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1.
PLoS One ; 19(4): e0301819, 2024.
Article in English | MEDLINE | ID: mdl-38625925

ABSTRACT

This work investigates a downlink nonorthogonal multiple access (NOMA) scheme with unmanned aerial vehicle (UAV) aided wireless communication, where a single UAV was regarded as an air base station (ABS) to communicate with multiple ground users. Considering the constraints of velocity and maneuverability, a UAV energy efficiency (EE) model was proposed via collaborative design resource allocation and trajectory optimization. Based on this, an EE maximization problem was formulated to jointly optimize the transmit power of ground users and the trajectory of the UAV. To obtain the optimal solutions, this nonconvex problem was transformed into an equivalent convex optimization problem on the basis of three user clustering algorithms. After several alternating iterations, our proposed algorithms converged quickly. The simulation results show an enhancement in EE with NOMA because our proposed algorithm is nearly 99.6% superior to other OMA schemes.


Subject(s)
Noma , Humans , Unmanned Aerial Devices , Algorithms , Communication , Resource Allocation
2.
Eur J Pediatr ; 183(3): 1435-1446, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38217695

ABSTRACT

Sucking patterns and early spontaneous movements have an important role in the determination of later developmental problems, but the relationship of the two together with long-term outcomes has not been investigated. The objectives of this study were to (i) examine the relationship between sucking patterns using the Neonatal Oral Motor Assessment Scale (NOMAS) and fidgety movements and other movement patterns using detailed General Movements Assessment (GMA), and (ii) investigate the relationship between these early assessment methods and developmental functioning outcomes at later ages. We analyzed the NOMAS from 34 weeks' postmenstrual age up to 10 weeks post-term and GMA between 9 and 20 weeks post-term age, and the Bayley Scales of Infant and Toddler Development-Third Edition (Bayley-III) was applied for the developmental functioning outcomes to 62 infants (61%, 62/102) between 12 and 42 months of age. Among 102 infants at-risk, 70 (69%) showed a normal sucking pattern, and 85 (83%) had fidgety movements. The median Motor Optimality Score-Revised (MOS-R), as determined by GMA, of all infants was 24. The NOMAS was related to the MOS-R and its subcategories (p < 0.05) in all infants at-risk. The NOMAS, MOS-R and its subcategories were also related to cognitive, language, and motor development at later ages according to Bayley-III (p < 0.05).   Conclusion: This longitudinal study showed that the quality of sucking patterns, fidgety movements, and MOS-R were related to later developmental functioning, indicating that abnormal sucking patterns, aberrant fidgety movements, and lower MOS-R might predict developmental disorders. What is Known: • Sucking patterns and early spontaneous movements in which central pattern generators play an important role are related. • Sucking patterns and early spontaneous movements might be used separately to predict developmental outcomes. What is New: • Sucking patterns and early spontaneous movements, when used together, were related to later developmental functioning, including cognitive, language, and motor development in at-risk infants. • Predictive value of sucking patterns was lower for each developmental functioning outcome than early spontaneous movements.


Subject(s)
Noma , Infant, Newborn , Infant , Humans , Child, Preschool , Cohort Studies , Longitudinal Studies , Movement , Eating
4.
Lancet Glob Health ; 12(2): e170, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38245102
5.
Neurology ; 102(2): e207961, 2024 Jan 23.
Article in English | MEDLINE | ID: mdl-38165319

