613,558 results on '"Arnold A"'
Search Results
2. A novel naturally superoleophilic coconut oil-based foam with inherent hydrophobic properties for oil and grease sorption
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Tomas Ralph B. Tomon, Christine Joy M. Omisol, Blessy Joy M. Aguinid, Karyl Xyrra L. Sabulbero, Arnold C. Alguno, Roberto M. Malaluan, and Arnold A. Lubguban
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Medicine ,Science - Abstract
Abstract Absorption methods using polyurethane foams (PUFs) have recently gained popularity in treating oil spills. However, conventional petroleum-based PUFs lack selectivity and are commonly surface-modified using complicated processes that require toxic and harmful solvents to enhance their hydrophobicity and oil sorption capacities. In this paper, a novel naturally superoleophilic foam with inherent hydrophobic properties has been developed through the conventional one-shot foaming method with the integration of coconut oil-based polyol. This bio-based polyol was explicitly handpicked as it is chiefly saturated, highly abundant, and inexpensive. The foam is characterized by an oil sorption capacity range of 14.89–24.65 g g−1 for different types of oil, equivalent to 578–871 times its weight. Its hydrophobic behavior is expressed through a water contact angle of ~ 139°. The foam also showcased excellent chemical stability and high recyclability without a significant loss in absorption capacity after 20 cycles. The incorporation of the coconut oil-based polyol is also shown to improve the morphological, mechanical, and thermal behavior of the foam. It can be inferred from these findings that this novel material holds great potential for revolutionizing sorbents, pioneering a more sustainable and eco-friendly functional material produced via a facile method.
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- 2024
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3. Facile Synthesis of Band Gap-Tunable Kappa-Carrageenan-Mediated C,S-Doped TiO2 Nanoparticles for Enhanced Dye Degradation
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Daisy Jane D. Erjeno, Dan Michael A. Asequia, Carlo Kurt F. Osorio, Christine Joy M. Omisol, Andrei E. Etom, Renzo Miguel R. Hisona, Amierson C. Tilendo, Ann Pearl G. Triana, Gerard G. Dumancas, Joshua B. Zoleta, Arnold C. Alguno, Roberto M. Malaluan, and Arnold A. Lubguban
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Chemistry ,QD1-999 - Published
- 2024
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4. Dopamine-Functionalized Gold Nanoparticles for Colorimetric Detection of Histamine
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Romnick B. Unabia, Renzo Luis D. Reazo, Rolen Brian P. Rivera, Melbagrace A. Lapening, Jahor L. Omping, Ryan M. Lumod, Archie G. Ruda, Noel Lito B. Sayson, Gerard Dumancas, Roberto M. Malaluan, Arnold A. Lubguban, Gaudencio C. Petalcorin, Rey Y. Capangpangan, Felmer S. Latayada, and Arnold C. Alguno
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Chemistry ,QD1-999 - Published
- 2024
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5. Intellectual capital measurement in higher education institutions context from the professors perspective
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Yuranis Vargas-Atencio, Julio César Acosta-Prado, and Arnold Alejandro Tafur-Mendoza
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intellectual capital ,human capital ,structural capital ,relational capital ,measurement scale ,General Works - Abstract
Intellectual capital has aroused growing interest in higher education; however, one area for improvement in its study is how to measure it adequately. Therefore, it is necessary to have instruments based on current models of intellectual capital. This study aims to design and validate an intellectual capital measurement scale in accredited higher education institutions (HEIs) from the perspective of professors. The study was instrumental because a measurement scale was developed. The sample consisted of 341 professors from six accredited HEIs on the Colombian Caribbean Coast. The statistical analysis consisted of three stages: item analysis, collection of validity evidence based on the internal structure and the relationship with other variables, and reliability analysis using the internal consistency method. The scale’s internal structure corroborated intellectual capital composition based on human, structural, and relational components. Regarding convergent evidence, all variables possess this source of validity evidence. Reliability levels were also good. Previously, an instrument has yet to be developed those measures intellectual capital in HEIs from the perspective of professors. This study provides a scale that focuses on the characteristics of this stakeholder and is based on an innovative model of intellectual capital composed of human, structural, and relational capital. The theoretical contribution of the study lies in developing a test based on two current models of intellectual capital: the Intellectus model and the Balanced Scorecard model. It also contributes to practice by providing a tool for measuring intellectual capital that allows its adequate management, improvement, and decision-making within higher education.
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- 2024
- Full Text
- View/download PDF
6. Jane Ahlstrand (2022), 'Women, media, and power in Indonesia'
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Ani Widyani Soetjipto and Arnold A.E. Masinambow
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History of scholarship and learning. The humanities ,AZ20-999 - Published
- 2024
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7. Facile Synthesis of PEGylated Gold Nanoparticles for Enhanced Colorimetric Detection of Histamine
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Jahor Omping, Romnick Unabia, Renzo Luis Reazo, Melbagrace Lapening, Ryan Lumod, Archie Ruda, Rolen Brian Rivera, Noel Lito Sayson, Felmer Latayada, Rey Capangpangan, Gerard Dumancas, Roberto Malaluan, Arnold Lubguban, Gaudencio Petalcorin, and Arnold Alguno
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Chemistry ,QD1-999 - Published
- 2024
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8. Development of High-Performance Coconut Oil-Based Rigid Polyurethane-Urea Foam: A Novel Sequential Amidation and Prepolymerization Process
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Louell Nikki A. Hipulan, Roger G. Dingcong, Dave Joseph E. Estrada, Gerard G. Dumancas, John Christian S. Bondaug, Arnold C. Alguno, Hernando P. Bacosa, Roberto M. Malaluan, and Arnold A. Lubguban
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Chemistry ,QD1-999 - Published
- 2024
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9. Valorization of Agricultural Rice Straw as a Sustainable Feedstock for Rigid Polyurethane/Polyisocyanurate Foam Production
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Roger G. Dingcong, Mary Ann N. Ahalajal, Leanne Christie C. Mendija, Rosal Jane G. Ruda-Bayor, Felrose P. Maravillas, Applegen I. Cavero, Evalyn Joy C. Cea, Kaye Junelle M. Pantaleon, Kassandra Jayza Gift D. Tejas, Edison A. Limbaga, Gerard G. Dumancas, Roberto M. Malaluan, and Arnold A. Lubguban
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Chemistry ,QD1-999 - Published
- 2024
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10. Multiple Imputation for Robust Cluster Analysis to Address Missingness in Medical Data
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Arnold A. Harder, Gayla R. Olbricht, Godwin Ekuma, Daniel B. Hier, and Tayo Obafemi-Ajayi
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Multiple data imputation ,clustering ,ensemble learning ,canonical discriminant analysis ,mixture models ,traumatic brain injury ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Cluster analysis has been applied to a wide range of problems as an exploratory tool to enhance knowledge discovery. Clustering aids disease subtyping, i.e. identifying homogeneous patient subgroups, in medical data. Missing data is a common problem in medical research and could bias clustering results if not properly handled. Yet, multiple imputation has been under-utilized to address missingness, when clustering medical data. Its limited integration in clustering of medical data, despite the known advantages and benefits of multiple imputation, could be attributed to many factors. This includes methodological complexity, difficulties in pooling results to obtain a consensus clustering, uncertainty regarding quality metrics, and a lack of accepted pipelines. A few studies have examined the feasibility of implementing multiple imputation for cluster analysis on simulated/small datasets. While these studies have begun to address how to pool imputed values and quantify uncertainty in clustering due to imputation, a need remains for a complete framework that integrates MI in the clustering of complex medical data and sophisticated cluster algorithms. We propose a cluster analysis framework that mitigates bias and addresses these limitations. It includes methods to pool multiple imputed datasets, create a consensus cluster solution by ensemble methods, and select an optimal number of clusters based on validity indices. It also estimates uncertainty about cluster membership attributable to the imputation and identifies features that characterize the derived clusters. The utility of this framework is illustrated by its application to a traumatic brain injury dataset with missing data. Our analysis revealed six multifaceted clusters that differed with respect to Glasgow Coma Score (GCS), mechanism of injury, sociodemographics, vitals, lab values, and radiological presentation. The most severe cluster consisted of single, relatively young patients injured by motor accident, with higher GCS severity scores. Comparative analysis with the miclust R package, along with statistical validation of cluster characterization, demonstrates its robust performance.
