1,882 research outputs found
Recommended from our members
The responses of single units to simple and complex sounds from the superior olivary complex of the Guinea pig
© 2018 The Author(s). We have recorded the responses of single units in the superior olivary complex (SOC) of the Guinea pig to simple and complex stimuli. We can readily identify the responses of the four principal ascending nuclei as described in other species and we are therefore confident that the Guinea pig is a suitable model for studying this region. We found single units in the medial superior olive that represent both diotic iterated rippled noise and dichotic repetition pitch in their temporal discharge patterns. Our data demonstrate a use of the SOC beyond sound-source localisation
The pre-main sequence binary HK Ori : Spectro-astrometry and EXPORT data
In this paper we present multi-epoch observations of the pre-main sequence
binary HK Ori. These data have been drawn from the EXPORT database and are
complemented by high quality spectro-astrometric data of the system. The
spectroscopic data appear to be very well represented by a combination of an A
dwarf star spectrum superposed on a (sub-)giant G-type spectrum. The radial
velocity of the system is consistent with previous determinations, and does not
reveal binary motion, as expected for a wide binary. The spectral, photometric
and polarimetric properties and variability of the system indicate that the
active object in the system is a T Tauri star with UX Ori characteristics. The
spectro-astrometry of HK Ori is sensitive down to milli-arcsecond scales and
confirms the speckle interferometric results from Leinert et al. The
spectro-astrometry allows with fair certainty the identification of the active
star within the binary, which we suggest to be a G-type T Tauri star based on
its spectral characteristics.Comment: MNRAS in press 8 pages 7 figure
A Review of Nitrates in Drinking Water: Maternal Exposure and Adverse Reproductive and Developmental Outcomes
In this review we present an update on maternal exposure to nitrates in drinking water in relation to possible adverse reproductive and developmental effects, and also discuss nitrates in drinking water in the United States. The current standard for nitrates in drinking water is based on retrospective studies and approximates a level that protects infants from methemoglobinemia, but no safety factor is built into the standard. The current standard applies only to public water systems. Drinking water source was related to nitrate exposure (i.e., private systems water was more likely than community system water to have nitrate levels above the maximum contaminant limit). Animal studies have found adverse reproductive effects resulting from higher doses of nitrate or nitrite. The epidemiologic evidence of a direct exposure–response relationship between drinking water nitrate level and adverse reproductive effect is still not clear. However, some reports have suggested an association between exposure to nitrates in drinking water and spontaneous abortions, intrauterine growth restriction, and various birth defects. Uncertainties in epidemiologic studies include the lack of individual exposure assessment that would rule out confounding of the exposure with some other cause. Nitrates may be just one of the contaminants in drinking water contributing to adverse outcomes. We conclude that the current literature does not provide sufficient evidence of a causal relationship between exposure to nitrates in drinking water and adverse reproductive effects. Future studies incorporating individual exposure assessment about users of private wells—the population most at risk—should be considered
Involvement of Noradrenergic Neurotransmission in the Stress- but not Cocaine-Induced Reinstatement of Extinguished Cocaine-Induced Conditioned Place Preference in Mice: Role for β-2 Adrenergic Receptors
The responsiveness of central noradrenergic systems to stressors and cocaine poses norepinephrine as a potential common mechanism through which drug re-exposure and stressful stimuli promote relapse. This study investigated the role of noradrenergic systems in the reinstatement of extinguished cocaine-induced conditioned place preference by cocaine and stress in male C57BL/6 mice. Cocaine- (15 mg/kg, i.p.) induced conditioned place preference was extinguished by repeated exposure to the apparatus in the absence of drug and reestablished by a cocaine challenge (15 mg/kg), exposure to a stressor (6-min forced swim (FS); 20–25°C water), or administration of the α-2 adrenergic receptor (AR) antagonists yohimbine (2 mg/kg, i.p.) or BRL44408 (5, 10 mg/kg, i.p.). To investigate the role of ARs, mice were administered the nonselective β-AR antagonist, propranolol (5, 10 mg/kg, i.p.), the α-1 AR antagonist, prazosin (1, 2 mg/kg, i.p.), or the α-2 AR agonist, clonidine (0.03, 0.3 mg/kg, i.p.) before reinstatement testing. Clonidine, prazosin, and propranolol failed to block cocaine-induced reinstatement. The low (0.03 mg/kg) but not high (0.3 mg/kg) clonidine dose fully blocked FS-induced reinstatement but not reinstatement by yohimbine. Propranolol, but not prazosin, blocked reinstatement by both yohimbine and FS, suggesting the involvement of β-ARs. The β-2 AR antagonist ICI-118551 (1 mg/kg, i.p.), but not the β-1 AR antagonist betaxolol (10 mg/kg, i.p.), also blocked FS-induced reinstatement. These findings suggest that stress-induced reinstatement requires noradrenergic signaling through β-2 ARs and that cocaine-induced reinstatement does not require AR activation, even though stimulation of central noradrenergic neurotransmission is sufficient to reinstate
