48 research outputs found
Mapping of a new locus for congenital anomalies of the kidney and urinary tract on chromosome 8q24
Background. Congenital anomalies of the kidney and urinary tract (CAKUT) account for the majority of end-stage renal disease in children (50%). Previous studies have mapped autosomal dominant loci for CAKUT. We here report a genome-wide search for linkage in a large pedigree of Somalian descent containing eight affected individuals with a non-syndromic form of CAKUT. Methods. Clinical data and blood samples were obtained from a Somalian family with eight individuals with CAKUT including high-grade vesicoureteral reflux and unilateral renal agenesis. Total genome search for linkage was performed using a 50K SNP Affymetric DNA microarray. As neither parent is affected, the results of the SNP array were analysed under recessive models of inheritance, with and without the assumption of consanguinity. Results. Using the non-consanguineous recessive model, a new gene locus (CAKUT1) for CAKUT was mapped to chromosome 8q24 with a significant maximum parametric Logarithm of the ODDs (LOD) score (LODmax) of 4.2. Recombinations were observed in two patients defining a critical genetic interval of 2.5 Mb physical distance flanked by markers SNP_A-1740062 and SNP_A-1653225. Conclusion. We have thus identified a new non-syndromic recessive gene locus for CAKUT (CAKUT1) on chromosome 8q24. The identification of the disease-causing gene will provide further insights into the pathogenesis of urinary tract malformations and mechanisms of renal developmen
Recurrent Activity in Higher Order, Modality Non-Specific Brain Regions: A Granger Causality Analysis of Autobiographic Memory Retrieval
It has been proposed that the workings of the brain are mainly intrinsically generated recurrent neuronal activity, with sensory inputs as modifiers of such activity in both sensory and higher order modality non-specific regions. This is supported by the demonstration of recurrent neuronal activity in the visual system as a response to visual stimulation. In contrast recurrent activity has never been demonstrated before in higher order modality non-specific regions. Using magneto-encephalography and Granger causality analysis, we tested in a paralimbic network the hypothesis that stimulation may enhance causal recurrent interaction between higher-order, modality non-specific regions. The network includes anterior cingulate/medial prefrontal and posterior cingulate/medial parietal cortices together with pulvinar thalami, a network known to be effective in autobiographic memory retrieval and self-awareness. Autobiographic memory retrieval of previous personal judgments of visually presented words was used as stimuli. It is demonstrated that the prestimulus condition is characterized by causal, recurrent oscillations which are maximal in the lower gamma range. When retrieving previous judgments of visually presented adjectives, this activity is dramatically increased during the stimulus task as ascertained by Granger causality analysis. Our results confirm the hypothesis that stimulation may enhance causal interaction between higher order, modality non-specific brain regions, exemplified in a network of autobiographical memory retrieval
Aboveground biomass density models for NASA's Global Ecosystem Dynamics Investigation (GEDI) lidar mission
NASA's Global Ecosystem Dynamics Investigation (GEDI) is collecting spaceborne full waveform lidar data with a primary science goal of producing accurate estimates of forest aboveground biomass density (AGBD). This paper presents the development of the models used to create GEDI's footprint-level (similar to 25 m) AGBD (GEDI04_A) product, including a description of the datasets used and the procedure for final model selection. The data used to fit our models are from a compilation of globally distributed spatially and temporally coincident field and airborne lidar datasets, whereby we simulated GEDI-like waveforms from airborne lidar to build a calibration database. We used this database to expand the geographic extent of past waveform lidar studies, and divided the globe into four broad strata by Plant Functional Type (PFT) and six geographic regions. GEDI's waveform-to-biomass models take the form of parametric Ordinary Least Squares (OLS) models with simulated Relative Height (RH) metrics as predictor variables. From an exhaustive set of candidate models, we selected the best input predictor variables, and data transformations for each geographic stratum in the GEDI domain to produce a set of comprehensive predictive footprint-level models. We found that model selection frequently favored combinations of RH metrics at the 98th, 90th, 50th, and 10th height above ground-level percentiles (RH98, RH90, RH50, and RH10, respectively), but that inclusion of lower RH metrics (e.g. RH10) did not markedly improve model performance. Second, forced inclusion of RH98 in all models was important and did not degrade model performance, and the best performing models were parsimonious, typically having only 1-3 predictors. Third, stratification by geographic domain (PFT, geographic region) improved model performance in comparison to global models without stratification. Fourth, for the vast majority of strata, the best performing models were fit using square root transformation of field AGBD and/or height metrics. There was considerable variability in model performance across geographic strata, and areas with sparse training data and/or high AGBD values had the poorest performance. These models are used to produce global predictions of AGBD, but will be improved in the future as more and better training data become available