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- 2024
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11. Evidence of Students’ Academic Performance at the Federal College of Education Asaba Nigeria: Mining Education Data
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Arnold Adimabua Ojugoa, Christopher Chukwufunaya Odiakaose, Frances Emordi, Rita Erhovwo Ako, Winifred Adigwe, Kizito Eluemonor Anazia, and Victor Geteloma
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Information resources (General) ,ZA3040-5185 ,Electronic computers. Computer science ,QA75.5-76.95 - Abstract
One main objective of higher education is to provide quality education to its students. One way to achieve the highest level of quality in the higher education system is by discovering knowledge for prediction regarding enrolment of students in a particular course, alienation of traditional classroom teaching model, detection of unfair means used in online examination, detection of abnormal values in the result sheets of the students, and prediction about students’ performance. The knowledge is hidden among the educational data set and is extractable through data mining techniques. The present paper is designed to justify the capabilities of data mining techniques in the context of higher education by offering a data mining model for the higher education system in the university. In this research, the classification task is used to evaluate student’s performance, and as many approaches are used for data classification, the decision tree method is used here. By this, we extract data that describes students’ summative performance at semester’s end, helps to identify the dropouts and students who need special attention, and allows the teacher to provide appropriate advising/counseling.
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- 2023
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12. Rice Yield Forecasting Using Hybrid Quantum Deep Learning Model
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De Rosal Ignatius Moses Setiadi, Ajib Susanto, Kristiawan Nugroho, Ahmad Rofiqul Muslikh, Arnold Adimabua Ojugo, and Hong-Seng Gan
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hybrid quantum deep learning ,rice production forecasting ,quantum feature processing ,quantum machine learning ,XGBoost regressor ,Electronic computers. Computer science ,QA75.5-76.95 - Abstract
In recent advancements in agricultural technology, quantum mechanics and deep learning integration have shown promising potential to revolutionize rice yield forecasting methods. This research introduces a novel Hybrid Quantum Deep Learning model that leverages the intricate processing capabilities of quantum computing combined with the robust pattern recognition prowess of deep learning algorithms such as Extreme Gradient Boosting (XGBoost) and Bidirectional Long Short-Term Memory (Bi-LSTM). Bi-LSTM networks are used for temporal feature extraction and quantum circuits for quantum feature processing. Quantum circuits leverage quantum superposition and entanglement to enhance data representation by capturing intricate feature interactions. These enriched quantum features are combined with the temporal features extracted by Bi-LSTM and fed into an XGBoost regressor. By synthesizing quantum feature processing and classical machine learning techniques, our model aims to improve prediction accuracy significantly. Based on measurements of mean square error (MSE), the coefficient of determination (R2), and mean average error (MAE), the results are 1.191621 × 10−5, 0.999929482, and 0.001392724, respectively. This value is so close to perfect that it helps make essential decisions in global agricultural planning and management.
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- 2024
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13. Clinical Utility of Mobocertinib in the Treatment of NSCLC – Patient Selection and Reported Outcomes
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Arnold A and Ganti AK
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mobocertinib ,exon 20 insertion of egfr ,nsclc ,tki ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Abram Arnold,1 Apar Kishor Ganti2 1Department of Medicine, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE, USA; 2Division of Oncology/Hematology, Department of Internal Medicine, Veterans Affairs Nebraska-Western Iowa Health Care System and University of Nebraska Medical Center, Omaha, NE, USACorrespondence: Apar Kishor Ganti, 986840 Nebraska Medical Center, Omaha, NE, 68198, USA, Tel +1 402 559-5622, Email aganti@unmc.eduAbstract: Mobocertinib is an oral tyrosine kinase inhibitor (TKI) that selectively targets epidermal growth factor receptor exon 20 insertion (EGFRex20ins) mutations. It is a structural analog of the third-generation TKI osimertinib, which targets EGFR T790M mutant non-small cell lung cancer (NSCLC); however, mobocertinib gains selectivity for EGFRex20ins mutants over wild type (WT) by interacting with the C790 gatekeeper residue of EGFR. This is accomplished via a carboxylated isopropyl ester moiety at the C5-position of mobocertinib’s central pyrimidine core. In Phase 1/2 dose-escalation and dose-expansion studies, mobocertinib was found to have an investigator-confirmed overall response rate (ORR) of 56% (9/16; 95% CI: 30– 80%) and 25% (3/12; 95% CI: 5– 57%) in patients without and with baseline brain metastasis, respectively. Median investigator-assessed progression-free survival (mPFS) was 10.2 months (95% CI: 5.6 – not reached) and 3.7 months (95% CI: 1.8– 15.9) in patients without and with baseline brain metastasis, respectively. A third phase evaluated patients who had received pre-treatment with platinum-based chemotherapy (PPP) and included an extension cohort (EXCLAIM cohort) which evaluated patients treated previously with 1 or 2 lines of therapy. An Independent Review Committee (IRC) found both cohorts to have similar outcomes in terms of ORR, median time to response, mPFS, and disease progression or death. The treatment-emergent adverse events (TEAE) related to mobocertinib are similar to other EGFR inhibitors and are predominately gastrointestinal (eg diarrhea, nausea, vomiting) and cutaneous (eg rash). In September 2021, the FDA granted accelerated approval for mobocertinib in the treatment of patients with locally advanced or metastatic NSCLC with EGFRex20ins mutation whose disease progressed while on platinum-based chemotherapy. The present review describes data that led to the approval of mobocertinib.Keywords: mobocertinib, exon 20 insertion of EGFR, NSCLC, TKI
