52 research outputs found
Optimal Strategies for a Knowledge Workers Acquisition Problem with Expanding and Volatile Demand: Train Internally or Recruit Externally?
The aim of this paper is to consider the process of supplying trained workers with knowledge and skills for upcoming business opportunities, and of training apprentices prepared to meet future demands in an IT service firm. As the demand for new workers has fluctuations, a firm should employ a buffer workforce such as apprentices or interns. However, as a result of rapid development of a business, the bufferโs capacity may be exceeded, thus requiring the company to recruit skilled workers from outside the firm. It is thus important for a firm to map out a strategy for manpower planning so as to fulfill the demands of new business and minimize operation costs related to training apprentices and recruiting experienced workers. This paper first analyzes the demand and supply of workers for IT service in a knowledge-intensive field. It then presents optimal human resource planning via the familiar method of stochastic process - queueing analysis
A Sensitivity Analysis on the Impact of Uncertanties of the Supply and Demand of a Workforce on a Recruiting Strategy in an IT Service Company
This paper investigates a managerial problem related to human resource planning for an IT service company which mainly carries out time-base projects. As the demand for new workers is subject to wide fluctuations, the firm should hire workers in advance and train them. However, the firm should urgently recruit skilled workers from outside the firm due to the shortages in the workforce. Hence, it is important for the firm to design an optimal human resource planning program so as to fulfill the needs of new IT service projects and minimize operation costs, though this involves a trade-off between holding excess workers to prepare for upcoming demand and recruiting experienced workers. This paper presents a quantitative model that describes the stochastic behavior of the supply and demands of the workforce. Numerical results pertaining to the optimal solution are given via a simulation
Quantitative Evaluation of the Dispersion of Graphene Sheets With and Without Functional Groups Using Molecular Dynamics Simulations
Unveiling the key factor for the phase reconstruction and exsolved metallic particle distribution in perovskites
To significantly increase the amount of exsolved particles, the complete phase reconstruction from simple perovskite to Ruddlesden-Popper (R-P) perovskite is greatly desirable. However, a comprehensive understanding of key parameters affecting the phase reconstruction to R-P perovskite is still unexplored. Herein, we propose the Gibbs free energy for oxygen vacancy formation in Pr-0.5(Ba/Sr)(0.5)TO3-delta (T = Mn, Fe, Co, and Ni) as the important factor in determining the type of phase reconstruction. Furthermore, using in-situ temperature & environment-controlled X-ray diffraction measurements, we report the phase diagram and optimum 'x' range required for the complete phase reconstruction to R-P perovskite in Pr0.5Ba0.5-xSrxFeO3-delta system. Among the Pr0.5Ba0.5-xSrxFeO3-delta, (Pr0.5Ba0.2Sr0.3)(2)FeO4+delta - Fe metal demonstrates the smallest size of exsolved Fe metal particles when the phase reconstruction occurs under reducing condition. The exsolved nano-Fe metal particles exhibit high particle density and are well-distributed on the perovskite surface, showing great catalytic activity in fuel cell and syngas production.
The complete phase reconstruction to Ruddlesden-Popper perovskite is greatly desirable to increase the exsolved particle distribution. Here, the authors report a key factor for the complete phase reconstruction in perovskites, leading to good catalytic activity in fuel cell and syngas production
Transmembrane topology and oligomeric nature of an astrocytic membrane protein, MLC1
MLC1 is a membrane protein mainly expressed in astrocytes, and genetic mutations lead to the development of a leukodystrophy, megalencephalic leukoencephalopathy with subcortical cysts disease. Currently, the biochemical properties of the MLC1 protein are largely unknown. In this study, we aimed to characterize the transmembrane (TM) topology and oligomeric nature of the MLC1 protein. Systematic immunofluorescence staining data revealed that the MLC1 protein has eight TM domains and that both the N- and C-terminus face the cytoplasm. We found that MLC1 can be purified as an oligomer and could form a trimeric complex in both detergent micelles and reconstituted proteoliposomes. Additionally, a single-molecule photobleaching experiment showed that MLC1 protein complexes could consist of three MLC1 monomers in the reconstituted proteoliposomes. These results can provide a basis for both the high-resolution structural determination and functional characterization of the MLC1 protein.1
Variation block-based genomics method for crop plants
BACKGROUND: In contrast with wild species, cultivated crop genomes consist of reshuffled recombination blocks, which occurred by crossing and selection processes. Accordingly, recombination block-based genomics analysis can be an effective approach for the screening of target loci for agricultural traits. RESULTS: We propose the variation block method, which is a three-step process for recombination block detection and comparison. The first step is to detect variations by comparing the short-read DNA sequences of the cultivar to the reference genome of the target crop. Next, sequence blocks with variation patterns are examined and defined. The boundaries between the variation-containing sequence blocks are regarded as recombination sites. All the assumed recombination sites in the cultivar set are used to split the genomes, and the resulting sequence regions are termed variation blocks. Finally, the genomes are compared using the variation blocks. The variation block method identified recurring recombination blocks accurately and successfully represented block-level diversities in the publicly available genomes of 31 soybean and 23 rice accessions. The practicality of this approach was demonstrated by the identification of a putative locus determining soybean hilum color. CONCLUSIONS: We suggest that the variation block method is an efficient genomics method for the recombination block-level comparison of crop genomes. We expect that this method will facilitate the development of crop genomics by bringing genomics technologies to the field of crop breeding
Variation block-based genomics method for crop plants
This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.Abstract
Background
In contrast with wild species, cultivated crop genomes consist of reshuffled recombination blocks, which occurred by crossing and selection processes. Accordingly, recombination block-based genomics analysis can be an effective approach for the screening of target loci for agricultural traits.
