Showing papers by "University of California, Santa Barbara published in 1970"

New equivalent circuits for elementary piezoelectric transducers

Abstract: New equivalent circuits, having several advantages over previous circuits, are presented for three types of piezoelectric transducer: the thickness-expander plate, the end-electroded bar and the side-electroded bar. Each of the circuits involves an electrical network of frequency-dependent components connected to the centre of an acoustic transmission line.

The secchi disk in turbid coastal waters1

Abstract: Measurements of Secchi disk depth are correlated with beam transmittance (B) in turbid coastal water. Both k (the irradiance attenuation coefficient) and a! (the beam attenuante coefficient) can be estimated from the Secchi depth either on an empirical basis or by using the Duntley-Preisendorfer equation of contrast reduction, Such estimates possess relatively large standard errors of estimate. The effects of the size of Secchi disk and viewing techniques are discussed. An estimate of contrast threshold of the human eye under field conditions has been obtained. A modification of the factor in the Poole and Atkins equation for estimating k from Secchi depth is suggested.

A functional analysis of language.

Abstract: Language has been given a largely structural definition by linguistics, but in order to have a psyclhological theory of language, the structural emphasis must be replaced by a functional one. What must an organism do in order to give evidence that it has language? More specifically, when is a response a word? A sequence of responses a sentence? What makes one response sequence an assertion or predication, another an imperative, still another a question? In this paper I try to give these questions the most general answers possible, general in the sense of relieving them of their exclusively human form. The functions an organism carries out when engaged in language need to be separated from the form these functions take in man. Not only human phonology but quite possibly human syntax may be unique to man; both may encompass mechanisms not found in any other species (Chomsky, 1965; Lenneberg, 1968). But if this is so, it does not commit the mechanisms of logic and semantics to the same status. The latter may be more widely distributed and it may be them, not the human form of syntax and phonology, upon which the basic functions of language depend.

Population regulation and population inertia

Abstract: Regulation is defined as the return of a population to equilibrium density. An operational definition of regulation is convergence to a single density by subpopulations which have been manipulated previously to different densities. The equilibrium density may be fixed or variable. If the equilibrium is variable then regulation may produce instability (numerical inconstancy) and non-density-dependence. Population inertia is the tendency for a population to resist changes away from its current density. If speed of regulation is defined as Isi, the speed of convergence to equilibrium, then inertia is 1/IsI. The evolution of mechanisms of inertia involves changes in the demographic functions, mediated through physiology or behavior, which keep the rate of numerical change low. It is not clear if populations are control systems or non-control systems, which makes the convergence experiment difficult to interpret the- oretically. Experiments and observations are needed which will try to distinguish, among stable populations, between those with tight regulation and those with high inertia. In this note, I examine the concept of regula- tion, and I compare ways in which a population may maintain a rather constant density. Regula- tion may sometimes be the most important pro- cess, but in some circumstances, what I call in- ertia will be of prime importance. I assume that some stable populations exist, though it seems

Natural oil seepage at coal oil point, santa barbara, california.

Abstract: Aerial, surface, and underwater investigations reveal that natural seeps off Coal Oil Point, California, introduce about 50 to 70 barrels (approximately 8,000 to 11,000 liters) of oil per day into the Santa Barbara Channel. The resulting slicks are several hundred meters wide and are of the order of 10-5 centimeters thick; tarry masses within these slicks frequently wash ashore.

Sexual reproduction in the dinoflagellate noctiluca miliaris suriray1,2

Abstract: SUMMARY The existence of sexuality in dinoflagellates has long been controversial. Events described as the differentiation and release of isogametes and sexual fusion in cultures of Noctiluca miliaris were studied with the light microscope. In cultures fed. twice weekly with Dunaliella sp., kept under a 12-hr day, 12-hr night light regime at 25–30 ft-c and held at 18 C, certain vegetative cells, termed gametocyte mother cells, were observed to undergo what is interpreted as meiosis. This was followed by several synchronous mitotic divisions occurring at 45-min to 1-hr intervals and. resulting in the production of up to 1024 mature uniflagellated isogametes attached on the surface of the gametocyte mother cell body. After several hours gametes now seen swimming freely in the media were observed to fuse and form zygotes. One zygote subsequently became vacuolated and eventually differentiated into a small but reasonably typical vegetative cell. The life cycle of N. miliaris appears thus to be of the diplontic type. The taxonomic relationships between Noctiluca and other mesocaryotic dinoflagellates are discussed.

