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Planar matrices and arrays of Feynman diagrams

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Communications in Theoretical Physics 2024年第3期76卷 15-32页

作者： freddy Cachazo Alfredo Guevara Bruno Umbert Yong Zhang Perimeter Institute for Theoretical Physics WaterlooON N2L 2Y5Canada Department of Physics and Astronomy University of WaterlooWaterlooON N2L 3G1Canada CECs Valdivia y Departamento de Física Universidad de ConcepciónCasilla 160-CConcepciónChile Center for the Fundamental Laws of Nature Society of Fellows and Black Hole InitiativeHarvard UniversityCambridgeMA 02138United States of America Department of Applied Mathematics Western UniversityLondonON N6A 5B7Canada CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesNo.19A Yuquan RoadBeijing 100049China

Recently,planar collections of Feynman diagrams were proposed by Borges and one of the authors as the natural generalization of Feynman diagrams for the computation of k=3 biadjoint amplitudes.Planar collections are one-dimensional arrays of metric trees satisfying an induced planarity and compatibility condition.In this work,we introduce planar matrices of Feynman diagrams as the objects that compute k=4 biadjoint amplitudes.These are symmetric matrices of metric trees satisfying compatibility conditions.We introduce two notions of combinatorial bootstrap techniques for finding collections from Feynman diagrams and matrices from collections.As applications of the first,we find all 693,13612 and 346710 collections for(k,n)=(3,7),(3,8)and(3,9),respectively.As applications of the second kind,we find all90608 and 30659424 planar matrices that compute(k,n)=(4,8)and(4,9)biadjoint amplitudes,respectively.As an example of the evaluation of matrices of Feynman diagrams,we present the complete form of the(4,8)and(4,9)biadjoint amplitudes.We also start a study of higher-dimensional arrays of Feynman diagrams,including the combinatorial version of the duality between(k,n)and(n-k,n)objects.

关键词： Feynman diagrams biadjoint amplitudes tropical Grassmannian

Cutaneous leishmaniasis control in Alta Verapaz (northern Guatemala): evaluating current efforts through stakeholders' experiences

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Infectious Diseases of Poverty 2021年第3期10卷 14-25页

作者： Renata Mendizabal-Cabrera Isabel perez Victor Becerril Montekio freddy perez Erick Duran Mei L.Trueba Center for Health Studies(CHS) Universidad del Valle de Guatemala(UVG)18 Avenida 11-95zona 15V.H.3Guatemala CityGuatemala Instituto Nacional de Salud Publica(INSP) CuernavacaMexico Communicable Diseases and Environmental Determinants of Health Department Pan American Health OrganizationWashingtonDCUSA. Leishmaniasis Sub-Program National Ministry of Health of GuatemalaGuatemala CityGuatemala Department of Global Health and Infection(GHI) Brighton and Sussex Medical School(BSMS)University of SussexBrightonUK.

Background:Cutaneous leishmaniasis(CL),endemic in Guatemala,mostly affects poor people living in the northern region.A national control program that ineludes surveillanee,diagnose,and treatment offered free of cost by the Ministry of Health(MoH)has been in place since 2003.However,the incidence is increasing and treatment rates are not optimal,suggesting that current efforts are not being effective.This study aimed to understand barriers and facilitators of CL control in Guatemala as experienced and perceived by key stakeholders in order to comprehend what works well and does not and suggest evidence-informed interventions.Methods:The study was conducted in the Coban municipality,the most endemic of Guatemala,situated in the Department of Alta Verapaz.Data were collected during May and June 2019 via focus groups and semi-structured interviews with key stakeholders,including local and national health personnel and residents of four communities of the endemic region.Thematic and content analysis of the collected data was conducted using NVIVO.Results:Three overarching issues hamper the effectiveness of current CL efforts:resource scarcity,treatment challenges,and knowledge-action gaps.Scarce economic resources from the MoH and community residents negatively impact incidence,detection of cases and treatment rates in that preventive action is insufficient and healthcare access is low.In addition,local health workers often lack specialized CL training and access to the national CL control guidelines.With regards to the population living in the study area,misunderstanding of disease causation,shame associated with CL lesions,treatment pain fear,and long(often uncertain)waiting times for diagnose and treatment negatively affect people's willingness to seek help,treatment adherence,and their trust on the healthcare provided.Conclusions:Culturally sensitive CL preventive action must be developed.Given the scarce economic resources available for CL control in the country,the involvement of trained community health workers