Results
We propose the variation block method, which is a three-step process for recombination block detection and comparison. The first step is to detect variations by comparing the short-read DNA sequences of the cultivar to the reference genome of the target crop. Next, sequence blocks with variation patterns are examined and defined. The boundaries between the variation-containing sequence blocks are regarded as recombination sites. All the assumed recombination sites in the cultivar set are used to split the genomes, and the resulting sequence regions are termed variation blocks. Finally, the genomes are compared using the variation blocks. The variation block method identified recurring recombination blocks accurately and successfully represented block-level diversities in the publicly available genomes of 31 soybean and 23 rice accessions. The practicality of this approach was demonstrated by the identification of a putative locus determining soybean hilum color.
Conclusions
We suggest that the variation block method is an efficient genomics method for the recombination block-level comparison of crop genomes. We expect that this method will facilitate the development of crop genomics by bringing genomics technologies to the field of crop breeding
Study of a 13-weeks, Repeated, Intramuscular Dose, Toxicity Test of Sweet Bee Venom in Sprague-Dawley Rats
Objectives:This study was performed to analyze a 13-week repeated dose toxicity test of Sweet Bee Venom (SBV) extracted from bee venom and administered in Sprague-Dawley (SD) rats.
Methods:Male and female 5-week-old SD rats were treated once daily with SBV (high-dosage group: 0.28 mg/kg; medium-dosage group: 0.14 mg/kg; or low-dosage group: 0.07 mg/kg) for 13 weeks. Normal saline was administered to the control group in a similar manner (0.2 mL/kg). We conducted clinical observations, body weight measurements, ophthalmic examinations, urinalyses, hematology and biochemistry tests, and histological observations using hematoxylin and eosin (H&E) staining to identify any abnormalities caused by the SBV treatment.
Results:During this study, no mortality was observed in any of the experimental groups. Hyperemia and a movement disorder were observed around the area of in all groups that received SBV treatment, with a higher occurrence in rats treated with a higher dosage. Male rats receiving in the high-dosage group showed a significant decrease in weight during the treatment period. Compared to the control group, no significant changes in the ophthalmic parameters, the urine analyses, the complete blood cell count (CBC), and the biochemistry in the groups treated with SBV. Compared to the control group, some changes in organ weights were observed in the medium-and the high-dosage groups, but the low-dosage group showed no significant changes. Histological examination of thigh muscle indicated cell infiltration, inflammation, degeneration, and necrosis of muscle fiber, as well as fibrosis, in both the medium- and the high-dosage groups. Fatty liver change was observed in the periportal area of rats receiving medium and high dosages of SBV. No other organ abnormalities were observed.
Conclusion:Our findings suggest that the No Observed Adverse Effect Level (NOAEL) of SBV is approximately 0.07 mg/kg in male and female SD rats
Study on a 4-Week Recovery Test of Sweet Bee Venom after a 13-Week, Repeated, Intramuscular Dose Toxicity Test in Sprague-Dawley Rats
Objectives:This study was performed to check for reversibility in the changes induced by a 13-week, repeated, dose toxicity test of Sweet Bee Venom (SBV) in Sprague-Dawley (SD) rats.
Methods:Fifteen male and 15 female SD rats were treated with 0.28 mg/kg of SBV (high-dosage group) and the same numbers of male and female SD rats were treated with 0.2 mL/kg of normal saline (control group) for 13 weeks. We selected five male and five female SD rats from the high-dosage group and the same numbers of male and female SD rats from the control group, and we observed these rats for four weeks. We conducted body-weight measurements, ophthalmic examinations, urinalyses and hematology, biochemistry, histology tests.
Results:(1) Hyperemia and movement disorder were observed in the 13-week, repeated, dose toxicity test, but these symptoms were not observed during the recovery period. (2) The rats in the high-dose group showed no significant changes in weight compared to the control group. (3) No significant differences in the ophthalmic parameters, urine analyses, complete blood cell counts (CBCs), and biochemistry were observed among the recovery groups. (4) No changes in organ weights were observed during the recovery period. (5) Histological examination of the thigh muscle indicated cell infiltration, inflammation, degeneration, necrosis of muscle fiber, and fibrosis during the treatment period, but these changes were not observed during the recovery period. The fatty liver change that was observed during the toxicity test was not observed during the recovery period. No other organ abnormalities were observed.
Conclusion:The changes that occurred during the 13-week, repeated, dose toxicity test are reversible, and SBV can be safely used as a treatment modality
Utilization of an Isovalent Doping Strategy in Cobalt-Free Ferrites for Highly Active and Stable Solid Oxide Fuel Cell Cathodes
Cobalt-free ferrites are attracting tremendous spotlight as prospective solid oxide fuel cell cathode material nowadays owing to their good structural stability and great thermo-mechanical compatibility with electrolytes. Nevertheless, the oxygen reduction reaction (ORR) activity for cobalt-free ferrites is comparatively lower than that for cobalt-based cathodes. Hence, an isovalent doping strategy is an attractive option to significantly promote the ORR activity of cobalt-free ferrites. Herein, we systematically investigate the optimal Sr2+ concentration in cobalt-free Pr0.5Ba0.5-ySryFeO3-delta (PBSF series). The replacement of Ba2+ by Sr2+ is beneficial to decrease the thermal expansion coefficient. Moreover, the Pr0.5Ba0.2Sr0.3FeO3-delta material demonstrates the highest electrical conductivity and the lowest area-specific resistance (R-p, 0.027 Omega cm(2), 700 degrees C) among the PBSF series. To elucidate the close relationship between the Rp value and the electrical conductivity in the PBSF series, distribution of relaxation time analysis and density functional theory calculations are utilized. Furthermore, outstanding cell operational durability is exhibited for 200 h
- โฆ