423 research outputs found
Veränderungen im Bildaufbau in der Steigbildmethode durch die Alterung von Milch
The Uni Kassel, FG bio-dynamic agriculture, wants to use the capillary dynamolysis
according to Wala (Steigbildethode) for milk samples from different collection-days.
Based on former methodological investigation (Zalecka 2006) the aim of the study is
to show the aging effect and to test, whether a once taken sample represents the
farm. Result: the repeatedly taken samples seem to be equal, but variation in the
climatic conditions of the chamber as well as aging of the solution have a tremendous
influence on the pictures and must be standardised
Primary production during nutrient-induced blooms at elevated CO2 concentrations
Mesocosms experiments (PeECE II and PeECE III) were carried out in 9 transparent mesocosms. Prior to the experimental period, the seawater carbonate system was manipulated to achieve three different levels of CO2. At the onset of the experimental period, nutrients were added to all mesocosms in order to initiate phytoplankton blooms. Rates of primary production were measured by in-situ incubations using 14C-incorporation and oxygen production/consumption. Particulate primary production by 14C was also size fractionated and compared with phytoplankton species composition. Nutrient supply increased the primary production rates, and a net autotrophic phase with 14C-fixation rates up to 4 times higher than initial was observed midway through the 24 days experiment before net community production returned to near-zero and 14C-fixation rates relaxed back to lower than initial. We found a trend in the 14C-based measurements towards higher cumulative primary production at higher pCO2, consistent with recently published results for DIC removal (Riebesell et al., 2007). There where found differences to the size fractionated primary production response to CO2 treatments. The plankton composition changes throughout the bloom, however, resulted in no significant response until the final phase of the experiment where phytoplankton growth became nutrient limited, and phytoplankton community changed from diatom to flagellate dominance. This opens for the two alternative hypotheses that such an effect is associated with mineral nutrient limited growth, and/or with phytoplankton species composition. The lack of a clear net heterotrophic phase in the last part of the experiment supports the idea that a substantial part of production in the upper layer was not degraded locally, but either accumulated there or was exported vertically
UDP-Galactose 4′-Epimerase Activities toward UDP-Gal and UDP-GalNAc Play Different Roles in the Development of Drosophila melanogaster
In both humans and Drosophila melanogaster, UDP-galactose 4′-epimerase (GALE) catalyzes two distinct reactions, interconverting UDP-galactose (UDP-gal) and UDP-glucose (UDP-glc) in the final step of the Leloir pathway of galactose metabolism, and also interconverting UDP-N-acetylgalactosamine (UDP-galNAc) and UDP-N-acetylglucosamine (UDP-glcNAc). All four of these UDP-sugars serve as vital substrates for glycosylation in metazoans. Partial loss of GALE in humans results in the spectrum disorder epimerase deficiency galactosemia; partial loss of GALE in Drosophila melanogaster also results in galactose-sensitivity, and complete loss in Drosophila is embryonic lethal. However, whether these outcomes in both humans and flies result from loss of one GALE activity, the other, or both has remained unknown. To address this question, we uncoupled the two activities in a Drosophila model, effectively replacing the endogenous dGALE with prokaryotic transgenes, one of which (Escherichia coli GALE) efficiently interconverts only UDP-gal/UDP-glc, and the other of which (Plesiomonas shigelloides wbgU) efficiently interconverts only UDP-galNAc/UDP-glcNAc. Our results demonstrate that both UDP-gal and UDP-galNAc activities of dGALE are required for Drosophila survival, although distinct roles for each activity can be seen in specific windows of developmental time or in response to a galactose challenge. By extension, these data also suggest that both activities might play distinct and essential roles in humans
Analytic mappings between noncommutative pencil balls
In this paper, we analyze problems involving matrix variables for which we
use a noncommutative algebra setting. To be more specific, we use a class of
functions (called NC analytic functions) defined by power series in
noncommuting variables and evaluate these functions on sets of matrices of all
dimensions; we call such situations dimension-free.
