Comparative foliar anatomy of three Khaya species(Meliaceae) used in Nigeria as antisickling agent

Khaya belongs to the family Meliaceae. In Nigeria the genus is represented by three species viz; K. senegalensis A. Juss.,K. grandifoliola C. DC. and K. ivorensis A. Chev. Comparative foliar anatomy of the three Khaya species was carried out to identify and describe distinctive anatomical characters that could possibly be used to delimit the three taxa. Transverse section, epidermal peels and cleared leaves of these three species were made. Characteristic similarity and disparity in the tissues arrangement as well as cell inclusions were noted for description and delimitation. The three Khaya species studied had essentially the same anatomical features, e.g., venation pattern having open polygonal areoles and the veins terminals biforkated. However, there were characters that seem to be species specific, e.g., vien termination number and areole width. The leaf epidermal studies of the three species revealed similarities in stomatal type which are generally staurocytic,epidermal cells and undulating anticlinal cell walls but stomata density varied. Hexacytic stomata is only observed in the abaxial surface of K. grandifoliola which distinguished this species from the others. The leaf petiole shape of the three species are round and difficult to distinguish into adaxial and abaxial surfaces. The cuticle is striated, vascular bundles are heart shape, conjoint, concentric and amphivasal, but are different in epidermal and collenchyma cell layer numbers. The leaf transverse sections of the three Khaya species studied have conjoint, concentric and amphicribral bundles while the leaf cuticle of K. senegalensis and K. grandifoliola are striated but that of Khaya ivorensis is non-striated.

Descriptive and Comparative Histology of the Urinary System of the Hematophagous Bats Desmodus rotundus and Diphylla ecaudata

Desmodus rotundus and Diphylla ecaudata, both of which are mammals of the order Chiroptera, Desmodontidae family, their diet consisting exclusively of blood. D. rotundus is the main vector and transmitter of the rabies virus, which affects human beings as well as several livestock species so the study of this bat species is of high importance within the fields of animal agriculture and public health. The present study describes and compares the histologic characteristics of the urinary system of two hematophagous bat species. A total of 5 bats from each species were captured in the municipalities of Progreso de Obregón, Hidalgo (D. rotundus), and Huayacocotla, Veracruz (D. ecaudata). Organs belonging to the urinary system were extracted: kidneys, ureters, urinary bladder, and urethra;samples were fixed using 10% formalin and processed by the paraffin embedding technique, obtaining sections of 5 µm thickness, which in turn were stained using hematoxylin-eosin (H-E) and Gomori trichrome (GT) stains. From the obtained histologic preparations, a descriptive and comparative analysis of the structural organography of the urinary system of both species was made, and no noteworthy histological differences between samples were noted. The present research is intended to provide a framework for future studies of these species’ currently understudied microscopic anatomy.

Comparative transcriptome analysis between rhesus macaques(Macaca mulatta) and crab-eating macaques(M. fascicularis)

Understanding gene expression variations between species is pivotal for deciphering the evolutionary diversity in phenotypes. Rhesus macaques(Macaca mulatta, MMU)and crab-eating macaques(M. fascicularis, MFA) serve as crucial nonhuman primate biomedical models with different phenotypes. To date, however, large-scale comparative transcriptome research between these two species has not yet been fully explored. Here, we conducted systematic comparisons utilizing newly sequenced RNA-seq data from84 samples(41 MFA samples and 43 MMU samples)encompassing 14 common tissues. Our findings revealed a small fraction of genes(3.7%) with differential expression between the two species, as well as 36.5% of genes with tissue-specific expression in both macaques. Comparison of gene expression between macaques and humans indicated that 22.6% of orthologous genes displayed differential expression in at least two tissues. Moreover,19.41% of genes that overlapped with macaque-specific structural variants showed differential expression between humans and macaques. Of these, the FAM220A gene exhibited elevated expression in humans compared to macaques due to lineage-specific duplication. In summary,this study presents a large-scale transcriptomic comparison between MMU and MFA and between macaques and humans. The discovery of gene expression variations not only enhances the biomedical utility of macaque models but also contributes to the wider field of primate genomics.

Rice-wheat comparative genomics:Gains and gaps

Rice and wheat provide nearly 40%of human calorie and protein requirements.They share a common ancestor and belong to the Poaceae(grass)family.Characterizing their genetic homology is crucial for developing new cultivars with enhanced traits.Several wheat genes and gene families have been characterized based on their rice orthologs.Rice–wheat orthology can identify genetic regions that regulate similar traits in both crops.Rice–wheat comparative genomics can identify candidate wheat genes in a genomic region identified by association or QTL mapping,deduce their putative functions and biochemical pathways,and develop molecular markers for marker-assisted breeding.A knowledge of gene homology facilitates the transfer between crops of genes or genomic regions associated with desirable traits by genetic engineering,gene editing,or wide crossing.