ABSTRACT

BACKGROUND AND OBJECTIVES: Red blood cell (RBC) concentrations are known to associate with ischemic stroke. It is unclear whether RBC concentrations associate specifically with small vessel disease lacunar infarcts. We investigated the hypothesis that RBC concentrations associate with both chronic covert and acute symptomatic brain MRI lacunar infarcts. METHODS: A cross-sectional observational analysis was performed across 2 cohorts with available hematocrit (as the assessment of RBC concentration exposure) and MRI outcome data. The primary setting was a population-based cohort of stroke-free, older adult (>50 years) participants from the Northern Manhattan Study (NOMAS) enrolled between 2003 and 2009. A second replication sample consisted of patients admitted with acute stroke and enrolled into the Columbia Stroke Registry (CSR) between 2005 and 2020. Associations of hematocrit with (1) chronic, covert lacunar infarcts and (2) symptomatic (i.e., acute) lacunar strokes were separately assessed from the NOMAS and CSR cohorts, respectively, using general additive models after adjusting for relevant covariates. RESULTS: Of 1,218 NOMAS participants analyzed, 6% had chronic, covert lacunar infarcts. The association between hematocrit and these covert lacunar infarcts was U-shaped (χ2 = 9.21 for nonlinear associations; p = 0.03), with people with hematocrit extremes being more likely to have covert lacunar infarcts. Of the 1,489 CSR patients analyzed, 23% had acute lacunar strokes. In this sample, only the relationships of increased hematocrit concentrations and lacunar strokes were replicated (adjusted coefficient ß = 0.020; SE = 0.009; p = 0.03). DISCUSSION: We identified relationships of hematocrit with MRI lacunar infarcts in both stroke-free and ischemic stroke cohorts, respectively. The relationship between increased hematocrit concentrations with lacunar infarcts was replicated in both cohorts. Further studies are required to clarify the mechanisms behind the relationships of hematocrit with ischemic cerebral small vessel disease.


Subject(s)
Ischemic Stroke , Noma , Stroke, Lacunar , Stroke , Aged , Humans , Cross-Sectional Studies , Hematocrit , Stroke, Lacunar/diagnostic imaging , Middle Aged
6.
Int J Pediatr Otorhinolaryngol ; 177: 111845, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38176115

ABSTRACT

OBJECTIVES: Noma is a neglected infectious disease that causes severe destruction of facial tissues and poses a significant public health threat. The disease reportedly affects individuals with a debilitating health condition. This study aimed to identify the most vulnerable age group affected by Noma disease and assess the severity of tissue damage among Noma cases in Ethiopia. METHODS: A cross-sectional study was conducted to determine the age group most susceptible to noma and assess the disease-associated severity of tissue damage. The research objectives were met by scrutinizing electronic medical records of noma cases treated in Addis Ababa, Ethiopia, from 2007 to 2019, obtained from the Facing Africa database. Data collection was carried out using a standardized survey form, while the severity of facial tissue damage was assessed using the NOIPTUS score. RESULTS: Among 164 Noma cases with documented data on disease onset, 92.7 % occurred during childhood, with 92.1 % of those cases being children aged ten years and younger. Approximately 11.6 % of all noma cases had mild tissue damage, classified as NOITULP grade 1, while 26.2 % had an intermediate level of tissue damage, classified as NOITULP grade 2. Severe tissue damage (NOITULP grade 3) was present in 37.2 % of cases, while 25 % had very severe tissue damage (NOITULP grade 4). CONCLUSIONS: The findings underscore the vulnerability of children, particularly those aged ten years and younger, to Noma disease, supporting the argument that Noma is a facial-disfiguring childhood disease. Targeted interventions and preventive measures during childhood can be vital in controlling Noma incidence.


Subject(s)
Noma , Child , Humans , Noma/epidemiology , Noma/etiology , Ethiopia/epidemiology , Cross-Sectional Studies , Head
7.
Am J Trop Med Hyg ; 110(2): 303-310, 2024 Feb 07.
Article in English | MEDLINE | ID: mdl-38150738

ABSTRACT

Noma (cancrum oris) is an orofacial gangrene affecting young children living in extreme poverty. The acute morbidity is high, and survivors suffer from physical and social sequelae. When diagnosed early, noma can be cured. Noma is especially prevalent in sub-Saharan Africa, where traditional medicine is the norm. The aim of this work was to provide 1-day training to traditional healers in Burkina Faso and to evaluate change in knowledge of noma across time. A sample of 78 healers who attended the training were asked to complete the same questionnaire before, immediately after, and 8 months after the training. A total of 66 healers completed the entire study. Before training, more than 40% of the participants did not know any of its key messages. Most of the key messages were acquired and still present after 8 months by a large proportion of the participants. Systematic intraoral examination was practiced by 7 (9.0%) of the traditional healers before training, and 43 (65.2%) reported doing so 8 months after training. The key messages aiming to improve early diagnosis as well as rapid and adequate treatment (the recognition of facilitating factors and the need to perform a systematic oral examination and to advise hospital transfer) have been well integrated. The study suggests that organizing a self-managed training program is feasible when done within an association, as was the case here, and owing to the willingness to collaborate shown by the traditional healers who participated in our study.


