Prostitutes, Orphans, and Entrepreneurs: The Effect of Public Perceptions of Ghana\u27s Girl Child Kayayei on Public Policy

For a variety of reasons, including the growing disparity in resources and opportunities between Ghana’s mostly rural North and its urban South, the numbers and patterns of internal migration have changed dramatically over the last twenty years. Historically the province of men, and later women on a temporary basis that was tied to the rainy seasons, young girls between ten and sixteen years of age now make up the majority of the North-South migrants. The lives of these girl migrants, who live and work in Ghana’s markets as porters, known locally as kayayoo, are complex and multifaceted. They endure great hardships and are exposed to increasing risks as they struggle to survive while living and working on the streets. As more and more girls travel to the southern cities from their homes in the North, and fewer and fewer of them return on a permanent basis, the number of girl porters on the street at any given time is growing. This growth has had several consequences. The presence of more and more girls on the streets has created greater competition for everything—from jobs to sleeping spaces. Another consequence has been the change in the public perception of the girls. In the past, when the porters were mostly adult women and their numbers were fairly constant, they generally remained below the public’s radar. More recently, however, as young girls outnumber adult women working in the markets and when there are not enough jobs to go around, when more girls are turning to prostitution to make ends meet and when the overall scarcity of resources has given rise to greater and more frequent violence, the public has begun to take notice of the girls. The Ghanaian public has responded to their swelling numbers and increasing visibility in different ways. To some, the girl porters are dirty, street criminals to be avoided. To others, they are victims of circumstances and deserving of benevolence and protection. To others still, the girl porters are no different than any other person who makes a rational decision to relocate in an attempt to improve their situation and they are therefore not entitled to any special treatment or deference. In the fifty-plus years since its independence, Ghana has developed public policies across a range of critical areas. Three of these areas—child labor, education, and health care—are particularly relevant to the girl porters and reflect a range of punitive, protectionist, and laissez-faire social policy models. This Article argues that the kayayei girls do not benefit from these key public policies because, in part, the government officials who determine the shape and reach of public policy, and the frontline people who are tasked with its implementation and administration, are the very people who view the girls as prostitutes, orphans, or entrepreneurs. Quite simply, numerous problems in the sprawling Ministries system, including the lack of systematic oversight, inconsistent practices across districts, limited resources, and insufficient personnel training have resulted in a system in which individuals exercise enormous deference in public policy implementation. The consequence for the girls, then, is that more often than not whether they can access the benefits of public policies depends on one person’s perception of girl porters. It is no surprise then that, because much of the public’s perception of the girls is negative or indifferent, the girls have largely failed to benefit from public policies

The C Terminus of FtsZ Regulates FtsZ Assembly Dynamics and Is Required for Bacillus Subtilis Cell Division

Bacterial cell division is initiated by the assembly of the tubulin homolog FtsZ into a ring: Z ring) at the nascent division site. Once formed, the Z ring serves as a scaffold for recruitment of the division machinery and helps provide some of the constrictive force for cytokinesis. In vitro FtsZ undergoes GTP-dependent assembly where individual subunits form single-stranded protofilaments and laterally-associated filament bundles. How the filamentous FtsZ structures observed in vitro translate into the behavior of the Z ring in vivo remains a fundamental question. In this dissertation I establish important roles for the previously uncharacterized FtsZ C-terminal domains during both FtsZ assembly and Z ring formation. My work provides significant insight into how FtsZ behavior at the protein level impacts its cellular function. Structurally, the FtsZ monomer is divided into 5 domains: an unstructured N-terminal peptide, a highly conserved N-terminal globular core, an unstructured C-terminal linker: CTL), a conserved set of ~11 residues referred to here as the C-terminal constant region: CTC), and a small, highly variable group of residues at the extreme C-terminus of FtsZ termed the C-terminal variable region: CTV). For simplicity, the N-terminal peptide and core are treated here as a single unit. The core shows a high degree of sequence conservation amongst bacterial species and contains residues required for GTP binding and hydrolysis as well as forming the contacts necessary to make filaments. The entire FtsZ C terminus consists of the CTL, CTC, and CTV. The CTL displays very little conservation between species both in primary sequence and length, is irresolvable by X-ray crystallography, and is presumed to be intrinsically disordered. The CTC and CTV are implicated in interactions between FtsZ and modulatory proteins. To reflect this function the combined domains have been termed the grappling hook peptide: GHP). Prior to this work, the roles that the C-terminal domains had in FtsZ assembly were unknown. In this dissertation, I demonstrate that these domains do have distinct functions. First I show the CTV is important for regulating lateral interactions between FtsZ protofilaments. B. subtilis FtsZ readily forms bundled structures in vitro. In contrast, I show E. coli FtsZ typically assembles into single-stranded protofilaments. Through deletion analysis and domain swapping, I determine these phenotypes to derive from differences in the CTVs of each species. I also establish that electrostatic interactions are a driving force behind FtsZ bundling. Alterations to the CTV sequence also greatly affect cell division in B. subtilis cells, suggesting filament bundling is important for a stable Z ring in vivo. Finally, I demonstrate the FtsZ CTL is essential for FtsZ protofilament assembly and cell division. I determine that a functional CTL must behave as an intrinsically disordered peptide with little primary sequence requirement but must be between 25 and 100 residues in length. These findings lead to a model for FtsZ in which the CTL behaves as a flexible tether anchoring FtsZ filaments to the membrane through interactions between the GHP and FtsZ modulatory proteins like FtsA. The linker can undertake different conformations and allow FtsZ filaments bundle through positioning the CTV near adjacent filaments and to respond to the curvature of the membrane, having implications for how the constrictive force for cytokinesis is generated

