Decisions of producer-funded agricultural research and development

Agricultural research and development (R&D) investment is becoming an increasingly important policy issue as food prices push upwards and food security problems emerge. An important source of agricultural R&D funding is from producer check-offs, which are increasingly being used to fund applied agricultural research such as disease management, genetic improvement, and weed control. Existing studies of producer-funded agricultural R&D indicate that there are high private and social rates of return to agricultural R&D investment by farmers, and thus that farmers are under investing in R&D. The focus of this thesis is at the producer level. This study examines one of the factors -- the horizon problem -- behind the apparent disincentive for farmers to invest in producer-funded R&D activities. It has been argued that given the long period of time over which the benefits of R&D investment occur, the increasing age of the farm population implies that the horizon problem could be indeed an important factor in producer underinvestment. Contrary to this widely acknowledged argument, this study shows the horizon problem is likely not a factor affecting farmers R&D investment decisions. Two models are developed to examine the horizon problem. The first model consists of a framework for determining the marginal internal rate of return of investing in R&D. Specifically, the model calculates the internal rate of return -- i.e., IRRh -- associated with the farmers' planning horizon and compares this to the internal rate of return -- i.e., IRR bar-- associated with the benefit horizon of the R&D. The impact of the horizon problem is determined by examining the difference between IRRh and IRR bar. The results of the horizon problem model show how that, contrary to what some authors have argued, the horizon problem is likely not a disincentive for R&D investment, unless the time horizon of farmers is very short. Given that the membership horizon for the average Canadian producer is 15 to 20 years, it is expected that the horizon problem is not an issue for Canadian producers. Furthermore, the analysis assumes farmers only are concerned with profit maximization. However, farmers may also consider other factors when making R&D investment decisions, such as future generations of agricultural producers and environment issues. The results of this study show that, even under the assumption of profit maximization, the horizon problem is not an issue for Canadian farmers, let alone in a more realistic model implemented by including factors other than profit. The results of the horizon problem model also show that the impact of the horizon problem is not affected by land tenure relationships. The second model consists of a multi-region, multi-product trade model that is used to examine the impact of Canadian pea R&D funding on consumers and producers in Canada and in various countries around the world that produce and consume pulses. To address the underinvestment issue, it is important to understand the question of who benefits from the research that is undertaken, and who bears the cost. Given that Canada is the largest pea exporter in the world an increase in R&D investment can be expected to have a significant impact on international trade and overseas producers and consumers. The simulation results from the second model illustrate that with increased pea R&D investment, Canadian producers, as well as consumers in all regions, are better off as a result of the R&D investment, while overseas producers are worse off. The results of the sensitivity analysis show that a pivotal supply shift associated with an increased levy, combined with a parallel supply curve shift due to increases in the knowledge stock, does affect the IRR in the large country versus the small country case. This result differs from the result that occurs when there is a parallel shift in supply at both the levy and R&D stages, indicating that it is important to understand the interaction between the manner in which R&D is funded, the way in which R&D affects supply and the trade status of a country. The results of the sensitivity analysis also indicate that the IRR to Canadian producers depends critically on how large an impact pea R&D has on the production of other crops (e.g., wheat and canola). The larger is this impact -- i.e., the more that wheat and canola production falls as a result of higher yields/lower costs of pea production -- the smaller is the IRR. The results also indicate that the elasticities of demand for peas and lentils in the importing countries do not have an impact on the IRR in the case where Canada is a large country exporter for peas only; however, they do have an impact on IRR in the case where Canada is a large exporter for both peas and lentils. In all cases, the more elastic is the demand, the higher is the IRR

Improved quantum entropic uncertainty relations

We study entropic uncertainty relations by using stepwise linear functions and quadratic functions. Two kinds of improved uncertainty lower bounds are constructed: the state-independent one based on the lower bound of Shannon entropy and the tighter state-dependent one based on the majorization techniques. The analytical results for qubit and qutrit systems with two or three measurement settings are explicitly derived, with detailed examples showing that they outperform the existing bounds. The case with the presence of quantum memory is also investigated.Comment: 14 pages,6 figure

Characterizations of bilocality and nn-locality of correlation tensors

In the literature, bilocality and $n$-locality of correlation tensors (CTs) are described by integration local hidden variable models (called C-LHVMs) rather than by summation LHVMs (called D-LHVMs). Obviously, C-LHVMs are easier to be constructed than D-LHVMs, while the later are easier to be used than the former, e.g., in discussing on the topological and geometric properties of the sets of all bilocal and of all $n$-local CTs. In this context, one may ask whether the two descriptions are equivalent. In the present work, we first establish some equivalent characterizations of bilocality of a tripartite CT {\bf{P}}=\Lbrack P(abc|xyz)\Rbrack, implying that the two descriptions of bilocality are equivalent. As applications, we prove that all bilocal CTs with the same size form a compact path-connected set that has many star-convex subsets. Secondly, we introduce and discuss the bilocality of a tripartite probability tensor (PT) {\bf{P}}=\Lbrack P(abc)\Rbrack, including equivalent characterizations and properties of bilocal PTs. Lastly, we obtain corresponding results about $n$-locality of $n+1$-partite CTs {\bf{P}}=\Lbrack P({\bf{a}}b|{\bf{x}}y)\Rbrack and PTs {\bf{P}}=\Lbrack P({\bf{a}}b)\Rbrack, respectively