关键词： Cutaneous leishmaniasis Control effort Qualitative evaluation Stakeholders'experiences Alta Verapaz Guatemala

Characterisation of Human-Wildlife Conflicts around the Kahuzi-Biega National Park, Eastern Democratic Republic of Congo

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Journal of Environmental Protection 2024年第3期15卷 343-356页

作者： Basubi Muke Matthieu Vwima Stany Ayagirwe Basengere Rodrigue Mushagalusa freddy Benjamin-Fink Nicole Bobo Kadiri Serge Faculty of Agricultural and Environmental Sciences Evangelical University in Africa Bukavu Congo Wildlife and Protected Areas Laboratory Forestry and Wood Technology Department of Forestry University of Dschang Dschang Cameroon Faculty of Economics and Management Sciences Evangelical University in Africa Bukavu Congo Conservation beyond Borders Organization Minnetonka USA

The history of mankind contains so many illustrations of well-classified and violent struggles against various animals over crop production in agricultural fields, attacks on human life or competition in order to have access to certain natural resources. The aim of this study is to characterise the human-wildlife conflicts that occur around the KBNP, especially with regard to primates. Surveys were carried out in 260 households selected using the snowball method. The results showed that human-wildlife conflicts around the KBNP are characterised by the destruction of crops in riparian fields by monkeys, chimpanzees and gorillas, the destruction of houses, physical attacks and zoonoses. Despite the conservation and protection measures for wildlife and local populations put in place by the Park’s managers, conflicts between local populations and the Park’s wild animals are still visible. These conflicts lead to the detention of wild animals by local people roaming in the villages and to poaching on the Park’s boundaries. The weakness of the community management policy on the part of the park managers and the resentment of the indigenous peoples towards the restriction of their access to natural resources are the major constraints on the sustainable management of conflicts between the local populations and the wild animals in the KBNP. The strategies for the sustainable resolution of human-wildlife conflicts around the KBNP must be geared towards and integrated into a community conservation approach.

关键词： Community Conservation Human-Wildlife Conflict Kahuzi-Biega National Park

Profile of Multidrug Resistant Bacteria in Bukavu Hospitals and Antimicrobial Susceptibility to Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis and Staphylococcus aureus

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Advances in Microbiology 2024年第4期14卷 209-225页

作者： Christian Ahadi Irenge freddy Bikioli Patient Birindwa Mulashe Félicien Mushagalusa Kasali Patient Wimba Aksanti Lwango Yves Coppieters Justin Ntokamunda Kadima Department of Pharmacy and Public Health Official University of Bukavu Bukavu Democratic Republic of the Congo Department of Tropical Medecine Faculty of Medecine University of Kinshasa Kinshasa Democratic Republic of the Congo Department of Microbiology Faculty of Medicine Official University of Bukavu Bukavu Democratic Republic of the Congo Department of Medical Biology Higher Institute of Medical Technics Bukavu Democratic Republic of the Congo School of Public Health Free University of Bruxelles Bruxelles Belgium School of Medicine College of Medicine and Health Sciences University of Rwanda Huye Rwanda

