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Getting By With The Advice Of Their Friends: Ceos' Advice Networks And Firms' Strategic Responses To Poor Performance
This paper theorizes that relatively poor firm performance can prompt chief executive officers (CEOs) to seek more advice from executives of other firms who are their friends or similar to them and less advice from acquaintances or dissimilar others and suggests how and why this pattern of advice seeking could reduce firms' propensity to change corporate strategy in response to poor performance. We test our hypotheses with large-sample survey data on the identities of CEOs' advice contacts and archival data on firm performance and corporate strategy. The results confirm our hypotheses and show that executives' social network ties can influence firms' responses to economic adversity, in particular by inhibiting strategic change in response to relatively poor firm performance. Additional findings indicate that CEOs' advice seeking in response to low performance may ultimately have negative consequences for subsequent performance, suggesting how CEOs' social network ties could play an indirect role in organizational decline and downward spirals in firm performance.Business Administratio
Spontaneous spatial fractal pattern formation in absorptive systems
We predict, for the first time to our knowledge, that purely-absorptive nonlinearity can support spontaneous spatial fractal pattern formation. A passive optical ring cavity with a thin slice of saturable absorber is analyzed. Linear stability analysis yields threshold curves for Turing (static) instabilities with features proposed as characteristics of potential fractal pattern formation. Numerical simulations of the fully-nonlinear dynamics, with both one and two transverse dimensions, confirm theoretical predictions
Binary Capture Rates for Massive Protostars
The high multiplicity of massive stars in dense, young clusters is
established early in their evolution. The mechanism behind this remains
unresolved. Recent results suggest that massive protostars may capture
companions through disk interactions with much higher efficiency than their
solar mass counterparts. However, this conclusion is based on analytic
determinations of capture rates and estimates of the robustness of the
resulting binaries. We present the results of coupled n-body and SPH
simulations of star-disk encounters to further test the idea that disk-captured
binaries contribute to the observed multiplicity of massive stars.Comment: 4 pages, 3 figures, accepted to ApJ
Collide and Conquer: Constraints on Simplified Dark Matter Models using Mono-X Collider Searches
The use of simplified models as a tool for interpreting dark matter collider
searches has become increasingly prevalent, and while early Run II results are
beginning to appear, we look to see what further information can be extracted
from the Run I dataset. We consider three `standard' simplified models that
couple quarks to fermionic singlet dark matter: an -channel vector mediator
with vector or axial-vector couplings, and a -channel scalar mediator. Upper
limits on the couplings are calculated and compared across three alternate
channels, namely mono-jet, mono- (leptonic) and mono- (hadronic). The
strongest limits are observed in the mono-jet channel, however the
computational simplicity and absence of significant -channel model width
effects in the mono-boson channels make these a straightforward and competitive
alternative. We also include a comparison with relic density and direct
detection constraints.Comment: 32 pages, 8 figures; v2: minor changes, conclusion unchanged, matches
published versio
Genetic diversity of eukaryotic ultraphytoplankton in the Gulf of Naples during an annual cycle
Eukaryotic ultraphytoplankton (<5 ÎŒm) are an important component of phytoplankton populations, Dot blot hybridisation analysis using class level 16S rRNA gene probes as well as clone libraries were used to investigate the diversity of these ultraphytoplankton during a 15 mo period (2003 to 2004) in the Gulf of Naples. Hybridisation data showed the presence of 3 main classes, Cryptophyceae, Chrysophyceae and Prymnesiophyceae, along with lower signals from the Pelagophyceae. Clone libraries also contained these 4 classes as well as sequences from the Dictyochophyceae, Bacillariophyceae and Prasinophyceae. However, the Prymnesiophyceae gave the dominant hybridisation signal and constituted the majority of each clone library. Their diversity, with a total of 190 sequences belonging to 114 operational taxonomic units (OTUs), probably allows them to dominate the ultraphytoplankton throughout the whole year under differing environmental conditions. Over 100 of these OTUs were unique to different libraries, suggesting a succession of different taxa during the year. The Cryptophyceae were present most of the year with 1 OTU, corresponding to a Plagioselmis prolonga strain from the Gulf of Naples, being the dominant taxon (28 % of sequences). A striking result was the high hybridisation signal from the Chrysophyceae, which showed a preference for the summer months. The Pelagophyceae were present between December and March. Most (80 %) of the sequences found in the clone libraries were not identical to available 16S rRNA gene sequences, indicating a high amount of hidden diversity for these algal classes. However, sequences from Prasinophyceae Clade II (Mamiellales) were not detected in the clone libraries
Systematic Influences on Teaching Evaluations : The Case for Caution
The evaluation of teaching and learning has become an important activity in tertiary education institutions. Student surveys provide information about student perceptions and judgments of a particular subject. However, as is widely recognised, the appropriate interpretation of this data is problematic. There is a large literature, mainly for the US, on the use and usefulness of student subject evaluations. This literature has highlighted a number of âmitigating factorsâ such as subject difficulty, discipline area, etc., that should be taken into account in interpreting the results of these questionnaires. In this paper we examine 8 years of QOT responses from an Economics Department in an Australian University which accounted for more than 79,000 student subject enrolments in 565 subjects. The purpose of this analysis is to establish how the information contained in these data can be used to interpret the responses. In particular, we determine to what extent other factors besides the instructor in charge of the subject have an impact on the raw average student evaluation scores. We find that the following characteristics of the students in these classes had an influence on the average QOT score: year level, enrolment size, the quantitative nature of the subject, the country of origin of the students, the proportion that are female, Honours status of the student, the differential in their mark from previous marks, quality of workbook, quality of textbook and the relative QOT score versus other subjects taught at the same time. However, a number of other factors proposed in the literature to be important influences were found not to be. These include the studentâs fee paying status, whether they attended a public, private or catholic secondary school, which other faculty within the University they came from, and if the subject was taught in multiple sessions.
Z-Pencils
The matrix pencil (A,B) = {tB-A | t \in C} is considered under the
assumptions that A is entrywise nonnegative and B-A is a nonsingular M-matrix.
As t varies in [0,1], the Z-matrices tB-A are partitioned into the sets L_s
introduced by Fiedler and Markham. As no combinatorial structure of B is
assumed here, this partition generalizes some of their work where B=I. Based on
the union of the directed graphs of A and B, the combinatorial structure of
nonnegative eigenvectors associated with the largest eigenvalue of (A,B) in
[0,1) is considered.Comment: 8 pages, LaTe
Gravity on a Little Warped Space
We investigate the consistent inclusion of 4D Einstein gravity on a truncated
slice of AdS_5 whose bulk-gravity and UV scales are much less than the 4D
Planck scale, M_* << M_{Pl}. Such "Little Warped Spaces" have found
phenomenological utility and can be motivated by string realizations of the
Randall-Sundrum framework. Using the interval approach to brane-world gravity,
we show that the inclusion of a large UV-localized Einstein-Hilbert term allows
one to consistently incorporate 4D Einstein gravity into the low-energy theory.
We detail the spectrum of Kaluza-Klein metric fluctuations and, in particular,
examine the coupling of the little radion to matter. Furthermore, we show that
Goldberger-Wise stabilization can be successfully implemented on such spaces.
Our results demonstrate that realistic low-energy effective theories can be
constructed on these spaces, and have relevance for existing models in the
literature.Comment: 1+24 page
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