Comparative and Phylogenetic Analysis of the Complete Chloroplast Genomes of 19 Species in Rosaceae Family

Rosaceae represents a vast and complex group of species,with its classification being intricate and contentious.The taxonomic placement of many species within this family has been a subject of ongoing debate.The study utilized the Illumina platform to sequence 19 plant species from 10 genera in the Rosaceae.The cp genomes,vary-ing in size from 153,366 to 159,895 bp,followed the typical quadripartite organization consisting of a large single-copy(LSC)region(84,545 to 87,883 bp),a small single-copy(SSC)region(18,174 to 19,259 bp),and a pair of inverted repeat(IR)regions(25,310 to 26,396 bp).These genomes contained 132–138 annotated genes,including 87 to 93 protein-coding genes(PCGs),37 tRNA genes,and 8 rRNA genes using MISA software,52 to 121 simple sequence repeat(SSR)loci were identified.D.arbuscular contained the least of SSRs and did not have hexanotides,A.lineata contained the richest SSRs.Long terminal repeats(LTRs)were primarily composed of palindromic and forward repeat sequences,meanwhile,The richest LTRs were found in Argentina lineata.Except for Argentina lineata,Fragariastrum eriocarpum,and Prunus trichostoma,which varied in gene type and position on both sides of the boundary,the remaining species were found to be mostly conserved according to IR boundary analysis.The examination of the Ka/Ks ratio revealed that only the infA gene had a value greater than 1,indicating that this gene was primarily subjected to positive selection during evolution.Additionally,9 hotspots of variation were identified in the LSC and SSC regions.Phylogenetic analysis confirmed the scientific validity of the genus Prunus L.sensu lato(s.l.)within the Rosaceae family.The separation of the three genera Argentina Hill,Fragariastrum Heist.ex Fabr.and Dasiphora Raf.from Potentilla L.may be a more scientific classification.These results offer fresh perspectives on the taxonomy of the Rosaceae.

Wood anatomy chronologies of Scots pine in the foothills of the Western Sayan(Siberia)

Recent methodological advances in quantitative wood anatomy have provided new insights into the climatic responses of radial growth at the scale of cell structure of tree rings. This study considered long-term chronologies of tracheid measurements, indexed by a novel approach to separate their specific climatic responses from signal recorded in cell production(closely reflected in tree-ring width). To fill gaps in understanding the impact of climate on conifer xylem structure, Scots pine(Pinus sylvestris L.)trees > 200 years old were selected within the forest-steppe zone in southern Siberia. Such habitats undergo mild moisture deficits and the resulting climatic regulation of growth processes. Mean and maximum values of cell radial diameter and cell wall thickness were recorded for each tree ring.Despite a low level of climatogenic stress, components of cell chronologies independent of cambial activity were separated to obtain significant climatic signals revealing the timing of the specific stages of tracheid differentiation. Cell expansion lasted from mid-April to July and was impacted similarly to tree-ring width(stimulated by precipitation and stressed by heat), maximum cell size formed late June. A switch in the climatic responses of mean anatomical traits indicated transition to latewood in mid-July. Secondary wall deposition lasted until mid-September, suppressed by end of season temperatures. Generally, anatomical climatic responses were modulated by a less dry May and September compared with summer months.

Opinions of Students on the Contribution of the DIVA 3D Virtual Dissection Table to the Teaching of Anatomy at the Faculty of Medicine and Odontostomatology of Bamako

Objective: Study the contribution of the DIVA 3D dissection table in the teaching of anatomy at the Faculty of Medicine and Odontology of Bamako. Material and Methods: This was a qualitative study carried out from November 1 to December 30, 2023 at the clinical and morphological anatomy laboratory of the Faculty of Medicine and Odontostomatology of Bamako. Included in this study were students who participated in practical and tutorial sessions. The variables studied during this study were: the previous performance of dissection on a cadaver by the students, the opinion of the students on dissection on a cadaver, the replacement of dissection on a cadaver by virtual dissection in the absence of a body, the level student satisfaction. Results: We surveyed 130 participants. The average age was 22 ± 0.2 years with extremes of 17 and 29 years. 95.3% of participants were students. According to 66.7% of participants, virtual dissection is a good palliative in the absence of a corpse. 95.3% of participants found using the virtual dissection table easy with an average of 7.88 ± 1.4. The overall assessment was well rated by 99.3% of participants. Conclusion: According to the results of this study, the virtual dissection table should be improved by integrating commented videos. The use of the DIVA 3D virtual dissection table during practical and tutorial sessions is well appreciated by the students. We believe that the teaching of anatomy using 3D digital technology should be included in the study programs of the Faculty of Medicine and Odontostomatology.