Objective: To evaluate the spread of Multidrug-Resistant (MDR) bacterial infections in Bukavu hospitals and test antimicrobial susceptibility patterns of some isolates to usual marketed antibiotics. Methods: The prevalence of MDR strains was determined by using general antimicrobial susceptibility data collected from 3 hospital laboratories. The susceptibility of some isolates to usual antibiotics was processed by agar diffusion method with standard E. coli ATCC8739 and standard antibiotics discs as controls. The tested antibiotics were ampicillin, ceftriaxone, gentamicin, chloramphenicol and ciprofloxacin. Results: At the 3 hospitals, 758 tests were realized in urine, pus, stool, FCV, blood, LCR, split and FU specimens;46 strains were unidentified and 712 strains were identified. Of 712 identified strains, 223 (31.4%) were MDR or XDR strains including Escherichia coli, Klebsiella pneumoniae, Enterobacter, Proteus mirabilis, Salmonella enterica, Pseudomonas aeruginosa, Citrobacter freundii, Morganella morganii, Enterococcus faecalis and E. faecium, Neisseria gonorrohoae, Staphylococcus aureus, coagulase-negative, staphylococci, Streptococcus pneumoniae and Streptococcus pyogenes. Of the infected patients, 36 (21.5%) children were under 16 years and 188 (78.5%) adults were predominately women (58.5%). The susceptibility test showed that all strains but S. aureus were resistant to ampicillin and amoxicillin and ciprofloxacin. Gentamicin, ceftriaxone, and chloramphenicol remain partially active (27% - 80%) against P. mirabilis, E. coli and P. aeruginosa. The resistance is more likely related to strain mutation than to pharmaceutical quality of the antibiotics prescribed. Conclusion: Both data from hospital laboratories and in vitro post-testing findings confirmed the ongoing elevated prevalence of MDR strains in Bukavu. The causes of antibiotic misuse and socio-economic determinants of the phenomenon of resistance should be scrutinized in order to take adequate strategies in the prospective of establishing an effect

关键词： Prevalence Antimicrobials Multi-Resistance Bacterial Sensitivity Bukavu DRC

Rationale of a Cross Sectional Analytic Study on Determinants of Recurrent Preeclampsia at University Clinics of Kinshasa (Democratic Republic of Congo) and at Victor Dupouy Hospital Center (France)

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Open Journal of Obstetrics and Gynecology 2024年第5期14卷 824-831页

作者： Mushengezi Amani Dieudonné Sengeyi Muela Andy Mbangama Mokambanda Cynthia Awena Goy Sambwa Christian Kelele Nkongolo freddy Muamba Banza Jésual Lotoy Otem Christian Ndesanzim Department of Obstetrics and Gynecology University Clinics of Kinshasa Kinshasa Democratic Republic of Congo

Research Background: Pre-eclampsia is one of main causes of materno-foetal mortality and morbidity worldwide, with a prevalence of 3% - 7%. Although considered a primiparous condition, it can nevertheless recur. Several factors appear to be associated with risk of recurrence of pre-eclampsia, such as the term of delivery of previous pregnancy, severity of disease, the existence of co-morbidities and the inter-genital space. Purpose: The aim of our study will be to analyse and identify in a population of pregnant women with a history of preeclampsia risk factors associated with occurrence of recurrent preeclampsia at University clinics of Kinshasa (Democratic Republic of Congo) and at Victor Dupouy Hospital Center (France). Methods: In this study, pregnant women with an history of preeclampsia who will give birth between November 2018 and October 2024 at University Clinics of Kinshasa (UCK) and Victor Dupouy Hospital Center (VDHC) will be included. This will be a cross-sectional analytical study, data from previous and subsequent pregnancies will be studied. Expected Result: The prevalence of recurrent preeclampsia in the study population will be determined. And we will highlight the factors that will determine the recurrence of preeclampsia by analysing the risk factors. Conclusion: Knowledge of the factors associated with recurrent preeclampsia could be an excellent tool for predicting and preventing the disease.

