Control of Phytoplankton Production in a Shallow, Turbid Estuary.

Water column primary production and chlorophyll were sampled between 1986-1991 in Fourleague Bay, LA, a shallow (1.5 m), river-dominated estuary that is extremely turbid (K\sb{\rm D} = 4.44 m\sp{-1}). A high speed system for continuous flow-through sampling, Dataflow\sp\copyright, was developed to measure physicochemical variables and in vivo chlorophyll fluorescence at high temporal (1 s) and spatial (5 m) resolution from a small boat. Phytoplankton net primary production (NPP) was measured using an incubator which rotated bottles to prevent settling of the contents. NPP was found to be artificially increased by 10-83% at high light levels in non-rotated bottles when cells and sediments settled, reducing photoinhibition. Chlorophyll (17-27 $\mu$g L\sp{-1}) and NPP (0-4.5 g m\sp{-2} d\sp{-1}) distribution varied with season, and was correlated with K\sb{\rm D} and temperature, but not with nutrients. Spatially, chlorophyll was lower in the upper bay, increasing toward the middle estuary and laterally toward shores, especially in bayous, where concentrations were up to 42% higher than open bay waters. Bayous may tidally export chlorophyll to the bay. Turbidity from SPM (64 mg L\sp{-1}) was generated by river flow in spring and wind and current resuspension in summer and fall. Minimum water column NPP occurred in the upper estuary during spring, coincident with maximum turbidity. Annually, NPP averaged about 400 g C m\sp{-2}, peaking in fall in the upper estuary. Phytoplankton photosynthetic parameters were adapted to a high light regime: P\sp{\rm B}\sb{\rm max} averaged 10.99 $\mu$g C $\mu$g Chla\sp{-1} h\sp{-1}, I\sb{\rm K} ranged from 150-400 $\mu$E m\sp{-2} s\sp{-1}, and \alpha\sp{\rm B} averaged 0.05 $\mu$g C $\mu$g Chl a\sp{-1} h\sp{-1} $\mu$E m\sp{-2} s\sp{-1}. Frequent vertical circulation of phytoplankton in the shallow water column exposes them briefly to high light, sufficient to establish high photosynthetic capacity for the community, and prevent photoadaptation to lower light at depth. Parameters were not correlated with subsurface light, but integrated water column NPP was, indicating light control of NPP. In a simulation model, construction of a levee across the bay entrance had little impact on productivity, but shell dredging activity increased turbidity and reduced primary production nearly 50%, extinguishing the zooplankton population

Effects of Jamming and Excision Filtering Upon Error Rates and Detectability of a Spread Spectrum Communication System

This thesis examines the effects of a digital excision filter (DEF) upon the error rates and detectability of a Direct Sequence Binary Phase Shift Keyed communication signal in the presence of both continuous wave (CW) and pulsed jammers. Simulations were performed using the Comdisco Signal Processing Worksystem. Detector models used were the wideband radiometer and two forms of the chip-rate detector. Twelve jamming scenarios were used to test the performance of the DEF in the presence of the CW and pulsed jammers. In addition, the effects of the CW jammer frequency, the pulsed jammer duty cycle, and the pulsed jammer PPF were also examined. LPI quality factors were then used to quantify the performance of the DEF. This research determined that the DEF was able to remove almost 100% of the CW jammer and allowed the communication receiver and interceptors to operate with little degradation. The DEF was less effective against the pulsed jammers; however, it still allowed the receivers to operate at an acceptable level for single jammers. When two or more pulsed jammers were present, the radiometer was still able to operate; however, the other interceptors\u27 performance was unacceptable

Toward a Discography of Composer-Pianists Who Recorded Their Solo Compositions from 1889-2015

