A cobb douglas stochastic frontier model on measuring domestic bank efficiency in malaysia

Banking system plays an important role in the economic development of any country. Domestic banks, which are the main components of the banking system, have to be efficient; otherwise, they may create obstacle in the process of development in any economy. This study examines the technical efficiency of the Malaysian domestic banks listed in the Kuala Lumpur Stock Exchange (KLSE) market over the period 2005-2010. A parametric approach, Stochastic Frontier Approach (SFA), is used in this analysis. The findings show that Malaysian domestic banks have exhibited an average overall efficiency of 94 percent, implying that sample banks have wasted an average of 6 percent of their inputs. Among the banks, RHBCAP is found to be highly efficient with a score of 0.986 and PBBANK is noted to have the lowest efficiency with a score of 0.918. The results also show that the level of efficiency has increased during the period of study, and that the technical efficiency effect has fluctuated considerably over time.     

A molecular ruler for measuring quantitative distance distributions

We report a novel molecular ruler for measurement of distances and distance distributions with accurate external calibration. Using solution X-ray scattering we determine the scattering interference between two gold nanocrystal probes attached site-specifically to a macromolecule of interest. Fourier transformation of the interference pattern provides a model-independent probability distribution for the distances between the probe centers-of-mass. To test the approach, we measure end-to-end distances for a variety of DNA structures. We demonstrate that measurements with independently prepared samples and using different X-ray sources are highly reproducible, we demonstrate the quantitative accuracy of the first and second moments of the distance distributions, and we demonstrate that the technique recovers complex distribution shapes. Distances measured with the solution scattering-interference ruler match the corresponding crystallographic values, but differ from distances measured previously with alternate ruler techniques. The X-ray scattering interference ruler should be a powerful tool for relating crystal structures to solution structures and for studying molecular fluctuations.     

Validation and application of an automated rheoscope for measuring red blood cell deformability distributions in different species

BACKGROUND: The deformability of red blood cells (RBCs) is of great importance for the conservation of oxygen delivery in the microcirculation. Even a small fraction of rigid cells is considered to harm the exchange of respiratory gases. Techniques that measure RBC deformability often provide an indication of the mean deformability. It may not be possible, however, to assess whether this mean value is reduced by the presence of a small rigid cell fraction or by a slight overall reduction in RBC deformability. A technique that provides a deformability distribution would be of great value to study diseases that are marked by subpopulations with a reduced deformability. METHODS: This paper describes a rheoscope system that uses advanced image analysis techniques to quickly quantify the deformability of many individual cells in shear flow, in order to find the RBC-deformability distribution. Since variations in the shear stress are responsible for variations in cell elongation, and hence introduce an additional spread in the cell deformability distribution, we first determined the spread caused by instrumental error. We then utilized the technique to investigate the relation between cell deformability and cell size of single blood samples of different species (human, pig, rat and rabbit). RESULTS: The spread caused by instrumental error was small compared to the actual RBC-deformability spread in blood samples. The deformability distribution of human and pig cells are alike although their cell sizes are different. Rat and rabbit cells show comparable deformability and size distributions. With this technique no correlation was found between cell deformability and cell size in animal RBCs. In the human sample a minor correlation was found between cell deformability and cell size. CONCLUSIONS: The automated rheoscope enables us to study the mechanical properties of RBCs more thoroughly by their deformability distribution. These deformability distributions are hardly influenced by the technique or by cell size.     

Stochastic compartmental model with branching particles

A multi-compartmental model with particles producing offspring according to the Markov branching process has been studied. Explicit results are given for the two-compartmental system and for irreversible general multicompartmental systems. The known models in stochastic compartmental analysis are shown to be particular cases of this model and applications are cited.     

Stochastic Penna model for biological aging

Summary A stochastic genetic model for biological aging is introduced bridging the gap between the bit-string Penna model and the Pletcher-Neuhauser approach. The phenomenon of exponentially increasing mortality function at intermediate ages and its deceleration at advanced ages is reproduced for both the evolutionary steady-state population and the genetically homogeneous individuals.     

Mixture distributions in a stochastic gene expression model with delayed feedback: a WKB approximation approach

Journal of Mathematical Biology - Noise in gene expression can be substantively affected by the presence of production delay. Here we consider a mathematical model with bursty production of...     

