1,209 research outputs found
Contractor’s Financial Estimation based on Owner Payment Histories
A contractor’s financial viability is affected by late and incomplete payments from the owner. Late and incomplete payments lead to cash flow uncertainty, additional bank interest, and delays in paying creditors such as suppliers and subcontractors, and may lead to decreased project
performance, and possible additional time and cost due to disputes. The paper presents a method for cash flow and present value analysis under uncertainty based on an owner’s payment history or estimated payment characteristics. The paper generalises existing modelling of uncertainty associated with late and incomplete owner payments to a range of claim types by the contractor, and different owner types. Aging contractor claims are analysed for claims submitted on a regular basis for amounts which may vary depending on project phasing. For each of the pre-identified typical owner payment practices, the estimated paid proportions of claims and the steady state distribution of payments in different age categories are established. A present value analysis assesses project viability from the contractor’s viewpoint. Actual project data are used to confirm the validity of the method. The intent of the paper is to assist contractors establish suitable allowances in their tender pricing, to choose a suitable claim/payment schedule and/or to adopt suitable administration practices to optimise cash flow. The paper gives a summary approach for contractors, providing them with a practical tool in cash flow planning, control and risk management
Emission and Cost Configurations in Earthmoving Operations
Brief introduction to the problem. The paper examines the influence
of varying operation parameters such as equipment heterogeneity, payload,
and travel times, on unit emissions and unit costs in earthmoving
and like operations. The need to minimise cost and maximise production
of earthmoving and like operations has led to such operations being
heavily scrutinised. With environmental issues becoming more important,
there is now a need to additionally scrutinise and minimise emissions.
Cycle times and production were measured in a cut-and-fill case
study operation; average fuel burn data are converted to idling and nonidling
emission fractions; and queuing theory is used for the theoretical
evaluation of production for varying operation parameters. It is demonstrated
that the optimum fleet sizes in terms of minimum unit costs and
minimum unit emissions coincide in earthmoving operations. The result
is independent of any specific operational parameters. The paper concludes
that the traditional way of undertaking earthmoving operations,
namely configuring to give minimum unit costs, will also result in minimum
unit emissions. And that configuring differently to that will lead to
unnecessary emissions. The result carries over to quarrying and surface
mining operations
Vigilantism, Current Racial Threat, and Death Sentences
Capital punishment is the most severe punishment, yet little is known about the social conditions that lead to death sentences. Racial threat explanations imply that this sanction will be imposed more often in jurisdictions with larger minority populations, but some scholars suggest that a tradition of vigilante violence leads to increased death sentences. This study tests the combined explanatory power of both accounts by assessing statistical interactions between past lynchings and the recent percentage of African Americans after political conditions and other plausible effects are held constant. Findings from count models based on different samples, data, and estimators suggest that racial threat and lynchings combine to produce increased death sentences, but the presence of liberal political values explains the absence of death sentences. These findings both confirm and refine the political version of conflict theory because they suggest that the effects of current racial threat and past vigilantism largely directed against newly freed slaves jointly contribute to current lethal but legal reactions to racial threat
Coherent generation of EPR-entangled light pulses mediated by a single trapped atom
We show that a single, trapped, laser-driven atom in a high-finesse optical
cavity allows for the quantum-coherent generation of entangled light pulses on
demand. Schemes for generating simultaneous and temporally separated pulse
pairs are proposed. The mechanical effect of the laser excitation on the
quantum motion of the cold trapped atom mediates the entangling interaction
between two cavity modes and between the two subsequent pulses, respectively.
The entanglement is of EPR-type, and its degree can be controlled through
external parameters. At the end of the generation process the atom is
decorrelated from the light field. Possible experimental implementations of the
proposals are discussed.Comment: 11 pages, 4 figure
Relationship between childhood trauma and paranoia: a study of specificity and underlying theoretical mechanisms
Purpose: While biogenetic theories have traditionally dominated understandings of
psychosis, there is now a large body of evidence suggesting a causal relationship
between childhood trauma and psychosis. We sought to further study this
relationship by adopting a psychotic experience specific approach and applying two
of Bradford Hill’s causality criteria, namely specificity and underlying theoretical
mechanisms, to the relationship between childhood trauma and paranoia.
