Minimal parallelism for associative computations under time constraints

The parallel evaluation ofA _N =a ₁ °a ₂ °...°a _N , where ° is binary associative, is studied. Under an idealized model of parallel computation, the minimal number of parallel processors required to computeA _N in at mostt steps is determined for ?log₂ N?≤t≤N?1. This indicates that it is not always desirable to reduce the running time to an absolute minimum, and provides a lower bound on the processing power required for time-constrained evaluation of general arithmetic expressions. Results for two-input processors, are generalized tob-input processors, and then to non-homogeneous collections of processors. The latter does not have a closed-form solution, so approximations are analyzed.     

Verhalten der freien Fettsäuren nach tierexperimenteller Verbrennung

Behaviour of Free Fatty Acids After Burning in Animal Experiments The pattern of free fatty acids in the serum of rats after 20% burning was determined in order to elucidate the severe changes resulting from the shock after burning. Gas chromatographic analysis was carried out after 1/2, 1, 6, 24, 48 and 72 hours following burning trauma. For comparison the fatty acid pattern of a control group of unburned animals was examined. Gas chromatographic analysis showed following characteristic changes: 1. An increase of palmitic, stearic, palmitoleic, oleic, linoleic and linolenic acids after 6 hours following burning. 2. A constant level of palmitic acid even after 72 hours. 3. A slight decline of palmitoleic and oleic acids after 48 and 72 hours. 4. An increase of the polyunsaturated linoleic and linolenic acids till 24 hours after burning and a subsequent large decrease. The function of fatty acids, especially linoleic and linolenic acids, as constituents of membranes is of great importance. They determine essentially the membrane permeability. Moreover, the polyunsaturated fatty acids are precursors of prostaglandins, whose role in burning is little investigated. The characteristic change of polyunsaturated fatty acids suggests a relationship with membrane damage, increased thrombocyte aggregation and alterations of lung surfactant. Their steep decline might be caused by autoxidation due to lack of antioxidants, degradation during conversion to energy and incorporation into lipoproteins and membranes. The significance of free fatty acids in catabolism of the cell in severe trauma is unquestionable.     

Local control of squamous cell carcinoma following marginal and segmental mandibulectomy

The proportion of large dense-core vesicles (LDCVs) in motor nerve terminals of the rat biceps brachialis muscle was evaluated from embryonic day 20 to 4 weeks postpartum as well as in the adult. A progressive decrease was observed up to 3 weeks postpartum when maturation of the endplates is achieved. Differences compared with the adult were no longer significant at 4 weeks postpartum. Three types of LDVCs, classified according to their size and the core density, were detected. Their relative proportion did not vary significantly during the period of life examined. The high proportion of LDCVs during early development and their persistence at a low level in the adult suggest that they might play a role in the maturation and maintenance of the endplates.     

Use of diode lasers to recover holographically stored information

Using a diode laser, a holographic image ofsim40 000resolution elements has been retrieved. The diode laser was a GaxAl1-xAs close-confinement laser operating at 8300 Å at room temperature.     

Anilinium Montmorillonites and the Formation of Ammonium/Amine Associations

The IR spectra, X-ray patterns and DTA curves of various aryl ammonium montmorillonites, are characterized. Depending upon the particular amine, the aryl ammonium ions react with excess base by (1) showing a proton equally between two amine molecules through a water bridge, (2) by retaining the proton identified with one molecule, or (3) by polymerization liberating protons. It is inferred that interlayer alkyl ammonium ions also show protons with excess amine through water bridges but the stability of the aryl and alkyl compounds differs greatly.     

Changes in lymphocyte surface immunoglobulins in myeloma and the effect of an RNA-containing plasma factor

Patients with multiple myeloma have a reduced number of B lymphocytes with normal surface immunoglobulin. When, however, anti-idiotypic antiserums to the respective myeloma globulins were used for the visualization of surface immunoglobulin by indirect immunofluorescence, a large number of surface immunoglobulin carrying lymphocytes were detected. The possibility of absorption of these monoclonal surface immunoglobulins from the surrounding plasma was excluded by showing their resynthesis after removal from the cells by trypsinization. The change in the character of surface immunoglobulin was reproduced on normal lymphocytes with an RNA-rich extract from the plasma of patients with myeloma; this effect was inhibited by RNase and cycloheximide. These findings suggest the possibility that an RNA-containing plasma factor transmits information for synthesis of surface immunoglobulins between myeloma cells and normal lymphocytes. This mechanism may contribute to the dysfunction of B lymphocytes in patients with myeloma, leading to immunologic deficiency.