Iron reactivity in anoxic sediments in the Ría de Vigo (NW Spain).

The high sedimentation rates and high organic matter contents in the sediments of the Ría de Vigo (NW Spain) promote the development of anoxic conditions, determining the dynamics of elements like Fe and conditioning his speciation and reactivity. Four gravity cores were retrieved in anoxic sediments of the Ría de Vigo in November 2012. In order to understand the behavior of Fe in these complex environments different fractions of reactive iron were analyzed. The decrease in highly reactive iron and sulfide contents with depth showed the relationship between the iron and sulfur cycle in the middle and outer zones of the ría. In the inner zone, the apparition of shallow methane gas may cause the slower decrease of the highly reactive iron contents. In zones without methane, sediment layers enriched in iron -with a reactivity higher than in other sediment samples- were observed. An increase was observed in the dithionite and total reactive iron contents from the inner to the outer zone of the ría, according to the gas depth. Furthermore, a decrease in Fe (III)-bearing minerals contents with depth was observed in the outer and middle zones, but not in the innermost area where the gas is shallow. The high organic matter and sulfide contents, mainly in the inner zone of the ría, indicate that the most of the Fe (II) is FeS. Moreover, the high contents of total reactive iron and pH values (6.86-7.98) could contribute the formation of stable minerals like pyrite along the Ría de Vigo.

Redox processes in pore water of anoxic sediments with shallow gas.

The Ría de Vigo (NW Spain) has a high organic matter content and high rates of sedimentation. The microbial degradation of this organic matter has led to shallow gas accumulations of methane, currently distributed all along the ría. These peculiar characteristics favor the development of anoxic conditions that can determine the dynamics of iron and manganese. In order to study the role played by iron and manganese in the processes that take place in anoxic sediments with shallow gas, four gravity cores were retrieved in anoxic sediments of the Ría de Vigo in November 2012. Methane was present in two of them, below 90cm in the inner zone and below 200cm, in the outer zone. Pore water was collected and analyzed for vertical profiles of pH, sulfide, sulfate, iron and manganese concentrations. Sulfate concentrations decreased with depth but never reached the minimum detection limit. High sulfide concentrations were measured in all cores. The highest sulfide concentrations were found in the inner zone with methane and the lowest were in the outer zone without methane. Concentrations of iron and manganese reached maximum values in the upper layers of the sediment, decreasing with depth, except in the outer zone without gas, where iron and manganese concentration increased strongly toward the bottom of the sediment. In areas with shallow gas iron reduction, sulfate reduction and methane production processes coexist, showing that the traditional redox cascade is highly simplified and suggesting that iron may be involved in a cryptic sulfur cycle and in the oxidation of methane.

Heavy metal retention in copper mine soil treated with mussel shells: batch and column experiments.

Batch and column experiments are used to study the effects of ground mussel shell amendment on the retention of heavy metals in acidic mine soil. The soil pH increases proportionally with the mussel shell concentration employed. Mussel shell amendment increases Cu, Cd, Ni and Zn retention in mine soil when compared with unamended soil. In fact, Cu retention was 6480µmolkg(-1) (43% of the total added) when the maximum metal concentration (1570µM) was added to the unamended soil, whereas retention reached 15,039µmolkg(-1) (99.9% of the total Cu added) when soil was amended with 24gkg(-1) mussel shell; in the case of Cd, adsorption increases from 3257µmolkg(-1) (15% of the total added) for the unamended soil, to 13,200µmolkg(-1) (87% of the total added) for the shell-amended soil; Ni retention increased from 3767µmolkg(-1) (25% of the total added) corresponding to unamended soil, to 11,854µmolkg(-1) (77% of the total added) for the shell-amended soil; and finally, Zn retention increased from 4684µmolkg(-1) (31% of the total added), for unamended soil, to 14,952µmolkg(-1) (98% of the total added) for shell-amended soil. The results of the constant flow transport experiments show that the addition of the 24gkg(-1) mussel shells can retain Cu, Cd, Ni and Zn within the first few centimetres of the column length, indicating the usefulness of ground mussel shells to drastically decrease the mobility and availability of these pollutants and to facilitate soil remediation.

Validación de un nuevo test para medir habilidades tonales y verbales en la escucha dicótica / Validation of a new test for measuring of tonal and verbal skills on dichotic listening

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Fungal survival in ensiled swine faeces.

