Comparing the performance of public and private water companies in the Asia and Pacific region : what a stochastic costs frontier shows

Estache and Rossi estimate a stochastic costs frontier for a sample of Asian and Pacific water companies, comparing the performance of public and privatized companies based on detailed firm-specific information published by the Asian Development Bank in 1997. They find private operators of water companies to be more efficient than public operators. Costs in concessioned companies tend to be significantly lower than those in public companies. The authors show that rankings based on standard indicators are not always very consistent. This paper contributes to that growing literature. The rest of the paper is organized as follows. Section 2 presents the theoretical structure of the cost model estimated. Section 3 provides an overview of earlier studies of the water sector. Section 4 presents the estimates of costs frontiers obtained for a large sample of Asian and Pacific Region water companies, distinguishing between public and private operators. Section 5 compares the performance ranking from efficiency frontier measures to those obtained from productivity indicators. Section 6 concludes.Decentralization,Environmental Economics&Policies,Water and Industry,Economic Theory&Research,Water Conservation,Environmental Economics&Policies,Water Supply and Sanitation Governance and Institutions,Water and Industry,Economic Theory&Research,Town Water Supply and Sanitation

Regulatory agencies : impact on firm performance and social welfare

The authors explore the relation between the establishment of a regulatory agency and the performance of the electricity sector. The authors exploit a unique dataset comprising firm-level information on a representative sample of 220 electric utilities from 51 development and transition countries for the years 1985 to 2005. Their results indicate that regulatory agencies are associated with more efficient firms and with higher social welfare.Infrastructure Regulation,Privatization,Energy Production and Transportation,Emerging Markets,Regulatory Regimes

The case for international coordination of electricity regulation : evidence from the measurement of efficiency in South America

A decade long experience shows that monitoring the performance of public and private monopolies in South America is proving to be the hard part of the reform process. The operators who control most of the information needed for regulatory purposes have little interest in volunteering their dissemination unless they have an incentive to do so. The authors argue that, in spite of, and maybe because of, a much weaker information base and governance structure, South America's electricity sector could pursue an approach that relies on performance rankings based on comparative efficiency measures. The authors show that with the rather modest data currently available publicly, such an approach could yield useful results. They provide estimates of efficiency levels in South America's main distribution companies between 1994 and 2000. Moreover, the authors show how relatively simple tests can be used by regulators to check the robustness of their results and strengthen their position at regulatory hearings.Economic Theory&Research,Environmental Economics&Policies,Enterprise Development&Reform,Labor Policies,Health Monitoring&Evaluation,Environmental Economics&Policies,Economic Theory&Research,Geographical Information Systems,Health Monitoring&Evaluation,Educational Technology and Distance Education

Minimum Conductivity and Evidence for Phase Transitions in Ultra-clean Bilayer Graphene

Bilayer graphene (BLG) at the charge neutrality point (CNP) is strongly susceptible to electronic interactions, and expected to undergo a phase transition into a state with spontaneous broken symmetries. By systematically investigating a large number of singly- and doubly-gated bilayer graphene (BLG) devices, we show that an insulating state appears only in devices with high mobility and low extrinsic doping. This insulating state has an associated transition temperature Tc~5K and an energy gap of ~3 meV, thus strongly suggesting a gapped broken symmetry state that is destroyed by very weak disorder. The transition to the intrinsic broken symmetry state can be tuned by disorder, out-of-plane electric field, or carrier density

The Different Pathways of Epicardial Adipose Tissue across the Heart Failure Phenotypes: From Pathophysiology to Therapeutic Target

Epicardial adipose tissue (EAT) is an endocrine and paracrine organ constituted by a layer of adipose tissue directly located between the myocardium and visceral pericardium. Under physiological conditions, EAT exerts protective effects of brown-like fat characteristics, metabolizing excess fatty acids, and secreting anti-inflammatory and anti-fibrotic cytokines. In certain pathological conditions, EAT acquires a proatherogenic transcriptional profile resulting in increased synthesis of biologically active adipocytokines with proinflammatory properties, promoting oxidative stress, and finally causing endothelial damage. The role of EAT in heart failure (HF) has been mainly limited to HF with preserved ejection fraction (HFpEF) and related to the HFpEF obese phenotype. In HFpEF, EAT seems to acquire a proinflammatory profile and higher EAT values have been related to worse outcomes. Less data are available about the role of EAT in HF with reduced ejection fraction (HFrEF). Conversely, in HFrEF, EAT seems to play a nutritive role and lower values may correspond to the expression of a catabolic, adverse phenotype. As of now, there is evidence that the beneficial systemic cardiovascular effects of sodium-glucose cotransporter-2 receptors-inhibitors (SGLT2-i) might be partially mediated by inducing favorable modifications on EAT. As such, EAT may represent a promising target organ for the development of new drugs to improve cardiovascular prognosis. Thus, an approach based on detailed phenotyping of cardiac structural alterations and distinctive biomolecular pathways may change the current scenario, leading towards a precision medicine model with specific therapeutic targets considering different individual profiles. The aim of this review is to summarize the current knowledge about the biomolecular pathway of EAT in HF across the whole spectrum of ejection fraction, and to describe the potential of EAT as a therapeutic target in HF

Evaluating Measures of Fidelity for Substance Abuse Group Treatment With Incarcerated Adolescents