Pair tunneling as a probe of fluctuations in superconductors.

Abstract: We suggest a method of using the average pair field of one superconductor to probe the fluctuation pair field of a second metal at temperature above the latter's superconducting transition point. The two metals should be fabricated as a strongly coupled tunnel junction and the dc $I\ensuremath{-}V$ characteristic measured as a function of both the bias voltage $V$ and the amplitude of a magnetic field $H$ parallel to the junction interface. The resultant $I\ensuremath{-}V$ characteristic is predicted to give a direct measurement of the frequency and wave-vector dependence of the $\ensuremath{\Delta}$ susceptibility characteristic of the superconducting transition.

Heterogamety in Teleostean Fishes

Abstract: Teleostean fishes constitute a proliferous evolutionary grade, which shows a correspondingly diverse array of sex-mechanisms. Although most species are gonochorists, many groups have independently evolved monoecy as a response to varying degrees of breeding isolation. On the other hand, cytologically expressed heterogamety distinguishes several groups, especially those represented by the deep-sea species investigated, which belong to primitive and intermediate orders. Acetic-orcein squashes of kidney, spleen, and gonad reveal heteromorphic chromosome pairs in males of nearly half the 25 species of deep-sea teleosts examined. Within one family, the Y chromosome varies interspecifically in size from the second largest to the smallest element in the complement. Most such pairs are identifiable as atypically behaving bivalents associated end-to-end; some of these, perhaps, are expressed as heterochromatic bodies in preleptotene. The dimorphic components segregate in the secondary spermatocytes. Two k...

A History of Sub-Saharan Africa

Abstract: Introduction 1. The historical geography of Africa 2. Kingdoms on the Nile 3. The peoples of sub-Saharan Africa: society, culture and language 4. Crops, cows and iron 5. North-East Africa in the age of Aksum 6. Empires of the plains 7. East Africa and the Indian Ocean world 8. The lake plateau of East Africa 9. Societies and states of the West African forest 10. Kingdoms and trade in Central Africa 11.The peoples and states of Southern Africa 12. The arrival of the Europeans in sub-Saharan Africa 13. Diseases and crops: old and new 14. Slavery in Africa 15. The Atlantic slave trade 16. The Asian slave trade 17. Prelude to the European conquest of Africa 18. The European conquest of Africa 19. Africans, Dutch and the British in South Africa, 1480-1910 20. European colonial rule in Africa 21. The colonial legacy 22. Nationalism and the independence of colonial Africa 23. The union of South Africa and the apartheid state 24. A decade of hope 25. Cold War Africa 26. Africa at the beginning of the twenty-first century.

Exchange Narrowing: Magnetic Resonance Line Shapes and Spin Correlations in Paramagnetic KMn F 3 , RbMn F 3 , and Mn F 2

Abstract: Analyses of line shapes and correlation functions are made to investigate the ${\mathrm{Mn}}^{++}$ EPR and ${\mathrm{F}}^{19}$ NMR in Mn${\mathrm{F}}_{2}$, KMn${\mathrm{F}}_{3}$, and RbMn${\mathrm{F}}_{3}$. Quantitative comparison of theory and experiment is now possible for these systems, and the standard theoretical approximations have proven to be inadequate. However, the form of the exchange interaction and broadening mechanisms is simple enough to allow us to extend earlier work by calculating higher-order moments and higher-order times in the short-time expansion of the correlation function than are usually feasible. We investigate several model line profiles consistent with the second and fourth moments for EPR in the infinite temperature limit. Agreement with experimental line-widths is obtained only for line shapes whose wing structure is non-Lorentzian, in contrast to the truncated Lorentzian forms usually adopted. The correlation functions characteristic of these profiles are obtained for the purpose of comparison with direct calculations later. We present short-time expansions (to fourth order) of the correlation functions, and we find that they decay more slowly than the Gaussian form usually assumed. The NMR correlation can be obtained for all times by a small interpolation between the short-time solutions and the predictions of a diffusion model for long times. The resulting function is consistent with that obtained from the line-profile analysis and both are in substantial agreement with previous spin-correlation studies. The linewidths predicted from this analysis and the moment method are both in agreement with experiment.

