4,480 research outputs found

    Nephritis in the dog associated with Leptospira canicola infection

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    369 dogs infected with Leptospira canicola have been examined clinically. Agglutination tests and blood urea estimations have been carried out on each case. Details of examinations are given in the appendices. The cases have been classified into two main groups, primary and secondary renal, according to the agglutination titres and these two groups have been subdivided according to the degree of nitro- gen retention as evidenced by blood urea levels. Seven primary cases were shown to have a leptospiral bacteraemia in the early stage. 46 of the primary cases were kept under observation for periods of six months to four years, during which time agglutinins against L. canicola persisted as did proteinuria and the excretion of tubular casts.In Section 2 the renal lesions associated with L. cani- cola infection are described. The primary renal stage was characterised by an intense interstitial cellular infiltration which often localised predominantly in the corticomedullary zone. In subacute stages early fibrosis was evident but the infiltration remained the chief feature. In well established cases of chronic nephritis in the secondary stage the main lesion was extensive diffuse fibrosis with comparatively few small cellular foci remaining. Spirochaetes were sparse but were demonstrated mostly within the lumen of tubules or in the substance of a hyaline cast.In the experimental work described in Section 3 Koch's postulates have been fulfilled by reproducing the infection in dogs and recovering the organism in pure culture from the blood and kidneys of the infected animal. The recovered organism was then passaged through another two dogs. The renal lesions produced were similar to those observed in naturally occurring primary cases although not sufficiently extensive to produce obvious malaise or nitrogen retention in the dogs infected. It is suggested that loss of virulence of the organism in vitro is the main reason for the inability to produce renal failure. Despite the lack of severity of the condition produced in the dog the cellular infiltration was characteristically mononuclear and showed a definite tendency to localise in the boundary zone. Spirochaetes were readily demonstrated in the kidneys

    Can a witness report hearsay evidence unintentionally? The effects of discussion on eyewitness memory

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    When eyewitnesses are exposed to misinformation about an event from a co-witness, they often incorporate this misinformation in their recall of the event. The current research aimed to investigate whether this memory conformity phenomenon is due to change in the witness's memory for the event, or to social pressures to conform to the co-witness's account. Participants were shown a crime video and then asked to discuss the video in groups, with some receiving misinformation about the event from their discussion partners. After a one week delay some participants were warned about possible misinformation before all participants provided their own account of the event. In Study 1, participants made remember/know judgments about the items recalled, and in Study 2 they indicated the source of their memories. Co-witness information was incorporated into participants' testimonies, and this effect was not reduced by warnings or source monitoring instructions, suggesting memory change may have occurred. However, there was some indication that remember/know judgments may help distinguish between "real" memories and co-witness information

    A Laser System for the Spectroscopy of Highly-Charged Bismuth Ions

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    We present and characterize a laser system for the spectroscopy on highly-charged ^209Bi^82+ ions at a wavelength of 243.87 nm. For absolute frequency stabilization, the laser system is locked to a near-infra-red laser stabilized to a rubidium transition line using a transfer cavity based locking scheme. Tuning of the output frequency with high precision is achieved via a tunable rf offset lock. A sample-and-hold technique gives an extended tuning range of several THz in the UV. This scheme is universally applicable to the stabilization of laser systems at wavelengths not directly accessible to atomic or molecular resonances. We determine the frequency accuracy of the laser system using Doppler-free absorption spectroscopy of Te_2 vapour at 488 nm. Scaled to the target wavelength of 244 nm, we achieve a frequency uncertainty of \sigma_{244nm} = 6.14 MHz (one standard deviation) over six days of operation.Comment: Contribution to the special issue on "Trapped Ions" in "Applied Physics B

    On the stratigraphic integrity of leaf-wax biomarkers in loess paleosols

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    Paleoenvironmental and paleoclimate reconstructions based on molecular proxies, such as those derived from leaf-wax biomarkers, in loess-paleosol sequences represent a promising line of investigation in Quaternary research. The main premise of such reconstructions is the synsedimentary deposition of biomarkers and dust, which has become a debated subject in recent years. This study uses two independent approaches to test the stratigraphic integrity of leaf-wax biomarkers: (i) long-chain n-alkanes and fatty acids are quantified in two sediment-depth profiles in glacial till on the Swiss Plateau, consisting of a Holocene topsoil and the underlying B and C horizons. Since glacial sediments are initially very poor in organic matter, significant amounts of leaf-wax biomarkers in the B and C horizons of those profiles would reflect postsedimentary root-derived or microbial contributions. (ii) Compound-specific radiocarbon measurements are conducted on n-alkanes and n-alkanoic (fatty) acids from several depth intervals in the loess section "Crvenka", Serbia, and the results are compared to independent estimates of sediment age. <br><br> We find extremely low concentrations of plant-wax n-alkanes and fatty acids in the B and C horizons below the topsoils in the sediment profiles. Moreover, compound-specific radiocarbon analysis yields plant-wax <sup>14</sup>C ages that agree well with published luminescence ages and stratigraphy of the Serbian loess deposit. Both approaches confirm that postsedimentary, root-derived or microbial contributions are negligible in the two investigated systems. The good agreement between the ages of odd and even homologues also indicates that reworking and incorporation of fossil leaf waxes is not particularly relevant either