The relationship between compartment models and their stochastic counterparts:A comparative study with examples of the COVID-19 epidemic modeling

Deterministic compartment models(CMs)and stochastic models,including stochastic CMs and agent-based models,are widely utilized in epidemic modeling.However,the relationship between CMs and their corresponding stochastic models is not well understood.The present study aimed to address this gap by conducting a comparative study using the susceptible,exposed,infectious,and recovered(SEIR)model and its extended CMs from the coronavirus disease 2019 modeling literature.We demonstrated the equivalence of the numerical solution of CMs using the Euler scheme and their stochastic counterparts through theoretical analysis and simulations.Based on this equivalence,we proposed an efficient model calibration method that could replicate the exact solution of CMs in the corresponding stochastic models through parameter adjustment.The advancement in calibration techniques enhanced the accuracy of stochastic modeling in capturing the dynamics of epidemics.However,it should be noted that discrete-time stochastic models cannot perfectly reproduce the exact solution of continuous-time CMs.Additionally,we proposed a new stochastic compartment and agent mixed model as an alternative to agent-based models for large-scale population simulations with a limited number of agents.This model offered a balance between computational efficiency and accuracy.The results of this research contributed to the comparison and unification of deterministic CMs and stochastic models in epidemic modeling.Furthermore,the results had implications for the development of hybrid models that integrated the strengths of both frameworks.Overall,the present study has provided valuable epidemic modeling techniques and their practical applications for understanding and controlling the spread of infectious diseases.

Comparative efficacy of proximal femoral nail vs dynamic condylar screw in treating unstable intertrochanteric fractures

BACKGROUND Among the most frequent hip fractures are trochanteric fractures,which usually occur from low-energy trauma like minor falls,especially in older people with osteoporotic bones.AIM To evaluate the treatment efficacy of dynamic condylar screws(DCS)and proximal femoral nails(PFN)for unstable intertrochanteric fractures.METHODS To find pertinent randomized controlled trials and retrospective observational studies comparing PFN with DCS for the management of unstable femoral intertrochanteric fractures,a thorough search was carried out.For research studies published between January 1996 and April 2024,PubMed,EMBASE,Scopus,Web of Science,Cochrane Library,and Google Scholar were all searched.The complete texts of the papers were retrieved,vetted,and independently examined by two investigators.Disputes were settled by consensus,and any disagreements that persisted were arbitrated by a third author.RESULTS This study included six articles,comprising a total of 173 patients.Compared to the DCS,the PFN had a shorter operation time[mean difference(MD):-41.7 min,95%confidence interval(95%CI):-63.04 to-20.35,P=0.0001],higher success rates with closed reduction techniques[risk ratio(RR):34.05,95%CI:11.12-104.31,P<0.00001],and required less intraoperative blood transfusion(MD:-1.4 units,95%CI:-1.80 to-1.00,P<0.00001).Additionally,the PFN showed shorter fracture union time(MD:-6.92 wk,95%CI:-10.27 to-3.57,P<0.0001)and a lower incidence of reoperation(RR:0.37,95%CI:0.17-0.82,P=0.01).However,there was no discernible variation regarding hospital stay,implant-related complications,and infections.CONCLUSION Compared to DCS,PFN offers shorter operative times,reduces the blood transfusions requirements,achieves higher closed reduction success,enables faster fracture healing,and lowers reoperation incidence.

A Comparative Study on Factors Influencing Food Security in China and India

This paper analyzes and compares the key factors influencing food security in two populous countries(China and India),and cate-gorizes them into three types:agricultural production,economic development and income level,and income distribution.Using the prevalence of undernourishment as an indicator of food security,the paper empirically tests the degree of impact of various factors on food security in both countries using Tobit regression and Newey regression methods.The study finds that improving the level of economic development can significantly enhance food security in both countriesꎻreducing the Gini coefficient has a significant impact on India,but not on Chinaꎻincreasing the agricultural production per capita has a much greater effect on China than on India.Therefore,both countries should take measures that are both similar and different according to their national conditions to improve their food security level.

