Contribution to the study of PPP arrangements in airport development, management and operation

Following the liberalization wave in the airline sector, airports have been gradually taken out of the public sphere and open to the private initiative. This phenomenon is generally referred to as privatization, but not all the cases consist of, in fact, a full divestiture of assets. Although infrastructure construction, management and financing are undertaken by the private sector during a pre-defined period, usually 30 years or more, the property remains public or is transferred to the public domain after that period. This is a form of Public-Private Partnership (PPP) where two different models can be found: institutionalized PPP or a typical contractual regime, such as the concession arrangements. PPP options have been a “hot” topic over the last decade, being developed in several sectors, such as energy, water, road and seaports transportation infrastructures, etc, but few studies in the literature can be found on the PPP projects development in airport systems, for example, as far as risk-sharing is concerned. This paper looks at recent developments in airport “privatization” and “deregulation”, distinguishing privatizations from PPP arrangements, through a case study approach, and establishing a comparative analysis of different PPP models used for airport management. Some comments are made about the Portuguese model and the announcement of future privatization.Airport Concessions; Portugal; Public-Private Partnerships; Privatization.

Sharp weighted estimates for approximating dyadic operators

We give a new proof of the sharp weighted $L^2$ inequality ||T||_{L^2(w)} \leq c [w]_{A_2} where $T$ is the Hilbert transform, a Riesz transform, the Beurling-Ahlfors operator or any operator that can be approximated by Haar shift operators. Our proof avoids the Bellman function technique and two weight norm inequalities. We use instead a recent result due to A. Lerner to estimate the oscillation of dyadic operators.Comment: To appear in the Electronic Research Announcements in Mathematical Science

EVALUATION OF NEW INSECTICIDES FOR CONTROL OF THE GREEN PEACH APHID, MYZUS PERSICAE (SULZER), ON PEPPERS

EVALUATION OF NEW INSECTICIDES FOR CONTROL OF THE GREEN PEACH APHID, MYZUS PERSICAE (SULZER), ON PEPPER

Retention and Persistence for Underrepresented Students in Multicultural Greek Life: A Case Study

With increasing numbers of underrepresented students attending college in the United States and concomitant low college graduation rates from four-year institutions for these same students, it is important to explore possible interventions that may increase persistence and retention rates among these populations. The research literature suggests a positive association between students’ participation in Greek Life and persistence/retention from one year to the next. While the literature regarding the relationship between traditional Greek Life and student persistence and retention is robust, the same cannot be said for research on Multicultural Greek Life. If the same relationships are expected to hold between MCGL and student persistence and retention it becomes imperative to look at this link in the same manner. In an effort to expand the literature on this topic, we explore the relationship between institutional levels of persistence and retention at a western regional university for those who participate in Multicultural Greek Life by examining correlations among relevant institutional characteristics. Because of the costs and benefits associated with a college degree, various stakeholders have directed more attention to college student success. This has manifested itself most clearly in efforts to increase persistence and retention rates of both traditional and underrepresented students. Given the relative dearth of research on the impacts of MCGL and underrepresented students’ persistence and retention rates, our study is a step towards filling this gap in the literature

EFFECT OF SOIL MULCHES ON LEAFHOPPER (Empoasca spp.) POPULATION AND ON DRY BEAN YIELD

EFFECT OF SOIL MULCHES ON LEAFHOPPER (Empoasca spp.) POPULATION AND ON DRY BEAN YIEL