8,815 research outputs found
The Metaverse: Survey, Trends, Novel Pipeline Ecosystem & Future Directions
The Metaverse offers a second world beyond reality, where boundaries are
non-existent, and possibilities are endless through engagement and immersive
experiences using the virtual reality (VR) technology. Many disciplines can
benefit from the advancement of the Metaverse when accurately developed,
including the fields of technology, gaming, education, art, and culture.
Nevertheless, developing the Metaverse environment to its full potential is an
ambiguous task that needs proper guidance and directions. Existing surveys on
the Metaverse focus only on a specific aspect and discipline of the Metaverse
and lack a holistic view of the entire process. To this end, a more holistic,
multi-disciplinary, in-depth, and academic and industry-oriented review is
required to provide a thorough study of the Metaverse development pipeline. To
address these issues, we present in this survey a novel multi-layered pipeline
ecosystem composed of (1) the Metaverse computing, networking, communications
and hardware infrastructure, (2) environment digitization, and (3) user
interactions. For every layer, we discuss the components that detail the steps
of its development. Also, for each of these components, we examine the impact
of a set of enabling technologies and empowering domains (e.g., Artificial
Intelligence, Security & Privacy, Blockchain, Business, Ethics, and Social) on
its advancement. In addition, we explain the importance of these technologies
to support decentralization, interoperability, user experiences, interactions,
and monetization. Our presented study highlights the existing challenges for
each component, followed by research directions and potential solutions. To the
best of our knowledge, this survey is the most comprehensive and allows users,
scholars, and entrepreneurs to get an in-depth understanding of the Metaverse
ecosystem to find their opportunities and potentials for contribution
Recommended from our members
Ensuring Access to Safe and Nutritious Food for All Through the Transformation of Food Systems
Corporate Social Responsibility: the institutionalization of ESG
Understanding the impact of Corporate Social Responsibility (CSR) on firm performance as it relates to industries reliant on technological innovation is a complex and perpetually evolving challenge. To thoroughly investigate this topic, this dissertation will adopt an economics-based structure to address three primary hypotheses. This structure allows for each hypothesis to essentially be a standalone empirical paper, unified by an overall analysis of the nature of impact that ESG has on firm performance. The first hypothesis explores the evolution of CSR to the modern quantified iteration of ESG has led to the institutionalization and standardization of the CSR concept. The second hypothesis fills gaps in existing literature testing the relationship between firm performance and ESG by finding that the relationship is significantly positive in long-term, strategic metrics (ROA and ROIC) and that there is no correlation in short-term metrics (ROE and ROS). Finally, the third hypothesis states that if a firm has a long-term strategic ESG plan, as proxied by the publication of CSR reports, then it is more resilience to damage from controversies. This is supported by the finding that pro-ESG firms consistently fared better than their counterparts in both financial and ESG performance, even in the event of a controversy. However, firms with consistent reporting are also held to a higher standard than their nonreporting peers, suggesting a higher risk and higher reward dynamic. These findings support the theory of good management, in that long-term strategic planning is both immediately economically beneficial and serves as a means of risk management and social impact mitigation. Overall, this contributes to the literature by fillings gaps in the nature of impact that ESG has on firm performance, particularly from a management perspective
neuroAIx-Framework: design of future neuroscience simulation systems exhibiting execution of the cortical microcircuit model 20× faster than biological real-time
IntroductionResearch in the field of computational neuroscience relies on highly capable simulation platforms. With real-time capabilities surpassed for established models like the cortical microcircuit, it is time to conceive next-generation systems: neuroscience simulators providing significant acceleration, even for larger networks with natural density, biologically plausible multi-compartment models and the modeling of long-term and structural plasticity.MethodsStressing the need for agility to adapt to new concepts or findings in the domain of neuroscience, we have developed the neuroAIx-Framework consisting of an empirical modeling tool, a virtual prototype, and a cluster of FPGA boards. This framework is designed to support and accelerate the continuous development of such platforms driven by new insights in neuroscience.ResultsBased on design space explorations using this framework, we devised and realized an FPGA cluster consisting of 35 NetFPGA SUME boards.DiscussionThis system functions as an evaluation platform for our framework. At the same time, it resulted in a fully deterministic neuroscience simulation system surpassing the state of the art in both performance and energy efficiency. It is capable of simulating the microcircuit with 20× acceleration compared to biological real-time and achieves an energy efficiency of 48nJ per synaptic event
Estudo da remodelagem reversa miocárdica através da análise proteómica do miocárdio e do líquido pericárdico
Valve replacement remains as the standard therapeutic option for aortic
stenosis patients, aiming at abolishing pressure overload and triggering
myocardial reverse remodeling. However, despite the instant hemodynamic
benefit, not all patients show complete regression of myocardial hypertrophy,
being at higher risk for adverse outcomes, such as heart failure. The current
comprehension of the biological mechanisms underlying an incomplete reverse
remodeling is far from complete. Furthermore, definitive prognostic tools and
ancillary therapies to improve the outcome of the patients undergoing valve
replacement are missing. To help abridge these gaps, a combined myocardial
(phospho)proteomics and pericardial fluid proteomics approach was followed,
taking advantage of human biopsies and pericardial fluid collected during
surgery and whose origin anticipated a wealth of molecular information
contained therein.
