Phenomenology of a minimal extension of the standard model with a family-dependent gauge symmetry

We consider a gauge symmetry extension of the standard model given by $SU(3)_C\otimes SU(2)_L\otimes U(1)_X\otimes U(1)_N\otimes Z_2$ with minimal particle content, where $X$ and $N$ are family dependent but determining the hypercharge as $Y=X+N$, while $Z_2$ is an exact discrete symmetry. In our scenario, $X$ (while $N$ is followed by $X-Y$) and $Z_2$ charge assignments are inspired by the number of fermion families and the stability of dark matter, as observed, respectively. We examine the mass spectra of fermions, scalars, and gauge bosons, as well as their interactions, in presence of a kinetic mixing term between $U(1)_{X,N}$ gauge fields. We discuss in detail the phenomenology of the new gauge boson and the right-handed neutrino dark matter stabilized by $Z_2$ conservation. We obtain parameter spaces simultaneously satisfying the recent CDF $W$-boson mass, electroweak precision measurements, particle colliders, as well as dark matter observables, if the kinetic mixing parameter is not necessarily small.Comment: 32 pages, 4 figures, 5 tables; Matches published version in PR

A critical look at rice husk gasification in Cambodia: Technology and sustainability

International audienceIn recent years, many Cambodian enterprises have installed rice husk gasifiers to substitute diesel in the electricity production to run rice mills machinery, or to provide electricity for villages. This study provides a critical look at rice husk gasification by assessing the sustainability of deploying this technology in Cambodia, expressed through environmental, economic and social impacts, and evaluates if it can be applied in Vietnam. Results show that gasification technology works in Cambodia and contribute to the development of the rice-milling sector, however environmental issues are severe and should be treated. We observe that increase in rice husk demand also leads to increase in price of rice husk, therefore new investors should consider the effect of new rice husk market for their activities. We conclude that this technology would not be suitable for Vietnam and suggests studying other alternative technologies to convert rice husk into energy, such as steam engine or steam turbine, gasifier stove, briquetting or co-firing

A Study on a Model of Anchovy Solar

In central and southern coastal areas of Vietnam, annual yield of anchovy is enormous that leads the high demand for anchovy drying. Moreover, seafood in generally and anchovy in particularly brings more benefit for fishermen, especially dried anchovy as an exporting product is one of the main their income. The market requires that anchovy product has to be dried before packaging to export. There are many drying methods to process the anchovy but some problems might need to be solved such as the drying efficiency, the low product quality and sanitation, and the environmental annihilation. In order to using the profuse solar energy, a model for experiment investigation the anchovy dryer has been conducted in ThuDuc district, Hochiminh city with the anchovy caught from Kien giang and Baria-Vung tau province, southern Vietnam. The results indicate that solar energy is one of renewable energy which can be completely used for anchovy drying with high drying efficiency. The dried anchovy has good color, high quality, and especially it passes the requirements of food hygiene and environment protecting

An Efficient Precoder Design for Multiuser MIMO Cognitive Radio Networks with Interference Constraints

We consider a linear precoder design for an underlay cognitive radio multiple-input multiple-output broadcast channel, where the secondary system consisting of a secondary base-station (BS) and a group of secondary users (SUs) is allowed to share the same spectrum with the primary system. All the transceivers are equipped with multiple antennas, each of which has its own maximum power constraint. Assuming zero-forcing method to eliminate the multiuser interference, we study the sum rate maximization problem for the secondary system subject to both per-antenna power constraints at the secondary BS and the interference power constraints at the primary users. The problem of interest differs from the ones studied previously that often assumed a sum power constraint and/or single antenna employed at either both the primary and secondary receivers or the primary receivers. To develop an efficient numerical algorithm, we first invoke the rank relaxation method to transform the considered problem into a convex-concave problem based on a downlink-uplink result. We then propose a barrier interior-point method to solve the resulting saddle point problem. In particular, in each iteration of the proposed method we find the Newton step by solving a system of discrete-time Sylvester equations, which help reduce the complexity significantly, compared to the conventional method. Simulation results are provided to demonstrate fast convergence and effectiveness of the proposed algorithm.Comment: Accepted to appear in IEEE Trans. Vehicular Technology, 13 pages, 8 figure

Market-based approaches to food safety and animal health interventions: Lessons from smallholder pig value chains in Vietnam

