Land Reform and Farm Land Rental Market Operation in the Northern Uplands of Vietnam

This paper examines the factors affecting the participation of farm households in farm land rental markets with particular focus on the impact of the land reform. The operational outcomes of such market participation are also analysed. The study used a panel dataset of farm households surveyed before and after the land reform with Random Effect Tobit model. The analysis showed that the land reform have contributed to increased land rental participation. The operation of the market has both efficiency and equity outcomes. Therefore, constraints to functioning of land rental market are difficult to justify. In other words, farm land rental should be promoted to bring such desirable outcomes.land reform, land rental market participation, efficiency and equity in land use, northern uplands.

Land Reform and Rural Households in the Northern Uplands of Vietnam

This paper is the abstract of my doctoral dissertation entitled “The Impact of Land Reform on Rural Households in the Northern Uplands of Vietnam” at the Justus Liebig University of Giessen, Germany under the supervision of Prof. Dr. Siegfried Bauer. The study examined the impact of the recent land reform in Vietnam on the economy of rural households in the Northern Uplands of Vietnam. It was found that the land reform has positive impact on three important aspects of rural household’s economy, namely crop production, land market participation, and afforestation. However, further improvement in terms of private land rights is needed for a more sustainable development in the region.Land reform, panel data, crop production, land markets, afforestation, economic incentives, rural households

Land Reform and Farm Land Rental Market Operation in the Northern Uplands of Vietnam

This paper examines the factors affecting the participation of farmhouseholds in farm land rental markets with particular focus on the impact ofthe land reform. The operational outcomes of such market participation are alsoanalysed. The study used a panel dataset of farm households surveyed beforeand after the land reform with Random Effect Tobit model. The analysisshowed that the land reform have contributed to increased land rentalparticipation. The operation of the market has both efficiency and equityoutcomes. Therefore, constraints to functioning of land rental market aredifficult to justify. In other words, farm land rental should be promoted to bringsuch desirable outcomes

Land Reform and Rural Households in the Northern Uplands of Vietnam

This paper is the abstract of my doctoral dissertation entitled “The Impactof Land Reform on Rural Households in the Northern Uplands of Vietnam” at theJustus Liebig University of Giessen, Germany under the supervision of Prof. Dr.Siegfried Bauer. The study examined the impact of the recent land reform inVietnam on the economy of rural households in the Northern Uplands of Vietnam.It was found that the land reform has positive impact on three important aspects ofrural household’s economy, namely crop production, land market participation, andafforestation. However, further improvement in terms of private land rights isneeded for a more sustainable development in the region

Bi-Criteria Approximation Algorithms for Load Balancing on Unrelated Machines with Costs

We study a generalized version of the load balancing problem on unrelated machines with cost constraints: Given a set of m machines (of certain types) and a set of n jobs, each job j processed on machine i requires p_{i,j} time units and incurs a cost c_{i,j}, and the goal is to find a schedule of jobs to machines, which is defined as an ordered partition of n jobs into m disjoint subsets, in such a way that some objective function of the vector of the completion times of the machines is optimized, subject to the constraint that the total costs by the schedule must be within a given budget B. Motivated by recent results from the literature, our focus is on the case when the number of machine types is a fixed constant and we develop a bi-criteria approximation scheme for the studied problem. Our result generalizes several known results for certain special cases, such as the case with identical machines, or the case with a constant number of machines with cost constraints. Building on the elegant technique recently proposed by Jansen and Maack [K. Jansen and M. Maack, 2019], we construct a more general approach that can be used to derive approximation schemes to a wider class of load balancing problems with constraints

Utilization of Protein Tertiary Contacts to Improve Protein Structure Prediction Using Sequence Homology