Spin Fluctuations in Nearly Antiferromagnetic Metals

Abstract: It is shown theoretically that the linear contribution to the specific heat enhanced by spin fluctuations in nearly antiferromagnetic metals exhibits no logarithmic increase as the critical boundary is approached, nor does a term like ${T}^{3}\mathrm{ln}T$ in the specific heat exist, in contrast to the case of nearly ferromagnetic metals.

Late Paleozoic Glaciation: II, Africa Exclusive of the Karroo Basin

Abstract: Africa, between about 4°N. and 32°S. latitude, was glaciated during the late Paleozoic as shown by glacial strata in several major basins and fault blocks—Karroo, Botswana, Orange River, Zambezi, and Congo—and in smaller areas of the Kaokoveld in South West Africa, in southern Madagascar, and in the Kafue Flats, Zambia. Age of the glaciation ranges from Late Carboniferous to Early Permian but may have begun in the Early Carboniferous. Striated floors beneath the glacial rocks indicate that extensive lobes of ice flowed radially outward from the African interior in Rhodesia and Zambia, suggesting that a continental ice sheet occupied this region. This is supported by environmentally significant facies relationships and paleocurrent flow directions. Major ice lobes occupied the Botswana fault block (flowing southwest), the subglacial valleys of the Kaokoveld region (flowing westwardly) and probably the coastal region of Tanzania, where ice flowed onto Madagascar toward the northeast prior to fragmentation of Gondwanaland. The major lobe of the Karroo basin, the Transvaal ice sheet, also flowed southward from the central African region. Smaller centers gave rise to the Namaland lobe, which flowed to the south from an elevated region on the western extremity of the Precambrian Damara belt, and to a piedmont glacier positioned at the foot of a mountainous region on the eastern side of the Congo basin. The Kaokoveld lobe overrode a mountain barrier in South West Africa, perhaps more than 1500 m high, and thence may have extended to the Brazilian shield and the Parana basin. This lobe probably was the only one to contribute to the glacial deposits of South America before the continents separated and drifted apart. Development of a continental ice sheet in southern Africa probably was enhanced by position of the continent in relatively high latitudes, as deduced from studies of rock paleomagnetism. As many as six glacial advances arc locally recorded, but many more may have occurred, in view of the abundant evidence of reworking of glacial deposits.

Evidence on the time of chromosome pairing from the preleptotene spiral stage in Lilium longiflorum “Croft”

Abstract: A period of chromosome spiralization and contraction was observed between premeiotic interphase and leptotene in Lilium longiflorum “Croft”. There was variation in the extent of preleptotene spiralization and contraction of chromosomes among microsporocytes, anthers and buds. The chromosomes sometimes contracted sufficiently to be visible as separate entities. It could then be determined that the chromosomes were single and entirely separate; synapsis and crossing-over had not yet occurred. Furthermore there was no evidence of alignment or association of homologues during the preleptotene contraction period; the chromosomes appeared to be distributed at random. The chromosomes subsequently elongated into the leptotene stage. Wherever they were visible separately the chromosomes were single in early leptotene. These observations support the classical view that synapsis of homologous chromosomes takes place during zygotene, followed by crossing-over at pachytene.

Variability of physiological parameters of unacclimatized males during a two—hour cold stress of 5°C

Abstract: The metabolic and temperature responses of 11 male Caucasians to a 2-hr exposure to 5 ± 1°C, 70 ± 2% RH were compared with control data obtained in an ambient environment of 28 ± 1°C, 45 ± 2% RH. The heat production increased during the cold exposure attaining an approximately stable level during the final 30 min. The group variability in response to the cold was greatest during the first 30 min and declined for the remainder of the cold exposure. All skin temperatures approached a stable value during the final 30 min of cold exposure. The correlation between mean skin temperature and thigh temperature was significant (p < 0.001) and the use of thigh temperature as an approximate mean skin temperature was suggested. The calculation of tissue conductance with or without the inclusion of heat exchanges due to changes in body heat content and respiratory losses was in agreement only during the final 30 min of cold exposure, thus indicating a stage of physiological equilibrium. All measured parameters except the toe and finger temperatures approached minimum variability of response during the final 30 min of cold exposure.

Sieve-plate pores in tobacco and bean.