Comparative Study of the Reliability and Complexity of Symmetrical and Asymmetrical Cryptosystems for the Protection of Academic Data in the Democratic Republic of Congo

In the digital age, the data exchanged within a company is a wealth of knowledge. The survival, growth and influence of a company in the short, medium and long term depend on it. Indeed, it is the lifeblood of any modern company. A companys operational and historical data contains strategic and operational knowledge of ever-increasing added value. The emergence of a new paradigm: big data. Today, the value of the data scattered throughout this mother of knowledge is calculated in billions of dollars, depending on its size, scope and area of intervention. With the rise of computer networks and distributed systems, the threats to these sensitive resources have steadily increased, jeopardizing the existence of the company itself by drying up production and losing the interest of customers and suppliers. These threats range from sabotage to bankruptcy. For several decades now, most companies have been using encryption algorithms to protect and secure their information systems against the threats and dangers posed by the inherent vulnerabilities of their infrastructure and the current economic climate. This vulnerability requires companies to make the right choice of algorithms to implement in their management systems. For this reason, the present work aims to carry out a comparative study of the reliability and effectiveness of symmetrical and asymmetrical cryptosystems, in order to identify one or more suitable for securing academic data in the DRC. The analysis of the robustness of commonly used symmetric and asymmetric cryptosystems will be the subject of simulations in this article.

Integrated Machine Learning and Deep Learning Models for Cardiovascular Disease Risk Prediction: A Comprehensive Comparative Study

Cardiovascular Diseases (CVDs) pose a significant global health challenge, necessitating accurate risk prediction for effective preventive measures. This comprehensive comparative study explores the performance of traditional Machine Learning (ML) and Deep Learning (DL) models in predicting CVD risk, utilizing a meticulously curated dataset derived from health records. Rigorous preprocessing, including normalization and outlier removal, enhances model robustness. Diverse ML models (Logistic Regression, Random Forest, Support Vector Machine, K-Nearest Neighbor, Decision Tree, and Gradient Boosting) are compared with a Long Short-Term Memory (LSTM) neural network for DL. Evaluation metrics include accuracy, ROC AUC, computation time, and memory usage. Results identify the Gradient Boosting Classifier and LSTM as top performers, demonstrating high accuracy and ROC AUC scores. Comparative analyses highlight model strengths and limitations, contributing valuable insights for optimizing predictive strategies. This study advances predictive analytics for cardiovascular health, with implications for personalized medicine. The findings underscore the versatility of intelligent systems in addressing health challenges, emphasizing the broader applications of ML and DL in disease identification beyond cardiovascular health.

Quantitative Comparative Study of the Performance of Lossless Compression Methods Based on a Text Data Model

Data compression plays a key role in optimizing the use of memory storage space and also reducing latency in data transmission. In this paper, we are interested in lossless compression techniques because their performance is exploited with lossy compression techniques for images and videos generally using a mixed approach. To achieve our intended objective, which is to study the performance of lossless compression methods, we first carried out a literature review, a summary of which enabled us to select the most relevant, namely the following: arithmetic coding, LZW, Tunstall’s algorithm, RLE, BWT, Huffman coding and Shannon-Fano. Secondly, we designed a purposive text dataset with a repeating pattern in order to test the behavior and effectiveness of the selected compression techniques. Thirdly, we designed the compression algorithms and developed the programs (scripts) in Matlab in order to test their performance. Finally, following the tests conducted on relevant data that we constructed according to a deliberate model, the results show that these methods presented in order of performance are very satisfactory:- LZW- Arithmetic coding- Tunstall algorithm- BWT + RLELikewise, it appears that on the one hand, the performance of certain techniques relative to others is strongly linked to the sequencing and/or recurrence of symbols that make up the message, and on the other hand, to the cumulative time of encoding and decoding.

Henry Vandyke Carter (1831-1897): the forgotten co-author of Gray’s Anatomy

Henry Vandyke Carter(1831–1897),physician and illustrator from Saint George’s Hospital in London,England.He worked with Henry Williamson Gray(1827–1861)on anatomical dissections and Carter’s illustrations contributed significantly to the success of the Treaty of Anatomy,Descriptive and Surgical.Henry Carter never achieved any credit or royalty for his work.This book is currently regarded as one of the most influential human anatomy textbooks.The paper aims to present a brief review of Henry Carter’s contributions to the medical field.

