The coexistence of barriers to labor mobility with large output-per-worker disparities driven by Total Factor Productivity (TFP) differences suggests that the world's labor force is misallocated across countries. We investigate the extent and consequences of this potential misallocation in the context of a simple two-location growth model, in which production requires capital, labor and an essential immobile factor (land). We characterize the magnitude of labor movements implied by an efficient long-run allocation, and derive their implications for capital accumulation. Quantitatively, even for moderate TFP differences, we find substantial increases in world output associated with efficient allocations. These output increases are driven by large movements of labor from low to high TFP countries, as well as by a sizeable increase in the capital stock and changes in its endogenous division across countries. Our results are robust to a large set of parameter values, including unrealistically conservative ones.
Human kallikrein 6 (protease M/zyme/neurosin) is a serine protease that has been suggested to be a serum biomarker for ovarian cancer and may also be involved in pathologies of the CNS. The precursor form of human kallikrein 6 (proh-K6) was overexpressed in Pichia pastoris and found to be autoprocessed to an active but unstable mature enzyme that subsequently yielded the inactive, self-cleavage product, hK6 (DK). Site-directed mutagenesis was used to investigate the basis for the intrinsic catalytic activity and the activation mechanism of pro-hK6. A single substitution R->Q stabilized the activity of the mature enzyme, while substitution of the active site serine (S->A) resulted in complete loss of hK6 proteolytic activity and facilitated protein production. Our data suggest that the enzymatic activity of hK6 is regulated by an autoactivation/autoinactivation mechanism. Mature hK6 displayed a trypsin-like activity against synthetic substrates and human plasminogen was identified as a putative physiological substrate for hK6, as specific cleavage at the plasminogen internal bond S-V resulted in the generation of angiostatin, an endogenous inhibitor of angiogenesis and metastatic growth.
Gnathostomiasis is a prevalent zoonosis in humans in some regions of the world. The genus Gnathostoma is considered an accidental parasite for humans; G. binucleatum is the endemic species in Nayarit, Mexico. This work was designed to determine the proteolytic activity of the excretory-secretory products (ESP) of advanced third-stage larvae (ADVL3) of Gnathostoma binucleatum against human fibronectin and antibodies from human and sheep. Our findings showed protease activity against human fibronectin as well as sheep and human gamma globulins of the ESP at molecular weights of 80 and 56 kDa. The proteases found in the ESP of G. binucleatum are thus candidate molecules for consideration as pathogenic elements, owing to the fact that they destroy proteins of the host tissue, which probably allows them to migrate through those tissues and degrade molecules involved in the humoral immune response.
High-temperature Fourier transform infrared (HT-FTIR) spectroscopy was used to characterize the deprotonation process of synthetic potassic-ferro-richterite of composition A(K0.90Na0.07)B(Ca0.54Na1.46). Unpolarized single-crystal spectra were collected both in situ and on quenched samples, and heating experiments were conducted in air, at a rate of 10 °C/min. The room-T spectrum measured before annealing shows a main band at 3678 cm-1 and a minor band at 3622 cm-1; these are assigned to local configurations involving Fe2+ at M(1)M(1)M(3) and facing a filled and an empty alkali-site, respectively. At 400 °C, a new band grows at 3656 cm-1; this is the most intense feature in the pattern at 450 °C. At T ≥ 500 °C, all peaks decrease drastically in intensity, and finally disappear at T > 600 °C. The total absorbance measured in situ increases significantly in the 25 < T < 450 °C range, although the spectra collected on quenched samples show no OH loss in the same T range. This feature is consistent with an increase of the absorption coefficient (ε) with T, the reason for which is still unclear. However, this feature has significant implications for the quantitative use of FTIR data in HT experiments. Examination of the relevant OH-stretching bands shows that iron oxidation occurs preferentially at the M(1,3) sites associated with occupied A sites. The deprotonation temperature indicated by FTIR for single-crystals is around 100 °C higher that that obtained by HT-X-ray diffraction (XRD) on single crystal by , whereas that obtained by HT-XRD on powders is intermediate. This unexpected observation can be explained by considering that: (1) the iron oxidation process, which is coupled to deprotonation and is probed by XRD, occurs preferentially at the crystal surface where it is triggered by the availability of atmospheric oxygen; (2) the proton diffusion, probed by FTIR, is slower that the electron diffusion probed by XRD; thus, the temperature shift may be explained by a much longer escape path for H in single-crystals than in powders. These results suggest that possible effects due to crystals size should be carefully considered in HT experiments done on Fe-rich silicates.