Subject(s)
Noma , Humans , Child , Child, Preschool , Noma/diagnosis , Traditional Medicine Practitioners , Burkina Faso/epidemiology , Medicine, Traditional , Poverty
8.
J Neurol Sci ; 454: 120856, 2023 11 15.
Article in English | MEDLINE | ID: mdl-37913646

ABSTRACT

Prior work in the Northern Manhattan Study (NOMAS) identified impaired cognition in cross-sectional analyses and more rapid memory decline in individuals with evidence of prior common infectious disease exposures. In this study, we sought to determine the cross-sectional relationship between prior exposure to cytomegalovirus, herpes simplex viruses 1 and 2, Chlamydia pneumoniae, and Helicobacter pylori and three magnetic resonance imaging (MRI) signatures (whole-brain cortical thickness, a previously validated AD signature, and hippocampal volume) in 455 NOMAS participants. We performed confounder-adjusted linear regression analyses between neuroimaging scores and both continuous serologies and categorical seropositivity of each pathogen, as well as a combined infectious burden index (IBI). We identified that increased serologic titers of herpes simplex virus 2 were associated with reduced whole-brain cortical thickness, and a combined score of HSV-2 and C. pneumoniae displayed an additive effect on reduced cortical thickness. Our findings suggest herpes simplex virus 2 seropositivity may contribute to accelerated brain aging, possibly resulting in an increased vulnerability to cognitive impairment and neurodegenerative disease in aging populations.


Subject(s)
Alzheimer Disease , Herpes Simplex , Neurodegenerative Diseases , Noma , Humans , Aged , Herpesvirus 2, Human , Neurodegenerative Diseases/complications , Independent Living , Noma/complications , Brain , Herpes Simplex/complications , Herpes Simplex/diagnostic imaging , Alzheimer Disease/complications
9.
Stroke ; 54(12): 3030-3037, 2023 12.
Article in English | MEDLINE | ID: mdl-37909207

ABSTRACT

BACKGROUND: Inflammation contributes to atherosclerosis but is incompletely characterized in intracranial large artery stenosis (ICAS). We hypothesized that immune markers would be associated with ICAS and modify the risk ICAS confers on future vascular events. METHODS: This study included a subsample of stroke-free participants in the prospective NOMAS (Northern Manhattan Study), who had blood samples analyzed with a 60-plex immunoassay (collected from 1993 to 2001) and ICAS assessment with time-of-flight magnetic resonance angiography (obtained from 2003 to 2008). We dichotomized ICAS as either ≥50% stenosis or not (including no ICAS). We ascertained post-magnetic resonance imaging vascular events. We used least absolute shrinkage and selection operator procedures to select immune markers independently associated with ICAS. Then, we grouped selected immune markers into a derived composite Z score. Using proportional odds regression, we quantified the association of the composite immune marker Z score, ICAS, and risk of vascular events. RESULTS: Among 1211 participants (mean age, 71±9 years; 59% women; 65% Hispanic participants), 8% had ≥50% ICAS. Using least absolute shrinkage and selection operator regression, we identified CXCL9 (C-X-C motif chemokine ligand 9), HGF (hepatocyte growth factor), resistin, SCF (stem cell factor), and VEGF-A(vascular endothelial growth factor A) to have the strongest positive relationships with ≥50% ICAS in fully adjusted models. Selected markers were used to derive a composite immune marker Z score. Over an average follow-up of 12 years, we found that each unit increase in immune marker Z scores was associated with an 8% (95% CI, 1.05-1.11), 11% (95% CI, 1.06-1.16), and 5% (95% CI, 1.01-1.09) increased hazard of death, vascular death, and any vascular event, respectively, in adjusted models. We did not find a significant interaction between immune marker Z scores and ICAS in their relationship with any longitudinal outcome. CONCLUSIONS: Among a diverse stroke-free population, selected serum immune markers were associated with ICAS and future vascular events. Further study is needed to better understand their role in the pathogenesis of ICAS and as a potential therapeutic target in stroke prevention.


