The Prevalence of Carbon-13 in Respiratory Carbon Dioxide As an Indicator of the Type of Endogenous Substrate. The change from lipid to carbohydrate during the respiratory rise in potato slices

Isotope discrimination is a common feature of biosynthesis in nature, with the result that different classes of carbon compounds frequently display different 13C/12C ratios. The 13C/12C ratio of lipid in potato tuber tissue is considerably lower than that for starch or protein. We have collected respiratory CO2 from potato discs in successive periods through 24 hr from the time of cutting—an interval in which the respiration rate rises 3–5-fold. The 13C/12C ratio of the evolved CO2 was determined for each period, and compared with the 13C/12C ratios of the major tissue metabolites. In the first hours the carbon isotope ratio of the CO2 matches that of lipid. With time, the ratio approaches that typical of starch or protein. An estimation has been made of the contribution of lipid and carbohydrate to the total respiration at each juncture. In connection with additional observations, it was deduced that the basal, or initial, respiration represents lipid metabolism —- possibly the alpha-oxidation of long chain fatty acids -— while the developed repiration represents conventional tricarboxylic acid cycle oxidation of the products of carbohydrate glycolysis. The true isotopic composition of the respiratory CO2 may be obscured by fractionation attending the refixation of CO2 during respiration, and by CO2 arising from dissolved CO2 and bicarbonate preexisting in the tuber. Means are described for coping with both pitfalls

Functional characterization of a glutamate/aspartate transporter from the mosquito Aedes aegypti

Glutamate elicits a variety of effects in insects, including inhibitory and excitatory signals at both neuromuscular junctions and brain. Insect glutamatergic neurotransmission has been studied in great depth especially from the standpoint of the receptor-mediated effects, but the molecular mechanisms involved in the termination of the numerous glutamatergic signals have only recently begun to receive attention. In vertebrates, glutamatergic signals are terminated by Na^+/K^+-dependent high-affinity excitatory amino acid transporters (EAAT), which have been cloned and characterized extensively. Cloning and characterization of a few insect homologues have followed, but functional information for these homologues is still limited. Here we report a study conducted on a cloned mosquito EAAT homologue isolated from the vector of the dengue virus, Aedes aegypti. The deduced amino acid sequence of the protein, AeaEAAT, exhibits 40–50% identity with mammalian EAATs, and 45–50% identity to other insect EAATs characterized thus far. It transports l-glutamate as well as l- and d-aspartate with high affinity in the micromolar range, and demonstrates a substrate-elicited anion conductance when heterologously expressed in Xenopus laevis oocytes, as found with mammalian homologues. Analysis of the spatial distribution of the protein demonstrates high expression levels in the adult thorax, which is mostly observed in the thoracic ganglia. Together, the work presented here provides a thorough examination of the role played by glutamate transport in Ae. aegypti

The transporter-like protein inebriated mediates hyperosmotic stimuli through intracellular signaling

We cloned the inebriated homologue MasIne from Manduca sexta and expressed it in Xenopus laevis oocytes. MasIne is homologous to neurotransmitter transporters but no transport was observed with a number of putative substrates. Oocytes expressing MasIne respond to hyperosmotic stimulation by releasing intracellular Ca(2+), as revealed by activation of the endogenous Ca(2+)-activated Cl(-) current. This Ca(2+) release requires the N-terminal 108 amino acid residues of MasIne and occurs via the inositol trisphosphate pathway. Fusion of the N terminus to the rat gamma-aminobutyric acid transporter (rGAT1) also renders rGAT1 responsive to hyperosmotic stimulation. Immunohistochemical analyses show that MasIne and Drosophila Ine have similar tissue distribution patterns, suggesting functional identity. Inebriated is expressed in tissues and cells actively involved in K(+) transport, which suggests that it may have a role in ion transport, particularly of K(+). We propose that stimulation of MasIne releases intracellular Ca(2+) in native tissues, activating Ca(2+)-dependent K(+) channels, and leading to K(+) transport

Flow analysis system and method

A non-invasive flow analysis system and method wherein a sensor, such as an acoustic sensor, is coupled to a conduit for transmitting a signal which varies depending on the characteristics of the flow in the conduit. The signal is amplified and there is a filter, responsive to the sensor signal, and tuned to pass a narrow band of frequencies proximate the resonant frequency of the sensor. A demodulator generates an amplitude envelope of the filtered signal and a number of flow indicator quantities are calculated based on variations in amplitude of the amplitude envelope. A neural network, or its equivalent, is then used to determine the flow rate of the flow in the conduit based on the flow indicator quantities

The ground state of a spin-1/2 neutral particle with anomalous magnetic moment in a Aharonov-Casher configuration

We determine the (bound) ground state of a spin 1/2 chargless particle with anomalous magnetic moment in certain Aharonov-Casher configurations. We recast the description of the system in a supersymmetric form. Then the basic physical requirements for unbroken supersymmetry are established. We comment on the possibility of neutron trapping in these systems

Evaluation of Psychoacoustic Sound Parameters for Sonification

Sonification designers have little theory or experimental evidence to guide the design of data-to-sound mappings. Many mappings use acoustic representations of data values which do not correspond with the listener's perception of how that data value should sound during sonification. This research evaluates data-to-sound mappings that are based on psychoacoustic sensations, in an attempt to move towards using data-to-sound mappings that are aligned with the listener's perception of the data value's auditory connotations. Multiple psychoacoustic parameters were evaluated over two experiments, which were designed in the context of a domain-specific problem - detecting the level of focus of an astronomical image through auditory display. Recommendations for designing sonification systems with psychoacoustic sound parameters are presented based on our results

The New Jewish Community, New Jewish Schools: Trends and Promises

While representing a small percentage of all private, religious schools, Jewish schools are nonetheless a significant presence on the religious landscape. This article analyzes the rapid growth of Jewish schools over the past three decades and examines possible future directions for Jewish schools

A 3-D Gravity Tectonic Study of Ita Mai Tai Guyot: An Uncompensated Seamount in the East Mariana Basin

Ita Mai Tai is a large, locally uncompensated seamount on the eastern edge of the East Mariana Basin. A large positive gravity anomaly of 254 mgal characterizes the summit and a low of -69 mgal, the surrounding moat. Using polygonal prisms to approximate the bathymetry, the observed gravity was inverted to calculate an average density of 2.59 g/ems for the seamount. Observed-calculated gravity residuals are reduced by including the flanking sedimentary basins and a dense volcanic conduit. The drill sites from DSDP Legs 20 and 89 describe a volcanic edifice formed in the Aptian!Albian on Jmassic/Cretaceous crust. The volcanism is recorded in volcanoclastic and epiclastic deposits in the basins nearby. The guyot was covered initially by a succession of reefal and lagoonal sediments followed by a thick mantling of pelagic sediments after it subsided. Gravity models that adequately match the calculated and observed data sets for Ita Mai Tai show little crustal thickening, suggesting that Ita Mai Tai is almost completely locally uncompensated