944 research outputs found
Search for the Hypothetical pi -> mu x Decay
The KARMEN collaboration has reported the possible observation of a hitherto
unknown neutral and weakly interacting particle x, which is produced in the
decay pi -> mu + x with a mass m(x) = 33.9 MeV. We have searched for this
hypothetical decay branch by studying muons from pion decay in flight with the
LEPS spectrometer at the piE3 channel at PSI and find branching ratios BR(pi-
to mu- anti-x) < 4e-7 and BR(pi+ to mu+ x) < 7e-8 (95\% C.L.). Together with
the limit BR > 2e-8 derived in a recent theoretical paper our result would
leave only a narrow region for the existence of x if it is a heavy neutrino.Comment: 10 pages, TeX (uses epsf), 3 Postscript figures uu-encode
A GIS-based assessment of the Byzantine water supply system of Constantinople
Despite the extensive archaeological surveys carried out in the last decades, little attention has been paid to one of the longest water supply systems of ancient times - the Byzantine water infrastructure which fed Constantinople from the mid-late fourth century AD. This work uses modern satellite terrain data and Global Positioning System (GPS) data to assess this system and provide an improved description of its route, total length and gradient profile. Forty-four validated GPS Control Points were correlated with ASTER GDEM V2 digital satellite data and archaeological information in a Geographic Information System (GIS) environment. We concluded that the total length of the water supply system was 426 km, and possibly even 565 km if the fifth-century aqueduct continued in parallel all the way to Constantinople rather than merging with the fourth-century aqueduct. The gradient of the channels varied across their length, being steepest near the spring sources, with a gradient mostly in the region of 5 m/km, and flattest at around 0.4 m/km in the most downstream section nearest the City. This reconstruction of the gradient profile provides valuable insight into the physical characteristics of the system, allowing future study of its hydraulic function.</p
Concettualizzazione e contestualizzazione dei beni culturali archeologici
This report describes the observations made while developing a new methodology for historic surveys used for the re-contextualisation of archaeological finds. This particular methodology avails itself of both traditional historic surveys as well as the representation of knowledge through ontology. The methodology described here was developed in reference to specific cases of re-contextualisation of archaeological artefacts from Pompeii which are now in the National Archaeological Museum in Naples
Village Baseline Study: Site Analysis Report for Xai Xai, Zongoene Village, Bairro 1, Mozambique
This is the report of the village baseline study of Zongoene Village, Bairro 1, in the CCAFS benchmark site of Xai Xai, Mozambique in May 2013 to complement an earlier household baseline survey done in the same village. Zongoene village is located by the coast at the mouth of the Limpopo River where there are extensive wetlands along with forests and sand dunes. The village is divided into five sections: Bairro 1, Bairro 2, Bairro 3, Bairro 4 and Bairro 5. Zongoene is the result of a government resettlement program that brought people together to ease service provision. Nonetheless, the level and quality of services remain very low with roads in bad condition, local schools poorly built and lacking water, one hospital with insufficient staff and resources, and nascent electrical availability. The concentrated and expanding population is also increasing pressures on the environment as demand for food and farmland grows
Low Energy Analyzing Powers in Pion-Proton Elastic Scattering
Analyzing powers of pion-proton elastic scattering have been measured at PSI
with the Low Energy Pion Spectrometer LEPS as well as a novel polarized
scintillator target. Angular distributions between 40 and 120 deg (c.m.) were
taken at 45.2, 51.2, 57.2, 68.5, 77.2, and 87.2 MeV incoming pion kinetic
energy for pi+ p scattering, and at 67.3 and 87.2 MeV for pi- p scattering.
These new measurements constitute a substantial extension of the polarization
data base at low energies. Predictions from phase shift analyses are compared
with the experimental results, and deviations are observed at low energies.Comment: 15 pages, 4 figure
Village Baseline Study: Site Analysis Report for Chicualacuala, Maluana, Mozambique (MO0145)
This is the report of the village baseline study of Maluana village in the CCAFS benchmark site of Chicualacuala, Mozambique from May 5-12, 2013 to complement an earlier household baseline survey done in the same village
Neurodegenerative Disease: What Potential Therapeutic Role of Acid-Sensing Ion Channels?
Acidic pH shift occurs in many physiological neuronal activities such as synaptic transmission and synaptic plasticity but also represents a characteristic feature of many pathological conditions including inflammation and ischemia. Neuroinflammation is a complex process that occurs in various neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, and Huntington's disease. Acid-sensing ion channels (ASICs) represent a widely expressed pH sensor in the brain that play a key role in neuroinflammation. On this basis, acid-sensing ion channel blockers are able to exert neuroprotective effects in different neurodegenerative diseases. In this review, we discuss the multifaceted roles of ASICs in brain physiology and pathology and highlight ASIC1a as a potential pharmacological target in neurodegenerative diseases
Population differences in allele frequencies at the OLR1 locus may suggest geographic disparities in cardiovascular risk events.
Abstract
Background: Several studies have demonstrated a link between cardiovascular disease (CVD) susceptibility
and the genetic background of populations.
Endothelial activation and dysfunction induced by oxidized low-density lipoprotein (ox-LDL) is one of
the key steps in the initiation of atherosclerosis. The oxidized low density lipoprotein (lectin-like)
receptor 1 (OLR1) gene is the main receptor of ox-LDL. We have previously characterized two
polymorphisms (rs3736235 and rs11053646) associated with the risk for coronary artery disease
(CAD) and acute myocardial infarction (AMI).
Aim: Given their clinical significance, it is of interest to know the distribution of these variants in
populations from different continents.
Subjects and methods: A total of 1229 individuals from 17 different African, Asian and European
populations was genotyped for the two considered markers.
Results: The high frequencies of ancestral alleles in South-Saharan populations is concordant with the
African origin of our species. The results highlight that African populations are closer to Asians, and
clearly separated from the Europeans.
Conclusion: The results confirm significant genetic structuring among populations and suggest a
possible basis for varying susceptibility to CVD among groups correlated with the geographical
location of populations linked with the migrations out of Africa, or with different lifestyle
Inflammation subverts hippocampal synaptic plasticity in experimental multiple sclerosis
Abnormal use-dependent synaptic plasticity is universally accepted as the main physiological correlate of memory deficits in neurodegenerative disorders. It is unclear whether synaptic plasticity deficits take place during neuroinflammatory diseases, such as multiple sclerosis (MS) and its mouse model, experimental autoimmune encephalomyelitis (EAE). In EAE mice, we found significant alterations of synaptic plasticity rules in the hippocampus. When compared to control mice, in fact, hippocampal long-term potentiation (LTP) induction was favored over long-term depression (LTD) in EAE, as shown by a significant rightward shift in the frequency-synaptic response function. Notably, LTP induction was also enhanced in hippocampal slices from control mice following interleukin-1β (IL-1β) perfusion, and both EAE and IL-1β inhibited GABAergic spontaneous inhibitory postsynaptic currents (sIPSC) without affecting glutamatergic transmission and AMPA/NMDA ratio. EAE was also associated with selective loss of GABAergic interneurons and with reduced gamma-frequency oscillations in the CA1 region of the hippocampus. Finally, we provided evidence that microglial activation in the EAE hippocampus was associated with IL-1β expression, and hippocampal slices from control mice incubated with activated microglia displayed alterations of GABAergic transmission similar to those seen in EAE brains, through a mechanism dependent on enhanced IL-1β signaling. These data may yield novel insights into the basis of cognitive deficits in EAE and possibly of MS
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