Maternal Abusers: Underlying concerns for children

Child sexual abuse is an emotive topic, which raises public fears and political concerns. Commonly the perpetrators of such abuse are male and their victims female, but evidence suggests that there are a significant number of female perpetrators as well. It is the perceived gendered nature of the crime that creates a stumbling block to the recognition of women who sexually abuse and can silence the child victims. Using data from a wider research project, this paper examines the ways in which female perpetrators rationalise their behaviours and in doing so considers what part these justifications play in silencing the child victims

Management Awareness and Strategies for the Contemporary African Manager of Organizations

This paper addresses a topical issue: management awareness and strategies for the contemporary African manager. The overall aim of the work is to provide a framework for improved management practices for the manager and the intervener in both private and public sectors. This frame-work is not limited to the African manager but has a wider application for other managers of organizations. In pursuant of this objective, relevant key management concepts are explored and discussed bearing in mind that the subject of management is a dynamic and universal phenomenon. Emphasis is placed on the features of the endowed person and the potentials of the human being as the manager and as the most effective contributor to organizational life.The identified concepts and their properties are interwoven. Other highlights are: (i) the universality in the applications or practices of management; (ii) the peculiarity in the applications and practices of management in different environments or social settings; (iii) management practices, problems and prospects in the African settings (See Table I). Cases cited and examples drawn are meant inter alia to strengthen the objectives of the study

A computer‐aided continuous assessment system

A high‐quality assessment system should have the following attributes: rapid feedback to the students, appropriate and detailed feedback, and an effective grading system which provides an accurate overall grade as well as information which identifies the student's weak areas. As stafflstudent ratios worsen, providing such a system will become more difficult and consequently computer assistance in this task is becoming more attractive. This paper describes a Computer‐Aided Assessment (CAA) system based on a modified version of the multiple‐choice questionnaire. The CAA has been designed to be used in continuous assessment, with features that discourage plagiarism and provide appropriate feedback Over a hundred students were tested using this CAA and the results were compared with a more traditional assessment system. In addition, questionnaires were used to assess the student's reaction to the CAA. The results were highly satisfactory, and a more advanced version of the original software is under consideration

Stokes−Einstein−Debye failure in molecular orientational diffusion: exception or rule?

The Stokes–Einstein–Debye (SED) expression is used routinely to relate orientational molecular diffusivity quantitatively to viscosity. However, it is well-known that Einstein’s equations are derived from hydrodynamic theory for the diffusion of a Brownian particle in a homogeneous fluid and examples of SED breakdown and failure for molecular diffusion are not unusual. Here, using optical Kerr-effect spectroscopy to measure orientational diffusion for solutions of guanidine hydrochloride in water and mixtures of carbon disulfide with hexadecane, we show that these two contrasting systems each show pronounced exception to the SED relation and ask if it is reasonable to expect molecular diffusion to be a simple function of viscosity

Microstates at the boundary of AdS

The bound states of the D1D5 brane system have a known gravitational description: flat asymptotics, an anti-de Sitter region, and a 'cap' ending the AdS region. We construct perturbations that correspond to the action of chiral algebra generators on Ramond ground states of D1D5 branes. Abstract arguments in the literature suggest that the perturbation should be pure gauge in the AdS region; our perturbation indeed has this structure, with the nontrivial deformation of the geometry occurring at the 'neck' between the AdS region and asymptotic infinity. This 'non-gauge' deformation is needed to provide the nonzero energy and momentum carried by the perturbation. We also suggest implications this structure may have for the majority of microstates which live at the cap.Comment: 41 pages, 6 figures, v2: cross-check of results added, to appear in JHE

Momentum-carrying waves on D1-D5 microstate geometries

If one attempts to add momentum-carrying waves to a black string then the solution develops a singularity at the horizon; this is a manifestation of the 'no hair theorem' for black objects. However individual microstates of a black string do not have a horizon, and so the above theorem does not apply. We construct a perturbation that adds momentum to a family of microstates of the extremal D1-D5 string. This perturbation is analogous to the 'singleton' mode localized at the boundary of AdS; to leading order it is pure gauge in the AdS interior of the geometry.Comment: 24 pages, 4 figure

Oscillating supertubes and neutral rotating black hole microstates

The construction of neutral black hole microstates is an important problem, with implications for the information paradox. In this paper we conjecture a construction of non-supersymmetric supergravity solutions describing D-brane configurations which carry mass and angular momentum, but no other conserved charges. We first study a classical string solution which locally carries dipole winding and momentum charges in two compact directions, but globally carries no net winding or momentum charge. We investigate its backreaction in the D1-D5 duality frame, where this object becomes a supertube which locally carries oscillating dipole D1-D5 and NS1-NS5 charges, and again carries no net charge. In the limit of an infinite straight supertube, we find an exact supergravity solution describing this object. We conjecture that a similar construction may be carried out based on a class of two-charge non-supersymmetric D1-D5 solutions. These results are a step towards demonstrating how neutral black hole microstates may be constructed in string theory.Comment: 24 pages, 2 figures, v3: estimate of radiation rate added, references adde

The flaw in the firewall argument

A lot of confusion surrounds the issue of black hole complementarity, because the question has been considered without discussing the mechanism which guarantees unitarity. Considering such a mechanism leads to the following: (1) The Hawking quanta with energy E of order the black hole temperature T carry information, and so only appropriate processes involving E>>T quanta can have any possible complementary description with an information-free horizon; (2) The stretched horizon describes all possible black hole states with a given mass M, and it must expand out to a distance s_{bubble} before it can accept additional infalling bits; (3) The Hawking radiation has a specific low temperature T, and infalling quanta interact significantly with it only within a distance s_{alpha} of the horizon. One finds s_{alpha} << s_{bubble} for E>>T, and this removes the argument against complementarity recently made by Almheiri et al. In particular, the condition E>>T leads to the notion of 'fuzzball complementarity', where the modes around the horizon are indeed correctly entangled in the complementary picture to give the vacuum.Comment: 52 pages, 13 figures, v3: comments on Rindler space added, references adde

Holographic description of non-supersymmetric orbifolded D1-D5-P solutions

Non-supersymmetric black hole microstates are of great interest in the context of the black hole information paradox. We identify the holographic description of the general class of non-supersymmetric orbifolded D1-D5-P supergravity solutions found by Jejjala, Madden, Ross and Titchener. This class includes both completely smooth solutions and solutions with conical defects, and in the near-decoupling limit these solutions describe degrees of freedom in the cap region. The CFT description involves a general class of states obtained by fractional spectral flow in both left-moving and right-moving sectors, generalizing previous work which studied special cases in this class. We compute the massless scalar emission spectrum and emission rates in both gravity and CFT and find perfect agreement, thereby providing strong evidence for our proposed identification. We also investigate the physics of ergoregion emission as pair creation for these orbifolded solutions. Our results represent the largest class of non-supersymmetric black hole microstate geometries with identified CFT duals presently known.Comment: 35 pages, v2: comments added, typos corrected, reference adde