Trends of Terrorism Activity in Relation to Internet Accessability Throughout the Sahel Countries of Africa

For most of the developed world, the Internet plays an important role in everyday life. It is the primary infrastructure used for business, academics, social life, and many other societal institutions. However, many developing parts of the world, especially Sub-Saharan Africa, still lack reliable access to the Internet. Despite the Internet’s many positive attributes, it provides a breeding ground for nefarious actors. Terrorists have successfully used the Internet to spread propaganda and recruit followers, primarily through social media. Research has shown a relationship between rates of Internet usage, and increased terrorist activity in the Western world. As vulnerable developing nations gain more accessibility to the Internet, terrorists will likely try to capitalize on the newfound access to these hard-to-reach audiences around the world. This study seeks to identify what the effect increased Internet accessibility has on terrorist activity, as experienced in the Sahel region. Because access to the Internet is still extremely limited in most of the Sahel region, identifying trends early on may help defend against this threat as the Internet becomes more readily available to the region in the future. This quantitative analysis found that there was a strong positive relationship between these variables for the selected sample of Sahel countries analyzed. This information may be useful in educating policymakers on future threats that effective foreign policy and military aid can help proactively counter

Local regeneration in the retina of the goldfish

We have studied regeneration of the retina in the goldfish as a model of regenerative neurogenesis in the central nervous system. Using a transsclearal surgical approach, we excised small patches of retina that were replaced over several weeks by regeneration. Lesioned retinas from three groups of animals were studied to characterize, respectively, the qualitative changes of the retina and surrounding tissues during regeneration, the concomitant cellular proliferation, and the quantitative relationship between regenerated and intact retina. The qualitative and quantitative analyses were done on retinas prepared using standard methods for light microscopy. The planimetric density of regenerated and intact retinal neurons was computed in a group of animals in which the normal planimetric density ranged from high to low. Cell proliferation was investigated by making intraocular injections of 5-bromo-2′-deoxyuridine (BUdr) at various survival times to label proliferating cells and processing retinal sections for BUdr immunocytochemistry. The qualitative analysis showed that the surgery created a gap in the existing retina that was replaced with new retina over the subsequent weeks. The BUdr-labeling experiments demonstrated that the excised retina was replaced by regeneration of new neurons. Neuroepithiallike cells clustered on the wound margin and migrated centripetally, appositionally adding new retina to the old. The quantitative analysis showed that the planimetric density of the regenerated neurons approximated that of the intact ones.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50080/1/480230209_ftp.pd

Growth of the adult goldfish eye. III. Source of the new retinal cells

The manner in which new cells are added to the growing adult goldfish retina was examined using 3 H-thymidine radioutography. Cell proliferation leading to the formation of neurons is restricted to the retinal margin at the ora terminalis . New retina is added in concentric rings, with slightly more growth dorsonasally. The rate of cell addition is variable, averaging 12,000 cells/ day. These new cells account for about 20% of the total increase in retinal area; the remaining 80% is due to hypertrophy, or expansin, of the retina. In contrast to all of the other retinal cells, the rods do not appear to participate in the retinal expansion. This hypothesized immobility of the rods would create a shearing strain between the retinal layers resulting in a shift in their position relative to the other cells. Were they to maintain synaptic contacts with the same horizontal and bipolar cells, the rod axons would have to be elongated peripherally or the post-synaptic cell dendrites displaced centrally. Since neurons with this morphology have not been found in the goldfish retina, these observations suggest that the rods must be changing their synaptic connections as the retina grows.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50002/1/901760304_ftp.pd

Blueprint for an intestinal villus: Species‐specific assembly required

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144650/1/wdev317_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144650/2/wdev317.pd

Growth of the adult goldfish eye. II. Increase in retinal cell number

The retinas of adult goldfish, one to four years of age, 4–23 cm in length, were examined with standard paraffin histology to determine if new cells were being added with growth. Retinal cell nuclei were counted and the area of the retina was measured. An analysis of cell densities in various regions throughout the retina showed that the cells are distributed nearly homogeneously. The density (No./mm 2 of retinal surface) of ganglion cells, inner nuclear layer cells and cones decreases with growth, but the density of rods remains constant. Thus the rods account for a larger proportion of the cells in larger retinas. The total number of cells per retina increases: the ganglion cells from 60,000 to 350,000; the inner nuclear layer cells from 1,500,000 to 4,000,000; the cones from 250,000 to 1,400,000; the rods from 1,500,000 to 15,000,000. This increase in the number of retinal neurons implies the formation of even more new synapses, and suggests the adult goldfish retina as a model for both neuro- and synaptogenesis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50001/1/901760303_ftp.pd