In an earlier paper we characterized NC analytic maps that send
dimension-free matrix balls to dimension-free matrix balls and carry the
boundary to the boundary; such maps we call "NC ball maps". In this paper we
turn to a more general dimension-free ball B_L, called a "pencil ball",
associated with a homogeneous linear pencil L(x):= A_1 x_1 + ... + A_m x_m,
where A_j are complex matrices. For an m-tuple X of square matrices of the same
size, define L(X):=\sum A_j \otimes X_j and let B_L denote the set of all such
tuples X satisfying ||L(X)||<1.
We study the generalization of NC ball maps to these pencil balls B_L, and
call them "pencil ball maps". We show that every B_L has a minimal dimensional
(in a certain sense) defining pencil L'. Up to normalization, a pencil ball map
is the direct sum of L' with an NC analytic map of the pencil ball into the
ball. That is, pencil ball maps are simple, in contrast to the classical result
of D'Angelo on such analytic maps in C^m. To prove our main theorem, this paper
uses the results of our previous paper mentioned above plus entirely different
techniques, namely, those of completely contractive maps.Comment: 30 pages, final version. To appear in the Journal of Mathematical
Analysis and Application
Use of BODIPY (493/503) to Visualize Intramuscular Lipid Droplets in Skeletal Muscle
Triglyceride storage is altered across various chronic health conditions necessitating various techniques to visualize and quantify lipid droplets (LDs). Here, we describe the utilization of the BODIPY (493/503) dye in skeletal muscle as a means to analyze LDs. We found that the dye was a convenient and simple approach to visualize LDs in both sectioned skeletal muscle and cultured adult single fibers. Furthermore, the dye was effective in both fixed and nonfixed cells, and the staining seemed unaffected by permeabilization. We believe that the use of the BODIPY (493/503) dye is an acceptable alternative and, under certain conditions, a simpler method for visualizing LDs stored within skeletal muscle
Noncommutative ball maps
In this paper, we analyze problems involving matrix variables for which we
use a noncommutative algebra setting. To be more specific, we use a class of
functions (called NC analytic functions) defined by power series in
noncommuting variables and evaluate these functions on sets of matrices of all
dimensions; we call such situations dimension-free. These types of functions
have recently been used in the study of dimension-free linear system
engineering problems.
In this paper we characterize NC analytic maps that send dimension-free
matrix balls to dimension-free matrix balls and carry the boundary to the
boundary; such maps we call "NC ball maps". We find that up to normalization,
an NC ball map is the direct sum of the identity map with an NC analytic map of
the ball into the ball. That is, "NC ball maps" are very simple, in contrast to
the classical result of D'Angelo on such analytic maps over C. Another
mathematically natural class of maps carries a variant of the noncommutative
distinguished boundary to the boundary, but on these our results are limited.
We shall be interested in several types of noncommutative balls, conventional
ones, but also balls defined by constraints called Linear Matrix Inequalities
(LMI). What we do here is a small piece of the bigger puzzle of understanding
how LMIs behave with respect to noncommutative change of variables.Comment: 46 page
Build-up and decline of organic matter during PeECE III
Increasing atmospheric carbon dioxide (CO2) concentrations due to anthropogenic fossil fuel combustion are currently changing the ocean's chemistry. Increasing oceanic [CO2] and consequently decreasing seawater pH have the potential to significantly impact marine life. Here we describe and analyze the build-up and decline of a natural phytoplankton bloom initiated during the 2005 mesocosm Pelagic Ecosystem CO2 Enrichment study (PeECE III). The draw-down of inorganic nutrients in the upper surface layer of the mesocosms was reflected by a concomitant increase of organic matter until day t11, the peak of the bloom. From then on, biomass standing stocks steadily decreased as more and more particulate organic matter was lost into the deeper layer of the mesocosms. We show that organic carbon export to the deeper layer was significantly enhanced at elevated CO2. This phenomenon might have impacted organic matter remineralization leading to decreased oxygen concentrations in the deeper layer of the high CO2 mesocosms as indicated by deep water ammonium concentrations. This would have important implications for our understanding of pelagic ecosystem functioning and future carbon cycling
Predicting molecular vibronic spectra using time-domain analog quantum simulation
Spectroscopy is one of the most accurate probes of the molecular world.
