617 research outputs found
IS Project Risks as Emergent Phenomena: Towards a Model of Risk Escalation and its Management
While the number of substantive investments in IS projects continues to grow, the number of
failing projects also continues to increase at an alarming rate. Both the academic and industry
literature suggests that inadequate attention to risk and its management continues to be a key
factor in project failure. The typical approach taken is to identify and map potential risks, to
act as a planning and diagnostic tool, and to prepare a contingency plan has been a factorbased
approach. While it remains a valuable tool for mapping anticipated risks the factorbased
approach is less effective when viewing project risks as emergent phenomena that unfold
during the course of the project, and require ongoing attention and risk management. Informed
by a case study of a failing university IS development project, this paper focuses on the
phenomenon of risk escalation. The case findings suggest that rather than being defined ahead
of the project, some project risks may emerge during the project as a consequence of escalation
factors that were both antecedent to and a consequence of actual risk management decisions.
The article concludes with suggestions as to how project managers can better man-age the
emergent rather than static nature of risk phenomena
Predictions for decays
We present a phenomenological study of the rare double radiative decay in the Standard Model (SM) and beyond. Using the operator
product expansion (OPE) technique, we estimate the short-distance (SD)
contribution to the decay amplitude in a region of the phase space which is
around the point where all decay products have energy in the rest
frame of the -meson. At lowest order in 1/Q, where is of order ,
the matrix element is then expressed in terms of the
usual form factors known from semileptonic rare decays. The integrated
SD branching ratio in the SM in the OPE region turns out to be . We work
out the di-photon invariant mass distribution with and without the resonant
background through . In the SM,
the resonance contribution is dominant in the region of phase space where the
OPE is valid. The present experimental upper limit on
decays, which constrains the scalar/pseudoscalar Four-Fermi operators with
, leaves considerable room for new physics in the
one-particle-irreducible contribution to decays. In this
case, we find that the SD branching ratio can be
enhanced by one order of magnitude with respect to its SM value and the SD
contribution can lie outside of the resonance peaks.Comment: 17 pages, 4 figures; Note added on Schouten identity and 2 references
added; v4: typos in Eqs (8), (44) and erroneous statement on mixing before Eq
(44) fixed. All results and conclusions unchange
Topological Superfluid in one-dimensional Ultracold Atomic System with Spin-Orbit Coupling
We propose a one-dimensional Hamiltonian which supports Majorana
fermions when -wave superfluid appears in the ultracold atomic
system and obtain the phase-separation diagrams both for the
time-reversal-invariant case and time-reversal-symmetry-breaking case. From the
phase-separation diagrams, we find that the single Majorana fermions exist in
the topological superfluid region, and we can reach this region by tuning the
chemical potential and spin-orbit coupling . Importantly, the
spin-orbit coupling has realized in ultracold atoms by the recent experimental
achievement of synthetic gauge field, therefore, our one-dimensional ultra-cold
atomic system described by is a promising platform to find the
mysterious Majorana fermions.Comment: 5 papers, 2 figure
T-functions revisited: New criteria for bijectivity/transitivity
The paper presents new criteria for bijectivity/transitivity of T-functions
and fast knapsack-like algorithm of evaluation of a T-function. Our approach is
based on non-Archimedean ergodic theory: Both the criteria and algorithm use
van der Put series to represent 1-Lipschitz -adic functions and to study
measure-preservation/ergodicity of these
miR-23~27~24 clusters control effector T cell differentiation and function
Coordinated repression of gene expression by evolutionarily conserved microRNA (miRNA) clusters and paralogs ensures that miRNAs efficiently exert their biological impact. Combining both loss- and gain-of-function genetic approaches, we show that the miR-23~27~24 clusters regulate multiple aspects of T cell biology, particularly helper T (Th) 2 immunity. Low expression of this miRNA family confers proper effector T cell function at both physiological and pathological settings. Further studies in T cells with exaggerated regulation by individual members of the miR-23~27~24 clusters revealed that miR-24 and miR-27 collaboratively limit Th2 responses through targeting IL-4 and GATA3 in both direct and indirect manners. Intriguingly, although overexpression of the entire miR-23 cluster also negatively impacts other Th lineages, enforced expression of miR-24, in contrast to miR-23 and miR-27, actually promotes the differentiation of Th1, Th17, and induced regulatory T cells, implying that under certain conditions, miRNA families can fine tune the biological effects of their regulation by having individual members antagonize rather than cooperate with each other. Together, our results identify a miRNA family with important immunological roles and suggest that tight regulation of miR-23~27~24 clusters in T cells is required to maintain optimal effector function and to prevent aberrant immune responses
