Search results for "aqueduct"

Distribution of basal-expressed c-fos-like immunoreactive cells of the periaqueductal grey matter of the rat.

1996

The distribution of c-fos proto-oncogene expression has been studied in the periaqueductal grey matter (PAG) of non-intentional-stimulated rats by immunohistochemistry. A mean number of 53 +/- 9 Fos-like immunoreactive cells per hemiPAG, distributed into three groups, dorsolateral, lateral and ventrolateral, was found. The dorsolateral and the lateral groups appeared along the entire rostrocaudal PAG, whereas the ventrolateral group appeared only in the caudal half. These results reveal new data on the number and extent of the longitudinal columns within the hypothetical organization of the PAG. They also indicate a continuous activation of a significant population of neurones in the PAG, i…

Endoscopic third ventriculostomy in infants of less than 1�year of age: which factors influence the outcome?

2004

Endoscopic third ventriculostomy (ETV) is a successful method of treatment for obstructive hydrocephalus. In infants, however, it is reported to have a higher failure rate. On the basis of our own data and a meta-analysis of the literature, we try to define factors prognosticating potential failure in infants aged less than 1 year. Data were collected retrospectively. Between October 1994 and October 2002, 20 ETVs were performed in 16 patients younger than 1 year. Ages ranged from 8 to 311 days (median 103). Etiology was aqueductal stenosis in all 16 patients (idiopathic in 7, posthemorrhagic in 3, postmeningitic in 3, and related to CNS or vascular malformation in 3). ETV failure was defin…

Intrafamilial variability of the deafness and goiter phenotype in Pendred syndrome caused by a T416P mutation in the SLC26A4 gene.

2004

AbstractPendred syndrome (PS) is the most common cause of syndromic deafness, accounting for more than 5% of all autosomal-recessive hearing loss cases. It is characterized by bilateral sensorineural hearing loss and by goiter with or without hypothyroidism. Mutations in the SLC26A4 gene cause both classical PS and deafness associated with an enlarged vestibular aqueduct without goiter.To investigate a possible genotype-phenotype correlation in PS, we performed a detailed clinical and genetic study in three adult German sibs with typical PS caused by a common homozygous SLC26A4 mutation, T416P. An audiological long-term follow-up of 23 yr showed that the mutation T416P is associated with a …

Inter-basin water transfer conflicts. The case of the Tagus-Segura Aqueduct (Spain)

2020

Since its inauguration in 1979, the Tagus-Segura Aqueduct has become one of the hydraulic infrastructures that have given rise to the highest number of inter-regional conflicts in Spain during recent decades. The aim of this paper is to analyse the political, social, environmental and economic conflicts presented in the donor (Tagus) and recipient (Segura) basins of this infrastructure. To this end, through the holding of interviews with the main stakeholders and an analysis of the regulations, an assessment has been made of the results (for and against) of those who defend maintaining this infrastructure, owing to its far-reaching social and economic impact, and those who advocate its imme…

2016

AbstractAn inscription on the supporting wall of the inverted siphon of the aqueduct of the ancient Roman city of Patara, SW Turkey, explains how the wall collapsed during an earthquake and was subsequently restored. Carbonate deposits formed inside the aqueduct channel show cyclic stable isotope changes representing 17 years of deposition. This sequence, together with the text of the inscription, allows dating the earthquake to 68 AD and the original inauguration of the aqueduct to the winter of 51/52 AD. Thus, the carbonate deposits represent a high-resolution record of palaeotemperature and precipitation for SW Turkey covering the complete reign of the Emperor Nero. The period shows a co…

Experimental Study of Cross-flow Micro-turbines for Aqueduct Energy Recovery

2014

An important component of the management cost of aqueducts is given by the energy costs. Part of these costs can be recovered by transforming some of the many existing energy dissipations in electric energy by means of economic turbines. In this study an experimental work has been carried out: 1) to test the performance of an economic Cross-Flow turbine which maintains high efficiency within a large range of water discharges, and 2) to validate a new approximated formula relating main inlet velocity to inlet pressure. It is proved that the proposed formula, according to some simplifying assumption, exactly links inlet velocity to inlet pressure according to any possible geometry of the Cros…

230Th/U-dating of carbonate deposits from ancient aqueducts

2016

Abstract Carbonate deposits in aqueducts, known as calcareous sinter, can reach a considerable thickness and are commonly annually laminated. Environmental and palaeoclimate proxies measured in calcareous sinter samples, such as stable oxygen and carbon isotopes and trace elements, can provide important high-resolution information on hydrological conditions, temperature, and local precipitation in the catchment area of an aqueduct. In order to utilize the proxy data for palaeoclimate reconstruction, the sinter deposits must be dated by annual laminae counting and more precisely by 230 Th/U-dating. The major problem of 230 Th/U-dating of calcareous sinter in aqueducts is the relatively large…

Long-term hydrocephalus alters the cytoarchitecture of the adult subventricular zone

2014

Hydrocephalus can develop secondarily to a disturbance in production, flow and/or absorption of cerebrospinal fluid. Experimental models of hydrocephalus, especially subacute and chronic hydrocephalus, are few and limited, and the effects of hydrocephalus on the subventricular zone are unclear. The aim of this study was to analyze the effects of long-term obstructive hydrocephalus on the subventricular zone, which is the neurogenic niche lining the lateral ventricles. We developed a new method to induce hydrocephalus by obstructing the aqueduct of Sylvius in the mouse brain, thus simulating aqueductal stenosis in humans. In 120-day-old rodents (n = 18 per group), the degree of ventricular d…

Abnormal BAEP and internal auditory canal MRI in intracranial hypotension

2017

Intracranial hypotension (IH) is a treatable condition due to cerebrospinal fluid leak, characterised by variable clinical and MRI findings.1 Positional headache, neck stiffness, hearing changes with subdural fluid collection, enhancement of meninges, engorgement of venous structures and brain sagging are among the most frequent clinical and MRI findings. Typical abnormalities are found in 68%–85% of patients1. Hearing alterations (ranging from misperception to severe hearing loss) are known clinical symptoms of IH.1 The mechanism involves secondary perilymph depression due to patency of the cochlear aqueduct, inducing a compensatory expansion of the endolymphatic compartment, decreasing ba…

Carbonates from the ancient world's longest aqueduct:A testament of Byzantine water management

2021

The fourth‐ and fifth‐century aqueduct system of Constantinople is, at 426 km, the longest water supply line of the ancient world. Carbonate deposits in the aqueduct system provide an archive of both archaeological developments and palaeo‐environmental conditions during the depositional period. The 246‐km‐long aqueduct line from the fourth century used springs from a small aquifer, whereas a 180‐km‐long fifth‐century extension to the west tapped a larger aquifer. Although historical records testify at least 700 years of aqueduct activity, carbonate deposits in the aqueduct system display less than 27 years of operation. This implies that the entire system must have been cleaned of carbonate…