Abstract: Tobacco and bean plants were wilted and then fixed as whole plants with formaldehyde-glutaraldehyde for electron microscopy. In some tobacco plants the sieve-plate pores were large, with little callose. Light slime plugs were present, but there was no compaction of P-protein in the pores. Some pores in wilted bean plants were also unplugged. In other plants of both tobacco and bean the sieve-plate pores were plugged. The pores in unwilted control plants of both tobacco and bean were invariably plugged. Tobacco plants were also cut into thin slices and then immediately fixed. In specimens prepared in this way there was little callose in the pores, and many of the pores were not plugged with P-protein. These observations provide additional evidence that sieve-plate pores may be unplugged in vivo.

Mechanical Stability of Crystal Lattices with Two-Body Interactions

Abstract: The stability criteria developed by Max Born are applied to investigate the mechanical stability of body-centered-cubic (bcc) and face-centered-cubic (fcc) Morse-function crystal lattices {i.e., lattices in which the atoms interact via the morse interatomic potential energy function $\ensuremath{\phi}(r)=D[{e}^{\ensuremath{-}2\ensuremath{\alpha}(r\ensuremath{-}{r}_{0})}\ensuremath{-}2{e}^{\ensuremath{-}\ensuremath{\alpha}(r\ensuremath{-}{r}_{0})}]$}. It is shown that the conditions for stability can be expressed uniquely as a function of $\ensuremath{\alpha}a$, where $a$ is the lattice parameter of the crystal. The fcc lattice is stable for all values of $\ensuremath{\alpha}a$, while the bcc lattice is stable only for values of $\ensuremath{\alpha}a$ which are less than 4.8. The possibility of using Morse-function lattices to represent cubic crystals with particular values of elastic moduli ${C}_{11}$ and ${C}_{12}$ is investigated. The Morse function can serve quite well for this type of representation for fcc crystals. For bcc crystals, however, the ratio $\frac{{C}_{11}}{{C}_{12}}$ does not exceed about 1.36; thus the representation is inherently fairly poor.

Reproductive synchronization in squirrel monkeys (Saimiri)

Abstract: Groups of squirrel monkeys (Saimiri) that are exposed to certain seasonal environmental stimuli experience a yearly reproductive cycle with discrete mating and birth seasons. Seasonal rainfall or some rainfall induced seasonal changes (such as changes in vegetation or insect fauna) appear to be responsible for timing theSaimiri reproductive cycle. Animals of both sexes show significant physiological and behavioral changes during the yearly cycle. Whether the environmental timing factors affect both the males and the females equally, or affect only one sex directly and the other sex indirectly through social communication is not clear. Three mechanisms by which the reproductive activity of both males and females could be synchronized are presented, and data from a laboratory study and a field study relevant to each mechanism are presented. Several social interaction patterns frequently observed in the field study suggest that (1) male sexual activity may excite female sexual activity through male penile display and/or other stereotyped interactions and/or (2) female sexual activity may excite male sexual activity through pheromone and/or other communication channels.

Bed forms in base-surge deposits: lunar implications.

Abstract: Undulating dunelike deposits of surface debris, widespread over parts of the lunar landscape, are similar in form but greater in size than base-surge deposits found in many maar volcanoes and tuff rings on Earth. The bed forms of base-surge deposits develop by the interaction of the bed materials with those in the current passing overhead. Therefore the "patterned ground" produced differs from that formed by ballistic fallout.

Longshore Movements of the Sand Crab, Emerita Analoga (Decapoda, Hippidae)

Abstract: Wir haben Markierungsmoglichkeiten fur Sandkrabben (Emerita analoga) gepruft und entdeckten 3 brauchbare Methoden. Auf dem Ruckenschild angenahte Faden erwiesen sich als die wirksamste Methode mit Ruckfangraten von 6,1 Prozent. 114 bezeichnete Sandkrabben wurden 1 bis 27 Tage nach ihrer Freilassung ostlich und westlich des Aussetzungsorts mit einer durchschnittlich ostlichen Versetzung (Wanderung) von 47,6 Fus pro Tag wiedergefunden. Die Durchschnittsgeschwindigkeit der Wasserstromung betrug 15,4 Fus pro Minute ostwarts. Die Ansammlungen neigten dazu, in der gleichen relativen Lage (Verbindung mit Sandspitzen) zu bleiben. Die ostwarts gerichtete Entfernung einzelner Sandkrabben deutet darauf hin, das diese eher eine physikalische als eine biologische Ursache hat. Wir bezweifeln die Gultigkeit von Wachstumskurven, die auf der Annahme beruhen, das der Sandkrabbenbestand seshaft bleibt.