- Published
- 2023
14. A New Source and Large Quantity of Resveratrol in Cratoxylum Species and Their Activities on Normal Human and Cancer Cells
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Sanit Kaewdaungdee, Tankun Banlue, Napatsakon Youngsanbhu, Mallika Naeklang, Shiou Yih Lee, Arnold Ang, Runglawan Sudmoon, Tawatchai Tanee, Sakda Daduang, and Arunrat Chaveerach
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Cratoxylum ,resveratrol ,α-amyrin ,CHL-1 ,HCT-116 ,HepG2 ,Biology (General) ,QH301-705.5 - Abstract
Cratoxylum formosum ssp. formosum (Cff), C. formosum ssp. pruniflorum (Cfp), and C. sumatranum (Cs) were investigated for phytochemical analysis. Toxicity testing, programmed cell death, and cell cycle arrest were tested on CHL-1, HCT-116, and HepG2 cancer cell lines, and human normal PBMCs. The results are revealed in the following order. The phytochemical percentages varied in each species, the quantity and concentration of α-amyrin and resveratrol were 0.038 mg/g and 0.955 mg/mL, and 0.064 mg/g and 0.640 mg/mL. The most studied Cratoxylum extracts showed IC50 values in PBMCs and cancer cell lines except for the hexane Cff and ethanol Cfp extracts. All studied extracts did not induce DNA breaks in PBMCs but caused significant DNA breaks in the cancer cell lines. All studied extracts induced both apoptosis and necrosis in cancer cell lines, and the DNA quantity in the S and G2-M phases decreased significantly but did not induce apoptosis and necrosis in PBMCs. Except for the ethanolic extracts of Cff and Cfp that induced PBMCs apoptosis and necrosis, these data confirmed that the three studied Cratoxylum samples have inhibiting properties for the growth of cancer cells and low toxicity to PBMCs. Cs showed more toxicity to cancer cell lines than Cf and cisplatin.
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- 2024
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15. The Effects of a Statewide Ban on School Suspensions. EdWorkingPaper No. 24-1004
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Annenberg Institute for School Reform at Brown University, Jane Arnold Lincove, Catherine Mata, and Kalena E. Cortes
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This research uses the implementation of a school suspension ban in Maryland to test whether a top-down state-initiated ban on suspensions in early primary grades can influence school behavior regarding school discipline. Beginning in the fall of 2017, the State of Maryland banned the use of out-of-school suspensions for grades PK-2, unless a student posed an "imminent threat" to staff or students. This research investigates (1) what was the effect of the ban on discipline outcomes for students in both treated grades and upper elementary grades not subject to the ban? (2) did schools bypass the ban by coding more events as threatening or increasing the use of in-school suspensions? and (3) were there differential effects for students in groups that are historically suspended more often? Using a comparative interrupted time series strategy, we find that the ban is associated with a substantial reduction in, but not a total elimination of, out-of-school suspensions for targeted grades without substitution of in-school suspensions. Disproportionalities by race and other characteristics remain after the ban. Grades not subject to the ban experienced few effects, suggesting the ban did not trigger a schoolwide response that reduced exclusionary discipline.
- Published
- 2024
16. Modeling anaerobic co-digestion of water hyacinth with ruminal slaughterhouse waste for first order, modified gompertz and logistic kinetic models
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Erick Auma Omondi, Peter Kuria Ndiba, Gloria Koech Chepkoech, and Arnold Aluda Kegode
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kinetics ,modified gompertz model ,logistic model ,first order kinetic model ,anaerobic digestion ,Renewable energy sources ,TJ807-830 - Abstract
Water hyacinth (Eichhornia crassipes), an invasive aquatic weed with large biomass production is of socio-economic and environmental concern in fresh water bodies such as the Lake Victoria in East Africa. Efforts towards its control and removal can be complemented by biogas production for use as energy source. The co-digestion of water hyacinth (WH) with ruminal slaughterhouse waste (RSW) has the potential to improve biogas production from WH through collation of processes parameters such as the C/N and C/P ratios, potassium concentration and buffering capacity. Knowledge of optimum proportion of the RSW as the minor substrate is of both process and operational importance. Moreover, efficient operation of the process requires an understanding of the relationship between the biogas production and the process parameters. Kinetic models can be useful tools for describing the biogas production process in batch reactors. While the first order kinetics models assume that the rate of biogas production is proportional to the concentration of the remaining substrates, other models such as the modified Gompertz and the Logistic models incorporate the lag phase, a key feature of the anaerobic digestion process. This study aimed to establish the optimum proportion of RSW in co-digestion with WH under mesophilic conditions, and apply kinetics models to describe the biogas production. The study conducted batch co-digestion of WH with 0, 10, 20 and 30% RSW proportions at mesophilic temperature of 32ºC. Co-digestion of WH with 30% RSW proportion improved biogas yield by 113% from 19.15 to 40.85 CH4 ml/(gVS) at 50 days of co-digestion. It also exhibited the most stable daily biogas production and the largest biogas yield. The biomethanation data were fitted with the first order kinetics, modified Gompertz and the Logistic models. Biogas production for co-digestion of WH with 30% RSW proportion was best described by the modified Gompertz model with a biogas yield potential, Mo, of 43.2 ml (gVS)-1d-1; maximum biogas production rate, Rm, of 1.50 ml (gVS)-1d-1; and duration of lag, λ, of 3.89 d.
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- 2023
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17. FACTORS PREDISPOSING TO INCREASED PREVALENCE OF ANTEPARTUM HAEMORRHAGE AMONG PREGNANT WOMEN ATTENDING ANTENATAL CARE AT KISENYI HEALTH CENTRE IV, KAMPALA DISTRICT. A CROSS-SECTIONAL STUDY.
