Uncertainty and Human Capital Decisions: Traditional Valuation Methods and Real Options Logic

As the importance of human capital increases in organizations, so does the need to develop more sophisticated financial valuation models. This paper reviews some of the major traditional financial decision making models used in costing employment mode choices. It then introduces the real options valuation approach for costing such choices. The advantage of the real options model is demonstrated to build flexibility into employment decisions

Frank Lloyd Wright: Materials Science and Algebra in Prairie Style Art Glass

These two lessons are intended for students in Grades 7 - 10 and Pre-Algebra and Algebra courses as an introduction to the mathematics and materials science of Frank Lloyd Wright’s Prairie Style art glass

An Exceptional Actor System (Functional Pearl)

The Glasgow Haskell Compiler is known for its feature-laden runtime system (RTS), which includes lightweight threads, asynchronous exceptions, and a slew of other features. Their combination is powerful enough that a programmer may complete the same task in many different ways -- some more advisable than others. We present a user-accessible actor framework hidden in plain sight within the RTS and demonstrate it on a classic example from the distributed systems literature. We then extend both the framework and example to the realm of dynamic types. Finally, we raise questions about how RTS features intersect and possibly subsume one another, and suggest that GHC can guide good practice by constraining the use of some features.Comment: To appear at Haskell Symposium 202

Subjective measures of household resilience to climate variability and change: insights from a nationally representative survey of Tanzania

Promoting household resilience to climate extremes has emerged as a key development priority. Yet tracking and evaluating resilience at this level remains a critical challenge. Most quantitative approaches rely on objective indicators and assessment frameworks, but these are not fully satisfactory. Much of the difficulty arises from a combination of conceptual ambiguities, challenges in selecting appropriate indicators, and in measuring the many intangible aspects that contribute to household resilience. More recently, subjective measures of resilience have been advocated in helping to overcome some of the limitations of traditional objective characterizations. However, few large-scale studies of quantitative subjective approaches to resilience measurement have been conducted. In this study, we address this gap by exploring perceived levels of household resilience to climate extremes in Tanzania and the utility of standardized subjective methods for its assessment. A nationally representative cross-sectional survey involving 1294 individuals was carried out by mobile phone in June 2015 among randomly selected adult respondents aged 18 and above. Factors that are most associated with resilience-related capacities are having had advance knowledge of a previous flood, and to a lesser extent, believing flooding to be a serious community problem. Somewhat surprisingly, though a small number of weak relationships are apparent, most socio-demographic variables do not exhibit statistically significant differences with regards to perceived resilience-related capacities. These findings may challenge traditional assumptions about what factors characterize household resilience, offering a motivation for studying both subjective and objective perspectives, and understanding better their relationship to one another. If further validated, subjective measures may offer potential as both a complement and alternative to traditional objective methods of resilience measurement, each with their own merits and limitations

Inductive diagrams for causal reasoning

The Lamport diagram is a pervasive and intuitive tool for informal reasoning about causality in a concurrent system. However, traditional axiomatic formalizations of Lamport diagrams can be painful to work with in a mechanized setting like Agda, whereas inductively-defined data would enjoy structural induction and automatic normalization. We propose an alternative, inductive formalization -- the causal separation diagram (CSD) -- that takes inspiration from string diagrams and concurrent separation logic. CSDs enjoy a graphical syntax similar to Lamport diagrams, and can be given compositional semantics in a variety of domains. We demonstrate the utility of CSDs by applying them to logical clocks -- widely-used mechanisms for reifying causal relationships as data -- yielding a generic proof of Lamport's clock condition that is parametric in a choice of clock. We instantiate this proof on Lamport's scalar clock, on Mattern's vector clock, and on the matrix clocks of Raynal et al. and of Wuu and Bernstein, yielding verified implementations of each. Our results and general framework are mechanized in the Agda proof assistant

The Effects of Regulations on Private School Choice Program Participation: Experimental Evidence from Florida

When deciding whether to participate in a private school choice program, private school leaders weigh additional financial benefits against additional regulatory costs. In theory, raising the costs associated with entering private school choice programs should reduce the likelihood that individual schools participate in those programs. However, very little empirical evidence exists evaluating this idea. While a few studies suggest that more highly regulated programs are correlated with lower levels of school participation, none have established causal relationships between these factors, and none have determined which program regulations are the most costly. Because it is nearly impossible to randomly assign program regulations to individual private schools, we use surveys to randomly assign different regulations to 3,080 private school leaders in Florida and ask them whether they would participate in a new private school choice program during the following school year. Relative to no regulations, our most conservative models find that open-enrollment mandates reduce the likelihood that private schools are certain to participate by about 17 percentage points, or 70 percent. State standardized testing requirements reduce the likelihood that private schools are certain to participate by 11 percentage points, or 44 percent. We find no evidence to suggest that the prohibition of copayment affects program participation overall. These estimates of the impact of regulatory requirements on the expressed willingness of private school principals to participate in a private school choice program are causal because random assignment leads to equivalence in expectation across treatment and control groups on both measurable and unmeasurable factors. We also find evidence to suggest that higher quality schools – as measured by tuition levels and enrollment trends – are more likely to be deterred by program regulation

Elucidating the regulation of complex signalling systems in plant cells

The pollen tube represents a model system for the study of tip growth, and the root provides a valuable system to study gene and signalling networks in plants. In the present article, using the two systems as examples, we discuss how to elucidate the regulation of complex signalling systems in plant cells. First, we discuss how hormones and related genes in plant root development form a complex interacting network, and their activities are interdependent. Therefore their roles in root development must be analysed as an integrated system, and elucidation of the regulation of each component requires the adaptation of a novel modelling methodology: regulation analysis. Secondly, hydrodynamics, cell wall and ion dynamics are all important properties that regulate plant cell growth. We discuss how regulation analysis can be applied to study the regulation of hydrodynamics, cell wall and ion dynamics, using pollen tube growth as a model system. Finally, we discuss future prospects for elucidating the regulation of complex signalling systems in plant cells

The Effects of Regulations on Private School Choice Program Participation: Experimental Evidence from California and New York

Although private school voucher programs provide subsidies to students for tuition and other education-related costs, private school leaders weigh program participation against any associated regulatory costs. The higher the regulatory costs of participation, the less likely a private school is to participate in a school voucher program. Since we do not know with certainty which regulations will be viewed by school leaders as more or less costly, we explore whether specific regulations that are common to private school choice programs do or do not deter likely voucher program participation.We use surveys to randomly assign different regulations to 4,825 private school leaders in the states of California and New York and ask them whether or not they would participate in a new private school choice program during the following school year. Relative to no regulations, our most conservative models find that open-enrollment mandates reduce the likelihood that private school leaders are certain to participate in a hypothetical choice program by about 19 percentage points, or 60 percent. State standardized testing requirements reduce the likelihood that private school leaders are certain to participate by 9 percentage points, or 29 percent. We find no evidence to suggest that the prohibition of copayment or nationally norm-referenced testing requirements affect the overall willingness to participate in a school choice program