From over 1800 and 750 proteins identified, respectively, in the myocardium
and in the pericardial fluid of aortic stenosis patients, a total of 90 dysregulated
proteins were detected. Gene annotation and pathway enrichment analyses,
together with discriminant analysis, are compatible with a scenario of increased
pro-hypertrophic gene expression and protein synthesis, defective ubiquitinproteasome system activity, proclivity to cell death (potentially fed by
complement activity and other extrinsic factors, such as death receptor
activators), acute-phase response, immune system activation and fibrosis.
Specific validation of some targets through immunoblot techniques and
correlation with clinical data pointed to complement C3 β chain, Muscle Ring
Finger protein 1 (MuRF1) and the dual-specificity Tyr-phosphorylation
regulated kinase 1A (DYRK1A) as potential markers of an incomplete
response. In addition, kinase prediction from phosphoproteome data suggests
that the modulation of casein kinase 2, the family of IκB kinases, glycogen
synthase kinase 3 and DYRK1A may help improve the outcome of patients
undergoing valve replacement. Particularly, functional studies with DYRK1A+/-
cardiomyocytes show that this kinase may be an important target to treat
cardiac dysfunction, provided that mutant cells presented a different response
to stretch and reduced ability to develop force (active tension).
This study opens many avenues in post-aortic valve replacement reverse
remodeling research. In the future, gain-of-function and/or loss-of-function
studies with isolated cardiomyocytes or with animal models of aortic bandingdebanding will help disclose the efficacy of targeting the surrogate therapeutic
targets. Besides, clinical studies in larger cohorts will bring definitive proof of
complement C3, MuRF1 and DYRK1A prognostic value.A substituição da válvula aórtica continua a ser a opção terapêutica de
referência para doentes com estenose aórtica e visa a eliminação da
sobrecarga de pressão, desencadeando a remodelagem reversa miocárdica.
Contudo, apesar do benefício hemodinâmico imediato, nem todos os pacientes
apresentam regressão completa da hipertrofia do miocárdio, ficando com maior
risco de eventos adversos, como a insuficiência cardíaca. Atualmente, os
mecanismos biológicos subjacentes a uma remodelagem reversa incompleta
ainda não são claros. Além disso, não dispomos de ferramentas de
prognóstico definitivos nem de terapias auxiliares para melhorar a condição
dos pacientes indicados para substituição da válvula. Para ajudar a resolver
estas lacunas, uma abordagem combinada de (fosfo)proteómica e proteómica
para a caracterização, respetivamente, do miocárdio e do líquido pericárdico
foi seguida, tomando partido de biópsias e líquidos pericárdicos recolhidos em
ambiente cirúrgico.
Das mais de 1800 e 750 proteínas identificadas, respetivamente, no miocárdio
e no líquido pericárdico dos pacientes com estenose aórtica, um total de 90
proteínas desreguladas foram detetadas. As análises de anotação de genes,
de enriquecimento de vias celulares e discriminativa corroboram um cenário de
aumento da expressão de genes pro-hipertróficos e de síntese proteica, um
sistema ubiquitina-proteassoma ineficiente, uma tendência para morte celular
(potencialmente acelerada pela atividade do complemento e por outros fatores
extrínsecos que ativam death receptors), com ativação da resposta de fase
aguda e do sistema imune, assim como da fibrose.