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ARNOLD AKONJA and Vincent Kalungi
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Antepartum Hemorrhage ,Placenta Praevia ,Placenta Abruption ,Perinatal ,Post-Natal ,General works ,R5-130.5 ,Infectious and parasitic diseases ,RC109-216 ,Surgery ,RD1-811 ,Public aspects of medicine ,RA1-1270 - Abstract
Background: The purpose of the study was to assess the factors predisposing to the increased prevalence of antepartum hemorrhage among pregnant women attending antenatal care at Kisenyi Health Centre IV, Kampala district. The specific objectives were to find out the individual factors, community-related factors, and Health facility-related factors predisposing to increased prevalence of antepartum hemorrhage. Methodology: A cross-sectional study design with simple random sampling as the sampling technique. Data was collected on a sample size of 50 respondents using a semi-structured questionnaire written in the English language with open and closed-ended questions as the data collection tool, analysis was done manually by sheets, pens, and paper entered in an Excel computer program presented in tables and figures and then interpreted. Results: With regards to the individual factors, (60%) of the respondents had ever experienced anemia during pregnancy and the majority (60%) had ever used alcohol or smoked tobacco during pregnancy. Regarding the community-related factors, the majority (88%) of the respondents reported that Kisenyi HC IV was the nearest health center for ANC to them, the majority (74%) had ever been delivered by traditional birth attendants and finally, the majority (64%) had ever used local herbs during pregnancy. Regarding the Health facility-related factors, almost all (98%) of the respondents reported that the Facility was inadequately staffed, and the majority (72%) reported that the health facility was inadequately equipped to effectively manage pregnancy-related conditions like Antepartum hemorrhage. Conclusion. Despite the commendable measures put in place to manage Antepartum hemorrhage and related conditions, a lot still needs to be done especially with health facility practices and individual measures with regards to the topic. Recommendation. The Ministry of Health and the health facility should recruit more staff and procure more equipment for use, especially for the Maternity unit at the Health Centre.
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- 2023
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18. Producing polyglycerol polyester polyol for thermoplastic polyurethane application: A novel valorization of glycerol, a by-product of biodiesel production
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Mike Jhun P. Calderon, Gerard G. Dumancas, Carlo S. Gutierrez, Alona A. Lubguban, Arnold C. Alguno, Roberto M. Malaluan, and Arnold A. Lubguban
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Thermoplastic polyurethane ,Glycerol ,Polyglycerol ,Bio-based ,Coconut oil-based polyol ,Science (General) ,Q1-390 ,Social sciences (General) ,H1-99 - Abstract
The production of biodiesel generates glycerol as a by-product that needs valorization. Glycerol, when converted to polyglycerol, is a potential polyol for bio-based thermoplastic polyurethane (TPU) production. In this study, a novel polyglycerol polyester polyol (PPP) was developed from refined glycerol and coconut oil-based polyester polyol. Glycerol was first converted to glycerol acetate and then polymerized with coconut oil-based polyester polyol (CPP) as secondary polyol and phthalic anhydride. The resulting PPP polymerized at 220 °C and OH:COOH molar ratio of 2.5 exhibited an OH number of
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- 2023
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19. Retention and Predictors of Attrition Among People Living With HIV on Antiretroviral Therapy in Guinea: A 13-Year Historical Cohort Study in Nine Large-Volume Sites
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Niouma Nestor Leno, Foromo Guilavogui, Alioune Camara, Kadio Jean-Jacques Olivier Kadio, Timothé Guilavogui, Thierno Saidou Diallo, Mamadou Aliou Diallo, Daniel William Athanase Leno, Button Ricarte, Youssouf Koita, Laye Kaba, Arnold Ahiatsi, Nagnouman Touré, Pascal Traoré, Souleymane Chaloub, André Kamano, Carlos Arias Vicente, Alexandre Delamou, and Mohamed Cissé
- Subjects
predictors ,antiretroviral therapy ,HIV/AIDS ,retention ,attrition ,Public aspects of medicine ,RA1-1270 - Abstract
Objectives: The objective of this study was to estimate the retention rate of patients in an ART program and identify the predictors of attrition.Methods: This was a historical cohort study of HIV patients who started ART between September 2007 and April 2020, and were followed up on for at least 6 months in nine large-volume sites. Kaplan Meier techniques were used to estimate cumulative retention and attrition probabilities. Cox proportional hazards models were used to identify predictors of attrition.Results: The cumulative probability of retention at 12 and 24 months was 76.2% and 70.2%, respectively. The attrition rate after a median follow-up time of 3.1 years was 35.2%, or an incidence of 11.4 per 100 person-years. Having initiated ART between 2012 and 2015; unmarried status; having initiated ART with CD4 count
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- 2023
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20. Intellectual Capital Measurement in Higher Education Institutions Context from the Professors Perspective
- Author
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Yuranis Vargas-Atencio, Julio Cesar Acosta-Prado, and Arnold Alejandro Tafur-Mendoza
- Abstract
Intellectual capital has aroused growing interest in higher education; however, one area for improvement in its study is how to measure it adequately. Therefore, it is necessary to have instruments based on current models of intellectual capital. This study aims to design and validate an intellectual capital measurement scale in accredited higher education institutions (HEIs) from the perspective of professors. The study was instrumental because a measurement scale was developed. The sample consisted of 341 professors from six accredited HEIs on the Colombian Caribbean Coast. The statistical analysis consisted of three stages: item analysis, collection of validity evidence based on the internal structure and the relationship with other variables, and reliability analysis using the internal consistency method. The scale's internal structure corroborated intellectual capital composition based on human, structural, and relational components. Regarding convergent evidence, all variables possess this source of validity evidence. Reliability levels were also good. Previously, an instrument has yet to be developed those measures intellectual capital in HEIs from the perspective of professors. This study provides a scale that focuses on the characteristics of this stakeholder and is based on an innovative model of intellectual capital composed of human, structural, and relational capital. The theoretical contribution of the study lies in developing a test based on two current models of intellectual capital: the Intellectus model and the Balanced Scorecard model. It also contributes to practice by providing a tool for measuring intellectual capital that allows its adequate management, improvement, and decision-making within higher education.
- Published
- 2024
21. Direct and Indirect Exposure to Trauma, Posttraumatic Stress Disorder Symptoms, and Poor Subjective Sleep Quality in Patients with Substance Use Disorder
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Julia ten Holt, Arnold A.P. van Emmerik, Peter Blanken, Jesse E. Borgdorff, Pieter P.C. ten Holt, Rob M. Kok, Joanne Mouthaan, Bouwe Pieterse, and Julia F. Van den Berg
- Subjects
Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Published
- 2022
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22. Mehrfach befristet, doppelt rechtswidrig
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Simon Pschorr and Arnold Arpaci
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Arbeitsrecht, Wissenschaftszeitvertragsgesetz ,Law - Abstract
Die Ampelkoalition hat vereinbart, das Hochschulbefristungsrecht auf den Prüfstand zu stellen. Das Ziel: Planbarkeit und Verlässlichkeit wissenschaftlicher Karrierewege verbessern und frühzeitige Perspektiven für alternative Karrieren schaffen. Nachdem ein erster Vorschlag nach zahlreichen Protesten zurück genommen wurde, droht nun die Gefahr, dass das Reformvorhaben endgültig scheitert – und der Status quo erhalten bleibt. Das ist jedoch keine Option. Denn der status quo ist hinsichtlich der Befristung von PostDocs nicht nur europarechtswidrig, sondern wegen Verletzung der Arbeitsvertragsfreiheit auch verfassungswidrig.
