Operation of a horizontal subsurface flow constructed wetland--microbial fuel cell treating wastewater under different organic loading rates.

The aim of the present work is to determine whether a horizontal subsurface flow constructed wetland treating wastewater could act simultaneously as a microbial fuel cell (MFC). Specifically, and as the main variable under study, different organic loading rates were used, and the response of the system was monitored. The installation consisted of a synthetic domestic wastewater-feeding system and a pilot-scale constructed wetland for wastewater treatment, which also included coupled devices necessary to function as an MFC. The wetland worked under continuous operation for 180 d, treating three types of synthetic wastewater with increasing organic loading rates: 13.9 g COD m(-2) d(-1), 31.1 g COD m(-2) d(-1), and 61.1 g COD m(-2) d(-1). The COD removal efficiencies and the cell voltage generation were continuously monitored. The wetland worked simultaneously as an MFC generating electric power. Under low organic loading rates, the wastewater organic matter was completely oxidised in the lower anaerobic compartment, and there were slight aerobic conditions in the upper cathodic compartment, thus causing an electrical current. Under high organic loading rates, the organic matter could not be completely oxidised in the anodic compartment and flowed to the cathodic one, which entered into anaerobic conditions and caused the MFC to stop working. The system developed in this work offered similar cell voltage, power density, and current density values compared with the ones obtained in previous studies using photosynthetic MFCs, sediment-type MFCs, and plant-type MFCs. The light/darkness changes caused voltage fluctuations due to the photosynthetic activity of the macrophytes used (Phragmites australis), which affected the conditions in the cathodic compartment.

Aproximación psicobiológica a concepto del tiempo / Tittle

El modo que cada individuo tiene de vivir su tiempo es un aspecto con frecuencia olvidado en el abordaje terapéutico, pero el tenerlo en cuenta puede enriquecer el conocimiento de la historia de los pacientes y puede ser un elemento más de utilidad en el enfoque del tratamiento

The way of each individual to live its time is frequently forgotten in the therapeutic boarding, but having them in account can enrich the knowledge of the history of the patients and can be an element more of utility in the approach of the treatment

Postoperative gangrenous peritonitis after laparoscopic cholecystectomy: a new complication for a new technique.

We report a case of anaerobic peritonitis with bowel emphysema, but no hollow organ perforations, following gallbladder removal for acute acalculous cholecystitis using a laparoscopic procedure in a diabetic patient. Management consisted of profuse peritoneal irrigation and zipper laparostomy. After a long postoperative period, the patient recovered without sequelae. The patient suffered typical acute cholecystitis with empyema and a diabetic status; anaerobial flora is frequent in these cases. The patient was operated on by means of a closed technique without contact with either air or oxygen. Moreover, CO2 injection into the peritoneal cavity with this technique, along with gallbladder rupture, created an ideal medium for anaerobial growth. We suggest that acalculous cholecystitis in diabetic patients could represent a contraindication for laparoscopic cholecystectomy; alternatively, open cholecystectomy should at least be considered when gallbladder rupture occurs during laparoscopy.

Influence of contrast on the recognition of defocused letters: a geometrical model.

We show how contrast (C) affects the recognition of defocused letters. To do this, the maximum distance (threshold distance) at which a subject, with an induced refraction of -5.5 D, can recognize a letter was determined. Our results show that when C = 1, the recognition threshold distance is such that the ratio eta/xi, between the pseudoimage of the letter (eta) and the blur circle (xi), corresponding to any point of the letter at this distance is about eta/xi = 2; the exact value depends on the difficulty of recognition, in agreement with previous experiments. This ratio represents the sharpness of the image in a geometrical treatment of image formation, providing a geometrical criterion for recognition. Reduction in contrast can be compensated by improving the geometrical sharpness; i.e. bringing the object closer to the subject's are point. Our results show that the increment of eta/xi as a function of the contrast is between C = 0.1 and 1.0. We suggest that a similar geometrical criterion for recognition could be used for any contrast (at least down to C = 0.1 and defocus > 1 D), provided that the proper value of eta/xi is used in each case. On this basis we propose a purely geometrical model, which agrees well with the data and predicts the relationships between tolerance to defocus, contrast and visual acuity; including the well-known relation between visual acuity and defocus when contrast is unity.