A validação de alguns alvos específicos através de immunoblot e correlação
com dados clínicos apontou para a cadeia β do complemento C3, a Muscle
Ring Finger protein 1 (MuRF1) e a dual-specificity Tyr-phosphoylation
regulated kinase 1A (DYRK1A) como potenciais marcadores de uma resposta
incompleta. Por outro lado, a predição de cinases a partir do fosfoproteoma,
sugere que a modulação da caseína cinase 2, a família de cinases do IκB, a
glicogénio sintase cinase 3 e da DYRK1A pode ajudar a melhorar a condição
dos pacientes indicados para intervenção. Em particular, a avaliação funcional
de cardiomiócitos DYRK1A+/- mostraram que esta cinase pode ser um alvo
importante para tratar a disfunção cardíaca, uma vez que os miócitos mutantes
responderam de forma diferente ao estiramento e mostraram uma menor
capacidade para desenvolver força (tensão ativa).
Este estudo levanta várias hipóteses na investigação da remodelagem reversa.
No futuro, estudos de ganho e/ou perda de função realizados em
cardiomiócitos isolados ou em modelos animais de banding-debanding da
aorta ajudarão a testar a eficácia de modular os potenciais alvos terapêuticos
encontrados. Além disso, estudos clínicos em coortes de maior dimensão
trarão conclusões definitivas quanto ao valor de prognóstico do complemento
C3, MuRF1 e DYRK1A.Programa Doutoral em Biomedicin
Predictive Maintenance of Critical Equipment for Floating Liquefied Natural Gas Liquefaction Process
Predictive Maintenance of Critical Equipment for Liquefied Natural Gas Liquefaction Process
Meeting global energy demand is a massive challenge, especially with the quest of more affinity towards sustainable and cleaner energy. Natural gas is viewed as a bridge fuel to a renewable energy. LNG as a processed form of natural gas is the fastest growing and cleanest form of fossil fuel. Recently, the unprecedented increased in LNG demand, pushes its exploration and processing into offshore as Floating LNG (FLNG). The offshore topsides gas processes and liquefaction has been identified as one of the great challenges of FLNG. Maintaining topside liquefaction process asset such as gas turbine is critical to profitability and reliability, availability of the process facilities. With the setbacks of widely used reactive and preventive time-based maintenances approaches, to meet the optimal reliability and availability requirements of oil and gas operators, this thesis presents a framework driven by AI-based learning approaches for predictive maintenance. The framework is aimed at leveraging the value of condition-based maintenance to minimises the failures and downtimes of critical FLNG equipment (Aeroderivative gas turbine).
In this study, gas turbine thermodynamics were introduced, as well as some factors affecting gas turbine modelling. Some important considerations whilst modelling gas turbine system such as modelling objectives, modelling methods, as well as approaches in modelling gas turbines were investigated. These give basis and mathematical background to develop a gas turbine simulated model. The behaviour of simple cycle HDGT was simulated using thermodynamic laws and operational data based on Rowen model. Simulink model is created using experimental data based on Rowen’s model, which is aimed at exploring transient behaviour of an industrial gas turbine. The results show the capability of Simulink model in capture nonlinear dynamics of the gas turbine system, although constraint to be applied for further condition monitoring studies, due to lack of some suitable relevant correlated features required by the model.
AI-based models were found to perform well in predicting gas turbines failures. These capabilities were investigated by this thesis and validated using an experimental data obtained from gas turbine engine facility. The dynamic behaviours gas turbines changes when exposed to different varieties of fuel. A diagnostics-based AI models were developed to diagnose different gas turbine engine’s failures associated with exposure to various types of fuels. The capabilities of Principal Component Analysis (PCA) technique have been harnessed to reduce the dimensionality of the dataset and extract good features for the diagnostics model development.
Signal processing-based (time-domain, frequency domain, time-frequency domain) techniques have also been used as feature extraction tools, and significantly added more correlations to the dataset and influences the prediction results obtained. Signal processing played a vital role in extracting good features for the diagnostic models when compared PCA. The overall results obtained from both PCA, and signal processing-based models demonstrated the capabilities of neural network-based models in predicting gas turbine’s failures. Further, deep learning-based LSTM model have been developed, which extract features from the time series dataset directly, and hence does not require any feature extraction tool. The LSTM model achieved the highest performance and prediction accuracy, compared to both PCA-based and signal processing-based the models.