This paper reports the results of hydrothermal synthesis in the system Na2O-MgO-FeO-Fe2O3-SiO2- H2O. Four samples of stoichiometric magnesioriebeckite composition, ideally ◻Na2Mg3Fe23+Si8O22(OH)2, were run at 700-800 °C, 0.4 GPa, and redox conditions varying from NNO (Nickel.Nickel Oxide) to NNO + 2.3 log fO₂. Powder XRD and SEM-EDX show a high (>85%) amphibole yield for all samples; however, in no case was the end-member composition attained. EMP analyses show that the amphiboles obtained deviate strongly from nominal stoichiometry toward magnesio-arfvedsonite [NaNa2Mg4Fe3+Si8O22(OH)2]. Powder XRD patterns were indexed in the space group C2/m; refined cell-parameters reß ect variations in the amphibole composition, and the cell volume is correlated linearly with the A-site occupancy. Mössbauer spectra show that in all samples, Fe3+ is completely ordered at M2, whereas Fe2+ occurs at the M1, M3, and M4 sites. The Fe3+/Fe2+ ratio is a function of fO₂: for increasing oxidation conditions, there is significant increase in M2Fe3+ and decrease in Fe2+, notably in M4Fe2+. Mössbauer spectra also show significant variation in M1Fe2+ and M3Fe2+ quadrupole splitting as a function of the Fe3+ content in the amphibole. IR spectra in the OH-stretching region show a well-resolved quadruplet at frequencies <3680 cm-1, assigned to octahedral M1,3(Mg, Fe2+)-OH-A◻ configurations, and a broad band consisting of four overlapping components related to M1,3(Mg, Fe2+) configurations associated with occupied A-sites. Quantitative evaluation of the relative band intensities suggests a linear increase of A-site occupancy with decreasing fO₂ of synthesis. The composition of the amphiboles synthesized, can be best described by a combination of the C(Mg,Fe2+)1B(Mg,Fe2+)1 CFe3+-1BNa-1 and the ANa1C(Mg,Fe2+)1 A◻-1 CFe3+-1 exchange vectors. The experimental trend is in accord with the trend documented for natural amphiboles, and suggests that the amphibole composition can in fact be used to monitor changes in fO₂ during crystallization
El objetivo de este estudio es comprobar la evolución de las especificaciones de la prestación analítica (EPA) utilizadas en programas de garantía externa de la calidad (EQA) y el papel de un programa de categoría 1 en la vigilancia de la estandarización de la prestación de los laboratorios clínicos en España.
Se ha revisado la bibliografía sobre tipos de especificaciones de la calidad usados en programas de otros países y se ha comprobado su evolución; se ha comparado el posible impacto de distintas EPA empleadas en ocho países en la toma de decisiones clínicas con tres ejemplos de magnitudes: sodio, tirotropina (TSH) y tiempo de tromboplastina parcial activado (TTPA).
Se ha evidenciado la estandarización entre métodos analíticos comprobando si los resultados medios se desvían respecto al valor de referencia certificado del control dentro de las EPA derivadas de la variación biológica (VB). Las EPA usadas en EQA han evolucionado desde el estado del arte hacia la VB. Si se aplican los resultados que se aceptarían con algunas EPA se podrían producir decisiones clínicas erróneas.
En España, solo 2 de las 18 magnitudes biológicas estudiadas se pueden considerar bien estandarizadas. Sería necesaria una colaboración más estrecha entre los laboratorios y proveedores de sistemas analíticos para resolver las discrepancias.
External Quality Assurance (EQA) is vital to ensure acceptable analytical quality in medical laboratories. A key component of an EQA scheme is an analytical performance specification (APS) for each measurand that a laboratory can use to assess the extent of deviation of the obtained results from the target value. A consensus conference held in Milan in 2014 has proposed three models to set APS and these can be applied to setting APS for EQA. A goal arising from this conference is the harmonisation of EQA APS between different schemes to deliver consistent quality messages to laboratories irrespective of location and the choice of EQA provider. At this time there are wide differences in the APS used in different EQA schemes for the same measurands. Contributing factors to this variation are that the APS in different schemes are established using different criteria, applied to different types of data (e.g. single data points, multiple data points), used for different goals (e.g. improvement of analytical quality; licensing), and with the aim of eliciting different responses from participants. This paper provides recommendations from the European Federation of Laboratory Medicine (EFLM) Task and Finish Group on Performance Specifications for External Quality Assurance Schemes (TFG-APSEQA) and on clear terminology for EQA APS. The recommended terminology covers six elements required to understand APS: 1) a statement on the EQA material matrix and its commutability; 2) the method used to assign the target value; 3) the data set to which APS are applied; 4) the applicable analytical property being assessed (i.e. total error, bias, imprecision, uncertainty); 5) the rationale for the selection of the APS; and 6) the type of the Milan model(s) used to set the APS. The terminology is required for EQA participants and other interested parties to understand the meaning of meeting or not meeting APS.