Structural characterization of four Rhododendron spp.chloroplast genomes and comparative analyses with other azaleas

Azalea is a general designation of Rhododendron in the Ericaceae family.Rhododendron not only has high ornamental value but also has application value in ecological protection,medicine,and scientific research.In this study,we used Illumina and PacBio sequencing to assemble and annotate the entire chloroplast genomes(cp genomes)of four Rhododendron species.The chloroplast genomes of R.concinnum,R.henanense subsp.lingbaoense,R.micranthum,and R.simsii were assembled into 207,236,208,015,207,233,and 206,912 bp,respectively.All chloroplast genomes contain eight rRNA genes,with either 88 or 89 protein-coding genes.The four cp genomes were compared and analyzed by bioinformatics,and the phylogenetic analysis based on chloroplast genomes of 26 species of Ericaceae,Actinidiaceae,and Primulaceae under Ericales was conducted.A comparison of the linear structure of cp genomes of four Rhododendron showed that there were substantial sequence similarities in coding regions,but high differences in non-coding regions.A phylogenetic analysis,based on chloroplast whole genome sequences,showed that all Rhododendron species are in the clade Ericaceae.This study provides valuable genetic information for the study of population genetics and evolutionary relationships in Rhododendron and other azalea species.

Improved maceration techniques to study the fruit vascular anatomy of grape

The visualization and evaluation of fruit vascular bundles in grape are indispensable for understanding the development and growth of the fruit. The vascular bundles in grape are as thin as human hair, and strongly adhere to flesh cells, making it difficult to isolate individual intact vessel elements. Currently there is little information about methods to characterize grape vascular tissue. In this study, we describe an easy and effective technique to visualize the xylem cell structure of the ‘Red Globe' grape(Vitis L.). The intact vascular bundles of the grape were isolated through enzymatic degradation of flesh cells by hydrolases which were effective in removing flesh cells from vascular bundles. This enabled the illustration of the fine surface structure of vessel elements and their arrangement in the vascular bundles of the grape. This modified method to separate the vascular bundles into individual vessel elements was more effective than former methods of manually shaking to isolate individual vessels. Clear images of xylem vessel arrangement and structural characteristics of individual vessel element were acquired by light microscopy(BX51, Olympus, Tokyo, Japan), transmission electron microscopy(Tecnai 12, Philips, Netherlands) and scanning electron microscopy(GeminiSEM 300, Carl Zeiss, Germany). In addition, the 3D structure of vessel elements was observed using confocal laser scanning microscopy(Zeiss: model: LSM-880, Oberkochen, Germany). The imaging techniques for visualizing and analyzing the structure of xylem vessels in grape described in this study are an improvement of past methods. An effective method to isolate grape vascular bundles from flesh cells was also developed, which enables the imaging of the fine surface structure of vessel elements and their arrangement in grape vascular bundles. By adjusting the process of maceration of vascular bundles, an easy and effective method was developed to gently disrupt the plant tissue and isolate individual vessel elements. These improved techniques are suitable to observe the intact morphology of vascular bundles in the grape, improve experimental efficiency and accelerate new discoveries on the anatomical structure of the grape.

Helicobacter Pylori Infection and Gastroduodenal Lesions in Patients with Chronic Kidney Disease: A Comparative Study

Introduction: Gastroduodenal lesions are common in chronic kidney disease (CKD). They are linked to various factors including Helicobacter pylori infection (H. pylori). Few data are available in Africa on H. pylori infection and chronic kidney disease. The aim of this study was to assess the impact of H. pylori infection and to describe the gastroduodenal lesions found in patients with chronic kidney disease. Patients and Methods: A cross-sectional study was conducted, February 1st to May 31st, 2021, at the Douala General Hospital in Cameroon. We included patients with CKD classified as stages 3 to 5 according KDIGO classification, on hemodialysis or not, who agreed to participate in the study. They were matched with a “control” population including patients with normal renal function according to sex and age (ratio 1:2). Patients on antibiotics and/or proton pump inhibitors were excluded. We collected data from CKD patients and from medical records for non-CKD group. Each patient underwent an upper digestive endoscopy and identification of H. pylori using a urease rapid test. Logistic regression was used to identify independent associations for a significance level set at p Results: We included 99 patients including 33 with CKD and 66 control patients. Among patients with CKD, the predominance was male (n = 18/33 or 54.5%). The mean age was 51.2 ± 12.8 years. Arterial hypertension was the first etiology of CKD (n = 13 or 39.4%). The prevalence of H. pylori in patients with CKD was 63.6% versus 37.9% in control patients (p-value = 0.015). The main endoscopic lesions were erosive gastropathy (n = 14 or 42.4%) and erythematous gastropathy (n = 7 or 21.2%). Patients with CKD were 5 times more likely to have H. pylori infection (OR = 5.69;CI 95% 0.14 - 0.82;p = 0.017). Factors associated with H. pylori infection were chronic kidney disease (aOR = 1.02;CI 95% 0.14 - 0.82;p = 0.017) and hemodialysis (aOR = 10;CI 95% 1.08 - 91.9;p = 0.042). Conclusion: The prevalence of H. pylori infection is higher in patients with CKD. Endoscopic lesions are inflammatory. Factors associated with H. pylori infection are chronic kidney disease and hemodialysis.

