123 research outputs found
Optimality conditions in terms of Bouligand generalized differentials for a nonsmooth semilinear elliptic optimal control problem with distributed and boundary control pointwise constraints
We prove a novel optimality condition in terms of Bouligand generalized
differentials for a local minimizer of optimal control problems governed by a
nonsmooth semilinear elliptic partial differential equation with both
distributed and boundary unilateral pointwise control constraints, in which the
nonlinear coefficient in the state equation is not differentiable at one point.
Therefore, the Bouligand subdifferential of this nonsmooth coefficient in
every point consists of one or two elements that will be used to construct the
two associated Bouligand generalized derivatives of the control-to-state
operator in any admissible control.
We also establish the optimality conditions in the form of multiplier
existence. There, in addition to the existence of the adjoint state and of the
nonnegative multipliers associated with the pointwise constraints as usual,
other nonnegative multipliers exist and correspond to the nondifferentiability
of the control-to-state mapping.
The latter type of optimality conditions shall be applied to the optimal
control problems without distributed and boundary pointwise constraints to
derive the so-called \emph{strong} stationarity conditions, where the sign of
the associated adjoint state does not vary on the level set of the
corresponding optimal state at the value of nondifferentiability.Comment: 33 page
EVALUATION OF CITIZENS' SATISFACTION WITH THE QUALITY OF PUBLIC ADMINISTRATIVE SERVICES IN THE MEKONG DELTA, VIETNAM
Citizen satisfaction is one of the essential factors reflecting the quality of public administrative services provided by
state administrative agencies. The study aims to assess citizens' satisfaction with the quality of public administrative services in
the Mekong Delta, Vietnam. Research data were collected from survey results using questionnaires from 792 survey samples in
the Mekong Delta, Vietnam. Research results have shown that citizens are satisfied with the quality of public administrative services
in the Mekong Delta, Vietnam. At the same time, there are six factors affecting citizens' satisfaction with the quality of public
administrative services, including (1) Reliability; (2) Service capacity of staff; (3) Service attitude of staff; (4) The service level of
staff; (5) Infrastructure; (6) Administrative procedures. Research results show no difference in citizen satisfaction in gender, age
and education groups. Besides, the survey area group has a difference in citizen satisfaction. The research results have theoretical
and practical significance for public administration in Vietnam. From the research results, several contents are discussed and
proposed to improve citizens' satisfaction with the quality of public administrative services in the Mekong Delta, Vietnam
PATHOGENICITY OF EIMERIA SPECIES ISOLATED FROM CHICKEN IN THUA THIEN HUE PROVINCE
Abstract: The present study clarifies the effect of locally isolated Eimeria species on chickens in central Vietnam. Oocysts of Eimeria species were isolated from feces suspected to be infected with coccidiosis in 3 farms in Huong Thuy district, Thua Thien Hue province. A total of 54 2-week-old chickens were randomly allocated to 2 groups: 3 replicates containing 9 chickens in each replicate. The chicken in group 1 were orally inoculated with 2×104 isolated oocysts of Eimeria species, while the chickens in group 2 were inoculated with PBS as a control. Growth performance, oocyst output, gross lesions, and histopathological lesions were measured at 5, 10 and 28 days after infection. The chicks in group 1 showed general signs of ruffled feathers, anorexia, huddling together with diarrhea and/or bloody dropping from 4–7 days post-infection. Feed intake, growth performance and body weight in group 1 were lower than those of the control chicks. The oocyst was detected in the feces of chicks in group 1 from 6–14 days post-infection, among them, the number of oocysts reach the peak at 8 days post-infection. At day 5 post-infection, the most damaged part of the intestine is the ceca with a large amount of blood in the ceca content. The histopathological lesions were detected clearly by HE staining at day 5 and 10 post-infection. In conclusion, the locally isolated oocysts of Eimeria species have high virulence to the chickens. The present study provides useful information related to the pathogenicity of Eimeria species which may contribute to coccidiosis diagnosis and treatment in poultry production.Keywords: Eimeria, coccidiosis, infection, central Vietna
