Nonempirical Procedure Research Articles

New Technique to Verify Permeability and Anorectal Malformations, and Take Rectal Temperature in Neonates And Infants

The first neonatal examination should be carried out from the delivery room to assess: 1. Initial neonatal well- being; 2. Vital signs at birth; 3. Somatometry; 4. Complete physical examination; 5. Verify anorectal permeability and 6. Detect congenital malformations, including Anorectal Malformations. The Clinical Practice Guideline and the experts in Anorectal Malformations recommend detection by introducing a rectal thermometer through the anus with which, at the same time, the rectal temperature is taken. However, there is no real well-structured technique for such a procedure. In Mexico, Latin America, and in countries with limited resources, a large part of the personnel who care for newborns, including doctors, nurses, and students, take rectal temperatures "in their own way" SIC, unaware of "a technique" and the "true objective" of this procedure, generating detection failure and risk of injuring the distal digestive tract by carrying out the procedure empirically and by the incorrect use of thermometers to take the rectal temperature. This issue has not been addressed for more than three decades nor has the way of 1. Checking anorectal patency changed; 2. Detect anorectal malformations; 3. Take the rectal temperature in neonates and infants. For this reason, our objective is to publicize our "New Technique to Verify Permeability and Anorectal Malformations and take the rectal temperature in neonates and infants", with which we carry out these three actions with a single non-empirical procedure of a scientifically medical nature.

Adjustable potential probes for band-gap predictions of extended systems through nonempirical hybrid functionals

We describe a nonempirical procedure for achieving accurate band gaps of extended systems through the insertion of suitably defined potential probes. By enforcing Koopmans' condition on the resulting localized electronic states, we determine the optimal fraction of Fock exchange to be used in the adopted hybrid functional. As potential probes, we consider point defects, the hydrogen interstitial, and various adjustable potentials that allow us to vary the energy level of the localized state in the band gap. By monitoring the delocalized screening charge, we achieve a measure of the degree of hybridization with the band states, which can be used to improve the band-gap estimate. Application of this methodology to AlP, C, and MgO yields band gaps differing by less than 0.2 eV from experiment.

Size-Dependence of Nonempirically Tuned DFT Starting Points for G0W0 Applied to π-Conjugated Molecular Chains.

G0W0 calculations for predicting vertical ionization potentials (IPs) and electron affinities of molecules and clusters are known to show a significant dependence on the density functional theory (DFT) starting point. A number of nonempirical procedures to find an optimal starting point have been proposed, typically based on tuning the amount of HF exchange in the underlying hybrid functional specifically for the system at hand. For the case of π-conjugated molecular chains, these approaches lead to a significantly different amount of HF exchange for different oligomer sizes. In this study, we analyze if and how strongly this size dependence affects the ability of nonempirical tuning approaches to predict accurate IPs for π-conjugated molecular chains of increasing chain length. To this end, we employ three different nonempirical tuning procedures for the G0W0 starting point to calculate the IP of polyene oligomers up to 22 repeat units and compare the results to highly accurate coupled-cluster calculations. We find that, despite its size dependence, using an IP-tuned hybrid functional as a starting point for G0W0 yields excellent agreement with the reference data for all chain lengths.

Prospecting Lighting Applications with Ligand Field Tools and Density Functional Theory: A First-Principles Account of the 4f(7)-4f(6)5d(1) Luminescence of CsMgBr3:Eu(2+).

The most efficient way to provide domestic lighting nowadays is by light-emitting diodes (LEDs) technology combined with phosphors shifting the blue and UV emission toward a desirable sunlight spectrum. A route in the quest for warm-white light goes toward the discovery and tuning of the lanthanide-based phosphors, a difficult task, in experimental and technical respects. A proper theoretical approach, which is also complicated at the conceptual level and in computing efforts, is however a profitable complement, offering valuable structure-property rationale as a guideline in the search of the best materials. The Eu(2+)-based systems are the prototypes for ideal phosphors, exhibiting a wide range of visible light emission. Using the ligand field concepts in conjunction with density functional theory (DFT), conducted in nonroutine manner, we develop a nonempirical procedure to investigate the 4f(7)-4f(6)5d(1) luminescence of Eu(2+) in the environment of arbitrary ligands, applied here on the CsMgBr3:Eu(2+)-doped material. Providing a salient methodology for the extraction of the relevant ligand field and related parameters from DFT calculations and encompassing the bottleneck of handling large matrices in a model Hamiltonian based on the whole set of 33,462 states, we obtained an excellent match with the experimental spectrum, from first-principles, without any fit or adjustment. This proves that the ligand field density functional theory methodology can be used in the assessment of new materials and rational property design.