Subject(s)
Intracranial Arteriosclerosis , Noma , Stroke , Humans , Female , Middle Aged , Aged , Aged, 80 and over , Male , Vascular Endothelial Growth Factor A , Prospective Studies , Constriction, Pathologic/complications , Noma/complications , Risk Factors , Intracranial Arteriosclerosis/complications , Stroke/epidemiology , Biomarkers , Arteries
10.
Am J Trop Med Hyg ; 109(6): 1388-1392, 2023 12 06.
Article in English | MEDLINE | ID: mdl-37903433

ABSTRACT

Noma is a rapidly advancing and frequently deadly infection affecting the oral and facial regions. The condition causes severe destruction of the soft and osseous tissues of the face. Noma primarily affects impoverished children with weakened immune systems, yet epidemiological data on the disease are lacking. This cross-sectional study aimed to fill this knowledge gap by estimating the prevalence of noma in Ethiopia. A retrospective review of patients' medical records was conducted using data from the Facing Africa database, spanning from 2007 to 2019. The prevalence of noma was calculated for the general population and for children under 10 years old at national and regional levels. The estimation process involved analyzing raw data and referring to an expert consultation report organized by the Oral Health Division of the WHO, which used the Delphi method. Based on the analysis of 235 medical records, the study revealed an estimated prevalence of 16 cases per 100,000 population and 0.47 case per 1,000 children under 10 years old nationally, with approximately 1,446 and 1,237 new cases diagnosed annually, respectively. The Gambela region had the highest prevalence of noma, with 276.2 cases per 100,000 population, whereas the Benshangul Gumuz region had the lowest rate at 6.2 cases per 100,000 population. Similarly, the Gambela and Benshangul Gumuz regions exhibited the highest and lowest prevalences per 1,000 children under 10 years old, estimated at 8.12 and 0.18 cases per 1,000, respectively. The findings underscore the public health impact of noma in Ethiopia and the need for effective prevention and treatment strategies.


Subject(s)
Noma , Child , Humans , Cross-Sectional Studies , Ethiopia/epidemiology , Noma/diagnosis , Noma/epidemiology , Prevalence , Retrospective Studies
11.
PLoS Negl Trop Dis ; 17(10): e0011508, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37889919

ABSTRACT

INTRODUCTION: Noma is a rapidly spreading infection of the oral cavity which mainly affects young children. Without early treatment, it can have a high mortality rate. Simple gingivitis is a warning sign for noma, and acute necrotizing gingivitis is the first stage of noma. The epidemiology of noma is not well understood. We aimed to understand the prevalence of all stages of noma in hospitalised children. METHODS: We conducted a prospective observational study from 1st June to 24th October 2021, enrolling patients aged 0 to 12 years who were admitted to the Anka General Hospital, Zamfara, northwest Nigeria. Consenting parents/ guardians of participants were interviewed at admission. Participants had anthropometric and oral examinations at admission and discharge. FINDINGS: Of the 2346 patients, 58 (2.5%) were diagnosed with simple gingivitis and six (n = 0.3%) with acute necrotizing gingivitis upon admission. Of those admitted to the Inpatient Therapeutic Feeding Centre (ITFC), 3.4% (n = 37, CI 2.5-4.7%) were diagnosed with simple gingivitis upon admission compared to 1.7% of those not admitted to the ITFC (n = 21, CI 1.1-2.6%) (p = 0.008). Risk factors identified for having simple gingivitis included being aged over two years (2 to 6 yrs old, odds ratio (OR) 3.4, CI 1.77-6.5; 7 to 12 yrs OR 5.0, CI 1.7-14.6; p = <0.001), being admitted to the ITFC (OR 2.1; CI 1.22-3.62) and having oral health issues in the three months prior to the assessment (OR 18.75; CI 10.65, 33.01). All (n = 4/4) those aged six months to five years acute necrotizing gingivitis had chronic malnutrition. CONCLUSION: Our study showed a small proportion of children admitted to the Anka General Hospital had simple or acute necrotizing gingivitis. Hospital admission with malnutrition was a risk factor for both simple and acute necrotizing gingivitis. The lack of access to and uptake of oral health care indicates a strong need for oral examinations to be included in routine health services. This provision could improve the oral status of the population and decrease the chance of patients developing noma.