ANTECEDENTS OF TOURISTS’ LOYALTY: THE ROLE AND INFLUENCE OF TOURISM PRODUCTS, DESTINATION IMAGE IN HOIAN WORLD CULTURAL HERITAGE SITE
The study’s aim is to examine the antecedents of destination loyalty, and considers the role and influence of tourism
products and destination image to international tourisms’ loyalty in case of HoiAn World Cultural Heritage Site. The study
suggested an integrated approach to understand tourists’ loyalty model and investigate the empirical evidence about the
relationship among tourism products, destination image, risk perception, tourist experience, destination satisfaction and tourists’
loyalty. This study also mentions important questions concerning how tourism products, destination image, tourist experience,
risk perception, and tourists’ satisfaction affect tourists’ loyalty. Smart PLS3 is used to estimate and test the relationships in the
research model. Mediation analysis and importance performance matrix analysis are also used to consider clearly the relationship
between the constructs of research model. The study’s results indicate that tourism products, destination image, tourism
experience, risk perception, and satisfaction are antecedents of international tourists’ loyalty in Hoi An World Cultural Heritage
Site. And in them, tourism products affect significantly positively to destination imagine and satisfaction, beside destination
image and satisfaction hold the role of mediator in this relationship. Implementing IPMA to identify the predecessors that have
relatively high importance for loyalty but also a relatively low performance. The results pointed out that the constructs as
satisfaction, tourism product, risk perception and image have a high importance for the tourist loyalty. The study added the
antecedent of tourism products and risk perception to the model and could enrich the literature, pointing to be possibility of a
destination loyalty model that can be applied to various contexts, especially after COVID- 19 pandemic. The study also discussed
theoretical and managerial implications for marketing tourism
Studying and forecasting the evolution of the Day river coastal zone up to the year of 2070
The Day river coastal zone is the place of plentiful and eventful economical activities and the natural habitat of diverse endemic species that should be preserved and developed. According to the updated geological, remote-sensing and oceanographic data sources, this study figures out the actual state, evolutional history and forecasts the development of the Day river coastal zone up to the year 2070, which could be used to improve the effectiveness of the long-term spatial coastal zone management and master planning. Major conclusions are as follows: (i) The Day river coastline has been highly modified since the last 50 years, (ii) The shoreline seaward development tends to gradually decrease in recent years, and (iii) The river-bed continues to be shifted southwestwards in the context of global climate change and sea level rise.Abstract STUDYING AND FORECASTING THE EVOLUTION OF THE DAY RIVER COASTAL ZONE UPTO THE YEAR 2050 Duong Quoc Hung1, Vu Hai Dang1, Phan Dong Pha1, Nguyen Thi Anh Nguyet1, Ngo Bich Huong1, Nguyen Thai Son2 (1) Institute of Marine Geology and Goephysics; (2) Institute of Geography The coastal geographical features including alluvial grouds, estuaries, mangrove forest, etc. are products of the river - ocean interactions, reflect the dynamic equilibrium of the unsustainable ecosystems that are spacial and temporary changing. These areas are also the places of plentiful and eventful economical activities and the natural diversified endemic habitats to be preserved and developed. According to the updated data sources, this study mentions to the actual state, evolution history and developing forecasts for the Day River coastal zone up to the year of 2050, which could be used to inhale the effectiveness of the long-term spacial coastal zone management and master plannin
Geographic isolation created distinct pelage characters in Finlayson’s squirrel on isolated island offshore of the Indochina Peninsula in Central Vietnam
We found distinct pelage characters in Finlayson’s squirrel (Callosciurus finlaysonii) population, which is endemic to Lao Island of the Cham Islands, located off the coast of central Vietnam. Among squirrels of the ‘C. erythraeus-finlaysonii complex’, which consists of all forms of C. erythraeus and C. finlaysonii, mitochondrial cytochrome-b sequences show that the Lao Island squirrel forms a cluster with C. finlaysonii with external characters of C. erythraeus flavimanus, defined previously as ‘C. finlaysonii morpha flavimanus’. Both squirrel forms, however, differed in pelage colour. This different colouration may have arisen from the effect of geographic isolation
