Showing papers by "University of Miami published in 1970"
405 citations
TL;DR: In this paper, the authors report on a dust event which they observed at Barbados on June 12, 1967, and which they have traced to a dust storm covering a large area of West Africa on June 7, 1967; the storm is clearly visible in an ESSA 5 satellite photograph.
215 citations
TL;DR: Virtually unlimited numbers of hydra can be grown under precise conditions in the laboratory with relative ease and the advantages of laboratory cultivation of aquatic invertebrates are discussed.
Abstract: Virtually unlimited numbers of hydra can be grown under precise conditions in the laboratory with relative ease. Artemia cysts must be treated to remove gross contamination before hatching the nauplii to be used as the food of hydra. Large volumes of a variety of chemically defined culture solutions should be prepared. A particular regimen of animal care especially devised for aquatic invertebrates must be adhered to. General requirements for, and the advantages of, laboratory cultivation of aquatic invertebrates are discussed.
208 citations
TL;DR: The regularly rebranched structure originally proposed by Meyer and Bernfeld was the only one of the then existing proposals that could fit the results of exploration of glycogen and amylopectin with debranching enzymes, and the structure shown in fig. 1 has been generally accepted.
198 citations
TL;DR: In this paper, the authors describe the linear response of an inviscid two-layer model of a deep ocean on an fplane to a hurricane translating across the surface at constant speed.
Abstract: This paper describes the linear response of an inviscid two‐layer model of a deep ocean on an f‐plane to a hurricane translating across the surface at constant speed. The forcing is a localized, radially‐symmetric pattern of positive wind stress curl and negative pressure anomaly. Only the steady state response is considered. The principal result is the identification of an internal wake in the lee of the storm, present when the translation speed of the storm exceeds the baroclinic long wave speed. The amplitude of the wake depends on the length of time over which the stress is experienced at a given point. The angle of the wedge filled by the wake is small, an effect due to the fact that the scale of a hurricane is typically larger than the baroclinic radius of deformation. After the wake disperses, a geostrophically balanced baroclinic ridge remains along the storm track.
189 citations
TL;DR: Enzymic transformation of testosterone to the potent androgen, 5α-dihydrotestosterone, has been shown by incubation of testosterone-4-14C with microsomal preparations of human neonatal foreskin, with the activity stimulated by NADPH but not by NADH, and the reaction proceeded optimally at pH 5.6.
160 citations
TL;DR: Use of specific enzymes for the degradation of glycogen followed by enzymic determination of the glucose formed confers such a high degree of specificity to the described glycogen assay method that it is possible to determine glycogen directly, without prior isolation, in very dilute homogenates of less than 1 mg of liver or less than 10 mg of muscle.
153 citations
TL;DR: The data suggest that CFU migrate from marrow to spleen during the demands of severe anemia, and the induction of marrow CFU into cycle further suggests a negative feedback, which, perhaps through cell-cell interaction, maintains stem cells at a critical compartment size.
149 citations
TL;DR: The fine structure of synapses in the central nervous system of lamprey (Petromyzon marinus) ammocoetes has been investigated and the structural findings are considered in terms of current concepts of fast and slow transport in neurons and the mechanochemical control of intracellular movement of materials.
Abstract: The fine structure of synapses in the central nervous system of lamprey (Petromyzon marinus) ammocoetes has been investigated. Both synapses within the neuropil and synaptic links between giant fibers (including Muller cells) and small postsynaptic units are described. The distribution of neurofilaments and microtubules in nerve profiles over a wide diameter range is described, and the possible role of these structures in intracellular transport is discussed. Electron micrographs indicate that small lucent "synaptic vesicles" occur sparsely throughout the axoplasm and in regular arrays in association with microtubules in the vicinity of synapses. Within a synaptic focus, immediately adjoining the presynaptic membrane, vesicles are randomly arranged and are not associated with microtubules. Neurofilaments are present, generally in large numbers, but these are not associated with vesicles or other particulates. The structural findings are considered in terms of current concepts of fast and slow transport in neurons and the mechanochemical control of intracellular movement of materials.
139 citations
TL;DR: Evidence is presented to confirm the participation of ethylene in the geotropic response of roots and under certain conditions an additional effect of IAA accounts for a small portion of the inhibition of excised root tips.
Abstract: A large portion of indoleacetic acid (IAA)-induced inhibition of excised root tips and virtually all such inhibition of intact roots are the result of IAA-dependent ethylene production. Under certain conditions an additional effect of IAA accounts for a small portion of the inhibition of excised root tips. Ethylene production in response to applied IAA is governed by the level of applied auxin found inside the root. Evidence is presented to confirm the participation of ethylene in the geotropic response of roots.
126 citations
TL;DR: In this article, the authors found that the deposition rates of iron on the East Pacific Rise are 4-30 times larger than in surrounding areas of the Pacific, suggesting local volcanism to be the source of iron.
