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We identify critical science needed to understand conflict between black vultures and humans to inform effective management of this species in North America.

This work aims at presenting a novel Computer Vision approach in the development of a real-time, web-camera based, British Sign Language recognition system. A literature review focused on current (1) state of sign language recognition systems and (2) techniques used is conducted. This review process is used as a foundation on which a Convolutional Neural Network (CNN) based system is designed and then implemented. A bespoke British Sign Language dataset -containing 11,875 images - is then performed to train and test the CNN which is used for the classification of human hand performed gestures. Finally, the CNN architecture recognized 19 static British Sign Language gestures, incorporating both single and double-handed gestures. During testing, the system achieved an average recognition accuracy of 89%.

The skin of a tomato (Lycopersicon esculentum) is a rich source of lycopene, an important component of waste from tomato paste manufacturing plants. The lycopene content in the skin of a tomato pomace is about five times higher than in the pulp. According to the World Processing Tomato Council, 1,200,000 tons of tomato processing waste is produced worldwide annually. In this study, lycopene extraction from tomato skins is formulated as an optimization problem with respect to five independent variables, namely solvent/meal ratio, temperature, number of extractions, extraction time and particle size. The music-inspired harmony search (HS) metaheuristic algorithm is used to optimize the lycopene production, and the maximum lycopene (4.8 mg/100 g) was predicted when the solvent/meal ratio, temperature, number of extractions, extraction time and particle size is 20:1 v/w, 60 C, 5, 4 min and 0.43 mm, respectively. Response surface analysis (RSM) has been used in (Kaur et al, Food Chem 2008 [1]) to optimize the lycopene yield with respect to these variables, and the maximum yield predicted was 1.99 mg/100 g. Thus, the methodology applied in the present work for optimizing the extraction of lycopene is far better than response surface analysis. Further comparison with particle swarm optimization reveals that HS is more reliable optimization technique to solve the problem at hand.

The shipping industry is a multifaceted trading system, enabling the flow of goods between countries. Often the standards, methods and technologies become interspersed and difficult to plan, disrupting the supply chain. Data is not always accurate, necessitating further analysis. This paper presents an approach to solving key issues in two important facets of the supply chain, predicting the date of restitution for a cargo container and using an optical character recognition (OCR)-centred pipeline to extrapolate data from containers. Both approaches use long short-term memory (LSTM) models, including bi-directional LSTMs. These methods leverage state-of-the-art text recognition architecture and advanced algorithm ensembling, giving significant improvements in data quality. The experimental results illustrate that these methods vastly outperform current industry practices and more recent approaches.

This work compares the application of Reinforcement Learning (RL) and Swarm Intelligence (SI) based methods for resolving the problem of coordinating multiple High Altitude Platform Stations (HAPS) for communications area coverage. Swarm coordination techniques are essential for developing autonomous capabilities for multiple HAPS/UAS control and management. This paper examines the performance of artificial intelligence (AI) capabilities of RL and SI for autonomous swarm coordination. In this work, it was observed that the RL approach showed superior overall peak user coverage with unpredictable coverage dips; while the SI based approach demonstrated lower coverage peaks but better coverage stability and faster convergence rates.

Many email communications remain unencrypted between end points, raising the need for additional encryption. This paper addresses the need by proposing a new cryptographic scheme, which first encrypts a message using key-based Shamir’s secret sharing (using multiple polynomial terms as opposed to only the constant) and discretely hides the shares throughout a cover image using a steganographic technique with number padding. It thus employs multi-layer security requiring the key, the original cover image and the decryption algorithm implementation to unlock the message. Its security is analysed, confirmed and an example given.

Visual secret sharing is a cryptographic paradigm encrypting images into a number of individually random “shadow images”. When stacked, they reveal a contrast-reduced version of a secret image. In this paper, we consider random grid shadow images, which have gained increasing attention in recent years due to lack of pixel expansion inherent in Naor-Shamir visual cryptography. We propose a methodology to use such grids to encode series of frames comprising short animations, useful in situations when a mere static image is insufficient to convey a secret instruction. Although this method results in significant contrast degradation with longer animations, a method is devised to isolate the signal from the noise in a computational XOR-based decryption.

