Zooplankton Composition in Super-Intensive Whiteleg Shrimp, Litopenaeus vannamei (Boone, 1931) Culture Tanks

This study aimed to determine the zooplankton species composition in super-intensive whiteleg shrimp, Litopenaeus vannamei (Boone, 1931) tanks. The research was conducted from January to May 2021 in Bac Lieu City, Bac Lieu province, Vietnam. Eleven sampling times were divided into two periods, the nursery phase (six times) and the grow-out phase (five times) of shrimp culture. The results showed that water quality parameters fluctuated dramatically during the culture period, in which some nutrient concentrations tended to increase at the end of the shrimp culture period. Nine zooplankton species were recorded, of which five species belonged to Protozoa, three Rotifera species, and one Copepoda species. The number of zooplankton species did not differ significantly among the sampling periods. Protozoa had the highest species composition and density during most of the shrimp culture period. Copepoda was only identified in the nursery stage of shrimp culture. The species component of zooplankton had a close positive correlation with temperature, but their abundance did not have a significant relationship with water quality parameters because each species was affected by the different water quality parameters. Zoothamnium sp. had significantly positive correlations with total ammonia nitrogen (TAN), nitrate (NO3)-, total phosphorus (TP), and total nitrogen (TN) concentrations. The rotifer Brachionus plicatilis had a strong relationship with TP content, whereas Dartintinnus alderae had a strong relationship with alkalinity. Protozoa dominance in shrimp tanks could affect shrimp growth, decreasing the economic efficiency of shrimp farming. Therefore, the results of this study contribute to water quality and natural food management to improve shrimp productivity

SOCIAL SECURITY CONTRIBUTION INDEBTED FIRMS IN VIETNAM: CHARACTERISTICS AND MARKET VALUE

Abstract: This research is the first to empirically analyse the characteristics of firms that defer the social security contribution for their employees to the Vietnam Social Security agency, which is a chargeable offense starting 2018 as the Vietnam government focuses on ensuring worker welfare. Using data on 873 public firms headquartered in four major cities (Ha Noi, Ho Chi Minh, Da Nang, and Hai Phong), we find that non-state-owned firms and firms with lower profitability and higher debts are more likely to be in arrears on social security contribution. On the other hand, the roles of foreign ownership, size, number of employees, and number of branches/offices are insignificant. We further show that being social security contribution indebted would negatively affect shareholders’ interest as it is associated with lower firm market values.Key words: social security contribution, worker welfare, state ownership, foreign ownership, firm market valu

Evaluation of short-term toxicity of ammonia and nitrite on the survival of whiteleg shrimp, Litopenaeus vannamei juveniles

The effects of short-term toxicity of total ammonia nitrogen (TAN) and nitrite were estimated in juveniles of Litopenaeus vannamei under laboratory conditions. In the first experiment, L. vannamei juveniles were exposed to different concentrations of ammonia (0, 5, 10, 15, 20, 30, and 40 mg of TAN L-1) or nitrite (0, 5, 10, 20, 30, 40, and 50 mg of NO2--N L-1), using the static renewal method at a salinity of 20 ppt and pH 8.2. The survival rates of juveniles significantly decreased when exposed to increased concentrations of ammonia or nitrite during the 96 h bioassays. The 24, 48, 72, and 96 h LC50 values of TAN in juveniles were 45.5, 30.1, 13.8, and 6.3 mg L-1, respectively, while the LC50 values of NO2--N at 24, 48, 72, and 96 h were 37.6, 16.7, 8.8, and 4.8 mg L-1, respectively. Experiment 2 evaluated the tolerance of L. vannamei juveniles at various salinities (5, 10, 15, and 20 ppt) under a high concentration of ammonia or nitrite (5 mg L-1). Results showed that the survival rates of L. vannamei at 5 ppt and 10 ppt were significantly lower than those at 20 ppt after 72 h and 96 h of exposure

Effects of salinity and alkalinity on growth and survival of all-male giant freshwater prawn (Macrobrachium rosenbergii De Man, 1879) juveniles

