RESUMEN
Objective: To construct brain structural network based on DTI data,so as to investigate whether the brain structural network of with mild cognitive impairment (MCI) patients has small-world property,also to observe the changes of relevant characteristic parameters. Methods: Brain DTI data of 26 MCI patients (MCI group) and 27 healthy elders (NC group) were collected. The images were preprocessed with PANDA software, and the cerebral cortex was divided into 90 regions using automated anatomical labeling (AAL) template. Diffusion tensor tractography was implemented using deterministic fiber tracing algorithm, and the white matter fiber connection network was constructed with the fiber number (FN) between 2 brain regions as the threshold T value. T value was set in the range of 1-5, step length was 1, then the characteristic parameters of the brain network at different T value were calculated, including average path length (Lp), aggregation coefficient (CP), global efficiency (Eglobal) and local efficiency (Elocal). The network was considered to be a small-world network if γ=C/Crand>1 and λ=L/Lrand≈1 (rand representing relative random networks) or δ=γ/λ>1 were satisfied. The differences of brain structural network characteristic parameters were compared between 2 groups. Results: When 1≤T≤5, MCI group and NC group both met the criteria of γ>1 and λ≈1; LP of MCI group were all higher than those of NC group (all P0.05). When 1≤T≤4, Eglobal of MCI group were all lower than those of NC group (all P<0.05), when T=2, Elocal of MCI group was lower than that of NC group (P<0.05). Conclusion: The brain structural network of MCI patients has small-world property, but its small-world characteristics are impaired.
RESUMEN
El fenómeno de la difusión del darwinismo ha sido ampliamente estudiado. No solo existe una "industria de Darwin" que se ha ocupado de investigar cómo se produjo la obra de Darwin, sino que también existe una "industria de la difusión del darwinismo", que investiga los procesos de recepción del darwinismo en diversas partes del mundo. En el artículo se cuestiona la separación entre los estudios que examinan la producción del origen de las especies y los que tratan de su posterior difusión, considerados como procesos completamente independientes. Con base en unos pocos ejemplos, se muestra cómo Darwin fue produciendo y modificando su obra a partir de las contribuciones que fue recogiendo alrededor del mundo y a partir de las respuestas que fue recibiendo a medida que su obra era comentada y discutida. Finalmente se examina cómo, al estudiar la mundialización del darwinismo surge el problema de definir el fenómeno bajo estudio, si con una perspectiva normativa, que imponga un orden en la proliferación de sentidos que surge como consecuencia de la expansión, o con una perspectiva no esencialista que más bien sitúe al darwinismo en relación con sus diferentes usos y apropiaciones locales.
The phenomenon of the diffusion of Darwinism has been extensively studied. Not only is there a "Darwin Industry" concerned with investigating how Darwins work was produced, there is also a "Diffusion of Darwinism Industry", that investigates the processes of reception of Darwinism in various parts of the world. In this article, I question the intellectual independence of studies that examine the production of the Origin of Species from those that study its subsequent diffusion. Based on a small number of examples, I show Darwin producing and modifying his work from the contributions he collected from around the world and from the responses he received in commentaries and discussions. Finally I examine how, in the course of studying the ‘mundialización (worldness) of Darwinism, the problem arises of defining the phenomenon under study: either from a normative perspective, that seeks to impose an order on the proliferation of versions arising as a result of this global expansion, or from a non-essentialist perspective that seeks to better situate Darwinism in relation to its different uses and local appropriations.