Mục tiêu: Đánh giá kết quả việc sử dụng vạt da cân trên mắt cá ngoài trong che phủ khuyết hổng ph... more Mục tiêu: Đánh giá kết quả việc sử dụng vạt da cân trên mắt cá ngoài trong che phủ khuyết hổng phần mềm cổ bàn chân tại Bệnh viện Trung ương Thái Nguyên. Đối tượng và phương pháp nghiên cứu: từ tháng 01 năm 2018 đến tháng 12 năm 2022 có 24 vạt da cân trên mắt cá ngoài được sử dụng để che phủ khuyết hổng phần mềm cổ bàn chân cho 24 bệnh nhân (BN) tại khoa Chấn thương chỉnh hình. Có 15 BN nam, 09 BN nữ, độ tuổi trung bình là 39 (từ 18 đến 78). Thời gian theo dõi trung bình là 30 tháng. Kết quả lâm sàng được đánh giá dựa vào sức sống của vạt, mức độ che phủ khuyết hổng, các hoạt động chức năng thường ngày. Tất cả các số liệu được phân tích bằng phần mềm SPSS 20.0. Kết quả gần: tốt có 19/24 BN, chiếm tỉ lệ 80%, Vừa có 4/24 BN, chiếm tỉ lệ 16%, xấu có 01/24 BN, chiếm tỉ lệ 4%. Tất cả các vạt da đều liền tốt, bệnh nhân đều được trả lại chức năng mà không ảnh hưởng tới nơi cho vạt. Kết luận: Vạt da cân trên mắt cá ngoài che phủ được hầu hết các khuyết hổng vùng cổ bàn chân, cả nơi cho vạt ...
Dental caries has been considered the heaviest worldwide oral health burden affecting a significa... more Dental caries has been considered the heaviest worldwide oral health burden affecting a significant proportion of the population. To prevent dental caries, an appropriate and accurate early detection method is demanded. This proof-of-concept study aims to develop a two-stage computational system that can detect early occlusal caries from smartphone color images of unrestored extracted teeth according to modified International Caries Detection and Assessment System (ICDAS) criteria (3 classes: Code 0; Code 1–2; Code 3–6): in the first stage, carious lesion areas were identified and extracted from sound tooth regions. Then, five characteristic features of these areas were intendedly selected and calculated to be inputted into the classification stage, where five classifiers (Support Vector Machine, Random Forests, K-Nearest Neighbors, Gradient Boosted Tree, Logistic Regression) were evaluated to determine the best one among them. On a set of 587 smartphone images of extracted teeth, o...
Mục tiêu: Đánh giá hiệu quả nước súc miệng HMU Fluorinze 0,05% trên tổn thương sâu răng giai vĩnh... more Mục tiêu: Đánh giá hiệu quả nước súc miệng HMU Fluorinze 0,05% trên tổn thương sâu răng giai vĩnh viễn đoạn sớm (D1,D2) ở răng hàm lớn vĩnh viễn thứ nhất của nhóm học sinh 7-8 tuổi. Phương pháp nghiên cứu: là một nghiên cứu can thiệp lâm sàng ngẫu nhiên có đối chứng. Cỡ mẫu cho nghiên cứu là 340 học sinh (7-8 tuổi) khối lớp 2 tại hai trường tiểu học Xuân Lâm và trường tiểu học Trí Qủa, huyện Thuận Thành, tỉnh Bắc Ninh, mẫu được chọn và phân chia ngẫu nhiên vào 2 nhóm: nhóm can thiệp bằng nước súc miệng HMU Fluorinze 0,05% là 160 học sinh, nhóm đối chứng là 180 học sinh. Cả 2 nhóm đều được hướng dẫn vệ sinh răng miệng, nhóm can thiệp được súc miệng HMU Fluorinze 0,05% mỗi ngày 1 lần và được duy trì trong vòng 3 tháng. Khám đánh giá và ghi nhận sự thay đổi của các tổn thương sâu răng giai đoạn sớm trước và sau can thiệp 03 tháng dựa trên tiêu chuẩn chẩn đoán và ghi nhận sâu răng sớm ICDAS 2, có hỗ trợ của đèn lase huỳnh quang Diagnodent 2190. Kết quả: Tỷ lệ sâu răng hàm lớn vĩnh viễn ...