All-male giant freshwater prawns (AMGFPs) have been a popular crop cultivated in the Mekong Delta, Vietnam, due to their proven production efficiency compared to all-female or mixed-sex prawn cultures. However, the crucial water quality factors impacting AMGFP aquaculture efficiency have yet to be elaborately investigated. Two separate experiments were randomly arranged with three replicates to evaluate the effects of salinity or alkalinity on the growth and survival of AMGFP juveniles during the grow-out period. The results show that the prawn survival rate in the salinity range of 0–15‰ varied from 66.1 to 74.8％ and in a salinity range of 0–5‰ was relatively low compared to the range of 10-15‰; however, the difference was not significant among salinities after 90 days of culture (p > 0.05). All the prawn growth performance parameters significantly decreased with increasing salinities of 0, 5, 10, and 15‰ after 30, 60, and 90 days of culture (p 0.05), and both were significantly higher than those at salinities of 10 and 15‰ (p < 0.05) after 90 days of culture. In addition, the survival rate reached 82.5–84.4％ and did not significantly differ among alkalinities of 80, 100, 120, 140, and 160 mgCaCO3 L−1. However, the growth performance parameters and yield of AMGFPs at an alkalinity of 160 mg L−1 were significantly higher than those at lower alkalinities (80, 100, 120, and 140 mg CaCO3 L−1) after 90 days of culture. Therefore, it is recommended that a salinity range of 0–5‰ and alkalinity of 160 mgCaCO3 L−1 is optimal for the growth-out culture of AMGFP juveniles

Evaluation of a Resident-led Residency Preparation Series for Fourth Year Pharmacy Students

Description of Problem: The increased interest in residency programs nationwide has made the application process more competitive and complex. Statement of Innovation: In 2015, Wake Forest Baptist Health (WFBH) created a resident-led residency preparatory series (RPS) to assist advanced pharmacy practice experience (APPE) students in preparing for residency applications. This study sought to evaluate the perceived value of the resident-led RPS by fourth year APPE students. Innovation: This single-center, survey-based, descriptive study aimed to evaluate the perceived impact of a resident-led RPS. All APPE students during the 2016-2017 and 2017-2018 academic years who completed rotations in the Triad region of North Carolina were invited to participate in the RPS. Surveys were sent to eligible students and data was captured for respondents who indicated an interest in pursuing residency and attendance to at least one RPS. Survey questions evaluated satisfaction with the RPS. Survey data was collected and analyzed using Qualtrics©. Critical Analysis: &nbsp;A total of 84 students were invited to attend the RPS. Thirty-three respondents participated in the RPS and indicated an interest in applying for a residency. The resident-led RPS was consistently well received by the majority of students over the course of two years, with over two-thirds of all respondents finding every session extremely or very useful. The majority of students agreed or strongly agreed with all confidence statements. Conclusion A resident-led RPS resulted in positive student perceptions and increased confidence in the residency application process. &nbsp; Article Type: Not

Countering Eavesdroppers with Meta-learning-based Cooperative Ambient Backscatter Communications

This article introduces a novel lightweight framework using ambient backscattering communications to counter eavesdroppers. In particular, our framework divides an original message into two parts: (i) the active-transmit message transmitted by the transmitter using conventional RF signals and (ii) the backscatter message transmitted by an ambient backscatter tag that backscatters upon the active signals emitted by the transmitter. Notably, the backscatter tag does not generate its own signal, making it difficult for an eavesdropper to detect the backscattered signals unless they have prior knowledge of the system. Here, we assume that without decoding/knowing the backscatter message, the eavesdropper is unable to decode the original message. Even in scenarios where the eavesdropper can capture both messages, reconstructing the original message is a complex task without understanding the intricacies of the message-splitting mechanism. A challenge in our proposed framework is to effectively decode the backscattered signals at the receiver, often accomplished using the maximum likelihood (MLK) approach. However, such a method may require a complex mathematical model together with perfect channel state information (CSI). To address this issue, we develop a novel deep meta-learning-based signal detector that can not only effectively decode the weak backscattered signals without requiring perfect CSI but also quickly adapt to a new wireless environment with very little knowledge. Simulation results show that our proposed learning approach, without requiring perfect CSI and complex mathematical model, can achieve a bit error ratio close to that of the MLK-based approach. They also clearly show the efficiency of the proposed approach in dealing with eavesdropping attacks and the lack of training data for deep learning models in practical scenarios

Some initial experimental results on the conditions of free water layer formation in horizontal pipes

This paper presents an experimental facility conducted in Hanoi Institute of Mechanics to investigate multiphase How pattern in the pipes. First and foremost, it is used to define the conditions of water layer formation in the horizontal pipe.Experimental results have been obtained in stainless steel pipes of three different diameters (24.6mm; 30.8mm and 40.5mm) with white spindle oil N° 10 and water. They have been shown in the form of water layer maps