- Published
- 2023
23. Production of Bio-Based Polyol from Coconut Fatty Acid Distillate (CFAD) and Crude Glycerol for Rigid Polyurethane Foam Applications
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Ma. Louella D. Salcedo, Christine Joy M. Omisol, Anthony O. Maputi, Dave Joseph E. Estrada, Blessy Joy M. Aguinid, Dan Michael A. Asequia, Daisy Jane D. Erjeno, Glenn Apostol, Henry Siy, Roberto M. Malaluan, Arnold C. Alguno, Gerard G. Dumancas, and Arnold A. Lubguban
- Subjects
coconut fatty acid distillate ,rigid polyurethane foam ,bio-based polyols ,high open-cell content foam ,thermal insulating material ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
This study propounds a sustainable alternative to petroleum-based polyurethane (PU) foams, aiming to curtail this nonrenewable resource’s continued and uncontrolled use. Coconut fatty acid distillate (CFAD) and crude glycerol (CG), both wastes generated from vegetable oil processes, were utilized for bio-based polyol production for rigid PU foam application. The raw materials were subjected to catalyzed glycerolysis with alkaline-alcohol neutralization and bleaching. The resulting polyol possessed properties suitable for rigid foam application, with an average OH number of 215 mg KOH/g, an acid number of 7.2983 mg KOH/g, and a Gardner color value of 18. The polyol was used to prepare rigid PU foam, and its properties were determined using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis/derivative thermogravimetric (TGA/DTA), and universal testing machine (UTM). Additionally, the cell foam morphology was investigated by scanning electron microscope (SEM), in which most of its structure revealed an open-celled network and quantified at 92.71% open-cell content using pycnometric testing. The PU foam thermal and mechanical analyses results showed an average compressive strength of 210.43 kPa, a thermal conductivity of 32.10 mW·m−1K−1, and a density of 44.65 kg·m−3. These properties showed its applicability as a type I structural sandwich panel core material, thus demonstrating the potential use of CFAD and CG in commercial polyol and PU foam production.
- Published
- 2023
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24. The burden of Chronic Pelvic Pain (CPP): Costs and quality of life of women and men with CPP treated in outpatient referral centers.
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David Hutton, Aida Mustafa, Soha Patil, Saira Rathod, Gautam Shrikhande, Arnold Advincula, Jessica Drummond, Peter Gregersen, Jason Hall, Christine Metz, Alexandra Milspaw, Iris Kerin Orbuch, Peter Stahl, Amy Stein, and Allyson Shrikhande
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Medicine ,Science - Abstract
IntroductionChronic Pelvic Pain (CPP) is a complex, multifaceted condition that affects both women and men. There is limited literature on the cost utilization the healthcare system and CPP patients incur. The purpose of this analysis is to characterize the overall healthcare utilization, cost burden, and quality-of-life restrictions experienced by CPP patients using data from an outpatient pelvic rehabilitation practice.MethodsHealthcare utilization data was gathered by systematically reviewing and analyzing data from new patient visit progress notes stored in the clinic's electronic health records (EHR). We obtained in-network costs by using the FAIR Health Consumer online database. Overall costs were then calculated as the utilization times the per-unit costs from the FAIR database. Additionally, data on patients' visual analogue scale (VAS), absenteeism, presenteeism emergency room visits, usage of common pain medications, use of diagnostics, and participation in common treatment modalities was gathered.ResultsData from 607 patients was used. The overall cost burden per patient for all surgeries combined was $15,750 for in-network services. The cost burden for diagnostics was $5,264.22 and treatments was $8,937 per patient for in-network treatments.ConclusionChronic Pelvic Pain was found to have a large cost burden of $29,951 for in-network services which includes treatments, diagnostics, and surgeries. This analysis sets the stage for future investigations involving data on costs of medications that patients have tried prior to presenting to us and costs associated with work hours lost.
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- 2023
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25. Index
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Arnold Arluke and Andrew Rowan
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26. Bibliography
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Arnold Arluke and Andrew Rowan
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- 2020
27. Plates
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Arnold Arluke and Andrew Rowan
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28. 7 Forms of Veterinary Capital The Unintended Consequences of Increased Access
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Arnold Arluke and Andrew Rowan
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- 2020
29. Notes
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Arnold Arluke and Andrew Rowan
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30. Conclusion Increasing Access to Veterinary Care Problems, Partnerships, and Paradoxes
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Arnold Arluke and Andrew Rowan
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31. 5 The Costs of Care Nonfinancial Barriers to Using Free or Low-cost Veterinary Services
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Arnold Arluke and Andrew Rowan
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- 2020
32. 4 Underdogs and Their People Living With Pets in Racially Concentrated Poverty
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Arnold Arluke and Andrew Rowan
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- 2020
33. 6 Perfect Is the Enemy of Good Thinking Differently About Low-income Pet Owners
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Arnold Arluke and Andrew Rowan
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- 2020
34. 3 Sterilization as an Agent of Social Change Changing How Communities Think About Pets
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Arnold Arluke and Andrew Rowan
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- 2020
35. 2 Who Speaks for the Underserved? Cooperation and Conflict Among Welfare and Veterinary Groups
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Arnold Arluke and Andrew Rowan
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- 2020
36. Half Title, Title, Copyright
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Arnold Arluke and Andrew Rowan
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- 2020
37. 1 Liminal Pets and Their People Living With Street Animals in Traditional Costa Rican Culture
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Arnold Arluke and Andrew Rowan
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- 2020
38. Cover
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Arnold Arluke and Andrew Rowan
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39. Acknowledgements
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Arnold Arluke and Andrew Rowan
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- 2020
40. Introduction. Pets, Poverty, and the Problem of Access to Veterinary Care
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Arnold Arluke and Andrew Rowan