In summary, it is concluded from this thesis that despite some challenges related to gas turbines Simulink Model for not being integrated fully for gas turbine condition monitoring studies, yet data-driven models have proven strong potentials and excellent performances on gas turbine’s CBM diagnostics. The models developed in this thesis can be used for design and manufacturing purposes on gas turbines applied to FLNG, especially on condition monitoring and fault detection of gas turbines. The result obtained would provide valuable understanding and helpful guidance for researchers and practitioners to implement robust predictive maintenance models that will enhance the reliability and availability of FLNG critical equipment.Petroleum Technology Development Funds (PTDF) Nigeri
Controls on groundwater and surface water salinity in coastal Bangladesh
Salinity in surface water and groundwater is a pervasive issue along coastal Bangladesh,
a low-lying megadelta where around 35 million people live. A large amount of this land
has been reclaimed using a network of low-lying polders. The area is particularly susceptible
to flooding from tropical cyclones. Cyclone induced storm surges coupled with
the low-lying reclaimed land can breach polder embankments and cause extensive flooding,
resulting in excess salinity in soil and surface water. Salinity in drinking water is
known to cause adverse effects on human health. It is, therefore, important to identify
the controls surface water and groundwater salinity in these coastal areas.
A fully coupled surface-subsurface model of a coastal polder by using HydroGeo-
Sphere is developed to investigate the impact of storm surge events on groundwater
salinity. The hydrological parameters were calibrated from the fieldwork at a field site
in the Dacope Upazila, in the southwest coastal region of Bangladesh. The results suggest
that sudden salt fluxes in the pond are likely to build up salinity in the underlying
sediment.
A set of scenarios were considered: a cyclone induced storm surge during both the
monsoon and dry seasons, and both with and without remediation. The results show that
surge events caused a rise in salinity in drinking water and near-surface groundwater.
However, rapid remediation after a surge event could help mitigate the severity of the
impact on drinking water. This provides suggestions for water resources management
planning.
The 2D cross-section model was extended to the 3D model to improve the understanding
of the salinity process. Climate change scenarios were then used to evaluate the effects of episodic cyclone surges on shallow groundwater salinity. This study suggests that more
frequent cyclones would worsen not only salinity in near-surface groundwater but lateral
saltwater intrusion at the shallow or deep aquifers.Open Acces
Células endoteliais progenitoras e células endoteliais circulantes na insuficiência cardíaca: um estudo transversal
The objective of the present thesis was to compare the levels of circulating
endothelial progenitor cells (EPCs), circulating endothelial cells (CECs), and
hematopoietic stem cells (HSCs) between patients with heart failure with reduced
ejection fraction (HFrEF) and a group of subjects with cardiovascular risk factors.
We also compared the levels of circulating EPCs, CECs, and HSCs between
subgroups regarding the presence of cardiovascular risk factors (e.g. diabetes
mellitus) and the etiology of heart failure (HF). To achieved this, whole peripheral
blood was drawn from patients previously diagnosed with HFrEF (n = 42) and
age-matched subjects presenting similar cardiovascular risk factors but without
established cardiovascular disease (n = 42). Then, a combination of markers was
used in peripheral blood samples in order to assess the number of circulating
EPCs, CECs, and HSCs via flow cytometry analysis. Patients with HFrEF had
significantly decreased levels of circulating EPCs (5.28 x 10-3 ± 6.83 x 10-4 % vs
7.76 x 10-3 ± 4.91 x 10-4 %, P ≤ 0.001) and CECs (5.11 x 10-3 ± 7.87 x 10-4 % vs
6.51 x 10-3 ± 5.21 x 10-4 %, P = 0.005) compared to subjects with cardiovascular
risk factors. However, levels of HSCs were not significantly different between the
two groups (P = 0.590). Additionally, CECs (6.69 x 10-3 ± 6.38 x 10-3 % vs 3.61 x
10-3 ± 2.71 x 10-3 %, P = 0.057) tended to circulate in higher number in patients
with ischemic HF compared to patients with non-ischemic HF. Patients with
HFrEF and diagnosed as overweight/obese had significantly higher levels of
circulating EPCs (6.10 x 10-3 ± 4.78 x 10-3 % vs 4.13 x 10-3 ± 3.55 x 10-3 %, P =
0.043) and CECs (6.27 x 10-3 ± 5.66 x 10-3 % vs 3.47 x 10-3 ± 3.54 x 10-3 %, P =
0.019) when compared to patients with HFrEF presenting a normal weight.
