Lifting the Veil: The Face of TFP in an Indian Rail Mill

We use a proprietary data set on the floor-level operations at the Bhilai Rail and Structural Mill (RSM) in India to understand how output rose sharply in response to competitive pressures. Output increases came predominantly from reductions in production delays of various kinds. We model interruptions to the production process as a function of worker characteristics and training and find that a large part of the avoidable delay reductions are attributable to a particular form of training, suggesting that such investments can have very high returns. Our work suggests very high returns to knowledge-enhancing investments in emerging economies.Total Factor Productivity (TFP), plant level data, competitiveness and trade

Analyzing the Catalytic Role of Asp97 in the Methionine Aminopeptidase from \u3cem\u3eEscherichia coli\u3c/em\u3e

An active site aspartate residue, Asp97, in the methionine aminopeptidase (MetAPs) from Escherichia coli (EcMetAP-I) was mutated to alanine, glutamate, and asparagine. Asp97 is the lone carboxylate residue bound to the crystallographically determined second metal-binding site in EcMetAP-I. These mutant EcMetAP-I enzymes have been kinetically and spectroscopically characterized. Inductively coupled plasma–atomic emission spectroscopy analysis revealed that 1.0 ± 0.1 equivalents of cobalt were associated with each of the Asp97-mutated EcMetAP-Is. The effect on activity after altering Asp97 to alanine, glutamate or asparagine is, in general, due to a ∼ 9000-fold decrease in kca towards Met-Gly-Met-Met as compared to the wild-type enzyme. The Co(II) d–d spectra for wild-type, D97E and D97A EcMetAP-I exhibited very little difference in form, in each case, between the monocobalt(II) and dicobalt(II) EcMetAP-I, and only a doubling of intensity was observed upon addition of a second Co(II) ion. In contrast, the electronic absorption spectra of [Co_(D97N EcMetAP-I)] and [CoCo(D97N EcMetAP-I)] were distinct, as were the EPR spectra. On the basis of the observed molar absorptivities, the Co(II) ions binding to the D97E, D97A and D97N EcMetAP-I active sites are pentacoordinate. Combination of these data suggests that mutating the only nonbridging ligand in the second divalent metal-binding site in MetAPs to an alanine, which effectively removes the ability of the enzyme to form a dinuclear site, provides a MetAP enzyme that retains catalytic activity, albeit at extremely low levels. Although mononuclear MetAPs are active, the physiologically relevant form of the enzyme is probably dinuclear, given that the majority of the data reported to date are consistent with weak cooperative binding

Reconstruction of Cluster Masses using Particle Based Lensing I: Application to Weak Lensing

We present Particle-Based Lensing (PBL), a new technique for gravitational lensing mass reconstructions of galaxy clusters. Traditionally, most methods have employed either a finite inversion or gridding to turn observational lensed galaxy ellipticities into an estimate of the surface mass density of a galaxy cluster. We approach the problem from a different perspective, motivated by the success of multi-scale analysis in smoothed particle hydrodynamics. In PBL, we treat each of the lensed galaxies as a particle and then reconstruct the potential by smoothing over a local kernel with variable smoothing scale. In this way, we can tune a reconstruction to produce constant signal-noise throughout, and maximally exploit regions of high information density. PBL is designed to include all lensing observables, including multiple image positions and fluxes from strong lensing, as well as weak lensing signals including shear and flexion. In this paper, however, we describe a shear-only reconstruction, and apply the method to several test cases, including simulated lensing clusters, as well as the well-studied ``Bullet Cluster'' (1E0657-56). In the former cases, we show that PBL is better able to identify cusps and substructures than are grid-based reconstructions, and in the latter case, we show that PBL is able to identify substructure in the Bullet Cluster without even exploiting strong lensing measurements. We also make our codes publicly available.Comment: Accepted for publication in ApJ; Codes available at http://www.physics.drexel.edu/~deb/PBL.htm ; 12 pages,9 figures, section 3 shortene

A New Colorimetric Assay for Methionyl Aminopeptidases: Examination of the Binding of a New Class of Pseudopeptide Analog Inhibitors