On April 27, 2021, the fourth wave of the coronavirus disease 2019 (COVID-19) pandemic originatin... more On April 27, 2021, the fourth wave of the coronavirus disease 2019 (COVID-19) pandemic originating from the Delta variant of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) began in Vietnam. The adoption of travel restrictions, coupled with rapid vaccination and mask-wearing, is a global strategy to prevent the spread of COVID-19. Although trade-off between health and economic development are unavoidable in this situation, little evidence that is specific to Vietnam in terms of movement restrictions, vaccine coverage, and real-time COVID-19 cases is available. Our research question is whether travel restrictions and vaccine coverage are related to changes in the incidence of COVID-19 in each province in Vietnam. We used Google's Global Mobility Data Source, which reports different mobility types, along with reports of vaccine coverage and COVID-19 cases retrieved from publicly and freely available datasets, for this research. Starting from the 50th case per prov...
This paper discusses driving styles while overtaking a vulnerable road user who moves along the s... more This paper discusses driving styles while overtaking a vulnerable road user who moves along the shoulder in urban roads. Based on the data obtained from an experiment in pre-defined conditions (combinations of four main effects: vehicle’s initial speed, lane width of the road, vulnerable road users’ type, and location in the shoulder) with an immersive driving simulator, we analyzed four different driving styles of drivers while approaching and passing the objects. It is shown that drivers took avoidance maneuvers even if there was no clear risk of collision to vulnerable road users. The results showed that the drivers tended to have a unique perception about the lateral passing gap and overtaking strategy with two worth notice groups: overcaution drivers and reckless drivers. The road characteristic has a statistically significant effect for all types of drivers. Moreover, the effect of the vehicle’s initial speed on overtaking strategy and the effect of vulnerable road user locati...
We confirm the occurrence of the rare species Plectostoma tonkinianum (Dautzenberg & Fisher, 1905... more We confirm the occurrence of the rare species Plectostoma tonkinianum (Dautzenberg & Fisher, 1905) in Vietnam with a new georeferenced locality.
Several individuals of the terrestrial slug Deroceras laeve were collected in 2018 in the Hoàng L... more Several individuals of the terrestrial slug Deroceras laeve were collected in 2018 in the Hoàng Liên Son mountain range of northern Vietnam. The three specimens which were investigated anatomically were aphallic or hemiphallic. A partial COI sequence verified the species identity. This is the first discovery of D. laeve and also of the slug family Agriolimacidae on the Indochinese Peninsula. The collecting site is situated near a cable-car station and below a tourist complex on Fansipan mountain, both of which had just been built by a Swiss-Austrian company between 2013 and 2016. This and the fact that the species had not been found elsewhere in the surrounding area, although searched for thoroughly, indicate that D. laeve is most probably a recent introduction, potentially with building material from Austria or Switzerland.
We report the karyotype, some aspects of spermatogenesis, and ovarian trophocytes ploidy in three... more We report the karyotype, some aspects of spermatogenesis, and ovarian trophocytes ploidy in three aquatic bug species:Ilyocoris cimicoides(Linnaeus, 1758),Notonecta glaucaLinnaeus, 1758, andDiplonychus rusticusFabricius, 1871 from previously unexplored regions – South Europe (Bulgaria) and Southeast Asia (Vietnam). Our results add considerable support for the published karyotype data for these species. InI. cimicoides, we observed achiasmate male meiosis – the first report of achiasmy for the family Naucoridae. More comprehensive cytogenetic studies in other species of the Naucoridae are required to elucidate the role of achiasmy as a character in the systematics of the family.Our observations on the association between phases of spermatogenesis and developmental stages inI. cimicoidesandN. glaucadiffer from the previously published data. In these species, we assume that the spermatogenesis phases are not strongly associated with certain developmental stages. For further cytogenetic...