A long-standing anomaly regarding the difference in stabilities of a series of protonated cyclopropylcarbinyl ketones has been resolved. The enthalpies of protonation of the ketones to the oxocarbenium ions (DeltaH(i)) were calculated from the PM3 heats of formation of the ketones and ions using isodesmic cycles. The values of DeltaH(i) correlate well with the experimentally determined values of pK(R+) for the ketones in concentrated sulfuric acid. Methyl substitution on the cyclopropyl ring uniformly stabilizes the resulting ions. Orientation of the -OH(+) to the cyclopropyl affects stability as well: a syn (periplanar) orientation lowers stability, while an anti (antiperiplanar) orientation increases it, apparently because of charge repulsion between the protonated carbonyl and the partial positive charges on the ring carbons caused by carbinyl "resonance" stabilization. Decreasing the angle about the carbonyl carbon leads to a decrease in stability for all systems tested and appears to be a major source of destabilization of the nortricycle system relative to skeletal analogs with more open carbonyl bond angles. The more stable ions have pi HOMOs, while the nortricycle and related ions have sigma HOMOs, which is another source of destabilization of the nortricycle system. For comparison, the corresponding hydrocarbon carbenium ions were examined; similar orders of stability were identified.

Displacement reactions on the title compound (1) occur only for nucleophiles with intermediate hardness. Nucleophiles that react display a range of mechanisms. 1 reacts with the neutral nucleophile pyridine-d(5) through a mixed S(N)1/S(N)2 mechanism; salt added to control ionic strength affects the rate for the unimolecular process, but has no effect on the bimolecular rate constant. The mechanism of displacement by N(3)(-) and SO(3)(2)(-) depends on the presence or absence of exogenous salt. At constant ionic strength, the mechanism is mixed S(N)1/S(N)2 over most of the range of [Nu]. With nucleophile only present, plots of k(obsd) vs [Nu] exhibit severe breaks that are not the result of salt effects. Analysis of rate constants and product ratios suggests that at low [Nu] reaction occurs simultaneously through concerted Hughes-Ingold S(N)2 and preassociation-concerted mechanisms. At high [Nu], displacement occurs only through the preassociation-concerted mechanism. Comparison of these results with data for gas-phase dissociation of benzyl dimethylsulfoniums and with solution results for benzyl pyridiniums suggests that the intrinsic stability of the intermediate does not necessarily determine the mechanism.

Visual cryptography is a form of secret sharing requiring only human vision to decrypt a secret image, based on the stacking of seemingly random shadow images, or "shares". The main optimization metrics are pixel expansion and recovered image contrast. Maximization of the latter is crucial, as it determines the quality of the decrypted secret. This paper proposes genetic algorithms to evolve basis matrices striving for maximal contrast. They are encoded as binary chromosomes and an objective function is proposed to evaluate their respective fitness values. Evidence for the optimality of GA parameters is demonstrated experimentally, and the success this approach is shown with up to four shares. Furthermore, the algorithm is extended to a generalized graph access for comparison with other research, and the security of this method is analyzed and confirmed.

The relative rates for the gas-phase dissociation RX(+) --R(+) + X degrees of five (4-Y-substituted benzyl)dimethysulfoniums (Y = MeO, Me, H, Cl, and NO(2)) and 24 (4-Y-substituted benzyl)-3'-Z-pyridiniums (complete series for Z = CN, Cl, CONH(2), and H, and 4-methoxy- and 4-nitrobenzyls for Z = F and CH(3)CO) were measured using liquid secondary ion mass spectrometry. The Hammett plot (vs deltaDeltaG degrees or sigma(+)) is linear for the sulfoniums, but plots for the four pyridinium series have a drastic break between the 4-Cl and 4-NO(2) substrates. Brønsted-like plots for the pyridiniums show a strong leaving group effect only for 4-nitrobenzyls. An analysis of these linear free energy relations with supporting evidence from semiempirical computations suggests that collisionally activated pyridinium substrates dissociate by two pathways, direct dissociation and through an ion-neutral complex intermediate. Comparison of these results with results for the solution reactions of some of these compounds shows that the mechanism is different in the gas and solution phases. Sufficient experimental data are not available to assign a mechanism for dissociation to the sulfonium series, but computational results show characteristics of a direct dissociative mechanism.

At low concentrations (ca. 10 -4 M), the hydrolysis of (4-methoxybenzyl)dimethylsulfonium chloride (1) proceeds smoothly to completion in H 2 O or D 2 O at 80 o C. The rate constants measured directly by UV or NMR methods match the rate constants obtained as the ordinate intercepts of plots of k obsd vs [NaN 3 ] or [pyridine-d 5 ]. As expected, the rate constants decrease with increasing ionic strength (NaCl or NaClO 4 , μ=0.2). There is a small solvent deuterium isotope effect, k H /k D =1.1 at μ=0 and 1.7, and the α-deuterium secondary isotope effect is k H /k D =1.26 Per deuterium. At higher concentrations (10 mM), the hydrolysis does not go to completion, with the fraction of 1 remaining reaching plateau values that are stable. Plots of the fraction of 1 remaining vs the initial concentration of 1 extrapolate to zero. Running the reaction in the presence of either Hg +2 or Zn +2 drives the reaction to completion by removing SMe 2 as the Lewis complex. While these results are consistent with common leaving group suppression of hydrolysis, they are also consistent with the establishement of an equilibrium among the starting material and the product alcohol, SMe 2 , and hydronium ion. The suppression data are fitted to the equation for the equilibrium, and running the reaction in reverse gives the amount of 1 predicted by the equation. Reinterpretation of older data in light of the equilibrium, the results reported here, and results for the nucleophilic substitution reaction suggests that the mechanism of hydrolysis is S N 1 with no ion-dipole complex intermediate