Mapping of a new locus for congenital anomalies of the kidney and urinary tract on chromosome 8q24
Background. Congenital anomalies of the kidney and urinary tract (CAKUT) account for the majority of end-stage renal disease in children (50%). Previous studies have mapped autosomal dominant loci for CAKUT. We here report a genome-wide search for linkage in a large pedigree of Somalian descent containing eight affected individuals with a non-syndromic form of CAKUT
Aerosol observations and growth rates downwind of the anvil of a deep tropical thunderstorm
We present a case study of Aitken and accumulation mode aerosol
observed downwind of the anvil of a deep tropical thunderstorm. The
measurements were made by condensation nuclei counters flown on the
Egrett high-altitude aircraft from Darwin during the ACTIVE
campaign, in monsoon conditions producing widespread convection over
land and ocean. Maximum measured concentrations of aerosol with diameter
greater than 10 nm were 25 000 cm−3 (STP). By calculating
back-trajectories from the observations, and projecting onto
infrared satellite images, the time since the air exited cloud was
estimated. In this way a time scale of about 3 hours was derived
for the Aitken aerosol concentration to reach its peak. We
examine the hypothesis that the growth in aerosol concentrations can
be explained by production of sulphuric acid from SO2 followed by
particle nucleation and coagulation. Estimates of the sulphuric acid
production rate show that the observations are only consistent with
this hypothesis if the particles coagulate to sizes >10 nm much
more quickly than is suggested by current theory. Alternatively,
other condensible gases (possibly organic) drive the growth of
aerosol particles in the TTL
Flooding disturbances increase resource availability and productivity but reduce stability in diverse plant communities
The natural world is increasingly defined by change. Within the next 100 years, rising atmospheric CO2 concentrations will continue to increase the frequency and magnitude of extreme weather events. Simultaneously, human activities are reducing global biodiversity, with current extinction rates at B1,000 what they were before human domination of Earth’s ecosystems. The co-occurrence of these trends may be of particular concern, as greater biological diversity could help ecosystems resist change during large perturbations. We use data from a 200-year flood event to show that when a disturbance is associated with an increase in resource availability, the opposite may occur. Flooding was associated with increases in productivity and decreases in stability, particularly in the highest diversity communities. Our results undermine the utility of the biodiversity–stability hypothesis during a large number of disturbances where resource availability increases. We propose a conceptual framework that can be widely applied during natural disturbances
Nonsense Made Intelligible
My topic is the relation between nonsense and (un-)intelligibility, and the contrast between nonsense and falsehood which played a pivotal role in the rise of analytic philosophy (sct. 1). I shall pursue three lines of inquiry. First I shall briefly consider the positive case, namely linguistic understanding (sct. 2). Secondly, I shall consider the negative case—different breakdowns of understanding and connected forms of failure to make sense (sct. 3–4). Third, I shall criticize three important misconceptions of nonsense and unintelligibility: the austere conception of nonsense propounded by the New Wittgensteinians (scts. 5–6); the “no nonsense position” which roundly denies that there are cases of nonsense—Chomsky’s semantic anomalies or Ryle’s category mistakes–that are grammatically well-formed, without even having the potential for being used to make a truth-apt statement (scts. 7–8); the individualistic conception of language and of semantic mistakes championed by Davidson (scts. 9–10). All three positions, I shall argue, ignore or deny combinatorial nonsense, the fact that perfectly meaningful sentence-components can be combined in a way that may be grammatical, yet without resulting in a sentence that is itself “meaningful”, i.e. endowed with linguistic sense. At a more strategic level, the first and the third position deny or ignore that natural languages are communal historical practices that go beyond idiolects and the employments of expressions in specific contexts and that are guided by semantic rules—standards for the meaningful use of words