163,096 research outputs found
E-government evaluation: Reflections on three organisational case studies
The deployment of e-Government continues at a
significant cost and pace in the worldwide public sector.
An important area of research is that of the evaluation of
e-Government. In this paper the authors report the
findings from three interpretive in-depth organisational
case studies that explore e-Government evaluation within
UK public sector settings. The paper elicits insights to
organisational and managerial aspects with the aim of
improving knowledge and understanding of e-
Government evaluation. The findings that are
extrapolated from the analysis of the three case studies
are classified and mapped onto a tentative e-Government
evaluation framework and presented in terms lessons
learnt. These aim to inform theory and improve e-
Government evaluation practice. The paper concludes
that e-Government evaluation is an under developed area
and calls for senior executives to engage more with the e-
Government agenda and commission e-Government
evaluation exercises to improve evaluation practice
Early to middle Miocene foraminifera from the deep-sea Congo Fan, offshore Angola
Analysis of a 630m section of an exploration well penetrating the distal part of the Congo Fan (~2000m water depth)
yielded high abundance and diversity assemblages of agglutinated and calcareous benthic foraminifera. Planktonic foraminifera constrain
the age to Early – Middle Miocene, and \delta 18O records reveal the Mi1 (~16.3 Ma) isotopic shift. Relatively few taxonomic studies
of deep-water calcareous and agglutinated benthic foraminifera exist from this time period in this locality. All species encountered are
therefore taxonomically described and documented using SEM photography (over 170 species), along with 27 species of planktonic
foraminifera. Faunas show close affinities to those of the eastern Venezuela Basin, Gulf of Mexico and Central Paratethys.
Seven assemblages are defined and analysed using morphogroup analysis and Correspondence Analysis, documenting the response
of benthic foraminifera to three primary environmental-forcing factors; energy levels in the benthic boundary layer, oxygen levels
relating to changing surface water productivity, and fluctuations in the level of the CCD. Near the top and bottom of the studied
section both foraminiferal abundance and diversity decrease, corresponding with increased sand content implying greater energy levels
and environmental disturbance. The majority of the section consists of shales with very low percentage sand, high foraminiferal abundance
and diversity, and high sedimentation rates of ~10cm/kyr. Morphogroup analysis reveals a major switch in the fauna at around
oxygen isotope event Mi1, with the transition from an epifaunal-dominated Cibicidoides assemblage to shallow infaunal-dominated
Bulimina assemblage. We regard this as likely due to expansion of the oxygen minimum zone (paleobathymetric estimates are ~1000m)
related to increased surface-water productivity and global cooling. Shifts in calcareous foraminiferal percentage over the studied interval
overprint these signals and are believed to be related to a shoaling CCD, linked to reduced oceanic acidity and global atmospheric
CO2 levels during the early Middle Miocene Monterey Carbon Isotope Excursion
Production of Millisecond Dips in Sco X-1 Count Rates by Dead Time Effects
Chang et al. (2006) reported millisecond duration dips in the X-ray intensity
of Sco X-1 and attributed them to occultations of the source by small
trans-Neptunian objects (TNOs). We have found multiple lines of evidence that
these dips are not astronomical in origin, but rather the result of high-energy
charged particle events in the RXTE PCA detectors. Our analysis of the RXTE
data indicates that at most 10% of the observed dips in Sco X-1 could be due to
occultations by TNOs, and, furthermore, we find no positive or supporting
evidence for any of them being due to TNOs. We therefore believe that it is a
mistake to conclude that any TNOs have been detected via occultation of Sco
X-1.Comment: Submitted to ApJ; uses emulateapj.cls, 8 pages with 8 figure
E-Government Evaluation: Reflections on two Organisational studies
Senior executives in public sector organisations have been charged with delivering an e-Government agenda. A key emerging area of research is that of the evaluation of e-Government, given that economic factors have traditionally dominated any traditional ICT evaluation process. In this paper the authors report the findings from two interpretive in-depth case studies in the UK public sector, which explore e-Government organisational evaluation within a public sector setting. This paper seeks to offer insights to organisational and managerial aspects surrounding the improvement of knowledge and understanding of e-Government evaluation. The findings that are elicited from the case studies are analysed and presented in terms of a framework derived from organisational analysis to improve e-Government evaluation, with key lessons learnt being extrapolated from practice. The paper concludes that e-Government evaluation is both an under developed and under managed area, and calls for senior executives to engage more with the e-Government agenda and for organisations to review e-Government evaluation to improve evaluation practice
Low Temperature Electronic Transport through Macromolecules and Characteristics of Intramolecular Electron Transfer
A theory of electronic transport through molecular wires is applied to
analyze characteristics of a long-range electron transfer (ET) through
molecular bridges in macromolecules with complex donor/acceptor subsystems.