Advances in Natural Sciences: Nanoscience and Nanotechnology, 2018
Influence of Al-concentration on structure, magnetic properties and magnetocaloric effect of Ni 5... more Influence of Al-concentration on structure, magnetic properties and magnetocaloric effect of Ni 50 Mn 37−x Al x Sn 13 (x = 2, 4, 6 and 8) rapidly quenched ribbons was investigated. X-ray diffraction analysis shows that the ribbons exhibit single phase with a L2 1-cubic structure. Curie temperature, T C , of the alloy is slightly increased with increasing Al-concentration. Specially, the sample with x = 2 has both the first-(FOPT) and second-(SOPT) order magnetic phase transitions. The reason for the FOPT in the alloy ribbons is due to existence of the structural transformation between martensitic and austenitic phases. The Ni 50 Mn 35 Al 2 Sn 13 alloy owns both the positive and negative magnetocaloric effects with maximum magnetic entropy changes of −0.8 and 2.6 J • kg −1 • K −1 (in magnetic field change ∆H = 12 kOe), respectively. By using Arrott-Noakes and Kouvel-Fisher methods, the critical parameters of the alloy were determined to be close to those of the mean field theory of long-range ferromagnetic orders.
This study addresses the extent of change and region al differences in gender roles in the Vietna... more This study addresses the extent of change and region al differences in gender roles in the Vietnamese family based on innovative surveys in northern and southern Vietnam. The similarities and differences in political, economic, and social histories between northern and southern Vietnam provide a compelling setting to investigate the impact of socialist policies and the recent shift from a centrally planned to a market economy on gender stratification in the domestic spheres. We assess determinants of the gender division of household labor among three marriage cohorts that underwent early marital years during 1) the Vietnam War and mass mobilization, 2) nationwide socialist collectivization and economic stagnation, and 3) market reform. We find that Vietnamese wives still do the vast majority of housework. In this sense, government efforts to change gender roles apparently have had at most limited success. Vietnamese husbands in the most recent marriage cohort, however, are more invo...
Species are threatened globally by multiple and often synergistic environmental changes including... more Species are threatened globally by multiple and often synergistic environmental changes including habitat loss, fragmentation and climate change. However, how these changes act in concert is poorly understood, especially in the tropics where the vast majority of biodiversity resides. Here, using a unique dataset covering 10 years of butterfly surveys (2003-2013) at Tam Dao National Park in northern Vietnam, we examined the combined impacts of habitat degradation (following intensive infrastructure development in 2005) and the possible threat of warming (extrapolating upon the relationship between natural climatic variation and community indices) for tropical butterfly communities. We found that both habitat degradation and warmer temperatures led to fewer narrow-range and forest-associated species comprising the sampled communities. Under projected climate change scenarios, the impact of warming was comparable to habitat degradation with respect to community change, and degraded forest communities were projected to shift towards cosmopolitan and non-forest species even more. The tropics have been heavily deforested worldwide and also suffer from heavy impacts of degradation and fragmentation, especially road construction. Warming will compound habitat degradation impacts such that the conservation of tropical biodiversity will require addressing these multiple global changes simultaneously.
A series of Ag-doped TiO 2 composite were obtained by impregnation of the commercial powder TiO 2... more A series of Ag-doped TiO 2 composite were obtained by impregnation of the commercial powder TiO 2 by plasma-chemically synthesized silver nanoparticles. The phase structure and morphology of the samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of Ag content on the antibacterial and photocatalytic activity of nanoparticles was tested. Ag doping also improved the antibacterial and photocatalytic activity of TiO 2 powder. The 2.0 mole % of Ag-doped TiO 2 shows 96% degradation of methylene blue (MB) within 50 min under visible light irradiation and exhibits highest photocatalytic performance.