Subject(s)
Gingivitis, Necrotizing Ulcerative , Gingivitis , Malnutrition , Noma , Child , Child, Preschool , Humans , Gingivitis/epidemiology , Gingivitis/complications , Gingivitis, Necrotizing Ulcerative/complications , Gingivitis, Necrotizing Ulcerative/epidemiology , Hospitals, General , Malnutrition/complications , Nigeria/epidemiology , Noma/epidemiology , Noma/etiology , Prospective Studies
12.
Article in English | MEDLINE | ID: mdl-37605998

ABSTRACT

Strain HF14-78462T is an environmental bacterium found in clinical samples from an immunocompromized patient in 2014 at Hospital Universitari i Politècnic La Fe (Valencia, Spain). Phenotypically, strain HF14-78462T cells were Gram-stain-negative, aerobic, non-spore forming and non-motile small rods which formed mucous and whitish-translucent colonies when incubated at 20-36 °C. Phylogenetic analyses based on the 16S rRNA genes and the whole genomes of closest sequenced relatives confirmed that strain HF14-78462T is affiliated with the genus Starkeya. The strain was oxidase, catalase and urease positive; but indole, lysine decarboxylase, ornithine decarboxylase and DNase negative, did not produce H2S and was able to utilize a wide variety of carbon sources including acetamide, adonitol, amygdalin, l-arabinose, citric acid, glucose, mannitol and melibiose. Unlike Starkeya novella and Starkeya koreensis, strain HF14-78462T failed to grow in thiosulphate-oxidizing media and had a narrower temperature growth range. Its genome was characterized by a size of 4.83 Mbp and a C+G content of 67.75 mol%. Major fatty acids were C18:1 ω7c, cyclo C19 : 0 and C16 : 0, its polar acids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and an aminophospholipid; while the ubiquinones were Q9 (1.8 %) and Q10 (98.2 %). Digital DNA-DNA hybridization values were 41 and 41.4 against S. novella and S. koreensis, respectively, while average nucleotide identity values were around 84 %. Phenotypic, average nucleotide identity and phylogenomic comparative studies suggest that strain HF14-78462T is a new representative of the genus Starkeya and the name Starkeya nomas sp. nov. is proposed. The type strain is HF14-78462T (=CECT 30124T=LMG 31874T).


Subject(s)
Fatty Acids , Noma , Humans , Fatty Acids/chemistry , Phylogeny , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , DNA, Bacterial/genetics , Bacterial Typing Techniques , Base Composition , Bacteria
13.
BMC Res Notes ; 16(1): 162, 2023 Aug 07.
Article in English | MEDLINE | ID: mdl-37550768

ABSTRACT

OBJECTIVES: Noma is a facially disfiguring disease that affects the oral cavity and midface structures. If left untreated, the disease is fatal. Noma causes severe cosmetic and functional defects in survivors, leading to psychiatric and social problems. However, there are limited data on psychosocial and functional sequelae associated with this disease. This cross-sectional study aimed to investigate psychosocial and functional morbidity among facially disfigured untreated Noma cases. Study participants were volunteer patients diagnosed with noma and awaiting surgery at two noma treatment centers in Ethiopia. A questionnaire derived from the APA's DSM-5, the DAS59, and the Appearance Anxiety Inventory protocol was used to measure the psychosocial and functional morbidity of the cases between September 16 and October 10, 2022. RESULTS: A total of 32 noma cases (19 women and 13 men) awaiting the next surgical campaigns were involved in the study. Study participants reported severe social (Likert score = 2.8) and psychological (Likert score = 3.0) morbidity. Functional limitation was moderate (Likert score = 2.9). This study has shown that psychosocial and functional morbidity in untreated noma cases in Ethiopia is substantial. Therefore, policymakers, clinicians, and researchers need to pay sufficient attention to providing adequate health care and preventing the occurrence of the disease in the long term.