The relative abundances of ribosyl oxocarbenium ion-related cations in the gas-phase dissociation of five 2'-substituted β-nicotinamide arabinosides (substituents=H, OH, NH 2 , NAc, F) follow the Taft equation with σ F . The first-order rate constants for the pH-independent hydrolysis of these substrates follow Ρ I , which is based on solution acidities of the same series of compounds used to define σ F in the gas phase. The value of Ρ is much greater in solution (Ρ I =-6.7) than in the gas phase (Ρ F =-0.75). There is direct evidence that the NAc substrate reacts through an ion-dipole complex. Energy profiles were calculated in AM1; while there are some apparent anomalies in the method that can be sorted out easily, the activation enthalpies and energies of the various structures are consistent with the proposed mechanism. A plot of the AM1-calculated values of ΔH * for gas-phase dissociation vs the log of the relative abundances for the respective species is linear, as is a plot of the solution ΔG * and the gas-phase ΔH * . Comparison of solution and gas-phase results suggests that an ion-dipole complex is an intermediate in both phases, but that the rate-limiting step is different

A long-standing anomaly regarding the difference in stabilities of a series of protonated cyclopropylcarbinyl ketones has been resolved. The enthalpies of protonation of the ketones to the oxocarbenium ions (ΔHi) were calculated from the PM3 heats of formation of the ketones and ions using isodesmic cycles. The values of ΔHi correlate well with the experimentally determined values of pKR+ for the ketones in concentrated sulfuric acid. Methyl substitution on the cyclopropyl ring uniformly stabilizes the resulting ions. Orientation of the −OH+ to the cyclopropyl affects stability as well: a syn (periplanar) orientation lowers stability, while an anti (antiperiplanar) orientation increases it, apparently because of charge repulsion between the protonated carbonyl and the partial positive charges on the ring carbons caused by carbinyl “resonance” stabilization. Decreasing the angle about the carbonyl carbon leads to a decrease in stability for all systems tested and appears to be a major source of destabiliz...

Debate over the effects of public versus private health care financing has been, and continues to be, active in both academic outlets and policy circles. Theoretical literature on parallel health care financing is often built on untested behavioural assumptions and the empirical evidence generally depends upon the institutional details of the specific health care systems under analysis. This paper contributes to the literature on parallel health care finance by developing and executing a revealed preference laboratory experiment based on the theoretical model of parallel health care finance in Cuff et al. (2008). The theoretical model involves individuals in the labour force with varying severities of illness who demand health care from a limited supply of health care resources. Health care resources are purchased by the public sector and rationed free of charge to individuals, or purchased by individuals through a private insurance market. The general theoretical model is converted into a discrete experimental representation of a large-scale economy where individuals are price takers, the probability of receiving public health care is exogenous and the willingness-to-pay (WTP) for private health insurance is elicited from subjects. The experimental design includes two within-subject factors based on the theoretical model: the public sector rationing rule (rationing based on need or severity versus rationing based on a random allocation) and the probability of being publicly treated (high versus low). The experimental design also includes two between-subjects treatments based on the frame of the experiment (neutral frame versus health frame) and on the distribution of private health insurance prices (high prices versus low prices). The results show the public system's allocation rule and the probability of receiving health care from the public system both significantly affect an individual's WTP for private health insurance in the predicted direction, although the WTP values tend to be above the actual theoretical predictions. When the public system allocates health care based on need, the average WTP is lower than under random allocation. A higher probability of receiving health care from the public system elicits a lower WTP regardless of how the public system allocates health care. It is also found that when the public system allocates health care based on need, the WTPs are significantly higher under a neutral frame than a health frame.

