7,389 research outputs found
Corporate ethical policies: evidence from large firms in Chile
This study explores the current status of corporate ethical policies in the large-size firms currently operating in Chile and focus on the edition of formal documents on corporate ethics by means of a survey sent to the companies whose manning table exceeds 350 employees (460 firms), using for this selection the 2005 Directorio ITV de Empresas en Chile (ITV Directory of Corporations in Chile). The results obtained from the 116 responses received reveal that almost 60% of the firms possess ethics corporate documents; that in general there is consensus about the need to bear in mind the ethical conduct in the personnel selection, promotion and bonuses; and that generally a greater proportion of foreign firms have documents on ethics, as compared with the domestic firms. Likewise, a statistical verification was performed –whose results are only extrapolated to the large-size firms– on the correlation between possession of formal ethics documents and performance (measured as the value of 2005 sales), which had positive results and was statistically significant; at the same time, evidence was found, although somewhat weaker, to support the hypothesis of statistically positive correlation between such documents possession and the number of employees.Corporate ethical documents; Business ethics policy; Codes of conduct; Chile
Testing for Asymmetries in the Preferences of the Euro-Area Monetary Policymaker
This paper tests for asymmetries in the preferences of the Euro-Area monetary policymaker with 1995:I-2004:III data from the last update of the ECB's Area-wide database. Following the relevant literature, we distinguish between three types of asymmetry: precautionary demand for expansions, precautionary demand for price stability and interest rate smoothing asymmetry. Based on the joint GMM estimation of the Euler equation of optimal policy and the AS-AD structure of the macroeconomy, we find evidence of precautionary demand for price stability in the preferences revealed by the monetary policymaker. This type of asymmetry is consistent with the ECB’s definition of price stability and with the priority of credibility-building by a recently created monetary authority.Central Bank Preferences, Asymmetry, Euro Area, Optimal Control, GMM.
Macroeconomic Volatility Trade-off and Monetary Policy Regime in the Euro Area
This research uncovers a well-defined monetary policy regime starting in 1986 in the aggregate Euro Area. Both alternative solution-estimation methods employed - optimal control cum GMM, and dynamic programming cum FIML - identify a regime of strict inflation targeting with interest rate smoothing. The unemployment gap, properly estimated as quasi real-time information, is a relevant element in the information set of the monetary authority, despite not being included in its preferences. The emergence of the regime relates to the improvement of the volatility trade-off between inflation and unemployment gap since the mid-80s. Additional improving factors have been milder supply shocks and better ability of policymakers to set the interest rate closer to optimum.Monetary Policy Regime, Euro Area, Optimal Control, Dynamic Programming, GMM, FIML.
Development and experimental validation of a transient 2D numeric model for radiant walls
An experimental set-up consisting of a house like cubicle exposed to outdoor weather was used to validate a numerical model of a radiant wall. The 2D transient finite volume model used as inputs the indoor temperature, outdoor temperature, global solar radiation incident on a vertical surface, and temperature and flow of the supply water. The simulation results closely agreed with the temperature profiles and heat fluxes for the three studied orientations (East, South, and West). Furthermore, a parametric study was carried out with the radiant wall model, concluding that pipes spacing between 125 mm and 150 mm and depth between 45 mm and 65 mm minimized the temperature difference on the surface while maximizing the heat flux. Furthermore, a control strategy with shorter activation periods improved the heat transfer efficiency.The work was partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER), ENE2015-64117-C5-3-R (MINECO/FEDER), and ULLE10-4E-1305). GREA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123) and the city hall of Puigverd de Lleida. This projects has received funding from the European Commission Seventh Framework Programme (FP/2007–2013) under Grant agreement Nº PIRSES-GA-2013-610692 (INNOSTORAGE) and from European Union's Horizon 2020 research and innovation programme under grant agreement Nº 657466 (INPATH-TES). Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940
Disk masses in the Orion Molecular Cloud-2: distinguishing time and environment
The mass evolution of protoplanetary disks is driven by both internal
processes and external factors, such as photoevaporation. Disentangling these
two effects, however, has remained difficult. We measure the dust masses of a
sample of 132 disks in the Orion Molecular Cloud (OMC)-2 region, and compare
them to (i) externally photoevaporated disks in the Trapezium cluster, and (ii)
disks in nearby low-mass star forming regions (SFRs). This allows us to test if
initial disk properties are the same in high- and low-mass SFRs, and enables a
direct measurement of the effect of external photoevaporation on disks. A ~
mosaic of 3 mm continuum observations from the Atacama Large
Millimeter/submillimeter Array (ALMA) was used to measure the fluxes of 132
disks and 35 protostars >0.5 pc away from the Trapezium. We identify and
characterize a sample of 34 point sources not included in the Spitzer catalog
on which the sample is based. Of the disks, 37 (28%) are detected, with masses
ranging from 7-270 M_e. The detection rate for protostars is higher at 69%.