Nonprofit Marketing: Negative Case Analysis

The author deconstructs the prevailing controversial conceptualization of nonprofit marketing and concludes it rests on three principles: voluntary exchange, an open system organization, and self-interest motivation. Negative case analysis of these principles revealed that alternative principles were ignored in the social science literature. Based on a qualitative analysis a revised conceptualization of non-profit marketing was suggested which incorporated the principles of redistribution and reciprocity, the features of a closed model of formal organization, and public interest motivation. The critical theory approach to the study used non-empirical procedures that included negative case analysis. The paper presents results of negative case analysis.

Nonprofit Marketing: Investigative Research Inquiry

The objectives of the study were (a) to identify the reasons and concerns of those public administrators and marketing scholars who do not accept the usefulness of marketing in the public sector; (b) to deconstruct, comprehend, interpret, and critically appraise the current conceptualization of nonprofit marketing from the viewpoint of negativists identified in step (a); and (c) to reconstruct, redefine, reinterpret, and reoperationalize the current controversial conceptualization of public sector marketing into a new conceptualization. The critical theory approach to the study primary used non-empirical procedures data collection and analytic procedures that included investigative research. The paper presents results of investigative research analysis.

A simple non-empirical procedure for spin-component-scaled MP2 methods applied to the calculation of the dissociation energy curve of noncovalently-interacting systems

We present a simple and non-empirical method to determine optimal scaling coefficients, within the (spin-component)-scaled MP2 approach, for calculating intermolecular potential energies of noncovalently-interacting systems. The method is based on an observed proportionality between (spin-component) MP2 and CCSD(T) energies for a wide range of intermolecular distances and allows us to compute with high accuracy a large portion of the dissociation curve at the cost of a single CCSD(T) calculation. The accuracy of the present procedure is assessed for a series of noncovalently-interacting test systems: the obtained results reproduce CCSD(T) quality in all cases and definitely outperform conventional MP2, CCSD and SCS-MP2 results. The difficult case of the beryllium dimer is also considered.

A Critical Appraisal of the Conceptualization of Public Park and Recreation Marketing

The objectives of the study were (a) to identify the reasons and concerns of those public administrators and marketing scholars who do not accept the usefulness of marketing in the public sector; (b) to deconstruct, comprehend, interpret, and critically appraise the current conceptualization of public sector marketing from the viewpoint of negativists identified in step (a); and (c) to reconstruct, redefine, reinterpret, and reoperationalize the current controversial conceptualization of public sector marketing into a new conceptualization in the context of park and recreation services. The critical theory approach to the study primary used non-empirical procedures data collection and analytic procedures which included investigative research, negative case analysis, and theoretical triangulation. These procedures were supplemented with empirical data collected from in-depth interviews with five scholars and with three parks and recreation managers. Results of the non-empirical procedures revealed the biased selective nature of the current conceptualization of public park and recreation marketing and the existence of alternative conceptualizations which have been ignored. The existing and alternative models were discussed with scholars and park and recreation managers. Support was found for the alternative models. From these data an alternative conceptualization of public park and recreation marketing was developed and named the concept of administered marketing. Implications for park and recreation managers are discussed. Directions for future research into the administratively managed park and recreation marketing concept are suggested.

Magnetostructural Dynamics from Hubbard-U Corrected Spin-Projection: [2Fe-2S] Complex in Ferredoxin.

A Hubbard-corrected spin-projected two-determinant approach, EBS+Uscf, is introduced to treat low-spin ground states of antiferromagnetically coupled transition metal complexes. In addition to providing access to total energies, forces, and ab initio simulations, it allows one to readily compute Heisenberg's exchange coupling J(t) on the fly. By studying the binuclear [2Fe-2S] cofactor in a metalloprotein, Anabaena Fd, within this consistent nonempirical procedure in combination with a QM/MM framework, it is illustrated that spin-projection, self-interaction corrections, thermal fluctuations, and protein matrix shifts are crucial in obtaining ⟨J⟩ close to the experiment.