Assuming a coherent electron tunneling through the bridge to be the predominant
mechanism of ET at low temperatures it is shown that low temperature
current-voltage curves can exhibit a step-like structure, which contains
information concerning intrinsic features of ET processes such as the effect of
donor/acceptor coupling to the bridge and primary pathways of electrons
tunneling through the bridge. By contacting the proposed theoretical analysis
with such experimental data a variety of valuable characteristics of long-range
intramolecular ET can be identified. Analytical and numerical results are
presented. Using the Buttiker dephasing model within the scattering matrix
formalism we analyze dephasing effects, and we show that these effects could be
reduced enough to allow the structure of the electron transmission function to
be exposed in the experiments on the electronic transport through
macromolecules.Comment: 9 pages, 2 figures, text revise
Photon Frequency Mode Matching using Acousto-Optic Frequency Beam Splitters
It is a difficult engineering task to create distinct solid state single
photon sources which nonetheless emit photons at the same frequency. It is also
hard to create entangled photon pairs from quantum dots. In the spirit of
quantum engineering we propose a simple optical circuit which can, in the right
circumstances, make frequency distinguishable photons frequency
indistinguishable. Our circuit can supply a downstream solution to both
problems, opening up a large window of allowed frequency mismatches between
physical mechanisms. The only components used are spectrum analysers/prisms and
an Acousto-Optic Modulator. We also note that an Acousto-Optic Modulator can be
used to obtain Hong-Ou-Mandel two photon interference effects from the
frequency distinguishable photons generated by distinct sources.Comment: 4 pages, 4 figure
ESO 3060170 -- a massive fossil galaxy group with a heated gas core?
We present a detailed study of the ESO 3060170 galaxy group combining
Chandra, XMM and optical observations. The system is found to be a fossil
galaxy group. The group X-ray emission is composed of a central dense cool core
(10 kpc in radius) and an isothermal medium beyond the central 10 kpc. The
region between 10 and 50 kpc (the cooling radius) has the same temperature as
the gas from 50 kpc to 400 kpc although the gas cooling time between 10 and 50
kpc (2 - 6 Gyr) is shorter than the Hubble time. Thus, the ESO 3060170 group
does not have a group-sized cooling core. We suggest that the group cooling
core may have been heated by a central AGN outburst in the past and the small
dense cool core is the truncated relic of a previous cooling core. The Chandra
observations also reveal a variety of X-ray features in the central region,
including a ``finger'', an edge-like feature and a small ``tail'', all aligned
along a north-south axis, as are the galaxy light and group galaxy
distribution. The proposed AGN outburst may cause gas ``sloshing'' around the
center and produce these asymmetric features. The observed flat temperature
profile to 1/3 R_vir is not consistent with the predicted temperature profile
in recent numerical simulations. We compare the entropy profile of the ESO
3060170 group with those of three other groups and find a flatter relation than
that predicted by simulations involving only shock heating, S r. This is direct evidence for the importance of non-gravitational
processes in group centers. We derive the mass profiles within 1/3 R_vir and
find the ESO 3060170 group is the most massive fossil group known (1 - 2 X
10 M). The M/L ratio of the system, ~ 150 at 0.3 R_vir, is
normal.Comment: 17 pages, 12 figures, to appear in ApJ. A high-resolution version can
be downloaded from http://cxc.harvard.edu/~msun/esoa.p
Single-Peakedness and Disconnected Coalitions
