The brainstem reticular formation is a small-world, not scale-free, network

Recently, it has been demonstrated that several complex systems may have simple graph-theoretic characterizations as so-called ‘small-world’ and ‘scale-free’ networks. These networks have also been applied to the gross neural connectivity between primate cortical areas and the nervous system of Caenorhabditis elegans. Here, we extend this work to a specific neural circuit of the vertebrate brain—the medial reticular formation (RF) of the brainstem—and, in doing so, we have made three key contributions. First, this work constitutes the first model (and quantitative review) of this important brain structure for over three decades. Second, we have developed the first graph-theoretic analysis of vertebrate brain connectivity at the neural network level. Third, we propose simple metrics to quantitatively assess the extent to which the networks studied are small-world or scale-free. We conclude that the medial RF is configured to create small-world (implying coherent rapid-processing capabilities), but not scale-free, type networks under assumptions which are amenable to quantitative measurement

Spider silks: recombinant synthesis, assembly, spinning, and engineering of synthetic proteins

Since thousands of years humans have utilized insect silks for their own benefit and comfort. The most famous example is the use of reeled silkworm silk from Bombyx mori to produce textiles. In contrast, despite the more promising properties of their silk, spiders have not been domesticated for large-scale or even industrial applications, since farming the spiders is not commercially viable due to their highly territorial and cannibalistic nature. Before spider silks can be copied or mimicked, not only the sequence of the underlying proteins but also their functions have to be resolved. Several attempts to recombinantly produce spider silks or spider silk mimics in various expression hosts have been reported previously. A new protein engineering approach, which combines synthetic repetitive silk sequences with authentic silk domains, reveals proteins that closely resemble silk proteins and that can be produced at high yields, which provides a basis for cost-efficient large scale production of spider silk-like proteins

Diaspora-driven development in stateless Somalia: all relationships are local relationships

In the wake of state collapse, Somali society today has become decidedly globalized, leaning heavily on capital from its widely-dispersed diaspora funneled in through the conduits of an informal economic system for both subsistence and overall economic livelihood. Despite the great distances often separating them, Somalis remain linked by common ethnic and cultural bonds. These links are both social and economic, and are heavily reliant on telecommunications technology, a key concept discussed in this study. The Somali economy, driven largely by the widespread informal Hawalaad financial transfer system, bypasses the commercial and financial channels that have been voided by the lack of a state; it instead largely emphasizes societal networks and cultural norms. This study examines how the Somali commercial diaspora has made extensive use of these informal avenues to invest in their homeland. Special attention is paid to the nature of Somali social networking; the establishment and maintenance of trust, in commercial endeavors undertaken in an unstable environment. This in turn illustrates the notion that despite unstable, often hostile conditions inhibiting most commercial endeavors in a conflict-ridden state or a state in a complex emergency situation, different segments of the Somali diaspora have come into a position to make unique contributions towards development in their homeland. While the most evident and most analyzed of these contributions are taking place in the informal finance and telecommunications sectors, this thesis also suggests a gradual expansion of diaspora endeavors into other facets of development, including transport, health, and other basic services. This thesis argues that despite the absence of a government, Somalia\u27s commercial diaspora has been able to not only cope and devise creative solutions to replace certain critical services lost in the vacuum left by the collapse of the government, but also in facilitating a degree of development as well. This development is shaped and directed by the endogenous cultural attributes of Somali society, and contribute to improved standards of living and livelihoods for certain sectors of Somali society that would otherwise be worse-off

Nanoscale Carbon-Based Electrochemical and Temperature Sensors

Nanoscale sensors are required to study the interesting and complex physical, chemical, and biological phenomenon which occurs in microdomains. Carbon-based nanostructures (CNS) have been utilized in nanosensors with applications in many fields due to their versatility and unique properties. Several manufacturing processes can be used to produce CNSs though they often are expensive and require time-consuming purification and micro-assembly processes to integrate them into larger structures. Here, novel silica-based structures are explored as unique templates on which to form CNSs that are easily integrated into sensors which can directly interface with standard laboratory equipment. The high electrical conductivity of CNSs enables the structures to be modified through an electrodeposition process to produce a chemical and a physical sensor. Specifically, this work describes the design, fabrication, and characterization of a nanoscopic thermocouple and electrochemical sensor. The thermocouple developed through this research uses a novel manufacturing method and set of materials to overcome the reduction in thermoelectric performance associated with small sensor sizes. The electrochemical sensor presented in this work overcomes challenges associated with other nanoscale sensors by allowing a working and reference electrode to be located within 50 nm of each other, minimizing the overall sensor footprint. This work presents a novel and efficient method of preparing unique carbon-based sensors