Europium-doped-fluorochlorozirconate glass ceramics, known as ZBLAN, were produced in a glove box... more Europium-doped-fluorochlorozirconate glass ceramics, known as ZBLAN, were produced in a glove box which has a controlled environment of argon gas. For imaging applications BaCl 2 is used instead of BaF 2. Their properties after different thermal processing and different amounts of europium-doping were investigated. After annealing the ZBLAN glass, BaCl 2 nanoparticles are precipitated in the glass matrix. These glass ceramic storage phosphors are strong candidates for replacing traditional x-ray screen film system and commercial storage phosphors such as Agfa MD-30. Differential scanning calorimetry (DSC) was used to determine the crystallization temperature of the hexagonal phase of BaCl 2 , and orthorhombic BaCl 2 this in turn determines the subsequent annealing temperature. X-ray diffraction (XRD) and photoluminescence (PL) show that the hexagonal phase of BaCl 2 was formed upon annealing at temperatures between 250 °C and 280 °C for 5 minutes. The orthorhombic phase of BaCl 2 , which has storage properties, was formed at higher annealing temperatures, at approximately 290 °C and above. Secondary ion mass spectroscopy (SIMS) was used to determine adsorbed/diffused oxygen content of the glass. The weight loss of fluorine and chlorine is 3-5 % and was determined using ion chromatography (IC). The concentration of other cations was determined using inductively coupled plasma spectroscopy (ICP). Transmission electron microscopy (TEM) was used to take high resolution pictures and verify the composition of BaCl 2 nanoparticles. The relative concentration of Eu 2+ to Eu 3+ of heated EuCl 3 and ZBLAN was studied using Mössbauer spectroscopy. The oxidation of Eu 2+ to Eu 3+ was also observed during the experiment. This study has reinforced the strong potential for application of glass-ceramic storage phosphors for medical imaging. vi
Nowadays, together with the development of internet, online social networks provide lots of benef... more Nowadays, together with the development of internet, online social networks provide lots of benefits for human. People use social networks for different purposes, such as: communicating, information sharing, relations creating or for business purposes, and etc. However, accompanying with benefits of social networks, users also must face the security and privacy risks. These issues have recently paid much attention to. One of these issues is the user can penetrate and steal personal information. The assailants can penetrate through agreeing their friend requests. When confirming this friend request, the user unintentionally discloses personal information. Especially, if the user stolen information is an important person of a specific organization, losses are extremely considerable. Promoted by this phenomenon, in this paper, we propose a new solution to prevent and discover any penetration for a specific user in an organization. First of all, we propose a new model which is called as safety community model in order to protect everybody in the organization. We build a target function orienting to the safety for everybody in the organization. After that, we have designed an effective algorithm to discover the penetration of unsafe factors for specific users in the organization. Tests in social networks are actually implemented, and the result shows that our model can prevent the penetration of outside objects.
Forests provide critical habitat for tropical butterfl ies worldwide. However, habitat variation ... more Forests provide critical habitat for tropical butterfl ies worldwide. However, habitat variation and disturbance within forests can affect butterfl y communities and diversity in complex ways. Building on previous research and a known land-use history, we studied butterfl y diversity in the mountains of Tam Dao, Vinh Phuc Province, northern Vietnam monthly from 2005 to 2008 and 2012 to examine how habitat variation affects the butterfl y communities. We sampled butterfl ies in three different types of forest habitat: an open road in a disturbed forest (which was formerly a path in a closed-canopy forest), bamboo-dominated forest, and secondary forest. A total of 147 species and 4,685 individual butterfl ies were recorded. The species composition and richness of the open road within forest and the secondary forest were similar to one another but more forest-associated species were found in the secondary forest. The bamboo forest had the fewest species and had a clearly distinct butterfl y community consisting largely of satyrine species. This research suggests that road construction within the forests of Tam Dao likely affected the butterfl y community such that road-impacted areas now have communities that resemble communities found in secondary forest. Also, the unique but species-poor bamboo forest butterfl y community highlights the need for distinction between forest habitat types when studying the ecological and conservation requirements for butterfl ies and other tropical insects.
The sex pheromone of the pine moth Dendrolimus spectabilis Butler was tentatively identified as 5... more The sex pheromone of the pine moth Dendrolimus spectabilis Butler was tentatively identified as 5,7-dodecadien-l-ol by the use of the electroantennogram technique. Analyses of abdominal tip extracts of virgin females by gas-liquid chromatography and mass spectroscopy showed the presence of a (5Z, 7is)-isomer and a (5E, 7is)-isomer in the ratio of about ca. 5: 1. In field examinations with four synthetic isomers of 5,7-dodecadien-l-ol, only traps baited with the (5Z, 7is)-isomer captured an appreciable numbersof male moths.