However, predicting molecular spectra accurately is computationally difficult
because of the presence of entanglement between electronic and nuclear degrees
of freedom. Although quantum computers promise to reduce this computational
cost, existing quantum approaches rely on combining signals from individual
eigenstates, an approach that is difficult to scale because the number of
eigenstates grows exponentially with molecule size. Here, we introduce a method
for scalable analog quantum simulation of molecular spectroscopy, by performing
simulations in the time domain. Our approach can treat more complicated
molecular models than previous ones, requires fewer approximations, and can be
extended to open quantum systems with minimal overhead. We present a direct
mapping of the underlying problem of time-domain simulation of molecular
spectra to the degrees of freedom and control fields available in a trapped-ion
quantum simulator. We experimentally demonstrate our algorithm on a trapped-ion
device, exploiting both intrinsic electronic and motional degrees of freedom,
showing excellent quantitative agreement for a single-mode vibronic
photoelectron spectrum of SO.Comment: 13 pages, 8 figure
Galactose Epimerase Deficiency: Expanding the Phenotype
Galactose epimerase deficiency is an inborn error of metabolism due to uridine diphosphate-galactose-4'-epimerase (GALE) deficiency. We report the clinical presentation, genetic and biochemical studies in two siblings with generalized GALE deficiency.Patient 1: The first child was born with a dysmorphic syndrome. Failure to thrive was noticed during the first year. Episodes of heart failure due to dilated cardiomyopathy, followed by liver failure, occurred between 12 and 42 months. The finding of a serum transferrin isoelectrofocusing (IEF) type 1 pattern led to the suspicion of a congenital disorder of glycosylation (CDG). Follow-up disclosed psychomotor disability, deafness, and nuclear cataracts.Patient 2: The sibling of patient 1 was born with short limbs and hip dysplasia. She is deceased in the neonatal period due to intraventricular hemorrhage in the context of liver failure. Investigation disclosed galactosuria and normal transferrin glycosylation.Next-generation sequence panel analysis for CDG syndrome revealed the previously reported c.280G>A (p.[V94M]) homozygous mutation in the GALE gene. Enzymatic studies in erythrocytes (patient 1) and fibroblasts (patients 1 and 2) revealed markedly reduced GALE activity confirming generalized GALE deficiency. This report describes the fourth family with generalized GALE deficiency, expanding the clinical spectrum of this disorder, since major cardiac involvement has not been reported before.info:eu-repo/semantics/publishedVersio
Central projections of fibers in the auditory and tensor nerves of cicadas (Homoptera: Cicadidae)
The auditory and tensor nerves of cicadas are mixed nerves containing both afferent and efferent elements. In 17-year cicadas, and in Okanagana rimosa , the auditory nerve contains afferents from body hairs, from the detensor tympani -chordotonal organ, and some 1300–1500 afferents from the hearing organ. Within the fused metathoracic-abdominal ganglionic complex the receptors from both the auditory and tensor nerves form a neuropilar structure that reveals the metameric organization of this complex. A few fibers run anteriorly, projecting into the meso and prothoracic ganglia. Within the ganglionic complex a division of auditory nerve afferents into a dense intermediate and a more diffuse ventral neuropile is observed. In addition, a dorsal motor neuropile is outlined by arborizations of the timbal motor neuron. This neuron is one of several efferent cell types associated with the auditory nerve, and there is an indication that several efferent fibers innervate the timbal muscle. There is anatomical evidence for a possible neuronal coupling between the bilaterally symmetrical large timbal motor neurons. In general, central projections from the auditory and tensor nerves support evidence of a structural “layering” within the CNS of insects.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47673/1/441_2004_Article_BF00234327.pd
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