Lastly, when comparing subjects from the age-matched group, subjects with
dyslipidemia had significantly higher levels of CECs (7.74 x 10-3 ± 3.64 x 10-3 %
vs 5.34 x 10-3 ± 2.59 x 10-3 %, P = 0.042) compared to subjects without
dyslipidemia. In conclusion, the main result of this study is that the circulating
levels of EPCs and CECs were significantly decreased in patients with HFrEF in
comparison to subjects with cardiovascular risk factors. The current observations
regarding cardiovascular risk factors suggest that EPCs, CECs, and HSCs play
an important role in the detection and repair of vascular damage and endothelial
dysfunction.O presente trabalho teve como principal objetivo comparar os níveis de células
endoteliais progenitoras (CEPs), células endoteliais circulantes (CECs) e células
estaminais hematopoiéticas (CEHs) em circulação entre doentes com
insuficiência cardíaca com fração de ejeção reduzida (ICFEr) e um grupo de
adultos com fatores de risco cardiovasculares. Adicionalmente, os níveis das
CEPs, CECs e CEHs foram comparados entre subgrupos em função da
presença de fatores de risco (ex. diabetes) e da etiologia da insuficiência
cardíaca. Inicialmente foram recolhidas amostras de sangue periférico de
doentes com ICFEr (n = 42) e indivíduos da mesma faixa etária com fatores de
risco cardiovasculares, mas sem qualquer doença cardiovascular estabelecida
(n = 42). Em seguida, foi utilizada uma combinação de anticorpos nas amostras
de sangue periférico para quantificação do número de CEPs, CECs e CEHs por
citometria de fluxo. Doentes com ICFEr apresentaram níveis de CEPs (5.28 x
10-3 ± 6.83 x 10-4 % vs 7.76 x 10-3 ± 4.91 x 10-4 %, P ≤ 0.001) e CECs (5.11 x 10-
3 ± 7.87 x 10-4 % vs 6.51 x 10-3 ± 5.21 x 10-4 %, P = 0.005) significativamente
inferiores aos indivíduos com fatores de risco cardiovasculares. Contudo, não
foram encontradas diferenças significativas nos níveis de CEHs entre os dois
grupos (P = 0.590). Adicionalmente, observou-se que as CECs (6.69 x 10-3 ±
6.38 x 10-3 % vs 3.61 x 10-3 ± 2.71 x 10-3 %, P = 0.057) tendem a circular em
maior número em doentes com ICFEr com etiologia isquémica
comparativamente a doentes com ICFEr não isquémica. Doentes com ICFEr e
com sobrepeso/obesidade apresentaram níveis de CEPs (6.10 x 10-3 ± 4.78 x
10-3 % vs 4.13 x 10-3 ± 3.55 x 10-3 %, P = 0.043) e CECs (6.27 x 10-3 ± 5.66 x 10-
3 % vs 3.47 x 10-3 ± 3.54 x 10-3 %, P = 0.019) significativamente superiores
comparativamente a doentes com ICFEr e com peso normal. Por último, dentro
do grupo de indivíduos com fatores de risco cardiovasculares, indivíduos com
dislipidemia apresentaram níveis de CECs (7.74 x 10-3 ± 3.64 x 10-3 % vs 5.34 x
10-3 ± 2.59 x 10-3 %, P = 0.042) significativamente superiores em comparação a
indivíduos sem dislipidemia. Em conclusão, os principais resultados deste
estudo indicam que o número de CECs e CEPs em circulação encontra-se
significativamente reduzido em doentes com ICFEr comparativamente a
indivíduos com fatores de risco para doenças cardiovasculares. As observações
atuais em relação aos fatores de risco para doenças cardiovasculares sugerem
que CEPs, CECs e CEHs desempenham um papel fundamental na sinalização
e reparação do dano vascular e disfunção endotelial.Mestrado em Biomedicina Molecula
- …