The survival of several genera of fungi was determined in the ensiled solid fraction of swine faeces after 0, 7, 14, 28 and 56 days of ensiling. The experiment had two treatments, un-ensiled and ensiled manure, in a split-plot design. The manure was distributed into 50 containers; samples, taken at the specified times, were cultured in agar potato dextrose medium, incubated, and colony forming units (CFU/g) were counted and log-transformed. The ensiling process decreased the number of CFU after 56 days. Five fungal genera were identified (Absidia spp., Aspergillus spp., Penicillium spp., Rhizopus spp. and non-fructiferous fungi), and their vulnerability to the ensiling conditions varied, although most of them slowed their growth or disappeared after 14 days of ensiling.

[New interactive verbal dichotic listening test]. / Nuevo test interactivo de escucha dicótica digital verbal.

INTRODUCTION AND OBJECTIVE: From the multimedia technology and of the digital recording of the voice, we have redesigned the verbal dichotic listening test. The recognition of 15 monosyllabic word pairs offered though some earphones is presented in an interactive program. METHODS: Using the mouse button, the subject decides the moment in which each stimuli coupe will take place. Likewise, the screen displays 10 words, among which you have to recognize the words supplied by the earphones. Finally, the program results in complete right answers and right answers cross or referred to the opposite ear. RESULTS: Applied the test to a sample of 92 subjects, apparently normal, with a middle and high cultural level, from among 19 and 60 years (44 females and 48 males), the test resulted in a predominance of rights answers in the right ear (p < 0.0064). Separated the sample in in left-handed and right-handed men (67 right handed and 25 left-handed), it hasn't been found meaningful differences among their averages. Separated the sample by sex, the differences among the slightly meaningful averages (p < 0.04, according to the Student's t test). CONCLUSIONS: The test is offered as a resource appropriate for laterality studies, and for differential disorder study of gnosias and praxias of the dyslexias of aphasias, hearing aids, multiple sclerosis, and aptitudes studies.

[Tonal dichotic listening: discriminatory value between left and right handedness and between sexes]. / Escucha dicótica tonal: valor discriminativo entre zurdos, diestros y entre sexos.

INTRODUCTION: The dichotic hearing test consists of simultaneous stimulation of right and left ears with different messages, allowing analysis of the better or worse selective integration of these messages. MATERIAL AND METHODS: With the latest techniques, the tonal dichotic test is applied by listening to a sample of 90 persons, ages from between 20 and 50 years without antecedents of otologic, neurologic nor psiquiatric disorders, valuing their discriminative and dominant capacity for lateral hearing. RESULTS: The test is chosen effectively arranging the persons by their stereophonic capacity, like something adding but is as not as their simple biaural hearing capacity is, it is found an average capacity of hearing of the 79.856% in the left ear while there is only in 74.856% of in the right ear, which represents a dominance or increased value for the left ear. CONCLUSIONS: Separating within the general sample the right-handed (60 persons) from the left-handed (30 persons), there is not found any meaningful differences neither concerning capacity of discrimination nor of dominance. Separating them by sexes (58 women and 32 men) no meaningful differences are found either in discriminative capacity or in dominance.

[Computerized EEG and personality]. / EEG computorizado y personalidad.

The ordinary EEG, on only showing qualitative malfunction of abnormal graphoelements in the tracings, proves itself insufficient to go into the analysis of psychological and psycho-pathological problems. Since computerised studies of EEG permit quantitative comparisons, we tried to apply them in correlation with the characteristics of the personality classified also with quantitative criteria, such as those offered in the personality inventory 16 PF; from which have been chosen the so-called factors of the second order, and the subjectivity-objectivity factors. The test was carried out on 100 voluntary subjects from Almeria (Spain), all with High School grades, between 18 and 40 years of age, of both sexes, all right-handed, without neuro-psychiatric history, and with normal ordinary EEGs. From the statistical analysis of the results one could deduce that there are significant specific relationships from the computerised EEG, with those secondary polar values of 16 PF: high and low anxiety, extroversion-introversion. Subjects with low anxiety presented a significant increase of the alpha band opposed to the subjects with high anxiety. There is a significant differences in power of the frontal areas between extrovert and introvert subjects. The extroverted subjects have a greater power of the right side and the introverted subjects a greater power of the left.