Electrical Conductivity Studies of Quinic Acid and its Sodium Salt in Aqueous Solutions

The electrical conductivities of aqueous solutions of quinic acid and its sodium salt were measured from 293.15 to 328.15 K in steps of 5 K. The molar conductivities of the sodium salt were treated by the Lee–Wheaton equation, in the form of Pethybridge and Taba, and the Kohlrausch equations. The limiting molar conductivities of the quinate anion were estimated, as well as the corresponding ionic association constants and standard thermodynamic functions of the ionic association reaction. The hydrodynamic radius of the quinate anion was calculated from the Walden rule and compared with the van der Waals radius. The dissociation constant of quinic acid was evaluated from the known value of the limiting molar conductivity of quinic acid using the conductivity equation of Pethybridge and Taba. The standard thermodynamic functions of the dissociation process, i.e., the Gibbs energy, enthalpy, entropy and heat capacity, were obtained using the non-empirical procedure given by Clarke and Glew. The standard thermodynamic functions of dissociation of quinic acid are discussed in terms of solute–solvent interactions and stabilization of the quinate anion due to hydrogen bonding of the α-hydroxyl group to the carboxyl group.

Quantum-Chemical Study of the Relative Stability of N-Substituted Tetrazole Isomers

The enthalpies of formation and total energies of a series of 1- and 2-substituted tetrazoles in the gas phase and in solution were calculated by MNDO and AM1 semiempirical methods and by a set of nonempirical procedures. The effect of solvent on the relative stability of N-substituted tetrazoles was estimated in terms of the PCM, SM5, and SCRF models. The possibility for isomerization of N-substituted tetrazoles, depending on the substituent in position 1 or 2, was studied at the MP2/6-31G*//HF/6-31G* level. According to the results of nonempirical calculations, 2-substituted tetrazoles are more stable in the gas phase, in keeping with the experimental data for the corresponding isomers. The solvent nature is an important factor affecting isomerization of N-substituted tetrazoles: Rise in the solvent polarity leads to displacement of the equilibrium toward 1-substituted isomers.

VB-DFT: a nonempirical hybrid method combining valence bond theory and density functional energies

A nonempirical procedure is presented for combining the valence bond (VB) methodology with density functional theory (DFT). The method, called VB-DFT, is based on partitioning the system into two coupled electronic subsets, one treated by DFT and the other by VB theory. The DFT energy component includes the exchange correlation potential while the coupling involves electron repulsion and exchange interactions. Tests and applications show that the VB-DFT hybrid method has the qualities of a VB method along with a quantitative advantage over VB-only methods with traditional core–valence separation.

On a parameter-free model for treating polarisation forces in positron scattering processes

A rather simple semiclassical model is described for treating short-range correlation forces in the scattering of positrons from atoms at the energies below the thresholds of positronium formation in each of the considered systems. The present model allows one to introduce a non-empirical procedure for devising several damping functions, one for each of the perturbation terms which are included in the asymptotic expansion of the polarisation potential. It is shown by calculations, carried out for He, Ne and Ar as examples, that one can obtain very good agreement with experimental findings for surprisingly little computational effort, even for fairly complex atomic targets which would be otherwise out of reach for all but the most computationally intensive ab initio methods.

Solvent strength of multicomponent mobile phases in liquid—solid chromatography : Binary-solvent mixtures and solvent localization

The displacement model for the prediction of solvent strength in liquid—solid chromatography (LSC) has been summarized for the case of binary-solvent mobile phases. It is confirmed that a number of prior anomalies can be explained by the phenomenon of “solvent localization”. Taking solvent localization into account leads to a simple, non-empirical procedure for the more accurate calculation of solvent strength. Application of this approach to literature data for silica and alumina as adsorbent shows agreement between calculated and experimental solvent strength values (ε 0) of 0.017 (1 standard deviation) for 93 binary-solvent mobile phases covering a range in solvent strength of 0.02 < ε 0 < 0.66 ( r = 0.994). This means that more accurate predictions of solvent strength are now possible for binary-solvent LSC systems, for use in optimizing the separation of various samples. The only experimental system showing lack of correlation with the present model is isopropanol—pentane as mobile phase with alumina as adsorbent. It is believed that the behavior of alcohol solutions is more complex than can be described by the simple displacement model. Apart from the alcohols as mobile phases, however, the present study provides further verification of the physical correctness of the displacement model for mobile phases containing polar solvents.