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- 2020
41. Ellipsoid Spectacle Comparison of Plusoptix, Retinomax and 2WIN Autorefractors
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Arnold RW, Martin SJ, Beveridge JR, Arnold AW, Arnold SL, Beveridge NR, and Smith KA
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spectacles ,remote dispensing ,autorefractors ,validation ,Ophthalmology ,RE1-994 - Abstract
Robert W Arnold,1 Samuel J Martin,2 Joshua R Beveridge,3 Andrew W Arnold,4 Stephanie L Arnold,4 Nathanael R Beveridge,5 Kyle A Smith1,6 1Alaska Blind Child Discovery, Alaska Children’s EYE & Strabismus, Anchorage, AK, 99508, USA; 2Loma Linda Medical School, Loma Linda, CA, USA; 3Idaho College of Osteopathic Medicine, Boise, ID, USA; 4Ascension Genesys Residency Program, Grand Blanc, MI, USA; 5US Airforce Academy, Colorado Springs, CO, USA; 6Accurate Vision, Anchorage, AK, USACorrespondence: Robert W ArnoldAlaska Children’s EYE & Strabismus, 3500 Latouche Street #280, Anchorage, AK, 99508, USATel +1(907)561-1917Fax +1 9075635373Email eyedoc@alaska.netBackground: Handheld devices can automatically give an estimate of refraction. The established method for refraction comparison using spherical equivalent (M) and J0, J45 vector transformations by Bland–Altman analysis is too complex for non-eye doctors involved with vision screening and remote vision clinics. Therefore, a simpler comparison technique was developed.Methods: Based on the spectacle limit to resolve grade A 1 logMAR, B 3 logMAR and C 6 logMAR blur, J0, J45, and M are combined into the Alaska Blind Child Discovery (ABCD) composite ellipsoid GRADE system. Pediatric eye patients had confirmatory examination after dry refraction with three portable autorefractors: Plusoptix, 2WIN and Retinomax. The refractions were then compared using both Bland–Altman and ABCD composite. Performance to detect AAPOS amblyopia risk factors was also assessed.Results: A total of 202 children, mean age seven years, 28% high spectacle need and 43% AAPOS 2013 amblyopia risk factors showed high correlation with cycloplegic refraction (intraclass correlation 0.49 to 0.90) for sphere, J0 and J45 spectacle components. Plusoptix had more (10%) inconclusives due to patients out-of-range. The Retinomax was unable to screen some younger children and was less reliable for sphere but gave more precise astigmatism estimates. The proportion of autorefractions expected to give GRADE A/B high-need patients acuity improvement to 20/40 would be 41% for Plusoptix, 39% for 2WIN and 65% for Retinomax. Sensitivity/specificity for amblyopia risk factor detection was 80%/83% for Plusoptix, 72%/88% for 2WIN and 84%/73% for Retinomax.Conclusion: The simplified spectacle comparison resembled Bland–Altman and could assist lay vision screeners and non-eye doctors attempting remote spectacle donation worldwide.Keywords: spectacles, remote dispensing, autorefractors, validation
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- 2021
42. Bilateral Breast Ochronosis: a Case Report
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Fatema A.J. AbdulKarim, Safwat M. Ibrahim, Arnold AD Hill, and Nadeem Ajmal
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Ochronosis ,Alkaptonuria ,Homogentisic acid ,Breast ochronosis ,Mastectomy ,Surgery ,RD1-811 - Abstract
ABSTRACT: Ochronosis is a syndrome characterized by bluish black discoloration due to the deposition of polymerized products of homogentisic acid (HGA) in the connective tissues. The endogenous variety (alkaptonuria), is a rare autosomal recessive metabolic disorder. The disorder is manifested by deficiency of the enzyme homogentisate 1,2-dioxygenase. The characteristic of the condition is a triad of pigmentation of skin, cartilage, and sclera; ochronotic arthropathies and homogentisic aciduria (resulting in darkening of urine). More rarely, it may affect the breast. This rare and interesting case of a woman with ochronosis of both breasts and chest wall, prompted us to write this case report.
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- 2021
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43. Home-Based Respiratory Physiotherapy and Telephone-Based Psychological Support for COVID-19 Survivors in Peru: Protocol for a Randomized Controlled Trial
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Anderson N Soriano-Moreno, Elaine C Flores, Stella M Hartinger, Claudia Y Mallma, Arnold A Diaz, Gonzalo E Gianella, Juan A Galvez-Buccollini, Abdiel H Coico-Lama, German Malaga, Eufemia Fajardo, Rubí Paredes-Angeles, Sharlyn Otazú-Alfaro, Andres G Lescano, and William Checkley
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Medicine ,Computer applications to medicine. Medical informatics ,R858-859.7 - Abstract
BackgroundBoth pulmonary and mental health are affected following hospitalization for COVID-19 pneumonia. Pulmonary rehabilitation therapy has demonstrated benefits in improving mental health, but no validated combined programs that include mental health have been proposed. ObjectiveThis article presents the design of a trial that aimed to assess whether the participation in a combined rehabilitation program that includes home-based respiratory physiotherapy and telephone-based psychological support is associated with a greater improvement of pulmonary and mental health outcomes 7-12 weeks after COVID-19 hospitalization discharge compared with posthospital usual care provided by a public Peruvian hospital. MethodsWAYRA (the word for air in the Quechua language) was an open-label, unblinded, two-arm randomized controlled trial. We recruited 108 participants aged 18-75 years who were discharged from the hospital after COVID-19 pneumonia that required >6 liters/minute of supplemental oxygen during treatment. Participants were randomly assigned at a 1:1 ratio to receive the combined rehabilitation program or usual posthospital care provided by a public Peruvian hospital. The intervention consisted of 12 at-home respiratory rehabilitation sessions and 6 telephone-based psychological sessions. The primary outcome was the 6-minute walk distance. Secondary outcomes included lung function, mental health status (depression, anxiety, and trauma), and quality of life. Outcomes were assessed at baseline (before randomization) and at 7 and 12 weeks after hospital discharge to assess the difference between arms. ResultsThis study was funded by the Peruvian National Council of Science Technology and Technology Innovation in July 2020. Ethics approval was obtained on September 2, 2020. Recruitment and data collection occurred between October 2020 and June 2021. Results are expected to be published by the end of 2022. ConclusionsWAYRA was the first randomized controlled trial evaluating combined pulmonary-mental health rehabilitation for hospitalized COVID-19 survivors in resource-limited settings, potentially providing a foundation for the cost-effective scale-up of similar multidisciplinary rehabilitation programs. Trial RegistrationClinicalTrials.gov NCT04649736; https://clinicaltrials.gov/ct2/show/NCT04649736 International Registered Report Identifier (IRRID)RR1-10.2196/36001
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- 2022
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44. Trichromatic Enhanced Dynamic Color Screening on the PDI Check Nintendo 3DS Game
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Arnold A, Smith K, Molina A, Damarjian A, Desatoff T, and Arnold R
