896 research outputs found
On Reasoning on Time and Location on the Web
Reasoning on time and location is receiving increasing attention on the Web due to emerging fields like Web adaptation, mobile computing, and the Semantic Web. Web applications in these fields often refer to rather complex temporal, calendric, and location information. Unfortunately, todayâs Web languages and formalisms have merely primitive temporal and location data types and temporal and location reasoning capabilities â if any. This article reports on work in progress aiming at integrating temporal and locational reasoning into XML query and transformation operations. We analyze the problem and propose a concrete architecture. A prototype of the temporal reasoner, the WebCal system has already been realized
Quantum secure communication scheme with W state
Recently, Cao et al. proposed a new quantum secure direct communication
scheme using W state. In their scheme, the error rate introduced by an
eavesdropper who takes intercept-resend attack, is only 8.3%. Actually, their
scheme is just a quantum key distribution scheme because the communication
parties first create a shared key and then encrypt the secret message using
one-time pad. We then present a quantum secure communication scheme using
three-qubit W state. In our scheme, the error rate is raised to 25% and it is
not necessary for the present scheme to use alternative measurement or Bell
basis measurement. We also show our scheme is unconditionally secure.Comment: Comments are welcom
Recovery of 3D footwear impressions using a range of different techniques.
Three-dimensional (plastic) footwear impressions are frequently found at, or in the vicinity of a crime scene, and may provide a valuable form of evidence or intelligence. This paper compares the traditional methods of casting and/or two-dimensional photography with Structure from Motion (SfM) photogrammetry. We focus both on the recovery of class characteristics (sole pattern) and randomly acquired characteristics caused by damage. We examine how different recovery techniques influence visualization of outsole features and discuss what effect this may have on evidential value. Five shoes and their associated three-dimensional impressions made in both sand and soil were compared using a grid system and tread descriptors commonly used in the UK. We conclude that within the limitations of this study SfM photogrammetry allows superior levels of visualization of both class and randomly acquired characteristics, giving a better definition in detail in some instances. The use of SfM as a complementary approach can therefore lead to a potential increase in evidential value
Te covered Si(001): a variable surface reconstruction
At a given temperature, clean and adatom covered silicon surfaces usually
exhibit well-defined reconstruction patterns. Our finite temperature ab-initio
molecular dynamics calculations show that the tellurium covered Si(001) surface
is an exception. Soft longitudinal modes of surface phonons due to the strongly
anharmonic potential of the bridged tellurium atoms prevent the reconstruction
structure from attaining any permanent, two dimensional periodic geometry. This
explains why experiments attempting to find a definite model for the
reconstruction have reached conflicting conclusions.Comment: 4 pages, 3 gif figure
Entanglement dynamics of three-qubit states in noisy channels
We study entanglement dynamics of the three-qubit system which is initially
prepared in pure Greenberger-Horne- Zeilinger (GHZ) or W state and transmitted
through one of the Pauli channels or the
depolarizing channel. With the help of the lower bound for three-qubit
concurrence we show that the W state preserves more entanglement than the GHZ
state in transmission through the Pauli channel . For the Pauli
channels and the depolarizing channel, however, the
entanglement of the GHZ state is more resistant against decoherence than the
W-type entanglement. We also briefly discuss how the accuracy of the lower
bound approximation depends on the rank of the density matrix under
consideration.Comment: 2 figures, 32 reference
Adenylate effects on protein phosphorylation in the interenvelope lumen of pea chloroplasts
A 64-kilodalton (kDa) protein, situated in the lumen between the inner and outer envelopes of pea (Pisum sativum L.) chloroplasts (Soll and Bennett 1988, Eur. J. Biochem., 175, 301â307) is shown to undergo reversible phosphorylation in isolated mixed envelope vesicles. It is the most conspicuously labelled protein after incubation of envelopes with 33 nmol·1-1 [-32P]ATP whereas incubation with 50 mol·1-1 [-32P]ATP labels most prominently two outer envelope proteins (86 and 23 kDa). Half-maximum velocity for phosphorylation of the 64-kDa protein occurs with 200 nmol·1-1 ATP, and around 40 mol·1-1 ATP for phosphorylation of the 86- and 23-kDa proteins, indicating the operation of two distinct kinases. GGuanosine-, uridine-, cytidine 5-triphosphate and AMP are poor inhibitors of the labelling of the 64-kDa protein with [-32P]ATP. On the other hand, ADP has a potent influence on the extent of labelling (half-maximal inhibition at 1â5 mol·1-1). The ADP-dependent appearance of 32P in ATP indicates that ADP acts by reversal of kinase activity and not as a competitive inhibitor. However, the most rapid loss of 32P from pre-labelled 64-kDa protein occurs when envelope vesicles are incubated with ATP t1/2=15 s at 20 molsd1-1 ATP). This induced turnover of phosphate appears to be responsible for the rapid phosphoryl turnover seen in situ