TL;DR: The mechanisms of reciprocating tachycardias were studied in three patients with WPW syndrome using the catheter technic of His bundle recordings, finding that short-lived paroxysms of atrial fibrillation in cases 1 and 2 were most probably related to atrial vulnerability.
Abstract: The mechanisms of reciprocating tachycardias were studied in three patients with WPW syndrome using the catheter technic of His bundle recordings. In the first case it could not be determined with certainty whether the tachycardias involved two anatomically independent fascicles or a single longitudinally dissociated pathway. They were terminated by carotid sinus pressure, which caused A-V nodal block, or by properly timed atrial stimuli, which interrupted the circuit. Short-lived paroxysms of atrial fibrillation in cases 1 and 2 were most probably related to atrial vulnerability. In case 3 there were three types of QRS complexes in lead II representing (a) exclusive His bundle conduction, (b) simultaneous His and Kent bundle conduction, and (c) coexisting His and infra-nodal preferential (Mahaim fiber[?]) conduction. This patient also had three types of reciprocating tachycardias-two of ventricular, and one of atrial origin. The reciprocating circuit probably involved the three pathways.
TL;DR: Data indicate that the increase in endogenous cyclic AMP brought about by luteinizing hormone is due to a stimulation of the adenyl cyclase rather than to an inhibition of the phosphodiesterase.
TL;DR: Studies of the partially purified enzyme indicate that its specificity of action is similar to that of the Pseudomonas enzyme and that it has the ability to hydrolyse the branch linkages of amylopectin and glycogen with the complete dismemberment of the branched macromolecules.
TL;DR: Patients with the WPW (pre-excitation) syndrome and long histories of paroxysmal arrhythmias were successfully treated with a combination of oral propranolol and implanted (transvenous) demand pacemaker.
Abstract: The catheter technic for recording the electrical activity of the specialized conducting system in the human heart showed in two patients studied that ventricular pre-excitation was apparently due to a bypass of the His bundle. Intermediate forms of WPW complexes appeared to be combination beats resulting from the activation of the ventricles through impulses traversing both the His bundle and accessory communications. Preferential iatrogenic activation of an intra-atrial (and perhaps even of an atrioventricular) tract appeared to occur in one of the patients. The patients with the WPW (pre-excitation) syndrome and long histories of paroxysmal arrhythmias were successfully treated with a combination of oral propranolol and implanted (transvenous) demand pacemaker.
TL;DR: Differences in the fine structure of pullulan prompted an investigation into the possibility of the modification of extracellular polysaccharides during the course of P. pullulans growth.
TL;DR: Modern and fossil genera of the Pyrrhophyta are catalogued, and an indication is given as to their validity under the International Code of Botanical Nomenclature or International code of Zoological NomenClature.
Abstract: Additional modern and fossil genera of the Pyrrhophyta are catalogued, and an indication is given as to their validity under the International Code of Botanical Nomenclature or International Code of Zoological Nomenclature. Eighty-seven taxonomic entries are cited in addition to those in the original index and five supplements. A type species is selected for Pseudopyrocystis, a correction is made to the type species of Cystodinedria, comment is made concerning the relationship of Tuberculodinium and Trioperculodinium, and a new combination is made for the type species of Manchudinium. Sixty-two references are cited in the accompanying bibliography.
TL;DR: In this article, the authors examine some of these features and discuss how insidious changes in estuaries can occur, and discuss the vulnerability of the estuarine environment to subtle alteration.
Abstract: Shallow estuaries are characterized by certain features which make them rich and productive ecosystems; these same characteristics, however, are responsible for the delicate nature of the estuarine environment and greatly enhance its vulnerability to subtle alteration. In this paper and the subsequent discussions, we examine some of these features and discuss how insidious changes in estuaries can occur.
TL;DR: N-hydroxylation appears to be the key to bladder cancer production by aromatic amines.
Abstract: Repeated installation of N-hydroxy-2 naphthylamine into dog bladders produced tumors of this organ. There is a correlation of degree of carcinogenicity of 1-naphthylamine, 2-naphthylamine, and 4-aminobiphenyl with both methemoglobin production in the blood and concentration of N-oxidation products in the urine. Thus, N-hydroxylation appears to be the key to bladder cancer production by aromatic amines.
TL;DR: A valgus osteotomy technique is developed which makes the plane of the fractures more horizontal, approximates the cortical surfaces of the two major fragments, and places the neck of the femur in avalgus position for the treatment of unstable intertrochanteric fractures.
Abstract: 1. The stability of intertrochanteric fractures is primarily determined by the integrity of the medial cortex of the fracture fragments and the surgeon's ability to obtain accurate and stable apposition of the medial cortices of the major fragments.
2. In the presence of comminution of the medical cortex sufficient stability is not achieved by mere anatomical reduction of the fragments.
3. We have developed a valgus osteotomy technique for the treatment of unstable intertrochanteric fractures which makes the plane of the fractures more horizontal, approximates the cortical surfaces of the two major fragments, and places the neck of the femur in a valgus position.
