840 research outputs found
Observation bias: The impact of demand censoring on newsvendor level and adjustment behavior
In an experimental newsvendor setting we investigate three phenomena: Level behavior ? the decision-maker's average ordering tendency; adjustment behavior ? the tendency to adjust period-to-period order quantities; and observation bias ? the tendency to let the degree of demand feedback influence order quantities. We find that the portion of mismatch cost due to adjustment behavior exceeds the portion of mismatch cost due to level behavior in three out of four conditions. Observation bias is studied through censored demand feedback, a situation which arguably represents the majority of newsvendor settings. When demands are uncensored, subjects tend to order below the normative quantity when facing high margin and above the normative quantity when facing low margin, but in neither case beyond mean demand (a.k.a. the pull-to-center effect). Censoring in general leads to lower quantities, magnifying the below-normative level behavior when facing high margin but partially counterbalancing the above-normative level behavior when facing low margin, violating the pull-to-center effect in both cases.
Charge regulation: a generalized boundary condition?
The three most commonly-used boundary conditions for charged colloidal
systems are constant charge (insulator), constant potential (conducting
electrode) and charge regulation (ionizable groups at the surface). It is
usually believed that the charge regulation is a generalized boundary condition
that reduces in some specific limits to either constant charge or constant
potential boundary conditions. By computing the disjoining pressure between two
symmetric planes for these three boundary conditions, both numerically (for all
inter-plate separations) and analytically (for small inter-plate separations),
we show that this is not, in general, the case. In fact, the limit of charge
regulation is a separate boundary condition, yielding a disjoining pressure
with a different characteristic separation-scaling. Our findings are supported
by several examples demonstrating that the disjoining pressure at small
separations for the charge regulation boundary-condition depends on the details
of the dissociation/association process.Comment: 6 pages, 3 figure
Charged Membranes: Poisson-Boltzmann theory, DLVO paradigm and beyond
In this chapter we review the electrostatic properties of charged membranes
in aqueous solutions, with or without added salt, employing simple physical
models. The equilibrium ionic profiles close to the membrane are governed by
the well-known Poisson-Boltzmann (PB) equation. We analyze the effect of
different boundary conditions, imposed by the membrane, on the ionic profiles
and the corresponding osmotic pressure. The discussion is separated into the
single membrane case and that of two interacting membranes. For one membrane
setup, we show the different solutions of the PB equation and discuss the
interplay between constant-charge and constant-potential boundary conditions. A
modification of the PB theory is presented to treat the extremely high
counter-ion concentration in the vicinity of a charge membrane. For two
equally-charged membranes, we analyze the different pressure regimes for the
constant-charge boundary condition, and discuss the difference in the osmotic
pressure for various boundary conditions. The non-equal charged membranes is
reviewed as well, and the crossover from repulsion to attraction is calculated
analytically. We then examine the charge-regulation boundary condition and
discuss its effects on the ionic profiles and the osmotic pressure for two
equally-charged membranes. In the last section, we briefly review the van der
Waals (vdW) interactions and their effect on the free energy between two planar
membranes. We explain the simple Hamaker pair-wise summation procedure, and
introduce the more rigorous Lifshitz theory. The latter is a key ingredient in
the DLVO theory, which combines repulsive electrostatic with attractive vdW
interactions, and offers a simple explanation for colloidal or membrane
stability. Finally, the chapter ends by a short account of the limitations of
the approximations inherent in the PB theory.Comment: 57 pages, 19 figures, From the forthcoming Handbook of Lipid
Membranes: Molecular, Functional, and Materials Aspects. Edited by Cyrus
Safinya and Joachim Radler, Taylor & Francis/CRC Press, 201
Surface Tension of Electrolyte Solutions: A Self-consistent Theory
We study the surface tension of electrolyte solutions at the air/water and
oil/water interfaces. Employing field-theoretical methods and considering
short-range interactions of anions with the surface, we expand the Helmholtz
free energy to first-order in a loop expansion and calculate the excess surface
tension. Our approach is self-consistent and yields an analytical prediction
that reunites the Onsager-Samaras pioneering result (which does not agree with
experimental data), with the ionic specificity of the Hofmeister series. We
obtain analytically the surface-tension dependence on the ionic strength, ionic
size and ion-surface interaction, and show consequently that the
Onsager-Samaras result is consistent with the one-loop correction beyond the
mean-field result. Our theory fits well a wide range of concentrations for
different salts using one fit parameter, reproducing the reverse Hofmeister
series for anions at the air/water and oil/water interfaces.10.1029Comment: 5 pages, 2 figure
Complex Fluids with Mobile Charge-Regulated Macro-Ions
We generalize the concept of charge regulation of ionic solutions, and apply
it to complex fluids with mobile macro-ions having internal non-electrostatic
degrees of freedom. The suggested framework provides a convenient tool for
investigating systems where mobile macro-ions can self-regulate their charge
(e.g., proteins). We show that even within a simplified charge-regulation
model, the charge dissociation equilibrium results in different and notable
properties. Consequences of the charge regulation include a positional
dependence of the effective charge of the macro-ions, a non-monotonic
dependence of the effective Debye screening length on the concentration of the
monovalent salt, a modification of the electric double-layer structure, and
buffering by the macro-ions of the background electrolyte.Comment: 7 pages, 5 figure
Implementasi Kebijakan Fiskal: Pembiayaan Program Pembangunan Berbasis Rukun Tetangga (Pbrt) di Kabupaten Sumbawa Barat
Fiscal policy is one form of economic policies pursued in the context of macroeco-nomic stabilization, promote growth, equity, and sustainability menjega budget. WestSumbawa regency is one of regencies in NTB province has embarked on one of fiscalpolicy implementation is in the financing of Neighborhood-Based Development pro-gram (PBRT). PBRT program is a strategy of development by putting the region atthe lowest level of development of the neighborhood (RT). This policy is the empow-erment of RT with the understanding that the RT is not the lowest governmentalstructures and nongovernmental organizations that are able to understand all the com-plaints and needs of their citizens. RT becomes a very important institution in whichis located all the pecking order and also serves as a populist economic base which isthen defined as the Regulation (Regulation No. 27 Year 2008 regarding PBRT). Thispaper reviewed the implementation of the program PBRT is related to how big thebudget from the budget for financing. Furthermore, by using Regulatory Impact Analysiswill be analyzed whether the policy PBRT program will bring net benefits to societyand increase welfare in West Sumbawa regency
Cardiovascular-Related Death Risk Factors in Hypertensive Patients: Indonesia Family Life Survey 2000-2014
Objective: To determine the characteristics of the risk factors of cardiovascular death in hypertensive patients in Indonesia based on the Indonesian Family Life Survey (IFLS) longitudinal data. Methods: This was a retrospective descriptive study on secondary data from the IFLS population starting from2000 and was followed up in 2007 and 2014. The inclusion criteria for participation were15 years old or older, had hypertension, had cardiovascular events as thecause of death, and had complete data in both IFLS 3 (2000) and IFLS 4 (2007).Results: The IFLS 5 (2014) reported 918 deaths among eligible subjects with complete data, both in IFLS 3 (2000) and IFLS 4 (2007). Of those, a total of 608 subjects experienced hypertension started from 2000 and/or 2007. Of these deaths, 112 were due to cardiovascular events. Cardiovascular death was more common in males (58.9%), age of >65 years old when died (47.3%), had poor socioeconomic status (24.1%), and with normal body mass index (54.9%).Conclusion: Male, late adulthood, low level of education, normal BMI, and poor socioeconomic status represented the greater risks of cardiovascular death among hypertensive patients in Indonesia.
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