual degree of resharpening or recycling, and that the data that are available on these topics do not suggest that either was important. Detailed analysis of one assemblage, from the Allen site in southwestern Nebraska, carried out with these issues in mind, shows similar patterns. The great difference between what the literature says about Paleoindian technology and the documented character of that technology suggests that Paleoindian lifeways were far more variable than current discussions suggest. [ABSTRACT FROM AUTHOR]

This is the second of the two papers that review the literature of archaeological lithic analysis over the last decade. This paper concentrates on aspects of stone tool research that are not directly related to the production or procurement of the tools themselves. It is divided into classification, functional analyses, behavioral processes, and approaches to the subject currently popular among analysts. As with the previous paper, an attempt has been made to be as comprehensive as is reasonable, though availability of sources has resulted in an emphasis on North American literature. [ABSTRACT FROM AUTHOR]

The literature of stone tool procurement and technology published in the past decade is reviewed in this article. The presentation attempts to be geographically comprehensive but, because of where it was written, it provides fuller coverage of New World publications, particularly those from North America, than of literature from the rest of the world. Topics covered include raw materials and procurement, flake experimentation, technology, and specific tool types. An article in a subsequent issue of this journal will discuss issues of function, behavior, and classification in lithic analysis. [ABSTRACT FROM AUTHOR]

An amendment to this paper has been published and can be accessed via the original article. [ABSTRACT FROM AUTHOR]

This article focuses on how kitchens have been considered the best return for the dollar in home improvements. Until the end of the nineteenth century, not much thought was given to the kitchen as a structure. It is only within the last hundred years that kitchens have risen to its current status. In the mid-eighteenth century homes were usually modestly-sized and privacy was still a luxury. Cooking was performed as a utilitarian function, using few unspecialized utensils, over an open hearth. The mid-nineteenth century saw a transition away from open hearth cooking with the invention of cookstove. This gave women the opportunity to perform several cooking functions simultaneously. What was additionally noteworthy in an American household was the role of women themselves. By the 1850s, a cult of domesticity had taken hold in that women were seen as the moral backbone of society, responsible for producing good, honest citizens. Cooking at the turn of the century was primarily a matter of trial and error. Home economists changed this with dramatic improvements in the areas of time efficiency and standardization.

The article focuses on silver and its various applications. It states that silver is the number 47 element in the periodic table, which is named after the Germanic or Anglo-Saxon words silabar, seolfor. It says that silver has been used in utensils and ornaments, monetary systems, and for trade and a significant part of its history is black and white photography that was developed in the 1830s. It adds that silver nitrate is applied in eye drops for newborns.

The article presents a complaint from a customer regarding the response time, scan precision, and matter transfer integrity of the Eternitizer 3000, Alternatron D11, and MixWhizz 98. The customer asked the technical support operator about the problem occurred when she scanned the gadget for alternate and pressed the green. The operator directed the customer to press transfer, to hold down enter for three seconds, and release transfer.