Stochastic model for multipotent hemopoietic progenitor differentiation

In this study, the authors propose a stochastic model for multipotent hemopoietic progenitor differentiation, which assumes that there is a fixed probability (P) that a progenitor with a potential for differentiation along a particular lineage maintains the potential in each cell division in each daughter cell, and this differentiation process of each lineage proceeds independently. To examine the applicability of this model, a sequential micromanipulation of paired progenitors was carried out and followed by cytological examination of the cells contained in the colonies derived from these progenitors; then calculation was made of the ratio of the number of paired colonies containing cell(s) with a particular lineage to the number of paired colonies in which only one colony contained cell(s) with the lineage at the first and second cell division. The ratios were similar at the first and second cell division within each lineage. Furthermore, the frequences of each lineage in multilineage hemopoietic colonies were calculated using the P values obtained from these micromanipulation experiments. The expected frequencies were similar to those in the actual experiments. These results suggested that the stochastic model was applicable to multipotent hemopoietic progenitor differentiation.     

A new approach using the Pierce two-node model for different body parts

This paper presents a new approach, in applying the Pierce two-node model, to predict local skin temperatures of individual body parts with good accuracy. In this study, local skin temperature measurements at 24 sites on the bodies of 11 human subjects were carried out in a controlled environment under three different indoor conditions (i.e. neutral, warm and cold). The neutral condition measurements were used to adjust the local skin set-points in the model for each body part. Additional modifications to the calculation algorithm were introduced corresponding to different body parts. The local core set-points were then calculated, using a line search method, as the input values that allow the model to predict the skin temperatures with maximum deviation of ±0.1°C for the neutral condition. The model predictability was verified for the other two indoor conditions, and the results show that the modified model predicts local skin temperatures with average deviation of ±0.3°C.     

A method for measuring oxygen distributions in tissue using frequency domain phosphorometry

Phosphorescence lifetime of phosphors dissolved in biological fluids is dependent on the local oxygen concentration. When phosphor is added to the blood in vivo there is a distribution of lifetimes due to the distribution of oxygen concentrations in the blood of the sampled tissue volume. The distribution of oxygen can be assessed non-invasively and in practically real-time using frequency domain time-resolved phosphorometry. Here we describe a multi-frequency system for measurements of oxygen distributions in tissue in vivo.     

An interval approach for dealing with flux distributions and elementary modes activity patterns

This work introduces the use of an interval representation of fluxes. This representation can be useful in two common situations: (a) when fluxes are uncertain due to the lack of accurate measurements and (b) when the flux distribution is partially unknown. In addition, the interval representation can be used for other purposes such as dealing with inconsistency or representing a range of behaviour. Two main problems are addressed. On the one hand, the translation of a metabolic flux distribution into an elementary modes or extreme pathways activity pattern is analysed. In general, there is not a unique solution for this problem but a range of solutions. To represent the whole solution region in an easy way, it is possible to compute the alpha-spectrum (i.e., the range of possible values for each elementary mode or extreme pathway activity). Herein, a method is proposed which, based on the interval representation of fluxes, makes it possible to compute the alpha-spectrum from an uncertain or even partially unknown flux distribution. On the other hand, the concept of the flux-spectrum is introduced as a variant of the metabolic flux analysis methodology that presents some advantages: applicable when measurements are insufficient (underdetermined case), integration of uncertain measurements, inclusion of irreversibility constraints and an alternative procedure to deal with inconsistency. Frequently, when applying metabolic flux analysis the available measurements are insufficient and/or uncertain and the complete flux distribution cannot be uniquely calculated. The method proposed here allows the determination of the ranges of possible values for each non-calculable flux, resulting in a flux region called flux-spectrum. In order to illustrate the proposed methods, the example of the metabolic network of CHO cells cultivated in stirred flasks is used.     