关键词： Recurrent Pre-Eclampsia Risk Factor Determinants

Morbidity and Mortality during Anaesthesia in Patients with versus without Diabetes: Single-Centre Cohort Study

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Open Journal of Anesthesiology 2024年第3期14卷 93-107页

作者： Noelly Mukuna Wilfrid Mbombo Joseph Nsiala Aliocha Nkodila Alphonse Mosolo freddy Mbuyi Jonathan Kukila Paul Kambala Rémy Kashala Chris Nsitwavibidila Patrick Kobo Dan Kankonde Gracias Likinda Jean Claude Mubenga Khazi Anga Lionel Diyamona Berthe Barhayiga Department of Anaesthesia and Intensive Care Kinshasa University Clinics University of Kinshasa Kinshasa DRC Department of Anaesthesia and Intensive Care Monkole Hospital Kinshasa DRC Protestant University of Congo Kinshasa DRC Laboratory Department Monkole Hospital Kinshasa DRC Department of Clinical Biology Kinshasa University Clinics University of Kinshasa Kinshasa DRC Surgical Department Monkole Hospital Kinshasa DRC Department of Internal Medicine Monkole Hospital Kinshasa DRC

Background and objective: Classically, diabetic subjects are at high risk of anaesthesia compared with general population. However, some recent publications have shown contrasting and sometimes contrary results. The aim of our study was to evaluate morbidity and mortality during and after anaesthesia in patients with versus without diabetes operated on at Monkole Hospital over the last ten years. Methods: Retrospective cohort study including all patients who underwent all-comers surgery excluding cardiac surgery between 2011 and 2021. Each diabetic patient was matched to 2 non-diabetic controls on age and sex. The evaluation criterion was the frequency of occurrence of at least one perioperative complication and/or death up to day 30. A multivariate analysis using a Cox model was used to determine the factors associated with the occurrence of this morbidity and mortality. The model was adjusted for comorbidities, preoperative hyperglycaemia, ASA score, type of anaesthesia and severity of surgery. Results: A total of 351 diabetic patients (mean age 53.3 ± 14.18 years) and 701 non-diabetic patients (mean age 53.52 ± 14.7 years) were included and analysed. Preoperatively, hyperglycaemia (blood glucose > 180 mg/dl) was observed in 24.3% of diabetic patients compared with 1.6% of non-diabetic patients. The incidence of overall perioperative complications was 25.6% in diabetic patients compared with 28.6% in non-diabetic patients (p = 0.27). The risk factors associated with this morbidity were general anaesthesia with oro-tracheal intubation vs loco-regional anaesthesia (OR = 3.06 [95%CI: 1.91 - 4.94];p Conclusion: This study shows that there is not significant increase in perioperative morbidity and mortality in diabetic patients compared with non-diabetic ones of similar severity. These results suggest that diabetes itself (excluding associated comorbidities) has only a minor impact on perioperative morbidity and mortality.

关键词： Anaesthesia Diabetes Morbidity Mortality Perioperative

A Clinical Study to Assess the Effectiveness of Oral Combination Kit Therapy in Syndromic Management of Abnormal Vaginal Discharge (FEMINE Study) in Kinshasa, Democratic Republic of Congo

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Open Journal of Obstetrics and Gynecology 2024年第1期14卷 193-208页

作者： Feruzi Michel Mangala Muela Andy Mbangama Di-Mosi-Nkoy Roger Wumba Ambis Joëlle Lumaya Nkongolo freddy Muamba Tshitadi Jean Mukendi Ndombasi Neilda Lemba Otem Christian Ndesanzim Nkashama Bienvenu Kazadi Banza Jesual Lotoy Umba Adrien Tandu Mushengezi Dieudonné Sengeyi Mwimba Roger Mbungu Department of Gynecology and Obstetrics University Clinics of Kinshasa Kinshasa DR Congo Congolese Society of Gynecology and Obstetrics Kinshasa DR Congo Department of Gynecology and Obstetrics Kinshasa Provincial General Reference Hospital Kinshasa DR Congo Departement of Tropical Medicine University Clinics of Kinshasa Kinshasa DR Congo