A direct and convenient spectrophotometric assay has been developed for methionine aminopeptidases (MetAPs). The method employs the hydrolysis of a substrate that is a methionyl analogue of p-nitroaniline (l-Met-p-NA), which releases the chromogenic product p-nitroaniline. This chromogenic product can be monitored continuously using a UV–Vis spectrophotometer set at 405 nm. The assay was tested with the type I MetAP from Escherichia coli (EcMetAP-I) and the type II MetAP from Pyrococcus furiosus (PfMetAP-II). Using l-Met-p-NA, the kinetic constants kcat and Km were determined for EcMetAP-I and PfMetAP-II and were compared with those obtained with a “standard” high-performance liquid chromatography (HPLC) discontinuous assay. The assay has also been used to determine the temperature dependence of the kinetic constant kcat for PfMetAP-II as well as to screen two novel pseudopeptide inhibitors of MetAPs. The results demonstrate that l-Met-p-NA provides a fast, convenient, and effective substrate for both type I and type II MetAPs and that this substrate can be used to quickly screen inhibitors of MetAPs

The alpha-synuclein 5'untranslated region targeted translation blockers: anti-alpha synuclein efficacy of cardiac glycosides and Posiphen

Increased brain α-synuclein (SNCA) protein expression resulting from gene duplication and triplication can cause a familial form of Parkinson's disease (PD). Dopaminergic neurons exhibit elevated iron levels that can accelerate toxic SNCA fibril formation. Examinations of human post mortem brain have shown that while mRNA levels for SNCA in PD have been shown to be either unchanged or decreased with respect to healthy controls, higher levels of insoluble protein occurs during PD progression. We show evidence that SNCA can be regulated via the 5'untranslated region (5'UTR) of its transcript, which we modeled to fold into a unique RNA stem loop with a CAGUGN apical loop similar to that encoded in the canonical iron-responsive element (IRE) of L- and H-ferritin mRNAs. The SNCA IRE-like stem loop spans the two exons that encode its 5'UTR, whereas, by contrast, the H-ferritin 5'UTR is encoded by a single first exon. We screened a library of 720 natural products (NPs) for their capacity to inhibit SNCA 5'UTR driven luciferase expression. This screen identified several classes of NPs, including the plant cardiac glycosides, mycophenolic acid (an immunosuppressant and Fe chelator), and, additionally, posiphen was identified to repress SNCA 5'UTR conferred translation. Western blotting confirmed that Posiphen and the cardiac glycoside, strophanthidine, selectively blocked SNCA expression (~1 μM IC(50)) in neural cells. For Posiphen this inhibition was accelerated in the presence of iron, thus providing a known APP-directed lead with potential for use as a SNCA blocker for PD therapy. These are candidate drugs with the potential to limit toxic SNCA expression in the brains of PD patients and animal models in vivo

Optimal thickness of silicon membranes to achieve maximum thermoelectric efficiency: A first principles study

Silicon nanostructures with reduced dimensionality, such as nanowires, membranes, and thin films, are promising thermoelectric materials, as they exhibit considerably reduced thermal conductivity. Here, we utilize density functional theory and Boltzmann transport equation to compute the electronic properties of ultra-thin crystalline silicon membranes with thickness between 1 and 12 nm. We predict that an optimal thickness of ∼7 nm maximizes the thermoelectric figure of merit of membranes with native oxide surface layers. Further thinning of the membranes, although attainable in experiments, reduces the electrical conductivity and worsens the thermoelectric efficiency

Lessons Learned From all For them: Best Practices For a Cross-Collaboration approach to Hpv Vaccination in Public Schools

The Community Preventive Services Task Force endorses vaccination programs in schools to increase access to vaccinations. However, implementing a school-based approach requires substantial coordination, planning, and resources. All for Them (AFT) is a multilevel, multicomponent approach to increase HPV vaccination among adolescents attending public schools in medically underserved areas in Texas. AFT comprised a social marketing campaign, school-based vaccination clinics, and school nurse continuing education. Process evaluation metrics and key informant interviews to understand experiences with AFT program implementation informed lessons learned. Lessons emerged in six domains: strong champion, school-level support, tailored and cost-effective marketing approaches, mobile provider collaboration, community presence, and crisis management. Strong support at district and school levels is vital for gaining principal and school nurse buy-in. Social marketing strategies are integral to program implementation and should be adjusted to maximize their effectiveness in motivating parents to vaccinate children against HPV, which also can be achieved through increased community presence of the project team. Preparing contingency plans and flexibility within the program can facilitate appropriate responses to provider restrictions in mobile clinics or in the event of unforeseen crises. These important lessons can offer useful guidelines for the development of prospective school-based vaccination programs