Ordinally single-peaked preferences are distinguished from cardinally singlepeaked preferences, in which all players have a similar perception of distances in some one-dimensional ordering. While ordinal single-peakedness can lead to disconnected coalitions that have a "hole" in the ordering, cardinal single-peakedness precludes this possibility, based on two models of coalition formation: ¥ Fallback (FB): Players seek coalition partners by descending lower and lower in their preference rankings until a majority coalition forms. ¥ Build-Up (BU): Similar to FB, except that when nonmajority subcoalitions form, they fuse into composite players, whose positions are defined cardinally and who are treated as single players in the convergence process. FB better reflects the unconstrained, or nonmyopic, possibilities of coalition formation, whereas BU-because all subcoalition members must be included in any majority coalition that forms-restricts combinatorial possibilities and tends to produce less compact majority coalitions. The "strange bedfellows" frequently observed in legislative coalitions and military alliances suggest that even when players agree on, say, a left-right ordering, their perceptions of exactly where players stand in this ordering may differ substantially. If so, a player may be acceptable to a coalition but may not find every member in it acceptable, causing that player not to join and possibly creating a disconnected coalition.COALITION FORMATION; SINGLE-PEAKEDNESS; LEGISLATURES; ALLIANCES
Structural templating as a route to improved photovoltaic performance in copper phthalocyanine/fullerene (C60) heterojunctions
We have developed a method to improve the short circuit current density in copper phthalocyanine (CuPc)/fullerene (C60) organic solar cells by ~60% by modifying the CuPc crystal orientation through use of a molecular interlayer to maximize charge transport in the direction between the two electrodes. Powder x-ray diffraction and electronic absorption spectroscopy show that a thin 3,4,9,10-perylenetetracarboxylic dianhydride interlayer before CuPc growth templates the CuPc film structure, forcing the molecules to lie flat with respect to the substrate surface, although the intrastack orientation is unaffected. This modified stacking configuration facilitates charge transport and improves charge collection
CHANDRA observations of the NGC 1550 galaxy group -- implication for the temperature and entropy profiles of 1 keV galaxy groups
We present a detailed \chandra study of the galaxy group NGC 1550. For its
temperature (1.370.01 keV) and velocity dispersion ( 300 km
s), the NGC 1550 group is one of the most luminous known galaxy groups
(L = 1.65 erg s within 200 kpc, or 0.2 \rv).
We find that within kpc, where the gas cooling time is less than a
Hubble time, the gas temperature decreases continuously toward the center,
implying the existence of a cooling core. The temperature also declines beyond
100 kpc (or 0.1 \rv). There is a remarkable similarity of the
temperature profile of NGC 1550 with those of two other 1 keV groups with
accurate temperature determination. The temperature begins to decline at 0.07 -
0.1 \rv, while in hot clusters the decline begins at or beyond 0.2 \rv. Thus,
there are at least some 1 keV groups that have significantly different
temperature profiles from those of hot clusters, which may reflect the role of
non-gravitational processes in ICM/IGM evolution. NGC 1550 has no isentropic
core in its entropy profile, in contrast to the predictions of `entropy-floor'
simulations. We compare the scaled entropy profiles of three 1 keV groups
(including NGC 1550) and three 2 - 3 keV groups. The scaled entropy profiles of
1 keV groups show much larger scatter than those of hotter systems, which
implies varied pre-heating levels. We also discuss the mass content of the NGC
1550 group and the abundance profile of heavy elements.Comment: emulateapj5.sty, 18 pages, 11 figures (including 4 color), to appear
in ApJ, v598, n1, 20 Nov 200
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