ĐÁNH GIÁ TÌNH HÌNH SẠT LỞ, BỒI TỤ KHU VỰC VEN BIỂN TỈNH CÀ MAU VÀ BẠC LIÊU TỪ 1995-2010 SỬ DỤNG VIỄN THÁM VÀ CÔNG NGHỆ GIS

Rút trích đường bờ là một công việc cần thiết cho giám sát môi trường và đánh giá thay đổi đường bờ. Cà Mau và Bạc Liêu, hai tỉnh phía nam của Việt Nam quá trình sạt lở và bồi tụ diễn biến một cách nghiêm trọng. Đề tài đã xây dựng được bản đồ đường bờ năm 1995, 2000, 2005 và 2010. Kết quả cho thấy tình hình sạt lở và bồi tụ ven bờ biển Cà Mau và Bạc Liêu từ năm 1995 đến 2010 diễn biến vô cùng phức tạp. Quá trình sạt lở và bồi tụ luôn đan xen với nhau trong từng thời kỳ. Khu vực sạt lở nhiều nhất xảy ra tại xã Tân Thuận, Tân Tiến huyện Đầm Dơi và khu vực bồi tụ nhiều nhất diễn ra từ Rạch Cái Hương, huyện Ngọc Hiển kéo dài tới cửa Bảy Háp, huyện Năm Căn. Nhìn chung cho đến giai đoạn hiện nay, bờ biển Tây tỉnh Cà Mau xu hướng bồi tụ chiếm ưu thế hơn, bờ biển Đông của tỉnh Cà Mau và Bạc Liêu thì xu hướng sạt lở lại chiếm ưu thế. Đây là một trong những thông tin hữu ích giúp các cơ quan chức năng của chính quyền địa phương trong công tác quy hoạch và quản lý vùng ven bờ

On the Out of Distribution Robustness of Foundation Models in Medical Image Segmentation

Constructing a robust model that can effectively generalize to test samples under distribution shifts remains a significant challenge in the field of medical imaging. The foundational models for vision and language, pre-trained on extensive sets of natural image and text data, have emerged as a promising approach. It showcases impressive learning abilities across different tasks with the need for only a limited amount of annotated samples. While numerous techniques have focused on developing better fine-tuning strategies to adapt these models for specific domains, we instead examine their robustness to domain shifts in the medical image segmentation task. To this end, we compare the generalization performance to unseen domains of various pre-trained models after being fine-tuned on the same in-distribution dataset and show that foundation-based models enjoy better robustness than other architectures. From here, we further developed a new Bayesian uncertainty estimation for frozen models and used them as an indicator to characterize the model's performance on out-of-distribution (OOD) data, proving particularly beneficial for real-world applications. Our experiments not only reveal the limitations of current indicators like accuracy on the line or agreement on the line commonly used in natural image applications but also emphasize the promise of the introduced Bayesian uncertainty. Specifically, lower uncertainty predictions usually tend to higher out-of-distribution (OOD) performance.Comment: Advances in Neural Information Processing Systems (NeurIPS) 2023, Workshop on robustness of zero/few-shot learning in foundation model

Youths’ word-of-mouth in a developing country: roles of green promotion and green brand loyalty

Purpose – This paper investigates the mediating role of green brand loyalty between green brand image and word-of-mouth (WoM) and the moderating role of green promotion and brand social responsibility among Vietnamese youth. Research methodology – Using an online questionnaire from 1st October 2022 to 31st December 2022, 740 valid responses were collected. Findings – The study reveals that green brand loyalty mediates the relationship between brand trust and WoM. Additionally, green promotion significantly moderates the relationship between brand trust and green brand loyalty. The study concludes that green promotion is vital in influencing consumers’ trust in the brand, subsequently increasing their loyalty. Research limitations – This study has not categorized the groups of environmentally friendly products used by young Vietnamese to see if there is a difference. Practical implications – These results provide significant implications for brand managers to enhance the effectiveness of WoM. Originality/Value – Green promotion is an effective strategy for brands to regain consumers’ loyalty and maintain a close relationship between consumers and green brands. Additionally, green brand loyalty emphasizes the significance of green promotion for developing green companies and can serve as a conduit between customers and brands