The type IV nuclcophilic substitution reaction at the anomeric carbon of β-nicotinamidc riboside + was studied in the gas phase using the semiempirical PM3 method. Because there are few computational studies of displacement reactions on a positively charged substrate, the isoenergetic displacements of dimethyl ether on the trimethyloxonium cation and trimethylamine on the tetramethylammonium cation were studied to provide baseline comparisons. The results are compared to the thermodynamics of the unimolecular dissociation reaction and to prototype reactions of the extensively studied S N 2(type I) reaction

Many economic decisions are susceptible to either free-riding, or excessive rivalry or overextraction. Equally sharing output in partnerships introduces a free-riding incentive which may offset the latter. We conduct a laboratory experiment to assess the performance of output sharing in partnerships by introducing equal-sharing subgroups of size one, four and six into a twelve-person common pool resource (CPR) environment. Group members are either unchanging throughout a 15 period session (the partners treatment), or randomly reassigned each decision round (the strangers treatment). Group size significantly affects effort. Aggregate effort reflects the Nash equilibrium predictions. The first best solution is achieved when resource users are privately extracting from the CPR and equally sharing their output with the socially optimal number of partners. The strangers treatment does not significantly affect aggregate effort. Total payoff distribution, however, is more equitable for strangers than for partners.

Two approaches to emmisions trading are cap-and-trade, in which an aggragate cap on emmisions is distributed in the form of permits, and baseline-and-credit, in which firms earn credits for emissions below their baselines. Theoretical considerations suggest the long-run equilibria of the two plans will differ if baselines are proportional to output, because a variable baseline is equivalent to an output subsidy. This paper reports on a laboratory environment designed to test this prediction. A computerized environment has been created in which subjects representing firms choose capacity and emission rates and participate in markets for permits or credits and for output. Demand for output is simulated. All decisions are tracked through a double-entry bookkeeping system. The timing of decisions was adjusted to avoid short-run instability. The paper reports the parameterization for an experiment with human traders and results of a simulated experiment using robots.

This paper analyses a number of areas in which issues of gender and power between men and women arise in the context of relationship breakdown, most specifically in the Family Court. These areas include power imbalances in the family law process, family violence and denial of access to legal representation, as well as broader socio-economic issues such as differential earning capacity and its consequences.The Family Court is both a major provider of primary dispute resolution services and the forum in which many family law disputes are determined. The paper discusses several ways in which the Court recognises the vulnerability of its clients and seeks to address any imbalances between them.

AM1-calculated energy profiles for dissociation of (methoxymethyl)pyridinium and dimethylanilinium ion substrates show that the methoxymethyl carbenium ion is not sufficiently stable to exist as an intermediate on the reaction coordinate for this model reaction. [(Thiomethoxy)methyl]pyridinium ion, however, has a distinct transition state because of the stability of the resulting ion-neutral complex. The complete potential energy surfaces for water displacement on the methoxymethyl substrate with either pyridine or dimethylaniline as the leaving group show distinct transition states and very flat surfaces for the ion-neutral complexes in which interaction of the carbenium ion with both leaving group and nucleophile is stabilizing. Secondary systems studied, including linear methoxy and thiomethoxy substrates, 5- and 6-membered cyclic oxo and thio substrates, and ribosyl-, xylopyranosyl-, and glucopyranosylpyridinium ions yield ion-neutral complexes with sufficient intrinsic stability to exist as intermediates. Comparison with solution data, primarily activation entropy and Bronsted coefficients, suggests that the sugar oxocarbenium ions, either as distinct, solvent-equilibrated intermediates or elements of ion-neutral complexes, are formed by unimolecular dissociation of the respective substrates in solution.

Factors affecting the cleavage of the carbon-oxygen bond in linear and cyclic aldehyde hydrates, heimacetals, acetals, and methyl ribosides and glucosides have been investigated using semiempirical calculations (AM1 and PM3). (For some systems, low- and high-level ab initio energies are available for comparison with the semiempirical results. With one exception, the results obtained by the two methods show excellent agreement in relative energies and trends in reactivity.) The effects on reactivity and stability caused by substituting a sulfur for the alpha oxygen in the oxocarbenium ion were also studied. In general, systems that can have an antiperiplanar alignment of lone pairs on the leaving group and potential oxocarbenium ion oxygens undergo spontanteous cleavage. An examination of various conformers of the leaving group relative to the potential oxocarbenium oxygen shows, however, that lone pair repulsion and steric factors for MeOH as the leaving group are more important than the antiperiplanar effect for bond cleavage. All compounds in which the alpha-oxygen in the potential carbenium ion is replaced by sulfur undergo spontaneous cleavage regardless of the leaving group or structure of the compound. Energy profiles, DeltaH(), and DeltaH(R) values show that linear and cyclic thiocarbenium ions are much more stable than the corresponding oxocarbenium ions. Comparison of results for methyl ribosides and glucosides with results for corresponding pyridinium substrates suggests that both should hydrolyze through an A-1 mechanism. General-acid catalysis with hydronium as the acid was studied. With solution results, the computations suggest that substrates with either a good leaving group or stable oxocarbenium ion react with rate-limiting proton transfer from the acid to the leaving group but that substrates with both a good leaving group and stable carbenium ion react with concerted proton transfer and bond cleavage.