Direct Observation of Exceptional Points in Photonic Crystal by Cross-Polarization Imaging in Momentum Space
This study explores exceptional points (EPs) in photonic crystals (PhCs) and
introduces a novel method for their single-shot observation. Exceptional points
are spectral singularities found in non-Hermitian systems, such as leaky PhC
slabs. However, directly observing EPs in PhC systems using regular
reflectivity spectroscopy is a considerable challenge due to interference
between guided resonances and background signals. In this work, we present a
simple, nondestructive technique that employs crossed polarizations to directly
observe EPs in momentum-resolved resonant scattering. This approach effectively
suppresses the background signal, enabling exclusive probing of the guided
resonances where EPs manifest. Our results demonstrate the formation of EPs in
both energy-momentum mapping and isofrequency imaging. All experimental
findings align seamlessly with numerical simulations and analytical models. Our
approach holds great potential as a robust tool for studying non-Hermitian
physics in PhC platform
Estimating the cost of illness of acute Japanese encephalitis and sequelae care in Vietnam and Laos: a cross-sectional study
Background
Japanese encephalitis (JE) is a leading cause of acute encephalitis syndrome and resulting neurological disability in Asia and the Western Pacific. This study aims to estimate the cost of acute care, initial rehabilitation and sequelae care, in Vietnam and Laos.
Methodology
We conducted a cross-sectional retrospective study using a micro-costing approach from the health system and household perspectives. Out-of-pocket direct medical and non-medical costs, indirect costs, and family impact were reported by patients and/or caregivers. Hospitalization costs were extracted from hospital charts. Acute costs covered expenditures from pre-hospital to follow-up visits while sequelae care costs were estimated from expenditures in the last 90 days. All costs are in 2021 US dollars.
Principal findings
242 patients in two major sentinel sites in the North and South of Vietnam and 65 patients in a central hospital in Vientiane, Laos, with laboratory-confirmed JE were recruited regardless of age, sex, and ethnicity. In Vietnam, the mean total cost was 2,071, standard error [SE] 404 for initial sequelae care (median 220) and 0, SE 2,005 (median 279) and the mean annual costs were 0, SE 89 (median 57) for long-term sequelae care. In both countries, most patients did not seek care for their sequelae. Families perceived extreme impact from JE and 20% to 30% of households still had sustained debts years after acute JE.
Conclusions
JE patients and families in Vietnam and Laos suffer extreme medical, economic, and social hardship. This has policy implications for improving JE prevention in these two JE-endemic countries
Adoptive NK Cell Therapy - a Beacon of Hope in Multiple Myeloma Treatment
Major advances in the treatment of multiple myeloma (MM) have been achieved by effective new agents such as proteasome inhibitors, immunomodulatory drugs, or monoclonal antibodies. Despite significant progress, MM remains still incurable and, recently, cellular immunotherapy has emerged as a promising treatment for relapsed/refractory MM. The emergence of chimeric antigen receptor (CAR) technology has transformed immunotherapy by enhancing the antitumor functions of T cells and natural killer (NK) cells, leading to effective control of hematologic malignancies. Recent advancements in gene delivery to NK cells have paved the way for the clinical application of CAR-NK cell therapy. CAR-NK cell therapy strategies have demonstrated safety, tolerability, and substantial efficacy in treating B cell malignancies in various clinical settings. However, their effectiveness in eliminating MM remains to be established. This review explores multiple approaches to enhance NK cell cytotoxicity, persistence, expansion, and manufacturing processes, and highlights the challenges and opportunities associated with CAR-NK cell therapy against MM. By shedding light on these aspects, this review aims to provide valuable insights into the potential of CAR-NK cell therapy as a promising approach for improving the treatment outcomes of MM patients
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