The structure of a protein ultimately determines its function; therefore, knowledge of three-dimensional structure is essential for understanding its function and mechanism of action. The two most common methods for determining protein structure are x-ray crystallography and Nuclear Magnetic Resonance (NMR) spectroscopy. These methods are quite successful but can be very time-intensive and costly. An alternative method is protein structure prediction, where structure is computationally predicted from amino acid sequence. As opposed to x-ray crystallography and NMR spectroscopy, protein structure prediction is not encumbered by potential experimental problems. In this research, we attempted to determine if certain protein structure features, known as tertiary contacts, can improve the prediction of protein three-dimensional structure. By calculating and analyzing sequence homology and related values, it was shown that tertiary contacts, which typically are long-range amino acid interactions separated by at least 10 amino acids in sequence length, generally have lower pair averaged sequence homology-based values. From our calculations we were able to create a prediction filter based on our known literature-derived tertiary contacts of whether amino acid residues are buried or on the surface of a protein. From our tertiary contact prediction filter, it was shown that approximately 80% of the amino acid residues in our protein learning set were correctly filtered to be on the surface of a protein. These results imply that tertiary contacts are more conserved, densely packed, and less likely to be on the surface of a protein. From the tertiary contact prediction filter, we hope that tertiary contacts can be utilized in conjunction with other prediction approaches to more accurately predict where amino acids may be located in a protein

Internet use and agricultural productivity in rural Vietnam

The use of the internet is growing rapidly and has become an engine for economic development. However, few studies have examined the impact of internet use on agricultural production, and the results are not yet conclusive. Employing a dataset of more than 2000 observations in rural Vietnam, our study analyses the impact of internet use on agricultural productivity using the heteroscedasticity-based instrument approach suggested by Lewbel, Journal of Business and Economic Statistics, 2012, 30, 67–80 and examines the heterogeneity and distribution of the impact using quantile regressions. Our results show that internet use has significant and positive effects on agricultural productivity. However, these effects are heterogeneous across population groups. The positive effects of internet use are stronger for households with a lower level of education, with a young and female head, and from ethnic minorities. The benefits are also found to be skewed towards the group of farmers at the bottom of the productivity distribution. Therefore, we propose facilitating the diffusion of the internet, since it not only boosts agricultural productivity, but also reduces productivity inequality. In addition, we recommend promoting rural education, supporting local markets, investing more in irrigation systems, and facilitating farm mechanisation as these factors are found to contribute to increasing agricultural productivity

Appropriate sample size and effects of microscopic parameters on the shear strength and strain localisation of 2D cohesive-frictional granular assemblies

Granular materials are made up of smaller particles, manifestation of microstructure results in a macroscopic response of granular material. Understanding the overall mechanical behaviour from microscopic parameters is one of the main challenges in many engineering fields including civil engineering. When modelling this kind of material by Discrete Element Model (DEM) using idealized circular grains, the effects of appropriate sample size and microscopic parameter changes have been a crucial subject. Previous research has primarily relied on the case of purely frictional granular materials. In this paper, we use DEM to investigate the appropriate sample size and the relationship between microscopic parameters and the macroscopic responses of cohesive-frictional granular assemblies by performing a series of biaxial tests. Our findings indicate that a minimum number of particles is required to balance between mechanical behaviour and computing time. In addition, through extensive parametric studies, the paper explores the impact of factors such as interparticle bonds, intergranular friction coefficients, and initial void index on the overall shear behaviour of granular assemblies. Also, the result reveals a strong correlation between shear band formation and the break field of cohesive contact (static variable) and the translations and rotations of grains (kinematic variable)

DEM investigation on strain localization in a dense periodic granular assembly with high coordination number

Strain localization is one of key phenomena which have been studied extensively in geomaterials and for different kinds of materials including metals and polymers. This well-known phenomenon appears when structure/material is closed to failure. Theoretical, experimental, and numerical research have been dedicated to this subject for a long while. In the numerical aspects, strain localization inside the periodic granular assembly has not been well studied in the literature. In this paper, we investigate the occurrence and development of strain localization within a dense cohesive-frictional granular assembly with high coordination number under bi-periodic boundary conditions by Discrete Element Modeling (DEM). The granular assembly is composed of 2D circular disks and subjected to biaxial loading with constant lateral pressure. The results show that the formation of shear bands is of periodic type, consistent with the boundary conditions. This formation has the origins of the irreversible losing of cohesive contacts, viewed as micro-crackings which strongly concentrated in the periodic shear zones. This micromechanical feature is therefore strongly related to the strain localization observed at the sample scale. Finally, we also show that the strain localization is in perfect agreement with the sample’s displacement fluctuation fields