Cultivation of Tetraselmis suecica with different light regimes to improve the survival of Ostrea edulis larvae in hatcheries

In the context of the reintroduction project of the European oyster Ostrea edulis (Linnaeus, 1758), a hatchery is necessary as the stocks cannot be restored naturally due to the strong decline caused by anthropogenic impacts in the past years. Optimizing the survival rate of the larvae is of great importance in this respect. The increased use of antibiotics is intended to face this challenge. However, this approach cannot be applied in the framework of ecological restoration, since it does more harm than good. Alternatives must be developed. In this work, the long chain fatty acids (LCFA) of Tetraselmis suecica exposed to different light intensities (100, 150 and 200 μmol photons m-2 s-1) were analyzed. According to va- rious references, light is one of the factors that is supposed to influence LCFA concentration. Additionally, it is hypothesized that with higher LCFA concentrations, also antibacterial activity in microalgae culture is increased. This antibacterial activity can be utilized to reduce bacterial infection of sensitive Ostrea edulis larvae grown in large-scale aquaculture. The T. suecica cultures maintained at different light intensities were each added to a 3-mixed diet with Isochrysis galbana and Chaetoceros muelleri in beakers containing 700 mL of 1 μm filtered and UV-treated seawater and 3,500 O. edulis larvae. Controls with a 2-mixed-diet addition with only I. galbana and C. muelleri and a 3-mixed-diet addition with I. galbana, C. muelleri and Rhodomonas salina served as control. The results were used to examine whether the addition of T. suecica to the holding water increases the larval survival rates. Thus, in this work, sustainable alternatives to the use of antibiotics in hatcheries were sought. Light intensity was found to have no impact on the percentage of fatty acids in their com- plete composition per T. suecica cell, but did affect the total LCFA concentration. It was found that the highest LCFA concentration per T. suecica cell was found in cultures grown at a light intensity of 150 μmol m-2 s-1. The lowest LCFA concentration per T. suecica cell was found in cultures maintained at 200 μmol m-2 s-1. Compared to the 2-mixed-diet control, the 3-mixed-diet treatments did not perform as well. For example, in the treatments with the lowest LCFA concentration in the T. suecica cells (cultivation at 200 μmol m-2 s-1), a 100 % larval mortality rate was observed. Clear results could not be obtained in this sub-trial, but a tendency for better survival of O. edulis larvae with increased long chain fatty acid content in T. suecica cultures using as feed was evident. However, besides the LCFA concentration of the food, other influencing factors regarding the survival of the sensitive O. edulis larvae should be considered and excluded in the future. Here, it is recommended to optimize the experimental set-up to get clearer results

Brand identity in Finnish Higher Education Institutions

The study purpose is exploring the phenomenon brand identity in Finnish tertiary education; the influence factors to prospective students’ perception in choosing an institution and the actual impact of branding communication to their final choice. The study focus on presenting answers and suggestions to the question: “How to build up brand identity that has most influence toward effective enrolment and recruitment in Finnish higher education?” The theoretical framework shows how to define new concepts of emerging the brand identity philosophy in tertiary education sector and evaluating the actual impact of marketing communication practices to both internal and external resources to meet foreign students’ satisfaction. A qualitative approach with in-depth interviews was conducted as main method due to the complexity and differs from case to case of the new concepts. The sample was selected non-random 24 foreign students between 18 to 30 years old from different type of programmes with the average age of 23, 7. The result reveals that marketing efforts based on merging brand identical could lead to positive attitudes and significant students’ commitments. A detail suggestion of future improvement was given by interviewees. Regarding to the outcomes, the vital issue in transferring brand image to student´s perspectives is successful monitoring suitable communicating messages accordingly suitable time and strategies which can enhance its brand identity, be consistent and viable. The limitations of the study are also pointed out

Topological Lifshitz phase transition in effective model of QCD with chiral symmetry non-restoration

The topological Lifshitz phase transition is studied systematically within an effective model of QCD, in which the chiral symmetry, broken at zero temperature, is not restored at high temperature and/or baryon chemical potential. It is found that during phase transition the quark system undergoes a first-order transition from low density fully-gapped state to high density state with Fermi sphere which is protected by momentum-space topology. The Lifshitz phase diagram in the plane of temperature and baryon chemical potential is established. The critical behaviors of various equations of state are determined.Comment: 8 pages, 10 figure