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color blindness ,deuteranomaly ,proteranomaly ,farnsworth-munsell ,rabin color cone test ,dynamic ,vision screening ,Ophthalmology ,RE1-994 - Abstract
Andrew Arnold,1 Kyle Smith,2 Aaron Molina,2 Alex Damarjian,2 Tarah Desatoff,3 Robert Arnold4 1Pacific Northwest University College of Osteopathic Medicine, Yakima, WA, USA; 2PDI CHECK, Anchorage, AK, USA; 3Optometry Department, South Central Foundation, Wasilla, AK, USA; 4Alaska Blind Child Discovery, Alaska Children’s EYE & Strabismus, Anchorage, AK, USACorrespondence: Robert ArnoldAlaska Children’s EYE & Strabismus, 3500 Latouche #280, Anchorage, AK, 99508, USATel +1 907561-1917Fax +1 907563-5373Email eyedoc@alaska.netIntroduction: Classification of color deficiency has required substantial time and expense with the static Farnsworth-Munsell and Innova Rabin tests. Therefore, dynamic color tests were developed for the Nintendo 3DS.Methods: Fifteen color deficient patients and 17 age-matched normals performed Rabin color test in addition to PDI Check dynamic color games resembling Farnsworth-Munsell presentation (version 0.2.8) and 3-color iso-luminance gray (version 0.2.13).Results: Tests of red, green and blue cone-deficient with the v0.2.8 had sensitivity/specificity/PPV of 92%/86%/92% protanopes, 78%/90%/88% deutanopes and 87%/50%/93% tritanopes. Version 0.2.13 had sens/spec/PPV of 78%/83%/78% red-cone, 100%/85%/80% green cone and 67%/78%/33% blue cone. Corresponding IntraClass Correlation (ICC) utilizing v0.2.8 were red-cone 0.22 (− 0.02– 0.60), green-cone 0.34 (− 0.10– 0.67) and blue-cone 0.38 (0.12– 0.75). ICC for v0.2.13 was higher with protanope 0.62 (− 0.07– 0.87), deuteranope 0.64 (− 0.09– 0.88) and tritanope 0.31 (− 0.07– 0.70). The PDI Check color game took 65 seconds compared to 197 seconds for Innova Rabin.Conclusion: The PDI Check color game quickly identifies patients with inherited color deficiencies.Keywords: color blindness, deuteranomaly, protanomaly, Farnsworth-Munsell, Rabin color cone test, dynamic, vision screening
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- 2021
45. Psychometric properties of the Revised Children’s Manifest Anxiety Scale–Second Edition in Peruvian students
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Alicia Boluarte Carbajal, Frank Antony Grillo Delgado, Karla Alejandra Castellanos-Huerta, and Arnold Alejandro Tafur-Mendoza
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rcmas-2 ,anxiety ,psychometric properties ,factorial invariance ,peruvian students ,Psychology ,BF1-990 - Abstract
The aim of this study was to analyze the psychometric properties of the Revised Children’s Manifest Anxiety Scale–Second Edition (RCMAS-2) among Peruvian students. The sample consisted of 472 participants aged between 7 and 18 years, of whom 250 were female (53%). Likewise, 191 were enrolled from third to sixth grade of primary school (40.5%), and 281 were registered from first to fifth grade of secondary school (59.5%). The results of the study indicated that the RCMAS-2 scores had adequate levels of reliability for all its dimensions (ordinal alpha > .70). On the other hand, a four-factor structure (Physiological anxiety, Worry/Social anxiety, Defensiveness I, and Defensiveness II) was found to be invariant to gender and schooling level. Also, convergent and discriminant validity evidence was provided. Finally, a moderate difference in Defensiveness II according to the schooling level through the latent mean structure analysis was found. Taking into ac-count the results, it was concluded that the RCMAS-2 scores have evidence of reliability, validity, and equity for its use in Peruvian regular elementary school students.
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- 2021
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46. Recon-all-clinical: Cortical surface reconstruction and analysis of heterogeneous clinical brain MRI
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Gopinath, Karthik, Greve, Douglas N., Magdamo, Colin, Arnold, Steve, Das, Sudeshna, Puonti, Oula, and Iglesias, Juan Eugenio
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Electrical Engineering and Systems Science - Image and Video Processing ,Computer Science - Computer Vision and Pattern Recognition - Abstract
Surface-based analysis of the cerebral cortex is ubiquitous in human neuroimaging with MRI. It is crucial for cortical registration, parcellation, and thickness estimation. Traditionally, these analyses require high-resolution, isotropic scans with good gray-white matter contrast, typically a 1mm T1-weighted scan. This excludes most clinical MRI scans, which are often anisotropic and lack the necessary T1 contrast. To enable large-scale neuroimaging studies using vast clinical data, we introduce recon-all-clinical, a novel method for cortical reconstruction, registration, parcellation, and thickness estimation in brain MRI scans of any resolution and contrast. Our approach employs a hybrid analysis method that combines a convolutional neural network (CNN) trained with domain randomization to predict signed distance functions (SDFs) and classical geometry processing for accurate surface placement while maintaining topological and geometric constraints. The method does not require retraining for different acquisitions, thus simplifying the analysis of heterogeneous clinical datasets. We tested recon-all-clinical on multiple datasets, including over 19,000 clinical scans. The method consistently produced precise cortical reconstructions and high parcellation accuracy across varied MRI contrasts and resolutions. Cortical thickness estimates are precise enough to capture aging effects independently of MRI contrast, although accuracy varies with slice thickness. Our method is publicly available at https://surfer.nmr.mgh.harvard.edu/fswiki/recon-all-clinical, enabling researchers to perform detailed cortical analysis on the huge amounts of already existing clinical MRI scans. This advancement may be particularly valuable for studying rare diseases and underrepresented populations where research-grade MRI data is scarce., Comment: 16 pages in the manuscript with 11 page supplementary material
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- 2024
47. The Influence of Faulty Labels in Data Sets on Human Pose Estimation
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Schwarz, Arnold, Hernadi, Levente, Bießmann, Felix, and Hildebrand, Kristian
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Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Machine Learning - Abstract
In this study we provide empirical evidence demonstrating that the quality of training data impacts model performance in Human Pose Estimation (HPE). Inaccurate labels in widely used data sets, ranging from minor errors to severe mislabeling, can negatively influence learning and distort performance metrics. We perform an in-depth analysis of popular HPE data sets to show the extent and nature of label inaccuracies. Our findings suggest that accounting for the impact of faulty labels will facilitate the development of more robust and accurate HPE models for a variety of real-world applications. We show improved performance with cleansed data., Comment: 15 pages, 7 figures, 5 tables
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- 2024
48. TOI-3568 b: a super-Neptune in the sub-Jovian desert