Mục tiêu: Đánh giá kết quả việc sử dụng vạt da cân trên mắt cá ngoài trong che phủ khuyết hổng ph... more Mục tiêu: Đánh giá kết quả việc sử dụng vạt da cân trên mắt cá ngoài trong che phủ khuyết hổng phần mềm cổ bàn chân tại Bệnh viện Trung ương Thái Nguyên. Đối tượng và phương pháp nghiên cứu: từ tháng 01 năm 2018 đến tháng 12 năm 2022 có 24 vạt da cân trên mắt cá ngoài được sử dụng để che phủ khuyết hổng phần mềm cổ bàn chân cho 24 bệnh nhân (BN) tại khoa Chấn thương chỉnh hình. Có 15 BN nam, 09 BN nữ, độ tuổi trung bình là 39 (từ 18 đến 78). Thời gian theo dõi trung bình là 30 tháng. Kết quả lâm sàng được đánh giá dựa vào sức sống của vạt, mức độ che phủ khuyết hổng, các hoạt động chức năng thường ngày. Tất cả các số liệu được phân tích bằng phần mềm SPSS 20.0. Kết quả gần: tốt có 19/24 BN, chiếm tỉ lệ 80%, Vừa có 4/24 BN, chiếm tỉ lệ 16%, xấu có 01/24 BN, chiếm tỉ lệ 4%. Tất cả các vạt da đều liền tốt, bệnh nhân đều được trả lại chức năng mà không ảnh hưởng tới nơi cho vạt. Kết luận: Vạt da cân trên mắt cá ngoài che phủ được hầu hết các khuyết hổng vùng cổ bàn chân, cả nơi cho vạt ...
Dental caries has been considered the heaviest worldwide oral health burden affecting a significa... more Dental caries has been considered the heaviest worldwide oral health burden affecting a significant proportion of the population. To prevent dental caries, an appropriate and accurate early detection method is demanded. This proof-of-concept study aims to develop a two-stage computational system that can detect early occlusal caries from smartphone color images of unrestored extracted teeth according to modified International Caries Detection and Assessment System (ICDAS) criteria (3 classes: Code 0; Code 1–2; Code 3–6): in the first stage, carious lesion areas were identified and extracted from sound tooth regions. Then, five characteristic features of these areas were intendedly selected and calculated to be inputted into the classification stage, where five classifiers (Support Vector Machine, Random Forests, K-Nearest Neighbors, Gradient Boosted Tree, Logistic Regression) were evaluated to determine the best one among them. On a set of 587 smartphone images of extracted teeth, o...
Mục tiêu: Đánh giá hiệu quả nước súc miệng HMU Fluorinze 0,05% trên tổn thương sâu răng giai vĩnh... more Mục tiêu: Đánh giá hiệu quả nước súc miệng HMU Fluorinze 0,05% trên tổn thương sâu răng giai vĩnh viễn đoạn sớm (D1,D2) ở răng hàm lớn vĩnh viễn thứ nhất của nhóm học sinh 7-8 tuổi. Phương pháp nghiên cứu: là một nghiên cứu can thiệp lâm sàng ngẫu nhiên có đối chứng. Cỡ mẫu cho nghiên cứu là 340 học sinh (7-8 tuổi) khối lớp 2 tại hai trường tiểu học Xuân Lâm và trường tiểu học Trí Qủa, huyện Thuận Thành, tỉnh Bắc Ninh, mẫu được chọn và phân chia ngẫu nhiên vào 2 nhóm: nhóm can thiệp bằng nước súc miệng HMU Fluorinze 0,05% là 160 học sinh, nhóm đối chứng là 180 học sinh. Cả 2 nhóm đều được hướng dẫn vệ sinh răng miệng, nhóm can thiệp được súc miệng HMU Fluorinze 0,05% mỗi ngày 1 lần và được duy trì trong vòng 3 tháng. Khám đánh giá và ghi nhận sự thay đổi của các tổn thương sâu răng giai đoạn sớm trước và sau can thiệp 03 tháng dựa trên tiêu chuẩn chẩn đoán và ghi nhận sâu răng sớm ICDAS 2, có hỗ trợ của đèn lase huỳnh quang Diagnodent 2190. Kết quả: Tỷ lệ sâu răng hàm lớn vĩnh viễn ...