Background: Vaginal discharge is one of most common and nagging problems that women face. About 20% - 25% of women who visit gynecology department complain of vaginal discharge and leucorrhoea. An orally administered combination kit, containing 2 g secnidazole, 1 g azithromycin and 150 mg fluconazole (Azimyn FS Kit), has been successfully evaluated in clinical trials and used in several countries for management syndromic vaginal discharge due to infections. Methods: This is a longitudinal study which aimed to verify the clinical efficacy of the combined oral kit containing secnidazole, azithromycin and fluconazole (Azimyn FS Kit®) in the syndromic treatment of abnormal vaginal discharge in patients received in outpatient consultations in Kinshasa/DR Congo from March to September 2023. Results: Majority of patients had whitish vaginal discharge (51.6%) of average abundance (56.2%), accompanied by pruritus in 72.1% of cases, and dyspareunia in 23.5% of cases and hypogastralgia in 40.2% of cases. One week after treatment with the Azimyn FS® combined kit, at the greatest majority of patients (97.3%), abnormal vaginal discharge had decreased by more than 50% (84.1%). Two weeks after treatment with the Azimyn FS® combined kit, almost all patients (97.3%) no longer had abnormal vaginal discharge which had completely disappeared. Conclusion: A single dose of secnidazole, azithromycin and fluconazole in the form of an oral combi-kit (Azimyn FS Kit) has shown excellent therapeutic effectiveness in the syndromic treatment of abnormal vaginal discharge wherein patients were treated without diagnostic confirmation.

关键词： Oral Combination Kit Therapy Syndromic Management Abnormal Vaginal Discharge

Multiplex Rapid Test with Acceptable Diagnosis Performance as a Solution to Increase Diagnosis of Hepatitis B and C Viruses in Pregnant Women in an Area of High Prevalence of Both Hepatitis Viruses Associated with HIV

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Open Journal of Medical Microbiology 2024年第1期14卷 50-65页

作者： Catherine Boni-Cisse Nina Esther Onstira Ngoyi Hermione Dahlia Mossoro-Kpinde Noella Packo Rabi Senekian Hermann Ndoidet Koutou Coretha Bokia-Baguida Christelle Luce Bobossi-Gadia Arthur Simplice Sombot-Ndicky Daniel Yvon Gonessa freddy Samuel Ngbonga Konzapa Voulou Christian Diamant Mossoro-Kpinde Alassane OUATTARA National Center of Medical Oncology and Radiotherapy Abidjan Ivory Cost Department of Microbiology UFR of Medical Sciences University of Cocody Abidjan Ivory Cost Laboratory of Bacteriology-Virology of Teaching Hospital Center of Brazzaville Brazzaville Republic of Congo Faculty of Health Sciences Marien NGOUABI University Brazzaville Republic of Congo Department of Labor Medicine Service of HIV and STDs Control in the Workplace Bangui Central African Republic (CAR) Faculty of Health Sciences University of Bangui Bangui Central African Republic National Reference Center of Sexually Transmitted Diseases and Antiretroviral Therapy Bangui Central African Republic National Laboratory of Clinical Biology and Public Health Bangui Central African Republic Medicine Department District Hospital of Alindao Alindao Ouaka Prefecture Central African Republic Doctoral School of Sciences and Technology University of Bangui Bangui Central African Republic Coordination of Specialized Study of Clinical Biology University of Bangui Bangui Central African Republic Doctors without Borders Hospital Sica BanguiCRA Laboratory of Medical Analysis of Teaching Hospital Center Mother Elisabeth DOMITIEN of Bimbo Bimbo Central African Republic