Helicobacter Pylori Infection: Epidemiological, Clinical and Pathological Aspects in a Digestive Endoscopy Unit and the Pathological Anatomy Service of Parakou in Benin Republic

Introduction: Helicobacter pylori (Hp) infection is the most common bacterial infection in the world. World Health Organization has classified this bacterium as a Class I carcinogen. The objective of this work is to study the epidemiological, clinical and pathological aspects of Helicobacter pylori infection among adults in a digestive endoscopy unit and the pathological anatomy service of Parakou. Patients and Methods: This was a descriptive and analytical cross-sectional study conducted from January 2020 to September 2020 in the digestive endoscopy unit and pathological anatomy service at the Departmental University Hospital Center of Borgou. Patients aged 18 years and older, who had undergone a gastroscopy with biopsies and who gave their oral consent were included. Three antral biopsies and two fundic biopsies were performed. The search for Hp was done under an optical microscope after staining with hematoxylin eosin. Results: A total of 151 patients were included and 51.66% were infected with Hp. Their average age was 40.63 ± 15.32 years and the sex ratio was 0.9. Epigastric pain was the most reported symptom (71.01%). Endoscopically, the prevalence of erythematous gastropathy was 98.72%. The study of chronic Hp gastritis according to Sydney system had shown signs of activity in 100% of patients with Hp and glandular atrophy in 83.33% of them. Intestinal metaplasia and dysplasia accounted for 24.35% and 29.48% of cases, respectively. Factors associated with Hp infection were: absence of proton pump inhibitor intake prior to examination, absence of handwashing with soap and water before eating, erythematous aspect of gastritis on gastroscopy, absence of intestinal metaplasia of the fundus, active and chronic aspects of gastritis on histology. Conclusion: The frequency of Hp infection in hospitals among adults admitted to the Digestive Endoscopy Unit of Parakou is high. To reduce this prevalence, it will be necessary to act on the factors identified.

Comparative Advantage and Latecomer Advantage

To achieve development,developing countries must capitalize on their relative advantages,including comparative advantage and latecomer advantages.A country must develop an industrial structure that is consistent with the comparative advantage of its factor structure in order to avoid the trap of“structural catch-up”that stifles development.The issue for developing countries is that their comparative advantage in core factors of production is unstable and tends to decrease and dissipate.Such a comparative advantage cannot provide adequate growth for convergence to occur.Developed countries,on the other hand,can sustain economic growth due to their comparative advantage in high-quality factors.Latecomer advantage refers to the ability of developing countries to increase their knowledge factor in a cost-effective manner by learning,importing,assimilating,and using knowledge and technology that already exist.Although comparative and latecomer advantages may have a combined effect,each has its distinct characteristics.Latecomer advantage is a special development factor that applies to latecomers.It is crucial at all stages of development,but especially so in the middle-income stage and beyond.Bringing latecomer advantage into full play is essential for developing nations to converge with the advanced countries.

Understanding Poison:Study of a Word Du from the Perspective of Comparative History

This article investigates the word Du(毒)in premodern Chinese medicine and culture.It highlights the paradoxical meaning of the word that served as a foundation for the therapeutic use of poisons in traditional Chinese medicine.The article then situates the study in a comparative framework.By comparing the Chinese notion of Du with the Greek concept of pharmakon,it demonstrates significant similarities on the medical use of poisons in the two cultures.It further identifies a striking difference:While the European pharmacy started to separate poisons from medicines in the medieval era,poisons remained an integral part of healing repertoire throughout imperial China.The article ends with offering some cultural explanations for this divergence,and more broadly,a distinct worldview as revealed by the intimate relationship between poisons and medicines in traditional Chinese pharmacy.