On April 27, 2021, the fourth wave of the coronavirus disease 2019 (COVID-19) pandemic originatin... more On April 27, 2021, the fourth wave of the coronavirus disease 2019 (COVID-19) pandemic originating from the Delta variant of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) began in Vietnam. The adoption of travel restrictions, coupled with rapid vaccination and mask-wearing, is a global strategy to prevent the spread of COVID-19. Although trade-off between health and economic development are unavoidable in this situation, little evidence that is specific to Vietnam in terms of movement restrictions, vaccine coverage, and real-time COVID-19 cases is available. Our research question is whether travel restrictions and vaccine coverage are related to changes in the incidence of COVID-19 in each province in Vietnam. We used Google's Global Mobility Data Source, which reports different mobility types, along with reports of vaccine coverage and COVID-19 cases retrieved from publicly and freely available datasets, for this research. Starting from the 50th case per prov...
This paper discusses driving styles while overtaking a vulnerable road user who moves along the s... more This paper discusses driving styles while overtaking a vulnerable road user who moves along the shoulder in urban roads. Based on the data obtained from an experiment in pre-defined conditions (combinations of four main effects: vehicle’s initial speed, lane width of the road, vulnerable road users’ type, and location in the shoulder) with an immersive driving simulator, we analyzed four different driving styles of drivers while approaching and passing the objects. It is shown that drivers took avoidance maneuvers even if there was no clear risk of collision to vulnerable road users. The results showed that the drivers tended to have a unique perception about the lateral passing gap and overtaking strategy with two worth notice groups: overcaution drivers and reckless drivers. The road characteristic has a statistically significant effect for all types of drivers. Moreover, the effect of the vehicle’s initial speed on overtaking strategy and the effect of vulnerable road user locati...
We confirm the occurrence of the rare species Plectostoma tonkinianum (Dautzenberg & Fisher, 1905... more We confirm the occurrence of the rare species Plectostoma tonkinianum (Dautzenberg & Fisher, 1905) in Vietnam with a new georeferenced locality.
Several individuals of the terrestrial slug Deroceras laeve were collected in 2018 in the Hoàng L... more Several individuals of the terrestrial slug Deroceras laeve were collected in 2018 in the Hoàng Liên Son mountain range of northern Vietnam. The three specimens which were investigated anatomically were aphallic or hemiphallic. A partial COI sequence verified the species identity. This is the first discovery of D. laeve and also of the slug family Agriolimacidae on the Indochinese Peninsula. The collecting site is situated near a cable-car station and below a tourist complex on Fansipan mountain, both of which had just been built by a Swiss-Austrian company between 2013 and 2016. This and the fact that the species had not been found elsewhere in the surrounding area, although searched for thoroughly, indicate that D. laeve is most probably a recent introduction, potentially with building material from Austria or Switzerland.
We report the karyotype, some aspects of spermatogenesis, and ovarian trophocytes ploidy in three... more We report the karyotype, some aspects of spermatogenesis, and ovarian trophocytes ploidy in three aquatic bug species:Ilyocoris cimicoides(Linnaeus, 1758),Notonecta glaucaLinnaeus, 1758, andDiplonychus rusticusFabricius, 1871 from previously unexplored regions – South Europe (Bulgaria) and Southeast Asia (Vietnam). Our results add considerable support for the published karyotype data for these species. InI. cimicoides, we observed achiasmate male meiosis – the first report of achiasmy for the family Naucoridae. More comprehensive cytogenetic studies in other species of the Naucoridae are required to elucidate the role of achiasmy as a character in the systematics of the family.Our observations on the association between phases of spermatogenesis and developmental stages inI. cimicoidesandN. glaucadiffer from the previously published data. In these species, we assume that the spermatogenesis phases are not strongly associated with certain developmental stages. For further cytogenetic...
