Estimation Methods for Duration Models

This paper is a selected overview of econometric methods for duration models and will appear in the forthcoming book The Economics of Search by the authors. The focus of the paper is on martingale methods for continuous time data and general methods for the analysis of discretetime data including multi-spell models and general life-history models.

Signalling pathways and gene expression profiles in prostate cancer

In general, cancer, encompassing prostate cancer (PCa), is a disease that utilises signalling pathways to progress through the uncontrolled proliferation of cancerous cells. Although the mechanisms of how the cells evade intrinsic or extrinsic signals of death and keep on dividing is not completely understood, there is a plethora of evidence that point to certain signalling molecules that are crucial conveyors of the fine tuning that slightly differs in cancer in comparison to control states. The present chapter provides a detailed description of the key regulators of PCa cell life and unveils their closely communicating proteins that aid in the fine tuning of the cancerous state

Cockpit weather radar display demonstrator and ground-to-air sferics telemetry system

The results of two methods of obtaining timely and accurate severe weather presentations in the cockpit are detailed. The first method described is a course up display of uplinked weather radar data. This involves the construction of a demonstrator that will show the feasibility of producing a course up display in the cockpit of the NASA simulator at Langley. A set of software algorithms was designed that could easily be implemented, along with data tapes generated to provide the cockpit simulation. The second method described involves the uplinking of sferic data from a ground based 3M-Ryan Stormscope. The technique involves transfer of the data on the CRT of the Stormscope to a remote CRT. This sferic uplink and display could also be included in an implementation on the NASA cockpit simulator, allowing evaluation of pilot responses based on real Stormscope data

Diffuse Interstellar Bands Toward HD 62542

Diffuse interstellar bands (DIBs) have been detected for the first time along the peculiar translucent line of sight toward HD 62542, which passes through a diffuse cloud core. Although only a small fraction (18 out of more than 300) of generally weak DIB features have been shown to correlate with C_2 and C_3 (the "C_2 DIBs"), it is predominantly these DIBs that are observed toward HD 62542. The typically strong DIBs λλ5780 and 5797 are detected but are significantly weaker than toward other lines of sight with similar reddening. Other commonly observed DIBs (such as λλ4430, 6270, and 6284) remain noticeably absent. These observations further support the suggestion that the line of sight toward HD 62542 crosses only the core of a diffuse cloud and show that the correlation between the C_2 DIBs and small carbon chains is maintained in environments with very large fractions of molecular hydrogen, f_(H_2) > 0.8. A comparison of CH, CN, C_2, and C_3 column densities and C_2 DIB strengths toward HD 62542, HD 204827, and HD 172028 suggests that the line of sight toward HD 204827 passes through a diffuse cloud core similar to that seen toward HD 62542, as well as what might be referred to as a diffuse cloud envelope. This indicates that the bare core toward HD 62542 may not have significantly different relative chemical abundances from other diffuse cloud cores and that the C_2 DIBs may serve as a diagnostic of such cores

Observations of Rotationally Resolved C_3 in Translucent Sight Lines

The rotationally resolved spectrum of the A^1Π_u ← X^1Σ^+_g 000-000 transition of C_3, centered at 4051.6 Å, has been observed along 10 translucent lines of sight. To interpret these spectra, a new method for the determination of column densities and analysis of excitation profiles involving the simulation and fitting of observed spectra has been developed. The populations of lower rotational levels (J ≤ 14) in C_3 are best fitted by thermal distributions that are consistent with the kinetic temperatures determined from the excitation profile of C_2. Just as in the case of C_2, higher rotational levels (J > 14) of C_3 show increased nonthermal population distributions in clouds that have been determined to have total gas densities below ~500 cm^(-3)

Investigations in the semi-strong product of graphs and bootstrap percolation

The semi-strong product of graphs G and H is a way of forming a new graph from the graphs G and H. The vertex set of the semi-strong product is the Cartesian product of the vertex sets of G and H, V(G) x V(H). The edges of the semi-strong product are determined as follows: (g1,h1)(g2,h2) is an edge of the product whenever g1g2 is an edge of G and h1h2 is an edge of H or g1 = g2 and h1h2 is an edge of H. A natural subject for investigation is to determine properties of the semi-strong product in terms of those properties of its factors. We investigate distance, independence, matching, and domination in the semi-strong product Bootstrap Percolation is a process defined on a graph. We begin with an initial set of infected vertices. In each subsequent round, uninfected vertices become infected if they are adjacent to at least r infected vertices. Once infected, vertices remain infected. The parameter r is called the percolation threshold. When G is finite, the infection either stops at a proper subset of G or all of V(G) becomes infected. If all of V(G) eventually becomes infected, then we say that the infection percolates and we call the initial set of infected vertices a percolating set. The cardinality of a minimum percolating set of G with percolation threshold r is denoted m(G,r). We determine m(G,r) for certain Kneser graphs and bipartite Kneser graphs

Never Quite Settled: Southern Plain Folk on the Move

This thesis explores the settlement of the Mississippi Territory through the eyes of John Hailes, a Southern yeoman farmer, from 1813 until his death in 1859. This is a family history. As such, the goal of this paper is to reconstruct John’s life to better understand who he was, why he left South Carolina, how he made a living in Mississippi, and to determine a degree of upward mobility. Local, state, and federal government records provide the general context of this study and accurately track John’s movements and land purchases within the territory. John\u27s frequent movements and the land he bought suggest that he was a herder and relied on hogs and cattle for a living. This contextual biography suggests that John was mobile, that he was sensitive to land policies and market pressures, and that he maintained a yeoman\u27s standard of living throughout his life