Porphyry Cu-Mo deposits have influenced surface water quality in high-Andes of north-central Chile since the Miocene. Water anomalies may reduce species abundance and diversity in alpine meadows as ...acidic and metal-rich waters are highly toxic to plants The study assessed the importance of surface water quality on plant abundance and diversity in high-alpine meadows at the Yerba Loca Natural Santuary (YLNS), central Chile (33°15' S, 70°18' W). Hydrochemical and plant prospecting were carried out on Piedra Carvajal, Chorrillos del Plomo and La Lata meadows the growing seasons of 2006 and 2007. Direct gradient analysis was performed through canonical correspondence analysis (CCA) to look for relationships among water chemistry and plant factors. High variability in water chemistry was found inside and among meadows, particularly for pH, sulphate, electric conductivity, hardness, and total dissolved Cu, Zn, Cd, Pb and Fe. Data on species abundance and water chemical factors suggests that pH and total dissolved Cu are very important factor determining changes in plant abundance and diversity in study meadows. For instance, Festuca purpurascens, Colobanthus quitensis, and Arenaria rivularis are abundant in habitals with Cu-rich waters while Festuca magellanica, Patosia clandestina, Plantago barbata, Werneria pygmea, and Erigeron andícola are abundant in habitals with dilute waters.Los megadepósitos de pórfidos de Cu-Mo han influido sobre la calidad de las aguas superficiales en las zonas altoandinas del centro-norte de Chile desde el Mioceno. Estas alteraciones en la calidad de las aguas podrían afectar negativamente a la vegetación presente en las vegas altoandinas, ya que las aguas acidas y ricas en metales son altamente tóxicas para las plantas. En este estudio se evaluó el efecto de la calidad de las aguas en la abundancia y diversidad florística de las vegas altoandinas del Santuario de la Naturaleza Yerba Loca (SNYL), en Chile central (33° 15' S, 70° 18' O). Se realizaron prospecciones hidroquímicas y botánicas en las vegas de Piedra Carvajal, Chorrillos del Plomo y La Lata, durante las estaciones de crecimiento de 2006 y 2007. Se realizó un análisis directo de gradiente a través del Análisis de Correspondencia Canónica (CCA) para buscar relaciones entre los parámetros químicos del agua y los parámetros botánicos. Se encontró una alta variabilidad química del agua tanto dentro como entre las vegas, particularmente en cuanto a pH, sulfatos, conductividad eléctrica, dureza y contenidos totales disueltos de Cu, Zn, Cd, Pb y Fe. Los datos de abundancias específicas y los parámetros químicos del agua sugieren que el pH y el contenido de Cu total disuelto son factores importantes en determinar los cambios en la abundancia y la diversidad de las especies vegetales en las vegas estudiadas. Por ejemplo, Festuca purpurascens, Colobanthus quitensis y Arenaria rivularis son abundantes en ambientes de aguas con altos contenidos de Cu, mientras que Festuca magellanica, Patosia clandestina, Plantago barbata, Werneria pygmea y Erigeron andícola son abundantes en lugares de aguas con bajos contenidos de Cu.
BACKGROUND In rare cases, adults with normal or almost normal cognition may have giant brain ventricles surrounded by a sliver of brain. Because the usual flow of cerebrospinal fluid (CSF) is ...interrupted in these individuals, they may develop alternative CSF pathways to preserve brain function. OBJECTIVE To describe novel morphologic autopsy findings in a patient with chronic giant hydrocephalus that suggest the existence of alternative CSF draining pathways. DESIGN Case report. SETTING Autopsy study. PATIENT A 48-year-old man with chronic compensated hydrocephalus associated with a Dandy-Walker malformation. MAIN OUTCOME MEASURE Autopsy findings. RESULTS We observed microscopic structures on the ventricular wall that may facilitate CSF resorption. Their histologic appearance, reminiscent of pacchionian granulations, showed the opposite relation in regard to CSF/blood compartments: whereas the core of a pacchionian granulation contains CSF and the granulation is bathed in blood of the venous sinus, the core of the ventricular granulation in our patient contained venules, with the granulation bathed in ventricular CSF. CONCLUSIONS These previously unreported (to our knowledge) ventricular wall granulations may facilitate draining of CSF into the venous system when CSF outflow from the ventricular system is occluded. The presence of these ventricular structures illustrates biologic adaptation to anomalous conditions and successful compensation.Arch Neurol. 2009;66(2):262-267-->
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