Subject(s)
Noma , Male , Humans , Female , Noma/complications , Noma/psychology , Noma/surgery , Ethiopia/epidemiology , Cross-Sectional Studies , Face/surgery , Morbidity
14.
Sensors (Basel) ; 23(12)2023 Jun 11.
Article in English | MEDLINE | ID: mdl-37420670

ABSTRACT

Simultaneous transmitting and reflecting reconfigurable intelligent surfaces (STAR-RISs) can reflect signals and transmissive signals simultaneously and can extend the coverage of signals. A conventional RIS mainly focuses on the case where the signal source and the target are on the same side. In this paper, a STAR-RIS-assisted non-orthogonal multiple access (NOMA) downlink communication system is considered to maximize the achievable rate for users by jointly optimizing the power-allocation coefficients, active beamforming, and STAR-RIS beamforming under the mode-switching (MS) protocol. The critical information of the channel is first extracted using the Uniform Manifold Approximation and Projection (UMAP) method. Based on the key extracted channel features, STAR-RIS elements and users are clustered individually using the fuzzy C-mean clustering (FCM) method. The alternating optimization method decomposes the original optimization problem into three sub-optimization problems. Finally, the sub-problems are converted to unconstrained optimization methods using penalty functions for the solution. Simulation results show that when the number of elements of RIS is 60, the achievable rate of the STAR-RIS-NOMA system is about 18% higher than that of the RIS-NOMA system.


Subject(s)
Knee Prosthesis , Noma , Humans , Cluster Analysis , Computer Simulation , Intelligence
15.
Stroke ; 54(9): 2347-2355, 2023 09.
Article in English | MEDLINE | ID: mdl-37470161

ABSTRACT

BACKGROUND: Sleep duration is associated with stroke risk and is 1 of 8 essential components of cardiovascular health according to the American Heart Association. As stroke disproportionately burdens Black and Hispanic populations in the United States, we hypothesized that long and short sleep duration would be associated with greater subclinical carotid atherosclerosis, a precursor of stroke, in the racially and ethnically diverse NOMAS (Northern Manhattan Study). METHODS: NOMAS is a study of community-dwelling adults. Self-reported nightly sleep duration and daytime sleepiness were collected between 2006 and 2011. Carotid plaque presence, total plaque area, and intima-media thickness were measured by ultrasound between 1999 and 2008. Linear and logistic regression models examined the cross-sectional associations of sleep duration groups (primary exposure) or daytime sleepiness (secondary exposure) with measures of carotid atherosclerosis. Models adjusted for age, time between ultrasound and sleep data collection, sex, race and ethnicity, education, health insurance, smoking, alcohol use, physical activity, body mass index, hypertension, diabetes, hypercholesterolemia, and cardiac disease. RESULTS: The sample (n=1553) had a mean age of 64.7±8.5 years and was 61.9% female, 64.8% Hispanic, and 18.2% non-Hispanic Black. Of the sample, 55.6% had carotid plaque, 22.3% reported nightly short sleep (<7 hours), 66.6% intermediate sleep (≥7 and <9 hours), and 11.1% had long sleep (≥9 hours). Compared with intermediate sleep, long sleep was associated with greater odds of carotid plaque presence relative to plaque absence (odds ratio, 1.6 [95% CI, 1.1-2.4]) and larger total plaque area (odds ratio, 1.4 [95% CI, 1.0-1.9]) after full covariate adjustment. Short sleep and daytime sleepiness were not significantly associated with any carotid measures. CONCLUSIONS: The association between long sleep and subclinical carotid atherosclerosis may explain prior associations between long sleep and stroke.


