14,115 research outputs found
Influence of the Hydric Environment on Water Exchange and Hatchlings of Rigid-Shelled Turtle Eggs
To examine the possible influence of incubation substrate water potential on rigid-shelled chelonian eggs and hatchlings, rigid-shelled eggs from four clutches of Brisbane River turtle (Emydura signata) were incubated buried in vermiculite at water potentials of approximately -100, -350, and -850 kPa, and patterns of egg mass change and hatchling attributes were examined. All eggs hatched successfully, and there was no apparent effect of water potential on incubation period, fresh hatchling mass, hatchling water content, or hatchling size. Clutch of origin also had no apparent effect on these attributes when initial egg mass was used as a covariate. However, clutch of origin affected initial egg mass, and clutch of origin and incubation water potential influenced the amount of water exchanged between the eggs and their environment during incubation and the amount of residual yolk found in hatchlings. Substrate water potential has little effect on hatchling outcomes other than the proportion of yolk converted to hatchling tissue during incubation in the rigid-shelled eggs of E. signata. It would appear that in general, the substrate water potential during incubation affects the quality of chelonian hatchlings by influencing the amount of yolk converted to hatchling tissue during embryonic development and that this influence is stronger in flexible-shelled eggs than in rigid-shelled eggs
Gene Therapy in Cellular Immunodeficiencies
The treatment of cellular primary immunodeficiencies has benefitted from significant advances in the field of allogeneic stem cell transplantation (alloHSCT). However, while this therapy is curative for many PIDs, the procedure requires a suitably matched donor and carries significant risks of morbidity and mortality from complications such as graft-versus-host disease (GVHD). Autologous gene therapy (GT) approaches using stem cells isolated from patients and modified ex vivo using viral vectors or gene editing techniques have the potential to offer curative therapy for PID without the immunological complications of alloHSCT. GT for PID has been developed over the last 30 years, and while several setbacks have been encountered along the way, there is now a licensed GT product for ADA-SCID, and promising results from phase I/II clinical trials have demonstrated that GT may offer clinical efficacy comparable to alloHSCT in several other PIDs. Developments in the field are broadening the application of GT, and we expect that this therapeutic modality may become standard of care for the management of several PIDs in the near future. This chapter explores the development of GT over the last 30 years and outlines its role in the management of cellular primary immunodeficiencies
SU(3) Flavor Breaking in Hadronic Matrix Elements for Oscillations
We present an analysis, using quenched configurations at 5.7, 5.85,
6.0, and 6.3 of the matrix element \MP\equiv\langle \bar P_{hl}|\bar h
\gamma_\mu (1-\gamma_5)l \bar h \gamma_\mu(1-\gamma_5)l|P_{hl}\rangle for
heavy-light pseudoscalar mesons. The results are extrapolated to the physical
meson states, \Bd and \Bs. We directly compute the ratio \MS/\MB, and
obtain the preliminary result \MS/\MB=1.54(13)(32). A precise value of this
SU(3) breaking ratio is important for determining once the mixing
parameter for \Bs-\bar\Bs is measured experimentally. We also determine
values for the corresponding B parameters, , which we cannot distinguish in the present analysis.Comment: Poster presented at LATTICE96(heavy quarks). LaTeX, uses espcrc2.sty
and epsf, 4 pages, 4 postscript figures include
Fundamental properties and applications of quasi-local black hole horizons
The traditional description of black holes in terms of event horizons is
inadequate for many physical applications, especially when studying black holes
in non-stationary spacetimes. In these cases, it is often more useful to use
the quasi-local notions of trapped and marginally trapped surfaces, which lead
naturally to the framework of trapping, isolated, and dynamical horizons. This
framework allows us to analyze diverse facets of black holes in a unified
manner and to significantly generalize several results in black hole physics.