The evaluation of treatment fidelity has become increasingly important as the demand for evidence-based practice grows. The purpose of the present study is to describe the psychometric properties of two measures of treatment fidelity that can be used by therapists and supervisors - one for group-based cognitive–behavioral therapy (CBT) and one for combined Substance Education and Twelve-Step Introduction (SET) for adolescent substance use. At the end of group sessions (CBT n = 307; SET n = 279), therapists and supervisors completed an evaluation measure assessing adherence to certain core components of the intervention. The supervisor version of the fidelity measure also included items for rating the level of competency the therapist demonstrated when providing each component of the intervention. Results from split-half cross-validation analyses provide strong support for an 11-item, three-factor CBT fidelity measure. Somewhat less consistent but adequate support for a nine-item, two-factor SET fidelity measure was found. Internal consistencies ranged from acceptable to good for both the CBT and SET adherence scales and from acceptable to good for the CBT and SET competency scales, with the exception of the CBT practices competency scale. Preliminary validation of the measures suggests that both measures have adequate to strong factor structure, reliability, and concurrent and discriminant validity. The results of this study have implications for research and clinical settings, including the supervision process

The Raman coupling function in amorphous silica and the nature of the long wavelength excitations in disordered systems

New Raman and incoherent neutron scattering data at various temperatures and molecular dynamic simulations in amorphous silica, are compared to obtain the Raman coupling coefficient $C(\omega)$ and, in particular, its low frequency limit. This study indicates that in the $\omega \to 0$ limit $C(\omega)$ extrapolates to a non vanishing value, giving important indications on the characteristics of the vibrational modes in disordered materials; in particular our results indicate that even in the limit of very long wavelength the local disorder implies non-regular local atomic displacements.Comment: Revtex, 4 ps figure

Conformational changes produced by ATP binding to the plasma membrane calcium pump

The aim of this work was to study the plasma membrane calcium pump (PMCA) reaction cycle by characterizing conformational changes associated with calcium, ATP, and vanadate binding to purified PMCA. This was accomplished by studying the exposure of PMCA to surrounding phospholipids by measuring the incorporation of the photoactivatable phosphatidylcholine analog 1-O-hexadecanoyl-2-O-[9-[[[2-[125I]iodo-4-(trifluoromethyl-3H-diazirin-3-yl)benzyl]oxy]carbonyl]nonanoyl]-sn-glycero-3-phosphocholine to the protein. ATP could bind to the different vanadate-bound states of the enzyme either in the presence or in the absence of Ca2+ with high apparent affinity. Conformational movements of the ATP binding domain were determined using the fluorescent analog 2′(3′)-O-(2,4,6-trinitrophenyl)adenosine 5′-triphosphate. To assess the conformational behavior of the Ca2+ binding domain, we also studied the occlusion of Ca2+, both in the presence and in the absence of ATP and with or without vanadate. Results show the existence of occluded species in the presence of vanadate and/or ATP. This allowed the development of a model that describes the transport of Ca2+ and its relation with ATP hydrolysis. This is the first approach that uses a conformational study to describe the PMCA P-type ATPase reaction cycle, adding important features to the classical E1-E2 model devised using kinetics methodology only.Fil: Mangialavori, Irene C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Fisicoquímica Biológicas; ArgentinaFil: Ferreira Gomes, Mariela S.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Fisicoquímica Biológicas; ArgentinaFil: Saffioti, Nicolas A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Fisicoquímica Biológicas; ArgentinaFil: Gonzalez-Lebrero, Rodolfo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Fisicoquímica Biológicas; ArgentinaFil: Rossi, Rolando Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Fisicoquímica Biológicas; ArgentinaFil: Rossi, Juan Pablo Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Fisicoquímica Biológicas; Argentin

Vector bundles on the projective line and finite domination of chain complexes

Finitely dominated chain complexes over a Laurent polynomial ring in one indeterminate are characterised by vanishing of their Novikov homology. We present an algebro-geometric approach to this result, based on extension of chain complexes to sheaves on the projective line. We also discuss the K-theoretical obstruction to extension.Comment: v1: 11 page

Rapid prototyped porous nickel-titanium scaffolds as bone substitutes

While calcium phosphate–based ceramics are currently the most widely used materials in bone repair, they generally lack tensile strength for initial load bearing. Bulk titanium is the gold standard of metallic implant materials, but does not match the mechanical properties of the surrounding bone, potentially leading to problems of fixation and bone resorption. As an alternative, nickel–titanium alloys possess a unique combination of mechanical properties including a relatively low elastic modulus, pseudoelasticity, and high damping capacity, matching the properties of bone better than any other metallic material. With the ultimate goal of fabricating porous implants for spinal, orthopedic and dental applications, nickel–titanium substrates were fabricated by means of selective laser melting. The response of human mesenchymal stromal cells to the nickel–titanium substrates was compared to mesenchymal stromal cells cultured on clinically used titanium. Selective laser melted titanium as well as surface-treated nickel–titanium and titanium served as controls. Mesenchymal stromal cells had similar proliferation rates when cultured on selective laser melted nickel–titanium, clinically used titanium, or controls. Osteogenic differentiation was similar for mesenchymal stromal cells cultured on the selected materials, as indicated by similar gene expression levels of bone sialoprotein and osteocalcin. Mesenchymal stromal cells seeded and cultured on porous three-dimensional selective laser melted nickel–titanium scaffolds homogeneously colonized the scaffold, and following osteogenic induction, filled the scaffold’s pore volume with extracellular matrix. The combination of bone-related mechanical properties of selective laser melted nickel–titanium with its cytocompatibility and support of osteogenic differentiation of mesenchymal stromal cells highlights its potential as a superior bone substitute as compared to clinically used titanium