A method for measuring support for synapomorphy using character state distributions on phylogenetic trees

Synapomorphies are fundamental to phylogenetic systematics as they offer empirical evidence of monophyletic groups. However, no method exists to directly measure synapomorphy. Here, we propose a method that quantifies synapomorphy using the pattern of character state distribution over a cladogram separately for each character and for each clade. We define a fully synapomorphic character state as one shared by all of a clade’s terminal taxa and at the same time completely absent from all terminal taxa outside that clade. The extent to which this condition is met corresponds to the support for the character state being synapomorphic or, in short, support for synapomorphy. It is calculated as the probability of randomly selecting, by multi‐stage sampling following the topology of the tree, two terminals from inside a clade sharing the same character state and one terminal from outside the clade bearing a different character state. The method is independent of tree inference and free of transformational assumptions, and so can be applied to any tree and used for any type of discrete character. By measuring synapomorphy, the method offers a potential tool for determining diagnostic character states for taxa on different hierarchical levels, for evaluating alternative systems of character coding, and for evaluating clade support. We show how the method differs from ancestral character state reconstruction methods and goodness‐of‐fit indices. We demonstrate the behaviour of our method with several hypothetical scenarios and its potential use with two real‐life examples.     

Stochastic branching model for hemopoietic progenitor cell differentiation

We present algebraic expressions describing the predictions of a stochastic branching model for differentiation of hemopoietic progenitor cells. The model assumes that there is a fixed probability, p (0 less than or equal to p less than or equal to 1), that commitment to a differentiative event occurs per progenitor cell division for each daughter cell. The model describes properties of in vitro hemopoietic cell differentiation including the population structure at the time the first progenitor cell becomes committed, the number of committed progenitor cells engendered by a single progenitor cell, and the probability of eventual commitment of all daughter cells derived from a single progenitor or stem cell. Application of the model to experimental data obtained from erythroid cultures suggests that the observed data can be explained by the stochastic branching model alone without making the deterministic assumption that there is a differentiative hierarchy in the lineage of the progenitors of erythropoiesis (BFU-E). The qualitative and quantitative aspects of the proposed stochastic model are discussed in conjunction with other analogous stochastic branching models.     

A model for restriction fragment length distributions.

We develop here a model for restriction fragment length distributions based on DNA dimer frequencies in humans. Mean fragment lengths are computed for known restriction enzymes. This model is tested using data from the hybridization of a series of arbitrary single-copy DNA probes screened with a set of restriction enzymes. The fit to the model appears good. We apply the model to the problem of how much DNA is scanned by a set of enzymes. This result is then further applied to optimizing the search for insertion/deletion DNA-polymorphisms.     

Structural heterogeneity and quantitative FRET efficiency distributions of polyprolines through a hybrid atomistic simulation and Monte Carlo approach

Förster Resonance Energy Transfer (FRET) experiments probe molecular distances via distance dependent energy transfer from an excited donor dye to an acceptor dye. Single molecule experiments not only probe average distances, but also distance distributions or even fluctuations, and thus provide a powerful tool to study biomolecular structure and dynamics. However, the measured energy transfer efficiency depends not only on the distance between the dyes, but also on their mutual orientation, which is typically inaccessible to experiments. Thus, assumptions on the orientation distributions and averages are usually made, limiting the accuracy of the distance distributions extracted from FRET experiments. Here, we demonstrate that by combining single molecule FRET experiments with the mutual dye orientation statistics obtained from Molecular Dynamics (MD) simulations, improved estimates of distances and distributions are obtained. From the simulated time-dependent mutual orientations, FRET efficiencies are calculated and the full statistics of individual photon absorption, energy transfer, and photon emission events is obtained from subsequent Monte Carlo (MC) simulations of the FRET kinetics. All recorded emission events are collected to bursts from which efficiency distributions are calculated in close resemblance to the actual FRET experiment, taking shot noise fully into account. Using polyproline chains with attached Alexa 488 and Alexa 594 dyes as a test system, we demonstrate the feasibility of this approach by direct comparison to experimental data. We identified cis-isomers and different static local environments as sources of the experimentally observed heterogeneity. Reconstructions of distance distributions from experimental data at different levels of theory demonstrate how the respective underlying assumptions and approximations affect the obtained accuracy. Our results show that dye fluctuations obtained from MD simulations, combined with MC single photon kinetics, provide a versatile tool to improve the accuracy of distance distributions that can be extracted from measured single molecule FRET efficiencies.