Hilbert modules over semicrossed products of the disk algebra

Given the disk algebra A( I !D) and an automorphism [alpha], there is associated a non-self-adjoint norm closed subalgebra doubz+x[alpha]A( I !D) of the crossed product doubzx[alpha]C( T) called the semicrossed product of A( I !D) with [alpha]. It is well known that the automorphisms of A( I !D) arise via composition with conformal bijections [phi] of I !D. These automorphisms are labeled according to the corresponding conformal maps as parabolic, hyperbolic, or elliptic and each case is studied. The contractive and completely contractive representations of doubz+x[alpha]A( I !D) on a Hilbert space H (i.e. contractive Hilbert modules) are found to be in a one-to-one correspondence with pairs of contractions S and T on H satisfying TS=S[phi](T). To this end, a noncommutative dilation result is obtained. It states that given a pair of contractions S and T on H satisfying TS=S[phi](T) there exist a pair of unitaries U and V on K supseteqH satisfying VU=U[phi](V) and dilating S and T respectively. Some concrete representations of doubz+x[alpha]A( I !D) are then found in order to compute the characters, the maximal ideal space, and the strong radical. The Shilov and orthoprojective Hilbert modules over doubz+x[alpha]A( I !D) are shown to correspond to pairs of isometries S and T satisfying TS=S[phi](T)

Setup of a Beam Control System for High Power Laser Systems at DLR

Different types of high power or high energy lasers in the multi kW class are currently available or are under development with promising progress reports. A major challenge is to deliver as much as possible of the available power onto a small and fast moving target over a long distance through a disturbing atmosphere. High resolution imaging is a common way to identify the category of targets dedication and to determine the spatial position relative to the observer. By illuminating the target with a laser the imaging system becomes more resilient towards ambient light and the exposure time can be reduced drastically. Fast and deterministic control loops are demanding for the moving parts in order to maintain a high accuracy for the pointing of the turret and aiming of the laser countermeasure system. Here, we report on the progress of such a beam control system developed at the Institute of Technical Physics of DLR. In an overview we present the beam control system and explain different sub-systems. Performance tests were taken at our outdoor test range. We investigated various scenarios for probing the limits of the tracking and pointing accuracy with a target sample mounted on a fast moving linear stage. We present first results of the beam control system performance

A simple formula for the evaluation of value and position of ground level concentration from a point source

After setting realistic scenarios of the wind and diffusivity parameterizations the Ground Level Concentration is worked out by an analytical solution of the advection-diffusion equation, then an explicit approximate expression is provided for it allowing a simple expression for the position and value of the maximum.Depois de estabelecer cenários realistas das parametrizações do vento e da difusividade, a concentração do nível do solo é elaborada por uma solução analítica da equação de advecção-difusão e, em seguida, é fornecida uma expressão simples para a posição e o valor do máximo de concentração no nível do solo