Subject(s)
Carotid Artery Diseases , Disorders of Excessive Somnolence , Noma , Plaque, Atherosclerotic , Stroke , Adult , Humans , Female , United States , Middle Aged , Aged , Male , Carotid Intima-Media Thickness , Sleep Duration , Cross-Sectional Studies , Plaque, Atherosclerotic/diagnostic imaging , Plaque, Atherosclerotic/epidemiology , Carotid Artery Diseases/diagnostic imaging , Carotid Artery Diseases/epidemiology , Stroke/epidemiology , Risk Factors
16.
Sensors (Basel) ; 23(11)2023 Jun 03.
Article in English | MEDLINE | ID: mdl-37300040

ABSTRACT

By enabling multiple non-orthogonal transmissions, power domain non-orthogonal multiple access (PD-NOMA) potentially increases a system's spectral efficiency. This technique can become an alternative for future generations of wireless communication networks. The efficiency of this method fundamentally depends on two previous processing steps: an appropriate grouping of users (transmission candidates) as a function of the channel gains and the choice of power levels that will be used to transmit each signal. Thus far, the solutions presented in the literature to address the problems of user clustering and power allocation do not consider the dynamics of communication systems, i.e., the temporal variation in the number of users and the channel conditions. In order to consider these dynamic characteristics in the clustering of users in NOMA systems, this work proposes a new clustering technique based on a modification of the DenStream evolutionary algorithm, chosen for its evolutionary capacity, noise robustness and online processing. We evaluated the performance of the proposed clustering technique considering, for simplicity, the use of an already widely known power allocation strategy called improved fractional strategy power allocation (IFSPA). The results show that the proposed clustering technique can follow the system dynamics, clustering all users and favoring the uniformity of the transmission rate between the clusters. Compared to orthogonal multiple access (OMA) systems, the proposed model's gain was approximately 10%, obtained on a challenging communication scenario for NOMA systems since the channel model adopted does not favor a large difference in the channel gains between users.


Subject(s)
Noma , Humans , Algorithms , Biological Evolution , Cluster Analysis , Records
17.
Sensors (Basel) ; 23(11)2023 Jun 03.
Article in English | MEDLINE | ID: mdl-37300046

ABSTRACT

The localization of agents for collaborative tasks is crucial to maintain the quality of the communication link for successful data transmission between the base station and agents. Power-domain Non-Orthogonal Multiple Access (P-NOMA) is an emerging multiplexing technique that enables the base station to accumulate signals for different agents using the same time-frequency channel. The environment information such as distance from the base station is required at the base station to calculate communication channel gains and allocate suitable signal power to each agent. The accurate estimate of the position for power allocation of P-NOMA in a dynamic environment is challenging due to the changing location of the end-agent and shadowing. In this paper, we take advantage of the two-way Visible Light Communication (VLC) link to (1) estimate the position of the end-agent in a real-time indoor environment based on the signal power received at the base station using machine learning algorithms and (2) allocate resources using the Simplified Gain Ratio Power Allocation (S-GRPA) scheme with the look-up table method. In addition, we use the Euclidean Distance Matrix (EDM) to estimate the location of the end-agent whose signal was lost due to shadowing. The simulation results show that the machine learning algorithm is able to provide an accuracy of 0.19 m and allocate power to the agent.


Subject(s)
Noma , Humans , Algorithms , Communication , Light , Machine Learning
18.
Trop Doct ; 53(4): 470-474, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37165663

ABSTRACT

Noma is a neglected tropical disease of an underserved population. Our review describes the volume and scope of existing research evidence on psychosocial aspects of Noma in sub-Saharan Africa (SSA). Our literature search was conducted on all original peer-reviewed research articles on the psychosocial aspects of Noma in each country in SSA using PubMed, Google Scholar, and a direct search of reference list of pertinent journal articles. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guidelines was used to describe the review. A total of six studies were found in four countries of the region. One in three persons with Noma has a mental health condition, indices of social disadvantage and belief in the supernatural causation of the disease are very common. However, despite evidence of enormous need, a huge gap still exists in the area of psychosocial alleviation.


