Recovery of metals and other beneficial products from coal fly ash： a sustainable approach for fly ash management

Increasing production and disposal of coal fly ash （CFA） is a matter of serious environment concern. However, CFA contains various beneficial metals and mineral matters whose demand is increasing in the industrialized world, while natural supplies are diminishing. Therefore, recovery of these potential resources from CFA can be an alternative way to save mineral resources, as well as to reduce the environmental burden of CFA disposal. There are numerous methods developed for the recovery of beneficial products from CFA. Based on the US patents and journal literatures, the present review describes the recovery status and technologies of major elements such as Al, Si, Fe and Ti, and trace elements such as V, Ga, Ge, Se, Li, Mo, U, Au, Ag, Pt groups and rare earth elements （REEs） and other beneficial products such as magnetic materials, cenospheres, and unburned carbon from CFA. It also highlights the recovery efficiency and drawbacks for their extraction, and suggests future research to develop satisfactory results in terms of selective recovery and purification.

Saturated Hydraulic Conductivity Changes with Time and Its Prediction at SAR and Salinity in Quevedo Region Soils

Darcy’s law is applied to describe the steady flow processes in which the flux remains constant with time along the conducting system. Due to the dispersion and migration of colloidal particles and lodging in the soil pores the reduction in hydraulic conductivity occurs with time in particular when the soil and the percolating solution are affected by electrolyte concentration. Hence, the aim of this study is to find empirical equations that can be used to predict the flux with time. Data for the effluent volume versus time (up to 6 hours) which was collected for three soils (located at Quevedo-Los Rios region) treated by two salt solutions (5 and 50 meq/l) with different SAR values were used to test certain mathematical forms of equations. Only four empirical equations were found to perfectly fit the data (flux vs time) whereas, fitting the calculated and measured data of the hydraulic conductivity for all soils produced regression factors R2 ≥ 0.99. So, these equations can be applied to predict the hydraulic conductivity and to characterize the flow process at saturated conditions of the studied soils with great confidence. The Hoerl function model was the best of all equations for application as the fitting degrees were almost perfect for all studied soils at 5 and 50 meq/l. It was observed for all equations that one of the fitting parameters would always represent the initial hydraulic conductivity (Kos) that was evaluated graphically at zero time by extrapolation.

Critical analysis of the definition of severe dengue, based on the Ecuador outbreak in 2012

Of the 238 cases reported to the Ecuador Health Authorities in 2012 as severe dengue, only 53.3% met diagnostic criteria. The definition of severe dengue should be based on more precise criteria. Information about compliance with criteria should be fed back to local levels.

Functional N-Representability in 2-Matrix,1-Matrix,and Density Functional Theories

The N-representability conditions on the reduced second-order reduced density matrix (2-RDM), impose restrictions not only in the context of reduced density matrix theory (RDMT), but also on functionals advanced in one-matrix theory such as natural orbital functional theory (NOFT), and on functionals depending on the one-electron density such as those of density functional theory (DFT). We review some aspects of the applications of these N-representability conditions in these theories and present some conclusions.

Normozoospermic versus teratozoospermic domestic cats： differential testicular volume, sperm morphometry, and subpopulation structure during epididymal maturation

Teratozoospermia （〈40% morphologically normal spermatozoa/ejaculate） is a frequent phenomenon in feline species. This research was carried out to study the possible differences in testicular volume, differential sperm morphometric traits, and potential differences regarding the sperm subpopulational structure during epididymal sperm maturation in teratozoospermic feline donors. Epididymal sperm samples were collected from the caput （R1）, corpus （R2）, and cauda （R3） epididymidis in two donor groups （N： normozoospermic; T： teratozoospermic）. Aliquots were assessed for concentration, viability, motility, and acrosomal integrity. Sperm morphometric descriptors from CASA-Morph analysis were analyzed by the Principal Component Analysis （PCA） and clustering analyses. Irrespective of the group analyzed, PCA revealed two Principal Components （PCs） for each epididymal region explaining more than the 93% of the variance. Surprisingly, the number of subpopulations remained constant in regions R1-R2-R3 irrespective of the donor group analyzed. However, the distribution of these subpopulations was found to be structurally different and strongly influenced by the epididymal region and the donor group. In conclusion, testicular morphometry and the sperm subpopulation structure were different in N and T donors. The alterations in subpopulations during epididymal maturation could be used as a potential clinical indicator of teratozoospermic individuals since an important influence of teratozoospermia on sperm subpopulation structure has been demonstrated.

Sperm subpopulations in avian species： a comparative study between the rooster （Gallus domesticus） and Guinea fowl （Numida meleagris）

The main aims of this research were to study possible differences in objective morphometric sperm characteristics, establish normative sperm morphometry standards, and evaluate the presumed different subpopulation distribution of avian spermatozoa from the rooster （Gallus domesticus） and Guinea fowl （Numida meleagris） as model avian species. Seventy-two ejaculates （36 per species studied） were obtained manually, following a training period involving gently combined dorso-abdominal and lumbo.sacral massage of the birds. Ejaculates were processed for volume, sperm concentration, viability, motility, and morphology. Moreover, samples were submitted for sperm morphometric assessment using objective Computer-Assisted Semen Analysis for Morphometry （CASA-Morph） methods, with sperm morphometric descriptors evaluated by Principal Component Analysis （PCA） and multivariate clustering analyses. There were several differences observed between the avian species in values obtained for ejaculate volume and sperm concentration （P 〈 0.001）. Irrespective of species, PCA revealed two Principal Components （PCs） explaining more than 80% of the variance. In addition, the number of subpopulations differed with species （three and five subpopulations for rooster and Guinea fowl, respectively）. Moreover, the distribution of the sperm subpopulations was found to be structurally different between species. In conclusion, our findings from using CASA-Morph methods indicate pronounced sperm morphometric variation between these two avian species. Because of the strong differences observed in morphometric parameter values and their subpopulation distribution, these results suggest that application of objective analytical methods such as CASA-Morph could substantially improve the reliability of comparative studies and help establish valid normative sperm morphological values for avian species.