Privacy-Preserving Distributed SVD via Federated Power

Singular value decomposition (SVD) is one of the most fundamental tools in machine learning and statistics.The modern machine learning community usually assumes that data come from and belong to small-scale device users. The low communication and computation power of such devices, and the possible privacy breaches of users' sensitive data make the computation of SVD challenging. Federated learning (FL) is a paradigm enabling a large number of devices to jointly learn a model in a communication-efficient way without data sharing. In the FL framework, we develop a class of algorithms called FedPower for the computation of partial SVD in the modern setting. Based on the well-known power method, the local devices alternate between multiple local power iterations and one global aggregation to improve communication efficiency. In the aggregation, we propose to weight each local eigenvector matrix with Orthogonal Procrustes Transformation (OPT). Considering the practical stragglers' effect, the aggregation can be fully participated or partially participated, where for the latter we propose two sampling and aggregation schemes. Further, to ensure strong privacy protection, we add Gaussian noise whenever the communication happens by adopting the notion of differential privacy (DP). We theoretically show the convergence bound for FedPower. The resulting bound is interpretable with each part corresponding to the effect of Gaussian noise, parallelization, and random sampling of devices, respectively. We also conduct experiments to demonstrate the merits of FedPower. In particular, the local iterations not only improve communication efficiency but also reduce the chance of privacy breaches

A Pseudo DNA Cryptography Method

The DNA cryptography is a new and very promising direction in cryptography research. DNA can be used in cryptography for storing and transmitting the information, as well as for computation. Although in its primitive stage, DNA cryptography is shown to be very effective. Currently, several DNA computing algorithms are proposed for quite some cryptography, cryptanalysis and steganography problems, and they are very powerful in these areas. However, the use of the DNA as a means of cryptography has high tech lab requirements and computational limitations, as well as the labor intensive extrapolation means so far. These make the efficient use of DNA cryptography difficult in the security world now. Therefore, more theoretical analysis should be performed before its real applications. In this project, We do not intended to utilize real DNA to perform the cryptography process; rather, We will introduce a new cryptography method based on central dogma of molecular biology. Since this method simulates some critical processes in central dogma, it is a pseudo DNA cryptography method. The theoretical analysis and experiments show this method to be efficient in computation, storage and transmission; and it is very powerful against certain attacks. Thus, this method can be of many uses in cryptography, such as an enhancement insecurity and speed to the other cryptography methods. There are also extensions and variations to this method, which have enhanced security, effectiveness and applicability.Comment: A small work that quite some people asked abou

A three-dimensional finite element modelling of human chest injury following front or side impact loading

Based on anatomical features of a 50th percentile adult male, three-dimensional (3D) finite element (FE) models of ribs, sternum, vertebrae, intervertebral discs, clavicle, scapula, pelvis, skin, head, muscles and limbs were developed in this study. After integrating/assembling various organs and tissues, a bio-mechanical FE model of the human body with adult male characteristics was produced. Furthermore, a chest frontal and lateral collision theory model was built and was validated by using previously published data from corpse frontal and lateral chest impact collision experiments. Good agreements were found between the simulation results of our model and the experimental data as well as theoretical calculations in the contact force, sternum displacement, and force-displacement response. These data suggest that this 3D FE model is effective and has good bio-fidelity in assessing chest biomechanical responses and thoracic injuries upon impact loading. Therefore this model can potentially be useful for evaluating thoracic injuries in car crashes and assessing chest rib fractures and internal organ/tissue damages

Pb2+, Cu2+, Zn2+, Mg2+ and Mn2+ reduce the affinities of flavone, genistein and kaempferol for human serum albumin in vitro

Flavone (Fl), genistein (Gen) and kaempferol (Kol) were studied for their affinities towards human serum albumin (HSA) in the presence and absence of Pb2+,Cu2+,Zn2+,Mg2+ and Mn2+. The fluorescence intensities of HSA decreased with increasing concentration of the three flavonoids. Kaempferol resulted in a blue-shift of the λem of HSA from 336 to 330 nm; flavone showed an obvious red-shift of the λem of HSA from 336 to 342 nm; genistein did not cause an obvious blue-shift or red-shift of the λem of HSA. However, the extents of λem-shifts induced by the flavonoids in the presence of metal ions were much bigger than that in the absence of mental ions. Pb2+,Cu2+,Zn2+,Mg2+ and Mn2+ reduced the quenching constants of the flavonoids for HSA by 14.6% to 60.7% , 28% to 67.9%,3.5% to 59.4%, 23.2% to 63.7% and 14% to 65%, respectively. The affinities of flavone, genistein and kaempferol for HSA decreased about 10.84%, 10.05%and 3.56% in the presence of Pb2+, respectively. Cu2+ decreased the affinities of flavone, genistein and kaempferol for HSA about 14.04%, 5.14%and 8.89%, respectively. Zn2+ decreased the affinities of flavone, genistein and kaempferol for HSA about 3.79%, 0.55% and 3.58%, respectively. Mg2+ decreased the affinities of flavone, genistein and kaempferol for HSA about 16.94%, 2.94%and 7.04%, respectively. Mn2+ decreased the affinities of flavone, genistein and kaempferol for HSA about 14.24%, 3.66% and 4.78%, respectively

Integrable dispersionless KdV hierarchy with sources

An integrable dispersionless KdV hierarchy with sources (dKdVHWS) is derived. Lax pair equations and bi-Hamiltonian formulation for dKdVHWS are formulated. Hodograph solution for the dispersionless KdV equation with sources (dKdVWS) is obtained via hodograph transformation. Furthermore, the dispersionless Gelfand-Dickey hierarchy with sources (dGDHWS) is presented.Comment: 15 pages, to be published in J. Phys. A: Math. Ge