Variation of the visual acuity--luminance function with background colour.

The relationship between visual acuity (VA) and background colour is a question that still creates a certain amount of confusion even today, although most authors agree that colour background does not basically affect VA, or at best, values that are only slightly better are obtained with monochromatic yellow light. The object of this paper is to try to clarify if, when the axial chromatic aberration (ACA) has been compensated for, certain differences due exclusively to colour persist or not. In order for this, the VA-luminance functions with red, green, blue and white backgrounds have been measured for two emmetropic observers, before and after compensating for the ACA. The results show that after the compensation, the curve corresponding to red is above the one corresponding to blue, with the one corresponding to green in between. The achromatic function (white background) practically overlaps with the green one. This behaviour is consistent with that shown recently for contrast sensitivity functions (CSFs). However, the asymptotic values are identical for the three colours, and so, it is understandable that no significant differences are normally found when only a standard measurement of VA is taken using the typical illumination from an optotype projector.

[Psychiatric morbidity in young people in a rural area of Madrid]. / Morbilidad psiquiátrica juvenil en un área rural de Madrid.

We have studied the prevalence of the psychiatry disorders in the young people of a Madrid's rural area. We have found a prevalence of 0.09% if we consider the population as a whole, and 0.9% referred only to young people. The most frequent diagnoses, we have found, are the affective disorders and the anxiety disorders, and in the second place the schizophrenia and personality disorders.

Red-green flicker resolution as a function of heterochromatic luminous modulation.

Critical fusion frequencies have been evaluated in heterochromatic red-green flicker as a function of red-green luminous modulation defined by mL = (R-G)/(R+G)%, at five different mean luminance levels, two test sizes (2 degrees and 5 degrees) and square wave stimuli. The extreme values mL = +/- 100 correspond to ordinary light-dark flicker (red or green); mL = 0 corresponds to pure chromatic flicker, and any other values correspond to simultaneous luminous and chromatic flicker. To implement the stimuli we have developed a new stimuli generator (AVICO, colour vision analyser) using bicolour LEDs as the light source and electronic control of the luminances and frequencies. The results for any luminance level and both test sizes show a minimum critical fusion frequency in the case of pure chromatic flicker (photometric match condition) and a critical fusion frequency which is slightly higher in the green extreme (mL = -100) than in the red (mL = +100). The shape of the variation between the minimum and the extremes is consistent with the results recently reported by Swanson and the theoretical models for the luminance channel response to heterochromatic flicker.

Effect of color on contrast sensitivity with two different accommodative stimuli.

We studied the influence of color and accommodation on the contrast sensitivity function (CSF). At the same time, we measured the effect of axial chromatic aberration (ACA) on the CSF. The CSF's of two observers were determined using red, green, blue, and white light, at 5- and 0.5-m viewing distances. At 5 m the CSF's were measured with natural vision and also with lenses which compensated the ACA. Results show that the effect of ACA on the CSF is to reduce the sensitivity to blue with respect to the red. The difference in sensitivity between these two colors is between 50 and 150% and varies with the frequency and the subject. When the ACA is compensated the influence of the color on the CSF is very small, in our experiment, and this result is discussed in relation to the compensating effects of chromatic adaptation of the color mechanisms. In near vision, the CSF's were measured with natural vision and also with the lenses required to give the same accommodative stimulus for all colors. We discuss the effect of accommodation on the CSF. For both far and near the results are compared with the CSF with white light.

Vision defects in albinism.