4. The results in 100 cases of unstable intertrochanteric fracture treated in this manner are reported and the technique for osteotomy and insertion of a short 135-degree I-beam nail is described.
TL;DR: In this article, a preliminary petrological description is presented of rocks obtained where the Mid-Atlantic Ridge is intersected by the Chain, Romanche and St. Paul fracture zones and from unfractured sections of the Ridge between 6° and 8°N.
TL;DR: In smooth muscle physiology there is much uncertainty about the relative contribution of calcium influx to the initiation of contraction, and a calcium transport blocking agent would be very useful.
Abstract: LETTVIN et al.1 predicted that lanthanum ions, because of their relatively small size and high charge density, should have a much greater electrostatic attraction for any negative calcium binding site than calcium ions themselves. This was borne out for the membranes of the barnacle muscle fibres2 and the lobster axon3. If negatively charged sites located in the membrane also serve to transport calcium ions across it, then lanthanum ions would be expected to displace calcium from these sites, and thereby inhibit the calcium ion flux. It has been shown that this is true for an artificial membrane with negative groups of phospholipids lining aqueous pores4. Data obtained by Weiss and Goodman5 and Van Breemen6 indicate that lanthanum ions also block the calcium transport across smooth muscle membranes. In smooth muscle physiology there is much uncertainty about the relative contribution of calcium influx to the initiation of contraction, and a calcium transport blocking agent would be very useful. In addition, information regarding the nature of the lanthanum blockade should contribute to the understanding of the cell membrane calcium transport system itself.
TL;DR: Laboratory experiments suggest that upstream movements of the amphipod Gammarus pulex, especially in regions of slower current flow, are sufficient to compensate for the downstream displacements of animals by drift.
Abstract: Laboratory experiments, conducted within a current chamber, suggest that upstream movements of the amphipod Gammarus pulex, especially in regions of slower current flow, are sufficient to compensate for the downstream displacements of animals by drift. They indicate also that drift was greater in slow—flowing than in faster waters. See full-text article at JSTOR
TL;DR: It is found that the amylase-free enzyme is unable in many instances to bring about a complete conversion of the starch components and glycogen into glucose, and adulteration of the glucamylase with a-amyl enzyme restores the conversion to a quantitative level.
TL;DR: Experimental results from the heating of formaldehyde and ammonia yields a product that, on hydrolysis, is converted into seven amino acids: aspartic acid, glutamic acid, serine, proline, valine, glycine, and alanine.
Abstract: The heating of formaldehyde and ammonia yields a product that, on hydrolysis, is converted into seven amino acids: aspartic acid, glutamic acid, serine, proline, valine, glycine, and alanine. Glycine is the predominant amino acid. Inasmuch as formaldehyde and ammonia have been identified as compounds in galactic clouds, these experimental results are interpreted in a cosmochemical and geochemical context.
TL;DR: The concentration of radon-222 in air was measured during a flight from Miami to Barbados to Dakar and return; concentrations ranged from 1 to 55 picocuries per standard cubic meter of air and were highest in areas of dense haze, which were present along most of the flight path across the Atlantic Ocean as discussed by the authors.
Abstract: The concentration of radon-222 in air was measured during a flight from Miami to Barbados to Dakar and return; concentrations ranged from 1 to 55 picocuries per standard cubic meter of air and were highest in areas of dense haze, which were present along most of the flight path across the Atlantic Ocean. The haze is attributed to dust originating from the arid regions of western Africa. Radon-222 may be useful as a tracer for African air parcels over the equatorial Atlantic.
TL;DR: In this paper, the authors examine the concept of place utility in an operational context and construct and evaluate place utility functions which are based upon socioeconomic and migration characteristics of areal units within a city.
Abstract: This paper examines the concept of place utility in an operational context. Its major objective is to construct and evaluate place utility functions which are based upon socioeconomic and migration characteristics of areal units within a city. A secondary objective is to identify major factors related to intraurban migration flows in an aggregate framework. The empirical basis for the study is a sample of actual migration flows for Cedar Rapids, Iowa, for a single year commencing in 1966 and terminating in 1967. Regression methods are used for estimating parameters of the place utility functions. One conclusion of the analysis is that migration friction between neighborhood types is considerably less than expected. Factors identified as most important in guiding intraurban migration streams are the aspirations of the household with respect to housing and the spatial characteristics of the vacancy market, the latter of which has been neglected in geographic research. With respect to the method of ...
TL;DR: Serotonin in millimolar concentrations was toxic to fibroblasts and the two functional groups of the serotonin molecule were required for growth enhancement.
Abstract: 5-Hydroxytryptamine (serotonin) in micromolar amounts increased the growth of fibroblasts in culture while not affecting five other cell lines. Serotonin appeared to shorten the lag phase of cell growth. The effect was less when serotonin was added to the fibroblast culture after the initial 24-hour period. The two functional groups of the serotonin molecule were required for growth enhancement. Serotonin in millimolar concentrations was toxic to fibroblasts.