Aggregation signals

The compounds that we will consider here, in contrast, serve quite specific needs of various organisms, and for this reason we will call them special chemical compounds. Different species may employ the same special compound, in some cases for the same purpose and in other cases for different ends. For example, the carbon dioxide arising from the respiration of a crowd of ants is an aggregation signal that invites solitary ants to join their nestmates. Corn rootworms, however, use the carbon dioxide that living corn roots emit into the soil as a signal, leading them to their food. Different species may also employ diverse compounds for essentially the same purpose. Various ant species mark their food trails with different chemicals to keep their food sources secret from one another. 

Hydroxy-4,4,6-trimethyl-2,5-hexadien-l-one, lanierone, 254, is a component of the complex aggregation signal of male Ipspini [468]. The carbon skeleton of 254 is the same as in isophorone 255, which has been identified as a volatile constituents of females of Ips typographus. Whether these compounds are degradation products of higher terpenes awaits further investigations. 

Other aggregation operators are possible, for example, formation of the minimum or maximum over all n signals Xj. Before the aggregated signal leaves the neuron, a transformation is performed by means of a transfer function/to getthe output signally ... 

The second issue of how to compute the ensemble-aggregated signal reconstruction output is the focus of this paper. 

Lubushin, A.A. Wavelet-aggregated signal and s5mchronous peaks in problems of geophysical monitoring and earthquake prediction. Fizika Zemli (3), 20 30 (2000)... 

In general, dendrimers show sharp M+ signals at the expected values. This confirms the overall dendrimer structure. Mass spectra may be complicated by the presence of small peaks corresponding to two- or three-molecule aggregates bearing a single charge and this phenomenon is... 

There are two notable features of the quantitative performance of this type of interface. It has been found that non-linear responses are often obtained at low analyte concentrations. This has been attributed to the formation of smaller particles than at higher concentrations and their more easy removal by the jet separator. Signal enhancement has been observed due to the presence of (a) coeluting compounds (including any isotopically labelled internal standard that may be used), and (b) mobile-phase additives such as ammonium acetate. It has been suggested that ion-molecule aggregates are formed and these cause larger particles to be produced in the desolvation chamber. Such particles are transferred to the mass spectrometer more efficiently. It was found, however, that the particle size distribution after addition of ammonium acetate, when enhancement was observed, was little different to that in the absence of ammonium acetate when no enhancement was observed. 

Hence, pseudosimultaneous spectroscopic and flow-cytometric measurements suggest that actin polymerization may be functionally related to aggregation, possibly by reorganization of adhesive molecules on the cell surface. Simultaneous spectroscopic and fluorometric measurements suggest that the signal Ca may be related to oxidant production and degranulation. 

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