It also leads to a number of applications in mathematical general relativity,
numerical relativity, astrophysics, and quantum gravity. In this review, I will
discuss the basic ideas and recent developments in this framework, and
summarize some of its applications with an emphasis on numerical relativity.Comment: 14 pages, 2 figures. Based on a talk presented at the 18th
International Conference on General Relativity and Gravitation, 8-13 July
2007, Sydney, Australi
Democracy in Schools: Encouraging Responsibility and citizenship through student participation in school decision making
What should be the place of children’s voices in the running of their schools and in their education? Sadly, in Australia this question is often overlooked in the shifting sands of education policy. Commonly, state and federal governments focus on schools solely through a lens of educational attainment. Increasingly, the emphasis seems to be on the development of the national curriculum, and on the measuring of school and student performance in public examinations, publicised now on the MySchools website. Meanwhile, the media often focus on the behavioural problems with which schools are dealing and statistics reveal an increasing trend towards student disengagement from school through truancy and exclusion. The procedures for addressing problems, prescribed in policy and legislation, tend to be reactive rather than proactive. The formulation and establishment of the United Nations Convention on the Rights of the Child (UNCROC) has led to a mounting global discussion on the rights of children generally. Particularly relevant in the education context is the right of participation set out in Article 12(1) and the link between the development of citizenship principles through democratic practices in schools, and nation-building.3 While participatory and restorative practices in education have been the subject of debate for several decades, and have been implemented elsewhere, such concepts have been slow to enter public consciousness in Australia. The teaching of citizenship in schools here has concentrated on civics classroom education. Increasingly though educators in Australia are taking the initiative in their schools to introduce citizenship by practice and example within the school structure, by ‘doing’ rather than just ‘teaching’. Many of these practices are associated with active citizenship and democracy, and are based on participation in decision making in schools, including in the restoration of interpersonal relationships. Where measures are implemented it is typically through the impetus of a keen principal or staff member, and while there are many indications of their success, they have yet to attract serious attention of education policy makers, legislators, and designers of university education curricula
Prosocial response to client-instigated victimisation: the roles of forgiveness and workgroup conflict
We investigate forgiveness as a human service employee coping response to client-instigated victimizations and further explore the role of workgroup conflict in 1) facilitating this response, and 2) influencing the relationship between victimization and workplace outcomes. Using the theoretical lens of Conservation of Resources (Hobfoll, 1989), we propose that employees forgive clients – especially in the context of low workgroup conflict. From low to moderate levels of client-instigated victimization, we suggest that victimization and forgiveness are positively related; however, this positive relationship does not prevail when individuals confront egregious levels of victimization (i.e., an inverted-U shape). This curvilinear relationship holds under low but not under high workgroup conflict. Extending this model to workplace outcomes, findings also demonstrate that the indirect effects of victimization on job satisfaction, burnout, and turnover intentions are mediated by forgiveness when workgroup conflict is low. Experiment- and field-based studies provide evidence for the theoretical model
Monte Carlo Determination of Multiple Extremal Eigenpairs
We present a Monte Carlo algorithm that allows the simultaneous determination
of a few extremal eigenpairs of a very large matrix without the need to compute
the inner product of two vectors or store all the components of any one vector.
The new algorithm, a Monte Carlo implementation of a deterministic one we
recently benchmarked, is an extension of the power method. In the
implementation presented, we used a basic Monte Carlo splitting and termination
method called the comb, incorporated the weight cancellation method of Arnow
{\it et al.}, and exploited a new sampling method, the sewing method, that does
a large state space sampling as a succession of small state space samplings. We
illustrate the effectiveness of the algorithm by its determination of the two
largest eigenvalues of the transfer matrices for variously-sized
two-dimensional, zero field Ising models. While very likely useful for other
transfer matrix problems, the algorithm is however quite general and should
find application to a larger variety of problems requiring a few dominant
eigenvalues of a matrix.Comment: 22 pages, no figure
Probing 5f-state configurations in URu2Si2 with U L3-edge resonant x-ray emission spectroscopy
Resonant x-ray emission spectroscopy (RXES) was employed at the U L3
absorption edge and the La1 emission line to explore the 5f occupancy, nf, and
the degree of 5f orbital delocalization in the hidden order compound URu2Si2.
By comparing to suitable reference materials such as UF4, UCd11, and alpha-U,
we conclude that the 5f orbital in URu2Si2 is at least partially delocalized
with nf = 2.87 +/- 0.08, and does not change with temperature down to 10 K
within the estimated error. These results place further constraints on
theoretical explanations of the hidden order, especially those requiring a
localized f2 ground state.Comment: 11 pages,7 figure
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