Metakaolin as an Additive in Composite Cement

Metakaolin made from kaolin is used around the world but rarely in Vietnam where abundant deposits of kaolin is found. The first studies of producing metakaolin were conducted with high quality Vietnamese kaolins. The results showed the potential to produce metakaolin, and its effect has on strength development of mortars and concretes. However, utilisation of a low quality kaolin for producing Vietnamese metakaolin has not been studied so far. The objectives of this study were to produce a good quality metakaolin made from low quality Vietnamese kaolin and to facilitate the utilisation of Vietnamese metakaolin in composite cements. In order to reach such goals, the optimal thermal conversion of Vietnamese kaolin into metakaolin was carried out by many investigations, and as such the optimal conversion is found using the analysis results of DSC/TGA, XRD and CSI. During the calcination in a range of 500 – 800 oC lasting for 1 – 5 hours, the characterisation of calcinated kaolin was also monitored for mass loss, BET surface, PSD, density as well as the presence of the residual water. It is found to have a well correlation between residual water and BET surface. The pozzolanic activity of metakaolin was tested by various methods regarding to the saturated lime method, mCh and TGA-CaO method. The results of the study showed which method is the most suitable one to characterise the real activity of metakaolin and can reach the greatest agreement with concrete performance. Furthermore, the pozzolanic activity results tested using methods were also analysed and compared to each other with respect to the BET surface. The properties of Vietnam metakaolin was established using investigations on water demand, setting time, spread-flowability, and strength. It is concluded that depending on the intended use of composite cement and weather conditions of cure, each Vietnamese metakaolin can be used appropriately to produce (1) a composite cement with a low water demand (2) a high strength of composite cement (3) a composite cement that aims to reduce CO2 emissions and to improve economics of cement products (4) a high performance mortar. The durability of metakaolin mortar was tested to find the needed metakaolin content against ASR, sulfat and sulfuric acid attacks successfully

Household business index in Vietnam: a small area estimation method

This study aims to estimate of Business or Formality Index (FI) for business households at provincial and district levels in the rural areas of Vietnam. In order to construct the FI, we implemented a survey of 900 business households in three provinces in Vietnam. Then we estimate the FI for these 900 sampled households. Next, we use a small area estimation method to combine this business household survey and the 2009 Vietnam Population and Housing Census to estimate the FI for all provinces and districts in rural Vietnam. The FI at the national level is estimated to be at 62.7 (according to the score range 1 – 100, the higher the score is, the better the index reflects business environment). The FI varies more greatly at provincial level, from 57.3 to 69.5. The FI for households tends to be higher at more developed provinces and lower at less developed provinces

Poverty Assessment of Ethnic Minorities in Vietnam

Ethnic minorities in Vietnam have experienced high income fluctuation over time. This study aims to examine why a number of households experienced an income increase while others experienced an income decrease in poor areas with high density of ethnic minorities in Vietnam. It shows that the increase in household income results from an increase in average income per working hour. That is, the number of working hours did not change significantly but the increase in productivity per working hour helps households to increase their household income. In addition, the increase in number of working hour and increase in income transfers also contribute to the income increase. Our study also indicates that the increase in labor productivity mostly comes from agricultural sector but not from non-agricultural sector. For households with falling income, the major reasons for the income decrease are decreasing labor productivity, especially in agricultural sector

Household business index in Vietnam: a small area estimation method

This study aims to estimate of Business or Formality Index (FI) for business households at provincial and district levels in the rural areas of Vietnam. In order to construct the FI, we implemented a survey of 900 business households in three provinces in Vietnam. Then we estimate the FI for these 900 sampled households. Next, we use a small area estimation method to combine this business household survey and the 2009 Vietnam Population and Housing Census to estimate the FI for all provinces and districts in rural Vietnam. The FI at the national level is estimated to be at 62.7 (according to the score range 1 – 100, the higher the score is, the better the index reflects business environment). The FI varies more greatly at provincial level, from 57.3 to 69.5. The FI for households tends to be higher at more developed provinces and lower at less developed provinces