Development of a biomechanical energy harvester
© 2009 Li et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
Mortality from all cancers and lung, colorectal, breast and prostate cancer by country of birth in England and Wales, 2001–2003
Mortality from all cancers combined and major cancers among men and women aged 20 years and over was compared by country of birth with that of the whole of England and Wales as the reference group. Population data from the 2001 Census and mortality data for 2001–2003 were used to estimate standardised mortality ratios. Data on approximately 399 000 cancer deaths were available, with at least 400 cancer deaths in each of the smaller populations. Statistically significant differences from the reference group included: higher mortality from all cancers combined, lung and colorectal cancer among people born in Scotland and Ireland, lower mortality for all cancers combined, lung, breast and prostate cancer among people born in Bangladesh (except for lung cancer in men), India, Pakistan or China/Hong Kong, lower lung cancer mortality among people born in West Africa or the West Indies, higher breast cancer mortality among women born in West Africa and higher prostate cancer mortality among men born in West Africa or the West Indies. These data may be relevant to causal hypotheses and in relation to health care and cancer prevention
Insights on the Neuromagnetic Representation of Temporal Asymmetry in Human Auditory Cortex.
Communication sounds are typically asymmetric in time and human listeners are highly sensitive to this short-term temporal asymmetry. Nevertheless, causal neurophysiological correlates of auditory perceptual asymmetry remain largely elusive to our current analyses
and models. Auditory modelling and animal electrophysiological recordings suggest that perceptual asymmetry results from the presence of multiple time scales of temporal integration, central to the auditory periphery. To test this hypothesis we recorded auditory evoked fields (AEF) elicited by asymmetric sounds in humans. We found a strong correlation between perceived tonal salience of ramped and damped sinusoids and the AEFs, as quantified by the amplitude of the N100m dynamics. The N100m amplitude increased with stimulus
half-life time, showing a maximum difference between the ramped and damped stimulus for a modulation half-life time of 4 ms which is greatly reduced at 0.5 ms and 32 ms. This behaviour of the N100m closely parallels psychophysical data in a manner that: i) longer
half-life times are associated with a stronger tonal percept, and ii) perceptual differences between damped and ramped are maximal at 4 ms half-life time. Interestingly, differences in evoked fields were significantly stronger in the right hemisphere, indicating some degree of hemispheric specialisation. Furthermore, the N100m magnitude was successfully
explained by a pitch perception model using multiple scales of temporal integration of auditory
nerve activity patterns. This striking correlation between AEFs, perception, and model predictions suggests that the physiological mechanisms involved in the processing of pitch evoked by temporal asymmetric sounds are reflected in the N100m
MicroRNAome of Porcine Pre- and Postnatal Development
The domestic pig is of enormous agricultural significance and valuable models for many human diseases. Information concerning the pig microRNAome (miRNAome) has been long overdue and elucidation of this information will permit an atlas of microRNA (miRNA) regulation functions and networks to be constructed. Here we performed a comprehensive search for porcine miRNAs on ten small RNA sequencing libraries prepared from a mixture of tissues obtained during the entire pig lifetime, from the fetal period through adulthood. The sequencing results were analyzed using mammalian miRNAs, the precursor hairpins (pre-miRNAs) and the first release of the high-coverage porcine genome assembly (Sscrofa9, April 2009) and the available expressed sequence tag (EST) sequences. Our results extend the repertoire of pig miRNAome to 867 pre-miRNAs (623 with genomic coordinates) encoding for 1,004 miRNAs, of which 777 are unique. We preformed real-time quantitative PCR (q-PCR) experiments for selected 30 miRNAs in 47 tissue-specific samples and found agreement between the sequencing and q-PCR data. This broad survey provides detailed information about multiple variants of mature sequences, precursors, chromosomal organization, development-specific expression, and conservation patterns. Our data mining produced a broad view of the pig miRNAome, consisting of miRNAs and isomiRs and a wealth of information of pig miRNA characteristics. These results are prelude to the advancement in pig biology as well the use of pigs as model organism for human biological and biomedical studies
- …