Effective way to sum over long range Coulomb potentials in two and three dimensions

I propose a method to calculate logarithmic interaction in two dimensions and coulomb interaction in three dimensions under periodic boundary conditions. This paper considers the case of a rectangular cell in two dimensions and an orthorhombic cell in three dimensions. Unlike the Ewald method, there is no parameter to be optimized, nor does it involve error functions, thus leading to the accuracy obtained. This method is similar in approach to that of Sperb [R. Sperb, Mol. Simulation, 22, 199 (1999).], but the derivation is considerably simpler and physically appealing. An important aspect of the proposed method is the faster convergence of the Green function for a particular case as compared to Sperb's work. The convergence of the sums for the most part of unit cell is exponential, and hence requires the calculation of only a few dozen terms. In a very simple way, we also obtain expressions for interaction for systems with slab geometries. Expressions for the Madelung constant of CsCl and NaCl are also obtained.Comment: To appear in Phy. Rev.

(Not so) dangerous liaisons: A framework for evaluating collaborative research projects

Cite as: Oztop, P., Loesche, F., Maranan, D. S., Francis, K. B., Tyagi, V., & Torre, I. (2017). (Not so) dangerous liaisons: A framework for evaluating collaborative research projects [Special Issue]. AVANT, 8, 167–179© 2017, Centre for Philosophical Research. With advances in research environments and the accompanying increase in the complexity of research projects, the range of skills required to carry out research calls for an increase in interdisciplinary and collaborative work. CogNovo, a doctoral training program for 25 PhD students, provided a unique opportunity to observe and analyze collaborative processes. We propose a process-oriented framework for understanding research collaborations along two dimensions: interpersonal and project-related. To illustrate the utility of this process-oriented framework, we apply the framework matrix to several collaborations that emerged within the CogNovo program. The framework that we introduce has several advantages over existing metrics. Firstly, we offer a process-oriented-as opposed to product-oriented-evaluation of interdisciplinary and collaborative endeavors. Secondly, we propose a means of assessment that preserves the distinctive profile (or "fingerprint") of a given collaborative project, thus capturing the uniqueness of each project and its environment

Efficacy of Various IPM Modules on Biotic Pressure and Green Forage Yield in a Forage Production System (Cowpea + BN Hybrid – Berseem mixed with Mustard + BN Hybrid)

Various control measures by themselves are not free from one or the other limitations to provide safe, economically viable and efficient in pest population suppression. The economics is much more relevant when we talk of low value commodity like forage crops. Viewing this multifaceted problem and inherent limitations of each control method the ultimate solution lies in integrated pest control expedient. The connotation of the approach is to utilize all the possible methods of control including maximum exploitation of naturally existing populations and regulating factors in as compatible manner as possible to keep the pest population levels below economic threshold. Earlier, IPM in fodder crops has been worked out by Shri Ram and Gupta, 1989; Pandey et al., 2000; Shah et al., 2011

Room temperature Ferromagnetism in Th1-xFexO2-d (x = 0.0, 0.05, 0.10, 0.15, 0.20 and 0.25) nanoparticles

Nanocrystalline (Th1-xFex)O2-d particles with different Fe concentrations (x = 0.0, 0.05, 0.10, 0.15, 0.20 and 0.25) have been prepared by a gel combustion method. Rietveld refinement analyses of X-ray diffraction data revealed the formation of an impurity free cubic type Th1-xFexO2-d structure up to x = 0.20. This observation is further confirmed from the detailed studies conducted on 10 at. percent Fe doped ThO2 using high-resolution transmission electron microscopy (HRTEM) imaging and indexing of the selected-area electron diffraction (SAED) patterns. DC Magnetization studies as a function field indicate that they are ferromagnetic with Curie temperature (Tc) well above room temperature.Comment: 10 pages, 5 figure

Phonons and Colossal Thermal Expansion Behavior of Ag3Co(CN)6 and Ag3Fe(CN)6

Recently colossal positive volume thermal expansion has been found in the framework compounds Ag3Co(CN)6 and Ag3Fe(CN)6. Phonon spectra have been measured using the inelastic neutron scattering technique as a function of temperature and pressure. The data has been analyzed using ab-initio calculations. We find that the bonding is very similar in both compounds. At ambient pressure modes in the intermediate frequency part of the vibrational spectra in the Co compound are shifted to slightly higher energies as compared to the Fe compound. The temperature dependence of the phonon spectra gives evidence for large explicit anharmonic contribution to the total anharmonicity for low-energy modes below 5 meV. We found that modes are mainly affected by the change in the size of unit cell, which in turn changes the bond lengths and vibrational frequencies. Thermal expansion has been calculated via the volume dependence of phonon spectra. Our analysis indicates that Ag phonon modes in the energy range from 2 to 5 meV are strongly anharmonic and major contributors to thermal expansion in both compounds. The application of pressure hardens the low-energy part of the phonon spectra involving Ag vibrations and confirms the highly anharmonic nature of these modes.Comment: 19 pages, 14 figures and one tabl

Sorting live stem cells based on Sox2 mRNA expression.

PMCID: PMC3507951This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.While cell sorting usually relies on cell-surface protein markers, molecular beacons (MBs) offer the potential to sort cells based on the presence of any expressed mRNA and in principle could be extremely useful to sort rare cell populations from primary isolates. We show here how stem cells can be purified from mixed cell populations by sorting based on MBs. Specifically, we designed molecular beacons targeting Sox2, a well-known stem cell marker for murine embryonic (mES) and neural stem cells (NSC). One of our designed molecular beacons displayed an increase in fluorescence compared to a nonspecific molecular beacon both in vitro and in vivo when tested in mES and NSCs. We sorted Sox2-MB(+)SSEA1(+) cells from a mixed population of 4-day retinoic acid-treated mES cells and effectively isolated live undifferentiated stem cells. Additionally, Sox2-MB(+) cells isolated from primary mouse brains were sorted and generated neurospheres with higher efficiency than Sox2-MB(-) cells. These results demonstrate the utility of MBs for stem cell sorting in an mRNA-specific manner

Bilateral Ramsay Hunt syndrome in a diabetic patient

BACKGROUND: Herpes zoster oticus accounts for about 10% cases of facial palsy, which is usually unilateral and complete and full recovery occurs in only about 20% of untreated patients. Bilateral herpes zoster oticus can sometime occur in immunocompromised patients, though incidence is very rare. CASE PRESENTATION: Diabetic male, 57 year old presented to us with bilateral facial palsy due to herpes zoster oticus. Patient was having bilateral mild to moderate sensorineural hearing loss. Patient was treated with appropriate metabolic control, anti-inflammatory drugs and intravenous acyclovir. Due to uncontrolled diabetes, glucocorticoids were not used in this patient. Significant improvement in hearing status and facial nerve functions were seen in this patient. CONCLUSIONS: Herpes zoster causes severe infections in diabetic patients and can be a cause of bilateral facial palsy and bilateral Ramsay Hunt syndrome. Herpes zoster in diabetic patients should be treated with appropriate metabolic control, NSAIDS and intravenous acyclovir, which we feel should be started at the earliest. Glucocorticoids should be avoided in diabetic patients