8,899 research outputs found
Evolving IT management frameworks towards a sustainable future
Information Technology (IT) Management Frameworks are a fundamental tool used by IT professionals to efficiently manage IT resources and are globally applied to IT service delivery and management. Sustainability is a recent notion that describes the need for economic, environmental and social development with- out compromising the ability of future generations to meet their own needs; this applies to businesses as well as society in general. Unfortunately, IT Management Frameworks do not take sustainability into account. To the practitioner this paper demonstrates sustainability integration thereby allowing CIOs and IT managers to improve the sustainability of their organisation. To the researcher this paper argues that sustainability concerns need to be provided to IT Management through its integration into the mainstream of IT Management Frameworks. This is demonstrated through the high-level integration of sustainability in Six Sigma, C OBI T, ITIL and PRINCE2
Selective excitation of homogeneous spectral lines
It is possible, for homogeneously broadened lines, to excite selectively the
response signals, which are orders of magnitude narrower than the original
lines. The new type of echo, which allows detecting such signals, and the
formalism, useful for understanding the phenomenon, as well as the experimental
examples from NMR spectroscopy are presented.Comment: 19 pages, 8 figure
Berry's phase for coherent states of Landau levels
The Berry phases for coherent states and squeezed coherent states of Landau
levels are calculated. Coherent states of Landau levels are interpreted as a
result of a magnetic flux moved adiabatically from infinity to a finite place
on the plane. The Abelian Berry phase for coherent states of Landau levels is
an analog of the Aharonov- Bohm effect. Moreover, the non-Abelian Berry phase
is calculated for the adiabatic evolution of the magnetic field B.Comment: 4 pages, 1 figur
The many faces of multivisceral transplantation
The transplantation of multiple abdominal viscera, including liver-duodenum-pancreas, liver-stomach-duodenum-pancreas and liver-intestine, is being performed with increasing frequency and success. These procedures and other variations are derived from a seldom used multivisceral operation in which all of the foregoing organs are transplanted en bloc. It is described herein how the full multivisceral transplantation and its less extensive derivatives are based on the same principles of procurement, preservation and postoperative management. With all of these multiple organ permutations and with intestinal transplantation alone, management is complicated by inclusion in the grafts of a large lymphoreticular component that is capable of causing graft versus host disease (GVHD). Because of a systematic error in therapeutic philosophy, past efforts have been directed at altering or damaging the lymphoreticular cells by pretreatment of the donor or of the organs with drugs, irradiation or other means. From recent observations, the alternative approach is suggested of keeping these lymphoid depots intact, which then become the site of two way cell traffic after transplantation. With the use of powerful immunosuppression, such as that provided with FK 506, the donor lymphoreticular cells can circulate in the recipient without causing clinical GVHD, and the lymphoreticular cells in the graft become those of the recipient (local chimerism) without causing rejection. Even with avoidance of rejection and GVHD, metabolic interrelations between the grafted organs, and also between the graft organs and retained recipient viscera can affect the fate of the individual transplanted organs or retained recipient organs. The best delineated of these metabolic influences are mediated by the endogenous splanchnic hepatotrophic factors, of which insulin has been the most completely studied. An understanding of these various immunologic and nonimmunologic factors combined with more potent immunosuppression that is now available is sure to stimulate efforts at transplantation of abdominal organs and particularly of the hollow viscera that have resisted such clinical efforts
Dynamics of Neural Networks with Continuous Attractors
We investigate the dynamics of continuous attractor neural networks (CANNs).
Due to the translational invariance of their neuronal interactions, CANNs can
hold a continuous family of stationary states. We systematically explore how
their neutral stability facilitates the tracking performance of a CANN, which
is believed to have wide applications in brain functions. We develop a
perturbative approach that utilizes the dominant movement of the network
stationary states in the state space. We quantify the distortions of the bump
shape during tracking, and study their effects on the tracking performance.
Results are obtained on the maximum speed for a moving stimulus to be
trackable, and the reaction time to catch up an abrupt change in stimulus.Comment: 6 pages, 7 figures with 4 caption
Origin of lymph node-derived lymphocytes in human hepatic allografts
Hepatic allograft-derived lymph nodes were examined in the post-transplant period on order to determine the origin of lymphocytes and structural elements of the lymph node. Histologic assessment and immunohistochemical studies verified that T-cell infiltration of donor lymph nodes by recipient-derived lymphocytes occurred early in the post-transplant period. These T cells bore T-cell activation markers, e.g. TAC receptor and HLA-DR antigens. In addition, functional analysis demonstrated alloreactive T cells in secondary proliferation assays. The pattern of alloreactivity in these assays was dependent upon the phenotypic make-up (and therefore origin) of the lymphocytes within the lymph node. A gradual shift in predominance of donor-derived lymphocytes to recipient-derived lymphocytes occurred, but even late in the post-transplant course the stromal elements and a residium of lymphocytes within the lymph nodes continued to bear donor HLA antigens. The possible role of these 'passenger' lymphocytes in allograft immunity is discussed
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