Food safety and animal health issues are increasingly important constraints to smallholder pig production in Viet Nam. Recent studies have highlighted the significant prevalence of animal disease and food‐borne pathogens inherent within the Vietnamese pig sector. These in turn have important negative livelihoods effects on smallholder pig producers and other value chain actors, as well as important public health impacts. An important research gap is in identifying ex‐ante appropriate market‐based policy responses that take into account the tradeoffs between improved animal health and food safety outcomes and their associated costs for different value chain actors as a means of developing chain‐level solutions for their control. In this paper, we constructed a system dynamics model of the pig value chain that combines a detailed model of herd production and marketing with modules on short‐ and long‐term investment in pig capacity, and decisions by value chain actors to adopt different innovations. The model further highlights the feedbacks between different actors in the chain to identify both the potential entry points for upgrading food safety and animal health as well as potential areas of tension within the chain that may undermine uptake. Model results demonstrate that interventions at nodal levels (e.g. only at farm or slaughterhouse level) are less cost‐effective and sustainable than those that jointly enhance incentives for control across the value chain, as weak links downstream undermine the ability of producers to sustain good health practices

Using a system dynamics framework to assess disease risks of pig value chains in Vietnam

In Vietnam, there are more than 4 million households producing pigs and pork. This accounts for 57% of quantity of meat consumed. One of the most critical constraints to pig production is the presence of animal disease. Pig disease outbreaks are a regular occurrence in various parts of the country, with the industry affected by diseases such as foot and mouth disease, porcine reproductive and respiratory syndrome, classical swine fever, porcine high fever disease, and swine influenza. In addition, food safety issues related to pig diseases and pork-borne diseases have also increasingly become more important concerns for consumers. Recent studies have shown significant changes in consumption behaviour in response to disease outbreaks. For instance, at least half of urban consumers stop consuming pork in times of pig disease epidemics and/or shift consumption to other meat substitutes such as poultry or fish. Disease risks thus have both public health and livelihoods impacts that are important to understand for appropriate policy and practice response. A proposed methodology for investigating disease risks uses a system dynamics analysis framework. System dynamics models are particularly relevant in the study of livestock systems, as they capture the diverse actors and feedbacks present in value chains and their interface with disease risk and behaviour. A system dynamics model is developed that will describe different scenarios of disease risks and the consequences of different interventions to mitigate these risks. Data from a sample of 1000 farmers and value chain actors including all actors in the pig value chain in Vietnam was collected with support from an ACIAR-funded project on Reducing Disease Risks and Improving Food Safety in Smallholder Pig Value Chains in Vietnam. We propose to test the hypotheses that disease risk is affected by type of production system, feeding system and types of feed uses, access to inputs and services, and selected socio-demographic variables associated with farmers and location

Endoparasites in pigs raised in smallholder farms in Hung Yen province of Vietnam

As being part of an ongoing project, assessing animal health and food safety risks in smallholder pig value chains in Hung Yen province of Vietnam, the presence of endoparasites was investigated in a repeated study. Three communes, with a total of 545 smallhoder pig farms, from three districts were selected. In each commune, ten farms were randomly chosen. On farm data including farm management and biosecurity measures were recorded by using a checklist and observations. From each farm, one pooled fecal sample was collected from a randomly chosen barn monthly and followed from June to December 2014 for seven months. Fecal samples were analyzed for intestinal parasites by floatation and sedimentation methods. The intensity of most commonly seen parasites was determined by the McMaster counting technique. In 198 collected fecal samples, six types of parasites were detected, namely Eimeria 89 (44.95%), Ascaris suum 43 (21.72%), Strongyloides sp. 41 (20.71%), Trichocephalus suis 19 (9.60%), Fasciolopsis buski 10 (5.05%), and Fasciola 2 (1.01%). Highest intensities were observed for Eimeria (maximum 80900 oocyst/g), followed by Ascaris suum (2400 egg/g), Strongyloides sp. (1900 egg/g), and Trichocephalus suis (1300 egg/g); the others were reported at much lower intensities. Infection levels and intensities of the parasites tended to be higher during the hot months, June to September. No significant difference between communes was found. At least one type of parasites was present in 137 samples (69.19%). Most of farms (96.67%) were positive for at least one type of parasites in at least one sample. There was a significant difference in infection level of endoparasites between biogas and non-biogas farms. The general high parasite burden reported in this study will be addressed in future interventions which will include parasite control apart from other measures