We have examined the possible presence of color vision anomalies in 9 individuals (17 eyes, 1 blind) with fundus findings suggesting ocular albinism using the Ishihara plates, the 28-hue Roth test, and the Davico anomaloscope. Results indicate that four of these individuals show no sign of the anomalies expected in an albino in either of the two eyes. Of the remaining cases, two are simple deuteranomals in both eyes, according to Pickford's classification criteria. The rest have protanomaly; however, in these the deviation toward red appears in both eyes in only one subject, whereas in the other two subjects it appears in only one eye, their binocular color vision being basically normal. Our study shows that a large proportion of these albinos have photophobia, pendular nystagmus, strabismus, noticeable refractive errors (astigmatism and high myopia), and poor visual acuity [usually less than 6/30 (20/100) with correction]. The measurement of contrast sensitivity function (CSF) indicates that the frequency of 12 cpd cannot be perceived, even in binocular vision.

The immediate and long-term effects of mannitol and glycerol. A comparative experimental study.

A prolonged experimental situation of focal vasogenic oedema, producing mild intracranial hypertension, was developed. The aim was to study the immediate and long-term effects of repeated infusions of mannitol and glycerol on intracranial pressure (ICP) and cerebral blood flow (CBF). Eighteen goats were operated on twice to implant: an epidural latex balloon in each cerebral hemisphere to measure ICP; an electromagnetic flowmeter around both internal maxillary arteries (the only cerebral blood input), after tying the extracranial branches, to measure the CBF; and two femoral catheters to measure blood pressure (BP) and for intravenous infusion (IV). Three groups of 6 goats each were formed: A) control; the BP and bilateral ICPs and CBFs were recorded under basal conditions and every 4 hours for 3 days after a cold injury (CI) was provoked; B) 20% mannitol solution 1 g/kg body weight injected every 12 hr starting at 24 hr post-CI; and C) 10.1% glycerol solution 0.5 g/kg body weight, administered as mannitol. Glycerol, as compared to mannitol, presents the following major differences among its immediate post infusion effects: a lesser decrease in ICP, but no rebound phenomenon; lesser elevation of BP; CBF increases more gradually and constantly. Long-term effects with mannitol consisted of a rebound phenomenon observed in ICP during the last 12 hr. In all 3 groups, it was observed that CBF increases in relation to the ICP level.

[Non-reabsorptive communicating hydrocephalus: surgical results according to the diagnostic procedure]. / Hidrocefalia comunicante arreabsortiva: resultados quirúrgicos de acuerdo con el procedimiento diagnóstico.

Both ex-vacuo and non-reabsorptive hydrocephalus can present with a similar clinical triad of dementia, gait disturbances and incontinence. From a prognostic point of view, however, a great difference exists due to the possibility of surgical treatment with cerebrospinal fluid shunting in non-reabsorptive hydrocephalus. The difficulty lies in a correct preoperative diagnosis. In this study 37 patients aged from 60 to 72 with a clinical history suggestive of non-reabsorptive communicating hydrocephalus were evaluated; the diagnostic tests applied to them were: computerized axial tomography, infusion test with Nelson's technique and intracranial pressure monitoring. A clear correlation was observed between the clinical improvement obtained after a cerebrospinal fluid shunt had been placed and the presence of pathological computerized axial tomography (hydrocephalus without increased sulci with or without trans-ependymal edema) or the pathological infusion test (intracranial pressure increase over 2 mm Hg/min and no decrease back to the basal level once the infusion had ended). No correlation was observed between the different recordings obtained from the intracranial pressure monitoring and the surgical results. The clinical data which most easily revert are the gait disturbance, dementia and incontinence in this order and, more so, in patients with known etiology. Since non-reabsorptive hydrocephalus and ex-vacuo hydrocephalus may co-exist, mostly in elderly patients, it is important to further develop the dynamic studies of intracranial pressure with the aim of offering a more reliable surgical prognosis.