Advances in Natural Sciences: Nanoscience and Nanotechnology, 2018
Influence of Al-concentration on structure, magnetic properties and magnetocaloric effect of Ni 5... more Influence of Al-concentration on structure, magnetic properties and magnetocaloric effect of Ni 50 Mn 37−x Al x Sn 13 (x = 2, 4, 6 and 8) rapidly quenched ribbons was investigated. X-ray diffraction analysis shows that the ribbons exhibit single phase with a L2 1-cubic structure. Curie temperature, T C , of the alloy is slightly increased with increasing Al-concentration. Specially, the sample with x = 2 has both the first-(FOPT) and second-(SOPT) order magnetic phase transitions. The reason for the FOPT in the alloy ribbons is due to existence of the structural transformation between martensitic and austenitic phases. The Ni 50 Mn 35 Al 2 Sn 13 alloy owns both the positive and negative magnetocaloric effects with maximum magnetic entropy changes of −0.8 and 2.6 J • kg −1 • K −1 (in magnetic field change ∆H = 12 kOe), respectively. By using Arrott-Noakes and Kouvel-Fisher methods, the critical parameters of the alloy were determined to be close to those of the mean field theory of long-range ferromagnetic orders.
This study addresses the extent of change and region al differences in gender roles in the Vietna... more This study addresses the extent of change and region al differences in gender roles in the Vietnamese family based on innovative surveys in northern and southern Vietnam. The similarities and differences in political, economic, and social histories between northern and southern Vietnam provide a compelling setting to investigate the impact of socialist policies and the recent shift from a centrally planned to a market economy on gender stratification in the domestic spheres. We assess determinants of the gender division of household labor among three marriage cohorts that underwent early marital years during 1) the Vietnam War and mass mobilization, 2) nationwide socialist collectivization and economic stagnation, and 3) market reform. We find that Vietnamese wives still do the vast majority of housework. In this sense, government efforts to change gender roles apparently have had at most limited success. Vietnamese husbands in the most recent marriage cohort, however, are more invo...
Species are threatened globally by multiple and often synergistic environmental changes including... more Species are threatened globally by multiple and often synergistic environmental changes including habitat loss, fragmentation and climate change. However, how these changes act in concert is poorly understood, especially in the tropics where the vast majority of biodiversity resides. Here, using a unique dataset covering 10 years of butterfly surveys (2003-2013) at Tam Dao National Park in northern Vietnam, we examined the combined impacts of habitat degradation (following intensive infrastructure development in 2005) and the possible threat of warming (extrapolating upon the relationship between natural climatic variation and community indices) for tropical butterfly communities. We found that both habitat degradation and warmer temperatures led to fewer narrow-range and forest-associated species comprising the sampled communities. Under projected climate change scenarios, the impact of warming was comparable to habitat degradation with respect to community change, and degraded forest communities were projected to shift towards cosmopolitan and non-forest species even more. The tropics have been heavily deforested worldwide and also suffer from heavy impacts of degradation and fragmentation, especially road construction. Warming will compound habitat degradation impacts such that the conservation of tropical biodiversity will require addressing these multiple global changes simultaneously.
A series of Ag-doped TiO 2 composite were obtained by impregnation of the commercial powder TiO 2... more A series of Ag-doped TiO 2 composite were obtained by impregnation of the commercial powder TiO 2 by plasma-chemically synthesized silver nanoparticles. The phase structure and morphology of the samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of Ag content on the antibacterial and photocatalytic activity of nanoparticles was tested. Ag doping also improved the antibacterial and photocatalytic activity of TiO 2 powder. The 2.0 mole % of Ag-doped TiO 2 shows 96% degradation of methylene blue (MB) within 50 min under visible light irradiation and exhibits highest photocatalytic performance.