How Does Pubertal Development Impact Caregiver-Adolescent Communication About Sex in Rural, African American Families? An Examination of Mediation Effects
This study examined the relationship between pubertal development and type of caregiver-adolescent communication about sex (CACS) among 441 African American caregivers participating in an intervention trial in rural North Carolina. We assessed CACS about general sexual health topics and positive aspects of sexuality. Caregivers’ attitudes and self-efficacy for CACS, and open communication style were examined as potential mediators. Caregivers engaged in low levels of communication about sex regardless of type. Among caregivers of males, pubertal development was associated with greater communication about general sexual health, which was mediated by self-efficacy for CACS. Among caregivers of females, pubertal development was associated with less communication about general and positive sexual health topics; however, there were no mediating factors. These findings highlight the predictors of CACS among young men and women after pubertal onset. Age appropriate, practical guidance for initiating CACS may be critical for ensuring caregiver talk about sex
High-Energy Aspects of Solar Flares: Overview of the Volume
In this introductory chapter, we provide a brief summary of the successes and
remaining challenges in understanding the solar flare phenomenon and its
attendant implications for particle acceleration mechanisms in astrophysical
plasmas. We also provide a brief overview of the contents of the other chapters
in this volume, with particular reference to the well-observed flare of 2002
July 23Comment: This is the introductory article for a monograph on the physics of
solar flares, inspired by RHESSI observations. The individual articles are to
appear in Space Science Reviews (2011
Asymptotology of Chemical Reaction Networks
The concept of the limiting step is extended to the asymptotology of
multiscale reaction networks. Complete theory for linear networks with well
separated reaction rate constants is developed. We present algorithms for
explicit approximations of eigenvalues and eigenvectors of kinetic matrix.
Accuracy of estimates is proven. Performance of the algorithms is demonstrated
on simple examples. Application of algorithms to nonlinear systems is
discussed.Comment: 23 pages, 8 figures, 84 refs, Corrected Journal Versio
On limit theorems for continued fractions
It is shown that for sums of functionals of digits in continued fraction
expansion the Kolmogorov-Feller weak laws of large numbers and the
Khinchine-L\'evy-Feller-Raikov characterization of the domain of attraction of
the normal law hold.Comment: 16 page
Understanding the Relationship between Religiosity and Caregiver–Adolescent Communication About Sex within African-American Families
Caregiver–adolescent communication about sex plays a critical role in the sexual socialization of youth. Many caregivers, however, do not engage their youth in such conversations, potentially placing them at risk for negative sexual health outcomes. Lack of caregiver–adolescent communication about sex may be particularly harmful for rural African American youth, as they often report early sex initiation and are disproportionately impacted by STIs. Moreover, sexual communication may be particularly challenging for families with strong religious backgrounds, potentially affecting the occurrence and breadth of topics covered during communication. Study aims were to: determine whether there was a relationship between caregiver religiosity and type of topics covered during communication about sex (e.g., general sexual health vs. positive aspects of sexuality) among 435 caregivers of early adolescent, African American youth; and if so, identify factors that might explain how religiosity affects communication about sex. Results indicated that caregiver religiosity was positively associated with communication about general, but not positive aspects of sexuality for caregivers of males. Attitudes towards communication about sex and open communication style mediated the relationship. There was no association between religiosity and communication about sex for caregivers of females. The findings from this study could provide a base to better understand and support the sexual socialization process within religious, African American families
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