Subject(s)
Mental Disorders , Noma , Humans , Africa South of the Sahara/epidemiology , Mental Disorders/epidemiology , Mental Disorders/etiology , Neglected Diseases
19.
J Stroke Cerebrovasc Dis ; 32(8): 107185, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37186970

ABSTRACT

OBJECTIVE: To test the hypothesis that intracranial arterial calcification (IAC) is associated with intracranial large artery stenosis (ILAS) and a higher risk of vascular events and mortality. METHOD: We leveraged data from two cohorts, the New York-Presbyterian Hospital/Columbia University Irving Medical Center Stroke Registry Study (NYP/CUIMC-SRS) and the Northern Manhattan Study (NOMAS) to test our hypotheses. We measured IAC using CT scans of participants in both cohorts and expressed IAC as present (vs not) and in tertiles. For the CUIMC-SRS, demographic, clinical and ILAS status was collected retrospectively. In NOMAS, we used research brain MRI and MRA to define asymptomatic ILAS and covert brain infarcts(CBI). We built models adjusted for demographics and vascular risk factors for cross-sectional and longitudinal analyses. RESULTS: Cross-sectionally, IAC was associated with ILAS in both cohorts (OR 1.78, 95% CI: 1.16-2.73 for ILAS-related stroke in the NYP/CUIMC-SRS and OR 3.07, 95%CI 1.13-8.35 for ILAS-related covert brain infarcts in NOMAS). In a meta-analysis of both cohorts, IAC in the upper (HR 1.25, 95%CI 1.01-1.55) and middle tertile (HR 1.27, 95%CI 1.01-1.59) was associated with higher mortality compared with participants with no IAC. There were no longitudinal associations between IAC and risk of stroke or other vascular events. CONCLUSION: In these multiethnic populations, IAC is associated with symptomatic and asymptomatic ILAS as well as higher mortality. IAC may be a useful marker of higher mortality, the role of IAC as an imaging marker of risk of stroke is less certain.


Subject(s)
Noma , Stroke , Humans , Cross-Sectional Studies , Retrospective Studies , Stroke/diagnostic imaging , Stroke/etiology , Arteries , Constriction, Pathologic
20.
Article in English | MEDLINE | ID: mdl-36862579

ABSTRACT

Cells from strain GE09T, isolated from an artificially immersed nanofibrous cellulose plate in the deep sea, were Gram-stain-negative, motile, aerobic cells that could grow with cellulose as their only nutrient. Strain GE09T was placed among members of Cellvibrionaceae, in the Gammaproteobacteria, with Marinagarivorans algicola Z1T, a marine degrader of agar, as the closest relative (97.4 % similarity). The average nucleotide identity and digital DNA-DNA hybridization values between GE09T and M. algicola Z1T were 72.5 and 21.2 %, respectively. Strain GE09T degraded cellulose, xylan and pectin, but not starch, chitin and agar. The different carbohydrate-active enzymes encoded in the genomes of strain GE09T and M. algicola Z1T highlights their differences in terms of target energy sources and reflects their isolation environments. The major cellular fatty acids of strain GE09T were C18 : 1 ω7c, C16 : 0 and C16 : 1 ω7c. The polar lipid profile showed phosphatidylglycerol and phosphatidylethanolamine. The major respiratory quinone was Q-8. Based on these distinct taxonomic characteristics, strain GE09T represents a new species in the genus Marinagarivorans, for which we propose the name Marinagarivorans cellulosilyticus sp. nov. (type strain GE09T=DSM 113420T=JCM 35003T).


Subject(s)
Gammaproteobacteria , Noma , Humans , Japan , Agar , Fatty Acids/chemistry , Phylogeny , Sequence Analysis, DNA , RNA, Ribosomal, 16S/genetics , DNA, Bacterial/genetics , Bacterial Typing Techniques , Base Composition , Bacteria , Cellulose
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