Background and Objective: HIV, hepatitis B virus (HBV) and hepatitis C virus (HCV) are very widespread in the world, however, less than 20% of the people affected are diagnosed and treated. This study aimed to determine the prevalence of HIV, HCV and HBV co-infections in pregnant women at Bangui Community University Hospital and the cost of screening. Methods: A cross-sectional study involving consenting pregnant women who came for antenatal care was performed. HIV, HCV antibodies and HBV antigens were detected using Exacto Triplex? HIV/HCV/HBsAg rapid test, cross-validated by ELISA tests. Sociodemographic and professional data, the modes of transmission and prevention of HIV and both hepatitis viruses were collected in a standard sheet and analyzed using the Epi-Info software version 7. Results: Pregnant women aged 15 to 24 were the most affected (45.3%);high school girls (46.0%), and pregnant women living in cohabitation (65.3%) were the most represented. Twenty-five (16.7%) worked in the formal sector, 12.7% were unemployed housewives and the remainder in the informal sector. The prevalence of HIV, HBV, and HCV viruses was 11.8%, 21.9% and 22.2%, respectively. The prevalence of co-infections was 8.6% for HIV-HBV, 10.2% for HIV-HCV, 14.7% for HBV-HCV and 6.5% for HIV-HBV-HCV. All positive results and 10% of negative results by the rapid test were confirmed by ELISA tests. The serology of the three viruses costs 39,000 FCFA (60 Euros) by ELISA compared to 10,000 FCFA (15.00 Euros) with Exacto Triplex? HIV/HCV/AgHBs (BioSynex, Strasbourg, France). Conclusion: The low level of education and awareness of hepatitis are barriers to development and indicate the importance of improving the literacy rate of women in the Central African Republic (CAR). Likewise, the high prevalence of the three viruses shows the need for the urgent establishment of a national program to combat viral hepatitis in the CAR.

关键词： HIV-HCV-HBV Co-Infection Multiplex Immunochromatographic Rapid Test Central Africa Serology Test Cost Diagnostic Accessibility

CLT Fabricated with Gmelina arborea and Tectona grandis Wood from Fast-Growth Forest Plantations: Physical and Mechanical Properties

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Journal of Renewable Materials 2022年第1期10卷 1-17页

作者： freddy Munoz Carolina Tenorio Roger Moya Angel Navarro-Mora Escuela de Ingenieria Forestal Instituto Tecnologico de Costa RicaCartago159-7050Costa Rica Escuela de Ingenieria en Construccion Instituto Tecnologico de Costa RicaCartago159-7050Costa Rica

Fabrication and use of Cross Laminated Timber(CLT)using tropical woods is still limited at present.Therefore objective of the present study aims to determine the possibility of using CLT panels of 3 and 5 layers,fabricated withTectona grandis and Gmelina arborea wood using adhesive of isocyanate polymer emulsion system catalyzed with polymeric isocyanate.Delamination,water absorption,density,flexure test,compression and glue-line shear were evaluated using ANSI/APA PRG320-2012 ASTM D198 and ASTM D4761 standard.The results showed that CLT panels of T.grandis presented higher values of density,less water absorption and lower delamination,with no evident differences between the CLT of 3 and 5 layers.The high density of T.grandis resulted in higher values of the mechanical properties.The flatwise and edgewise flexure tests in 5-layer CLT panels of both species pre-sented higher values of bending stiffness compared to those of 3-layer CLT panels.Further the bending stress values in 3-layer CLT panels were higher than for 5-layer CLT panels.As for shear stress in bending flatwise,in both species,3-layer CLT surpassed 5-layer CLT panels,but in the edgewise test no differences were observed.The MOE and Fc in the compression test were superior in relation to the edgewise test.MOE and Fc in compres-sion flatwise in 3-layer CLT was greater than in 5-layer CLT in both species,but edgewise these values were higher in 5-layer CLT panels.The most common failures were stress and delamination in the flexure test,whereas in the compression test these were:shearing,splitting and crushing.In the glue-line shear test no differences were observed between CLT panels of 3 and 5 layers for both species.

关键词： Structural elements sustainable material building material tropical wood wood of plantation