Method: Chapter 1 was a systematic review and meta-analysis that sought to
examine the magnitude of the association between childhood sexual (CSA), physical
(CPA) and emotional abuse (CEA) and physical (CPN) or emotional neglect (CEN)
and paranoia across community and clinical samples. Chapter 2 is an empirical
research study that sought to test whether negative core schema mediated the
relationship between childhood trauma and paranoia. Study 1 sought to these
relationships within the general population, whereas Study 2 aimed to test these in a
clinical sample of people with persecutory delusions. We also sought to pilot a new
measure of negative core schema, The Schema Rating Scale (SCIRATS). Correlation
and mediation analysis were utilised to test our empirical study hypothesis.
Results: Our meta-analysis found small associations between all forms of childhood
trauma and paranoia examined, however the magnitude of the association may be
somewhat greater for CEA and CPA than for the other forms of childhood we
examined and paranoia . In Study 1, we found that negative-self, negative-other and
both negative-self and negative-other core schema mediated the relationship between
childhood trauma and paranoia. We found similar results when repeating these
analyses with the SCIRATS. In Study 2, we found significant associations between
childhood trauma and negative-self core schema that remained significant on the
SCIRATS. Negative-self and negative-other core schema were also significantly
associated with paranoia however, when we repeated this analysis with the
SCIRATS, only negative-self core schema remained significant. We found no
significant association between childhood trauma and paranoia. Positive initial
feedback on the SCIRATS would suggest participants view this as an acceptable
measure.
Conclusions: Whilst acknowledging the limitations associated with our studies, our
findings suggest that while there appears to be a general association between the
forms of childhood trauma we examined and paranoia, this relationship may be
somewhat greater for CEA and CPA and paranoia. They are consistent with
cognitive models of psychosis and suggest that negative core schema may be
important underlying mechanisms in the relationship between childhood trauma and
paranoia. We make recommendations for future research to further examine the
evidence for specificity and recommend that individuals with psychosis should be
asked about childhood trauma and that future research should further examine the
potential benefits of trauma-informed formulation and psychological therapies
targeting negative core schema in reducing paranoia
Who Survives on Death Row? An Individual and Contextual Analysis
What are the relationships between death row offender attributes, social arrangements, and executions? Partly because public officials control executions, theorists view this sanction as intrinsically political. Although the literature has focused on offender attributes that lead to death sentences, the post-sentencing stage is at least as important. States differ sharply in their willingness to execute and less than 10 percent of those given a death sentence are executed. To correct the resulting problems with censored data, this study uses a discrete-time event history analysis to detect the individual and state-level contextual factors that shape execution probabilities. The findings show that minority death row inmates convicted of killing whites face higher execution probabilities than other capital offenders. Theoretically relevant contextual factors with explanatory power include minority presence in nonlinear form, political ideology, and votes for Republican presidential candidates. Inasmuch as there is little or no systematic research on the individual and contextual factors that influence execution probabilities, these findings fill important gaps in the literature
A Comparative Study of Collegiate Aviation Students and Business Students Related to Myers-Briggs Type Indicator Preferences
There has been limited research to date that addresses the difference, if any, between students who choose the various fields of aviation as a major, and those who choose other majors, particularly business. This study utilizes the Myers-Briggs Type Indicator (MBTI) to compare preferences of aviation majors to business majors because of its unique characteristics and its noted lack of use in the aviation arena. The findings of the study revealed that there are no significant differences between business and aviation students in the Myers-Briggs Type Indicators except in the way they orient themselves in the environment (Judging and Perceiving). These findings are a reminder to teachers of aviation students that classroom structure should balance discussion, practice skills, fun and other activities with learning objectives to accommodate the dominant styles of aviation learners. On the other hand, the predominant Judging style of business students would demand that classroom discussion be somewhat limited in order to meet specific learning goals. Maintaining a balance of teaching style is important both for the teacher and the student in reducing the discomfort of the teacher operating outside a preferred style and eliminating the mental stress of the student attempting to learn new material while using an auxiliary type
Evidence base for health and planning – lessons from an ESRC seminar series
The article looks at the lessons on the health and planning evidence base, evidence-sharing and integration that have been emerging from an ESRC seminar series on reuniting health and planning bringing together academics and planning and public health professionals
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