    The H-Index as a Quantitative Indicator of the Relative Impact of Human Diseases

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    Assessment of the relative impact of diseases and pathogens is important for agencies and other organizations charged with providing disease surveillance, management and control. It also helps funders of disease-related research to identify the most important areas for investment. Decisions as to which pathogens or diseases to target are often made using complex risk assessment approaches; however, these usually involve evaluating a large number of hazards as it is rarely feasible to conduct an in-depth appraisal of each. Here we propose the use of the H-index (or Hirsch index) as an alternative rapid, repeatable and objective means of assessing pathogen impact. H-index scores for 1,414 human pathogens were obtained from the Institute for Scientific Information's Web of Science (WOS) in July/August 2010. Scores were compared for zoonotic/non-zoonotic, and emerging/non-emerging pathogens, and across taxonomic groups. H-indices for a subset of pathogens were compared with Disability Adjusted Life Year (DALY) estimates for the diseases they cause. H-indices ranged from 0 to 456, with a median of 11. Emerging pathogens had higher H-indices than non-emerging pathogens. Zoonotic pathogens tended to have higher H-indices than human-only pathogens, although the opposite was observed for viruses. There was a significant correlation between the DALY of a disease and the H-index of the pathogen(s) that cause it. Therefore, scientific interest, as measured by the H-index, appears to be a reflection of the true impact of pathogens. The H-index method can be utilized to set up an objective, repeatable and readily automated system for assessing pathogen or disease impact

    Petrogenic organic carbon retention in terrestrial basins: a case study from perialpine Lake Constance

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    Inland waters play a major role in the global carbon cycle, with particulate organic carbon (POC) burial in terrestrial wetlands surpassing that in ocean sediments. Lake Constance, the second largest lake at the periphery of the European Alps, receives POC sourced from both aquatic and terrestrial productivity as well as petrogenic OC (OCpetro) from bedrock erosion. Distinguishing POC inputs to lake sediments is key to assessing carbon flux and fate as reworked OCpetro represents neither a net sink of atmospheric CO2 nor source of O2. New stable and radiocarbon isotopic data indicate that 11 (9–12) Gg/yr of OCpetro is buried in Lake Constance with underlying sediments on average containing 0.3 (0.25–0.33) wt% OCpetro. Extrapolation of these results suggests that 27 TgOCpetro/yr (12–54 TgOC/yr) could be subject to temporary geological storage in lakes globally, which is comparable to estimates of 43−25+61 TgOCpetro/yr delivered to the ocean by rivers (Galy et al., 2015). More studies are needed to quantify OCpetro burial in inland sedimentary reservoirs in order to accurately account for atmospheric carbon sequestration in terrestrial basins

    Electron mobility in surface- and buried- channel flatband In<sub>0.53</sub>Ga<sub>0.47</sub>As MOSFETs with ALD Al<sub>2</sub>O<sub>3</sub> gate dielectric.

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    In this paper, we investigate the scaling potential of flatband III-V MOSFETs by comparing the mobility of surface and buried In&lt;sub&gt;0.53&lt;/sub&gt;Ga&lt;sub&gt;0.47&lt;/sub&gt;As channel devices employing an Atomic Layer Deposited (ALD) Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; gate dielectric and a delta-doped InGaAs/InAlAs/InP heterostructure. Peak electron mobilities of 4300 cm&lt;sup&gt;2&lt;/sup&gt;/V·s and 6600 cm&lt;sup&gt;2&lt;/sup&gt;/V·s at a carrier density of 3×1012 cm&lt;sup&gt;-2&lt;/sup&gt; for the surface and buried channel structures respectively were determined. In contrast to similarly scaled inversion-channel devices, we find that mobility in surface channel flatband structures does not drop rapidly with electron density, but rather high mobility is maintained up to carrier concentrations around 4x10&lt;sup&gt;12&lt;/sup&gt; cm&lt;sup&gt;-2&lt;/sup&gt; before slowly dropping to around 2000 cm&lt;sup&gt;2&lt;/sup&gt;/V·s at 1x10M&lt;sup&gt;13&lt;/sup&gt; cm&lt;sup&gt;-2&lt;/sup&gt;. We believe these to be world leading metrics for this material system and an important development in informing the III-V MOSFET device architecture selection process for future low power, highly scaled CM

    What on Earth have we been burning? Deciphering sedimentary records of pyrogenic carbon

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    Humans have interacted with fire for thousands of years, yet the utilization of fossil fuels marked the beginning of a new era. Ubiquitous in the environment, pyrogenic carbon (PyC) arises from incomplete combustion of biomass and fossil fuels, forming a continuum of condensed aromatic structures. Here we develop and evaluate 14C records for two complementary PyC molecular markers, benzene-polycarboxylic-acids (BPCAs) and polycyclic-aromatic-hydrocarbons (PAHs) preserved in aquatic sediments from a sub-urban and a remote catchment in the United States (U.S.) from mid-1700s to 1998. Results show that the majority of PyC stems from local sources and is transferred to aquatic sedimentary archives on sub-decadal to millennial time scales. Whereas a small portion stems from near-contemporaneous production and sedimentation, the majority of PyC (&lt;90%) experiences delayed transmission due to ‘pre-aging’ on millennial timescales in catchment soils prior to its ultimate deposition. BPCAs (soot) and PAHs (precursors of soot) trace fossil fuel-derived PyC. Both markers parallel historical records of the consumption of fossil fuels in U.S., yet never account for more than 19% total PyC. This study demonstrates that isotopic characterization of multiple tracers is necessary to constrain histories and inventories of PyC, and that sequestration of PyC can markedly lag its production
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