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Martioli, E., Petrucci, R. P., Jofre, E., Hebrard, G., Ghezzi, L., Chew, Y. Gomez Maqueo, Diaz, R. F., Perottoni, H. D., Garcia, L. H., Rapetti, D., Etangs, A. Lecavelier des, de Almeida, L., Arnold, L., Artigau, E., Basant, R., Bean, J. L., Bieryla, A., Boisse, I., Bonfils, X., Brady, M., Cadieux, C., Carmona, A., Cook, N. J., Delfosse, X., Donati, J. -F., Doyon, R., Furlan, E., Howell, S. B., Jenkins, J. M., Kasper, D., Kiefer, F., Latham, D. W., Levine, A. M., Lorenzo-Oliveira, D., Luque, R., McLeod, K., Melendez, J., Moutou, C., Netto, Y., Pritchard, T. A., Rowden, P., Seifahrt, A., Stefansson, G., Sturmer, J., and Twicken, D. J
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Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
The sub-Jovian desert is a region in the mass-period and radius-period parameter space, typically encompassing short-period ranges between super-Earths and hot Jupiters, that exhibits an intrinsic dearth of planets. This scarcity is likely shaped by photoevaporation caused by the stellar irradiation received by giant planets that have migrated inward. We report the detection and characterization of TOI-3568 b, a transiting super-Neptune with a mass of $26.4\pm1.0$ M$_\oplus$, a radius of $5.30\pm0.27$ R$_\oplus$, a bulk density of $0.98\pm0.15$ g cm$^{-3}$, and an orbital period of 4.417965(5) d situated in the vicinity of the sub-Jovian desert. This planet orbiting a K dwarf star with solar metallicity, was identified photometrically by TESS. It was characterized as a planet by our high-precision radial velocity monitoring program using MAROON-X at Gemini North, supplemented by additional observations from the SPICE large program with SPIRou at CFHT. We performed a Bayesian MCMC joint analysis of the TESS and ground-based photometry, MAROON-X and SPIRou radial velocities, to measure the orbit, radius, and mass of the planet, as well as a detailed analysis of the high-resolution flux and polarimetric spectra to determine the physical parameters and elemental abundances of the host star. Our results reveal TOI-3568 b as a hot super-Neptune, rich in hydrogen and helium with a core of heavier elements with a mass between 10 and 25 M$_\oplus$. We analyzed the photoevaporation status of TOI-3568 b and found that it experiences one of the highest EUV luminosities among planets with a mass M$_{\rm p}$ $<2$ M$_{\rm Nep}$, yet it has an evaporation lifetime exceeding 5 Gyr. Positioned in the transition between two significant populations of exoplanets on the mass-period and energy diagrams, this planet presents an opportunity to test theories concerning the origin of the sub-Jovian desert., Comment: Accepted for publication in A&A on September 4, 2024
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- 2024
49. Benchmarking the integration of hexagonal boron nitride crystals and thin films into graphene-based van der Waals heterostructures
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Ouaj, Taoufiq, Arnold, Christophe, Azpeitia, Jon, Baltic, Sunaja, Barjon, Julien, Cascales, Jose, Cun, Huanyao, Esteban, David, Garcia-Hernandez, Mar, Garnier, Vincent, Gautam, Subodh K., Greber, Thomas, Hassani, Said Said, Hemmi, Adrian, Jimenéz, Ignacio, Journet, Catherine, Kögerler, Paul, Loiseau, Annick, Maestre, Camille, Metzelaars, Marvin, Schmidt, Philipp, Stampfer, Christoph, Stenger, Ingrid, Steyer, Philippe, Taniguchi, Takashi, Toury, Bérangère, Watanabe, Kenji, and Beschoten, Bernd
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Condensed Matter - Materials Science ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
We present a benchmarking protocol that combines the characterization of boron nitride (BN) crystals and films with the evaluation of the electronic properties of graphene on these substrates. Our study includes hBN crystals grown under different conditions and scalable BN films deposited by either chemical or physical vapor deposition (CVD or PVD). We explore the complete process from boron nitride growth, over its optical characterization by time-resolved cathodoluminescence (TRCL), to the optical and electronic characterization of graphene by Raman spectroscopy after encapsulation and Hall bar processing. Within our benchmarking protocol we achieve a homogeneous electronic performance within each Hall bar device through a fast and reproducible processing routine. We find that a free exciton lifetime of 1 ns measured on as-grown hBN crystals by TRCL is sufficient to achieve high graphene room temperature charge carrier mobilities of 80,000 cm$^2$/(Vs) at a carrier density of |n| = 10$^{12}$ cm$^{-2}$, while respective exciton lifetimes around 100 ps yield mobilities up to 30,000 cm$^2$/(Vs). For scalable PVD-grown BN films, we measure carrier mobilities exceeding 10,000 cm$^2$/(Vs) which correlates with a graphene Raman 2D peak linewidth of 22 cm$^{-1}$. Our work highlights the importance of the Raman 2D linewidth of graphene as a critical metric that effectively assesses the interface quality (i.e. surface roughness) to the BN substrate, which directly affects the charge carrier mobility of graphene. Graphene 2D linewidth analysis is suitable for all BN substrates and is particularly advantageous when TRCL or BN Raman spectroscopy cannot be applied to specific BN materials such as amorphous or thin films. This underlines the superior role of spatially-resolved spectroscopy in the evaluation of BN crystals and films for the use of high-mobility graphene devices., Comment: 18 pages, 11 figures
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- 2024
50. Compact, folded multi-pass cells for energy scaling of post-compression
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Schönberg, Arthur, Rajhans, Supriya, Escoto, Esmerando, Khodakovskiy, Nikita, Hariton, Victor, Farace, Bonaventura, Põder, Kristjan, Raab, Ann-Kathrin, Westerberg, Saga, Merdanov, Mekan, Viotti, Anne-Lise, Arnold, Cord L., Leemans, Wim P., Hartl, Ingmar, and Heyl, Christoph M.
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Physics - Optics - Abstract
Combining high peak and high average power has long been a key challenge of ultrafast laser technology, crucial for applications such as laser-plasma acceleration and strong-field physics. A promising solution lies in post-compressed ytterbium lasers, but scaling these to high pulse energies presents a major bottleneck. Post-compression techniques, particularly Herriott-type multi-pass cells (MPCs), have enabled large peak power boosts at high average powers but their pulse energy acceptance reaches practical limits defined by setup size and coating damage threshold. In this work, we address this challenge and demonstrate a novel type of compact, energy-scalable MPC (CMPC). By employing a novel MPC configuration and folding the beam path, the CMPC introduces a new degree of freedom for downsizing the setup length, enabling compact setups even for large pulse energies. We experimentally and numerically verify the CMPC approach, demonstrating post-compression of 8 mJ pulses from 1 ps down to 51 fs in atmospheric air using a cell roughly 45 cm in length at low fluence values. Additionally, we discuss the potential for energy scaling up to 200 mJ with a setup size reaching 2.5 m. Our work presents a new approach to high-energy post-compression, with up-scaling potential far beyond the demonstrated parameters. This opens new routes for achieving the high peak and average powers necessary for demanding applications of ultrafast lasers., Comment: 18 pages, 13 figures
- Published
- 2024
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