Disks near the Trapezium are found to be less massive by a factor
, implying a mass loss rate of M_sun/yr.
Our observations allow us to distinguish the impact of time and environment on
disk evolution in a single SFR. The disk mass distribution in OMC-2 is
statistically indistinguishable from that in nearby low-mass SFRs, like Lupus
and Taurus. We conclude that age is the main factor determining the evolution
of these disks. This result is robust with respect to assumptions of dust
temperature, sample incompleteness and biases. The difference between the OMC-2
and Trapezium cluster samples is consistent with mass loss driven by
far-ultraviolet radiation near the Trapezium. Together, this implies that in
isolation, disk formation and evolution proceed similarly, regardless of cloud
mass.Comment: Accepted for publication in A&A. 16 pages, 6 figure
Passive cooling of buildings with phase change materials using whole-building energy simulation tools: A review
Buildings contribute to climate change by consuming a considerable amount of energy to provide thermal comfort for occupants. Cooling energy demands are expected to increase substantially in the world. On this basis, technologies and techniques providing high energy efficiency in buildings such as passive cooling are highly appreciated. Passive cooling by means of phase change materials (PCM) offers high potential to decrease the cooling energy demand and to improve the indoor comfort condition. However, in order to be appropriately characterized and implemented into the building envelope, the PCM use should be numerically analyzed. Whole-building energy simulation tools can enhance the capability of the engineers and designers to analyze the thermal behavior of PCM-enhanced buildings. In this paper, an extensive review has been made, with regard to whole-building energy simulation for passive cooling, addressing the possibilities of applying different PCM-enhanced components into the building envelope and also the feasibility of PCM passive cooling system under different climate conditions. The application of PCM has not always been as energy beneficial as expected, and actually its effectiveness is highly dependent on the climatic condition, on the PCM melting temperature and on the occupants behavior. Therefore, energy simulation of passive PCM systems is found to be a single-objective or multi-objective optimization problem which requires appropriate mathematical models for energy and comfort assessment which should be further investigated. Moreover, further research is required to analyze the influence of natural night ventilation on the cooling performance of PCM.The work is partially funded by the Spanish government (ENE2015-64117-C5-1-R
(MINECO/FEDER) and ENE2015-64117-C5-3-R (MINEDO/FEDER)). The authors would like to thank the Catalan Government for the quality accreditation g
iven to their research group GREA (2014 SGR 123). This project has received funding from the European Commission Seventh Framework Program (FP/2007-2013) under Grant agreement Nº PIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union’s Horizon 2020 research and innovation program under grant ag
reement No 657466 (INPATH-TES). Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940
A Minimalist Model of Characteristic Earthquakes
In a spirit akin to the sandpile model of self-organized criticality, we
present a simple statistical model of the cellular-automaton type which
produces an avalanche spectrum similar to the characteristic-earthquake
behavior of some seismic faults. This model, that has no parameter, is amenable
to an algebraic description as a Markov Chain. This possibility illuminates
some important results, obtained by Monte Carlo simulations, such as the
earthquake size-frequency relation and the recurrence time of the
characteristic earthquake.Comment: 9 pages, 4 figure
Simulation-based optimization of PCM melting temperature to improve the energy performance in buildings
Globally, a considerable amount of energy is consumed by the building sector. The building envelope can highly influence the energy consumption in buildings. In this regard, innovative technologies such as thermal energy storage (TES) can help to boost the energy efficiency and to reduce the CO2 emissions in this sector. The use of phase change materials (PCM), due to its high heat capacity, has been the centre of attention of many researchers. A considerable number of papers have been published on the application of PCM as passive system in building envelopes. Researches have shown that choosing the PCM melting temperature in different climate conditions is a key factor to improve the energy performance in buildings. In the present paper, a simulation-based optimization methodology will be presented by coupling EnergyPlus and GenOpt with an innovative enthalpy-temperature (h-T) function to define the optimum PCM peak melting temperature to enhance the cooling, heating, and the annual total heating and cooling energy performance of a residential building in various climate conditions based on Köppen-Geiger classification. Results show that in a cooling dominant climate the best PCM melting temperature to reduce the annual energy consumption is close to the maximum of 26ºC (melting range of 24ºC-28ºC), whereas in heating dominant climates PCM with lower melting temperature of 20ºC (melting range of 18ºC-22ºC) yields higher annual energy benefits. Moreover, it was found that the proper selection of PCM melting temperature in each climate zone can lead to notable energy savings for cooling energy consumption, heating energy consumption, and total annual energy consumption.The work is partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER) and ENE2015-64117-C5-3-R (MINECO/FEDER)). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREA (2014 SGR 123). GREA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. This project has received funding from the European Commission Seventh Framework Program (FP/2007-2013) under Grant agreement Nº PIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union’s Horizon 2020 research and innovation program under grant agreement No 657466 (INPATH-TES). Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940
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