Europium-doped-fluorochlorozirconate glass ceramics, known as ZBLAN, were produced in a glove box... more Europium-doped-fluorochlorozirconate glass ceramics, known as ZBLAN, were produced in a glove box which has a controlled environment of argon gas. For imaging applications BaCl 2 is used instead of BaF 2. Their properties after different thermal processing and different amounts of europium-doping were investigated. After annealing the ZBLAN glass, BaCl 2 nanoparticles are precipitated in the glass matrix. These glass ceramic storage phosphors are strong candidates for replacing traditional x-ray screen film system and commercial storage phosphors such as Agfa MD-30. Differential scanning calorimetry (DSC) was used to determine the crystallization temperature of the hexagonal phase of BaCl 2 , and orthorhombic BaCl 2 this in turn determines the subsequent annealing temperature. X-ray diffraction (XRD) and photoluminescence (PL) show that the hexagonal phase of BaCl 2 was formed upon annealing at temperatures between 250 °C and 280 °C for 5 minutes. The orthorhombic phase of BaCl 2 , which has storage properties, was formed at higher annealing temperatures, at approximately 290 °C and above. Secondary ion mass spectroscopy (SIMS) was used to determine adsorbed/diffused oxygen content of the glass. The weight loss of fluorine and chlorine is 3-5 % and was determined using ion chromatography (IC). The concentration of other cations was determined using inductively coupled plasma spectroscopy (ICP). Transmission electron microscopy (TEM) was used to take high resolution pictures and verify the composition of BaCl 2 nanoparticles. The relative concentration of Eu 2+ to Eu 3+ of heated EuCl 3 and ZBLAN was studied using Mössbauer spectroscopy. The oxidation of Eu 2+ to Eu 3+ was also observed during the experiment. This study has reinforced the strong potential for application of glass-ceramic storage phosphors for medical imaging. vi
Nowadays, together with the development of internet, online social networks provide lots of benef... more Nowadays, together with the development of internet, online social networks provide lots of benefits for human. People use social networks for different purposes, such as: communicating, information sharing, relations creating or for business purposes, and etc. However, accompanying with benefits of social networks, users also must face the security and privacy risks. These issues have recently paid much attention to. One of these issues is the user can penetrate and steal personal information. The assailants can penetrate through agreeing their friend requests. When confirming this friend request, the user unintentionally discloses personal information. Especially, if the user stolen information is an important person of a specific organization, losses are extremely considerable. Promoted by this phenomenon, in this paper, we propose a new solution to prevent and discover any penetration for a specific user in an organization. First of all, we propose a new model which is called as safety community model in order to protect everybody in the organization. We build a target function orienting to the safety for everybody in the organization. After that, we have designed an effective algorithm to discover the penetration of unsafe factors for specific users in the organization. Tests in social networks are actually implemented, and the result shows that our model can prevent the penetration of outside objects.
Forests provide critical habitat for tropical butterfl ies worldwide. However, habitat variation ... more Forests provide critical habitat for tropical butterfl ies worldwide. However, habitat variation and disturbance within forests can affect butterfl y communities and diversity in complex ways. Building on previous research and a known land-use history, we studied butterfl y diversity in the mountains of Tam Dao, Vinh Phuc Province, northern Vietnam monthly from 2005 to 2008 and 2012 to examine how habitat variation affects the butterfl y communities. We sampled butterfl ies in three different types of forest habitat: an open road in a disturbed forest (which was formerly a path in a closed-canopy forest), bamboo-dominated forest, and secondary forest. A total of 147 species and 4,685 individual butterfl ies were recorded. The species composition and richness of the open road within forest and the secondary forest were similar to one another but more forest-associated species were found in the secondary forest. The bamboo forest had the fewest species and had a clearly distinct butterfl y community consisting largely of satyrine species. This research suggests that road construction within the forests of Tam Dao likely affected the butterfl y community such that road-impacted areas now have communities that resemble communities found in secondary forest. Also, the unique but species-poor bamboo forest butterfl y community highlights the need for distinction between forest habitat types when studying the ecological and conservation requirements for butterfl ies and other tropical insects.
The sex pheromone of the pine moth Dendrolimus spectabilis Butler was tentatively identified as 5... more The sex pheromone of the pine moth Dendrolimus spectabilis Butler was tentatively identified as 5,7-dodecadien-l-ol by the use of the electroantennogram technique. Analyses of abdominal tip extracts of virgin females by gas-liquid chromatography and mass spectroscopy showed the presence of a (5Z, 7is)-isomer and a (5E, 7is)-isomer in the ratio of about ca. 5: 1. In field examinations with four synthetic isomers of 5,7-dodecadien-l-ol, only traps baited with the (5Z, 7is)-isomer captured an appreciable numbersof male moths.
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