Superconductor coupled to two Luttinger liquids as an entangler for electron spins
We consider an s-wave superconductor (SC) which is tunnel-coupled to two
spatially separated Luttinger liquid (LL) leads. We demonstrate that such a
setup acts as an entangler, i.e. it creates spin-singlets of two electrons
which are spatially separated, thereby providing a source of electronic
Einstein-Podolsky-Rosen pairs. We show that in the presence of a bias voltage,
which is smaller than the energy gap in the SC, a stationary current of
spin-entangled electrons can flow from the SC to the LL leads due to Andreev
tunneling events. We discuss two competing transport channels for Cooper pairs
to tunnel from the SC into the LL leads. On the one hand, the coherent
tunneling of two electrons into the same LL lead is shown to be suppressed by
strong LL correlations compared to single-electron tunneling into a LL. On the
other hand, the tunneling of two spin-entangled electrons into different leads
is suppressed by the initial spatial separation of the two electrons coming
from the same Cooper pair. We show that the latter suppression depends
crucially on the effective dimensionality of the SC. We identify a regime of
experimental interest in which the separation of two spin-entangled electrons
is favored. We determine the decay of the singlet state of two electrons
injected into different leads caused by the LL correlations. Although the
electron is not a proper quasiparticle of the LL, the spin information can
still be transported via the spin density fluctuations produced by the injected
spin-entangled electrons.Comment: 15 pages, 2 figure
Forages for Conservation and Improved Soil Quality
Forages provide several soil benefits, including reduced soil erosion, reduced water runoff, improved soil physical properties, increased soil carbon, increased soil biologic activity, reduced soil salinity, and improved land stabilization and restoration when grown continuously or as part of a crop rotation. Ongoing research and synthesis of knowledge have improved our understanding of how forages alter and protect soil resources, thus providing producers, policymakers, and the general public information regarding which forage crops are best suited for a specific area or use (e.g. hay, grazing or bioenergy feedstock). Forages can be produced in forestland, range, pasture, and cropland settings. These land use types comprise 86% of non-Federal United States rural lands (Table 12.1). In the United States, active forage production occurs on 22.6 million ha and is used for hay, haylage, grass silage, and greenchop (Table 12.2). Forages are used as cover crops in several production systems, and approximately 4.2 million ha were recently planted in cover crops (Table 12.3). Currently, the highest cover crop use rates, as a percentage of total cropland within a given state, occur in the northeastern United States. Globally, permanent meadows and pastures account for over 3.3 billion ha, greater than arable land and permanent crops combined (Table 12.4). Within all regions of the world, except Europe, permanent meadows and pastures are a greater proportion of land cover than permanent crops. Pasture management information and resources are available for countries around the world (FAO 2017a,b). As seen in Tables 12.1â12.4, forages are used globally and can provide soil benefits across varied soil and climate types
Closure properties of solutions to heat inequalities
We prove that if are
sufficiently well-behaved solutions to certain heat inequalities on then
the function given by
also satisfies a heat inequality of a
similar type provided . On
iterating, this result leads to an analogous statement concerning -fold
convolutions. As a corollary, we give a direct heat-flow proof of the sharp
-fold Young convolution inequality and its reverse form.Comment: 12 page
Situationally edited empathy: an effect of socio-economic structure on individual choice
Criminological theory still operates with deficient models of the offender as agent, and of social influences on the agentâs decision-making process. This paper takes one âemotionâ, empathy, which is theoretically of considerable importance in influencing the choices made by agents; particularly those involving criminal or otherwise harmful action. Using a framework not of rational action, but of ârationalised actionâ, the paper considers some of the effects on individual psychology of social, economic, political and cultural structure. It is suggested that the climate-setting effects of these structures promote normative definitions of social situations which allow unempathic, harmful action to be rationalised through the situational editing of empathy. The âcrime is normalâ argument can therefore be extended to include the recognition that the uncompassionate state of mind of the criminal actor is a reflection of the self-interested values which govern non-criminal action in wider society
- âŠ