The chemical ecology of armyworms

Moths of the genus Spodoptera are economically important pest insects. The necessity to develop novel control strategies which may be included in integrated pest management schemes has led to the study of chemical communication in several species within the genus. The polyphagous nature of most Spodoptera species makes it an interesting model to study the way in which different odor profiles are processed and interpreted by the insect brain and how this reflects upon the behavior and ecological interactions which may be of importance in agricultural systems. As such, armyworms have become a model organism in olfactory insect chemical ecology. Here, I attempt to give an overview of what is known about Spodptera chemical ecology to date and present perspectives and directions for future research

Lessons from Colombian Economic Development

Colombia is an interesting case study within emerging countries. Through 150 years of democratic tradition and seven decades of sound fiscal and monetary policies, the country has displayed institutional strength and economic growth, in spite of strong external shocks, rent- seeking by sectoral business confederations, and, recently, narco-traffickers and guerrillas. Reforms made during the nineties, just as in other Latin American nations, did not result in the expected take-off in growth. In Colombia, the reason lies partly in the consequences of discovering considerable oil reserves, the escalation of the internal conflict, the fiscal consequences of the 1991 Constitution and huge fiscal commitments related to pensions and social expenditure. In the current decade Colombia has made vast progress in invigorating the sources of economic growth, improving welfare of the poorest strata of population and reinstating the rule of law across the country. The current international crisis poses a considerable challenge in terms of growth and threatens social advancement achieved so far.Government, fiscal policies, national security and war, national budget, economic development, institutions and growth

Business Informality in Colombia: An Obstacle For Creative Destruction

This document studies the effects of business informality in terms of distortions in resource absorption, particularly labor, by informal companies. It also assesses the consequences of lower demand for labor of informal firms over aggregate productivity. With firm level data from the DANE Micro-establishments Survey, a matching exercise between formal and informal firms is conducted. It was found that the latter hire fewer employees than formal firms with the same characteristics, including Total Factor Productivity. The matching results allow using counterfactual demands of labor of informal firms to calculate and compare the real and counterfactual aggregate productivity levels. The results indicate that if informal firms would demand the amount of employment demanded by similar formal firms, market share distributionof firms would improve and this would positively affect aggregate productivity.Informal sector, Labor demand, Factor demand, Aggregate productivity, Colombia.

A Non-parametric Approach to Incorporating Incomplete Workouts Into Loss Given Default Estimates

When estimating Loss Given Default (LGD) parameters using a workout approach, i.e. discounting cash flows over the workout period, the problem arises of how to take into account partial recoveries from incomplete work-outs. The simplest approach would see LGD based on complete recovery profiles only. Whilst simple, this approach may lead to data selection bias, which may be at the basis of regulatory guidance requiring the assessment of the relevance of incomplete workouts to LGD estimation. Despite its importance, few academic contributions have covered this topic. We enhance this literature by developing a non-parametric estimator that -under certain distributional assumptions on the recovery profiles- aggregates complete and incomplete workout data to produce unbiased and more efficient estimates of mean LGD than those obtained from the estimator based on resolved cases only. Our estimator is appropriate in LGD estimation for wholesale portfolios, where the exposure-weighted LGD estimators available in the literature would not be applicable under Basel II regulatory guidance.Credit risk; bank loans; loss-given-default; LGD; incomplete observations; mortality curves

THE POLITICAL ECONOMY OF LABOR REFORM IN COLOMBIA

This paper analyzes the entire reformist effort that spans from 1990 until 2002, emphasizing the second wave that ended with the issuing of a new labor code in 2002. A successful reform has to surpass a set of deals" along the streamline of design, consensus building within civil society, submission to Congress and parliamentary debate, before it gets approved. The paper presents the story of two failed attempts for producing these "deals" within the government, along with labor unions and private sector firm confederations, before the 2002 labor reform was finally enacted. It shows what economic and social considerations created the need for reform, describes the actual policy changes implemented and evaluates their impact. The paper delves deep into the political aspects of the reform effort. Public officials of two governments pursued different lines of reform, discussion strategies and mechanisms for creating consensus, before the initiative gained momentum and circumvented key obstacles. The text of the 2002 reform proposal changed little during five years, but received important additions in the floor of Congress, with little technical support. Finally, an interesting dispute between lawyers and economists is presented regarding the role of the labor code for job creation and its function in the economic cycle. In the case of this reform, economists believed more on the computed elasticities, while lawyers believed more in the stability of established rules and in the limited role of norms. Economists should pay more attention to the workings of the political economy of reform and to the "life cycle of government", both of them critical for success."labor reform

Transient Turbulence in Taylor-Couette Flow

Recent studies have brought into question the view that at sufficiently high Reynolds number turbulence is an asymptotic state. We present the first direct observation of the decay of turbulent states in Taylor-Couette flow with lifetimes spanning five orders of magnitude. We also show that there is a regime where Taylor-Couette flow shares many of the decay characteristics observed in other shear flows, including Poisson statistics and the coexistence of laminar and turbulent patches. Our data suggest that characteristic decay times increase super-exponentially with increasing Reynolds number but remain bounded in agreement with the most recent data from pipe flow and with a recent theoretical model. This suggests that, contrary to the prevailing view, turbulence in linearly stable shear flows may be generically transient.Comment: 4 pages, 4 figures v2: Addressed referee comments for PRE. Made some cosmetic changes. Added inset to Fig.

BUDGET INFLEXIBILITY

The study of budgetary institutions has long been an important topic in the economic literature. Nonetheless, the degree of rigidity or inflexibility in budget preparation, a prime preoccupation for policy makers and in particular for finance ministers since a long time ago, has been relatively unexplored. In this paper we show that budget inflexibility can take several forms and argue that it is likely to be closely related to various types of political conflict present in the budget process. Moreover, we study one particular form of budget inflexibility and its connection with one specific (but perhaps the most important) political force driving the budget process. More specifically, we discuss some of the consequences of "expenditure inflexibility," defined as the existence of transfers to special interests enjoying constitutional or legal protection which impede their modification in the short run, in a simple model of legislative bargaining that captures the Tragedy of the Commons present in public budget allocation.Colombia, Fiscal Policy, Budget, Inflexibility

Learning to prove: enculturation or…?

Empirical evidence coming from a curriculum innovation experience that we have been implementing in the Universidad Pedagógica Nacional (Colombia), in a plane geometry course for secondary mathematics pre-service teachers, allows us to affirm that learning to prove, more than enculturation into mathematicians’ practices, is participation in proving activity within the community of mathematical discourse