This document presents a discography of 3,175 recordings by 214 composer-pianists who recorded their solo compositions from 1889-2015. In doing so, the discography achieves two goals. First, it clarifies information surrounding recording dates, original releases, and commercial reissues of recordings by well-known composer-pianists. Second, the discography provides a source of lesser-known solo piano music written by contemporary composers, many of whom continue to write and record their own music. Chapter one introduces the study and explains the importance of primary recordings—the term used in this document to describe composers' recordings of their own works. In addition to providing a list of primary recordings, the discography offers a cross-section of twentieth- and twenty-first century piano music. Chapter two provides a review of literature related to discographies and describes how discographies evolved from simple recording lists to serious academic pursuits. A discussion of historical recording technology pertaining to the piano is included in chapter three. Prior to the introduction of electrical microphones in 1925, pianists recorded via two devices: acoustic recording horns and reproducing pianos. This chapter aims to clarify questions of authenticity by describing the advantages and disadvantages of each medium. The discussion of piano rolls focuses on the "big three" reproducing piano companies: Welte-Mignon, Duo-Art, and Ampico. In addition to describing the methods used to capture artists' performances, the chapter also details each company's proprietary editing techniques. The discography itself is presented in chapter four. Composers' last names and the compositions they recorded are organized alphabetically. When available, the discography also provides the following information for each recording: performance length, recording date, recording medium, original release information, most recent remastered CD release, and album title. The discography synthesizes information from a multitude of sources including Internet databases, bio-bibliographies, composer websites, record company catalogues, and CD liner notes. Immediately following the discography is a rollography of 650 compositions by 223 composers whose recordings for Welte-Mignon, Duo-Art, and Ampico have yet to be released in a format that is accessible to modern listeners. Chapter five provides a summary of the research. Notable trends found throughout the discography are summarized and discussed. These trends include the presence of multiple primary recordings of the same work and the existence of both acoustic and piano roll recordings of the same composition. Chapter five also discusses the most prominent compositional styles and techniques found in the discography. Works featuring ragtime, jazz, minimalism, prepared piano, extended techniques, improvisation, and musical quotation are common throughout the discography

Religiosity, Moral Cognition, and Attitudes Toward Addiction

Religion is an important aspect of many people’s addiction recovery. But while some research shows religion predicts positive attitudes toward people who use drugs, other research suggests that it may also be associated with prejudice toward drug users. What accounts for this discrepancy? Some research suggests that one’s views on the nature and causes of addiction are related to people’s religious beliefs and experiences as well as their attitudes toward people struggling with addiction. Here we test whether conceptions of addiction can explain the relationship between religiosity and attitudes towards addiction. In a correlational study (N = 125), we test whether religiosity is associated with acceptability of discrimination toward addicts in the context of housing and employment, and whether this can be explained by different levels of endorsement of two conceptions of addiction. Our results suggest that religiosity is unrelated to whether addiction discrimination is viewed as acceptable. However, the view that addiction is primarily a problem of moral character was related to greater acceptance of discrimination, but the view that addiction is a biological condition was related to less acceptance of discrimination. Participants’ religiosity was negatively related to the biological view of addiction, but unrelated to the moral view. Limitations and future directions are discussed.Bachelor of Art

Central Control of Brown Adipose Tissue Thermogenesis

Thermogenesis, the production of heat energy, is an essential component of the homeostatic repertoire to maintain body temperature during the challenge of low environmental temperature and plays a key role in elevating body temperature during the febrile response to infection. Mitochondrial oxidation in brown adipose tissue (BAT) is a significant source of neurally regulated metabolic heat production in many species from mouse to man. BAT thermogenesis is regulated by neural networks in the central nervous system which responds to feedforward afferent signals from cutaneous and core body thermoreceptors and to feedback signals from brain thermosensitive neurons to activate BAT sympathetic nerve activity. This review summarizes the research leading to a model of the feedforward reflex pathway through which environmental cold stimulates BAT thermogenesis and includes the influence on this thermoregulatory network of the pyrogenic mediator, prostaglandin E2, to increase body temperature during fever. The cold thermal afferent circuit from cutaneous thermal receptors, through second-order thermosensory neurons in the dorsal horn of the spinal cord ascends to activate neurons in the lateral parabrachial nucleus which drive GABAergic interneurons in the preoptic area (POA) to inhibit warm-sensitive, inhibitory output neurons of the POA. The resulting disinhibition of BAT thermogenesis-promoting neurons in the dorsomedial hypothalamus activates BAT sympathetic premotor neurons in the rostral ventromedial medulla, including the rostral raphe pallidus, which provide excitatory, and possibly disinhibitory, inputs to spinal sympathetic circuits to drive BAT thermogenesis. Other recently recognized central sites influencing BAT thermogenesis and energy expenditure are also described

Helping Farmers and Reducing Car Crashes: The Surprising Benefits of Predators

Humans may be Earth’s apex predator, but the fleeting shadow of a vulture or the glimpse of a big cat can cause instinctive fear and disdain. But new evidence suggests that predators and scavengers are much more beneficial to humans than commonly believed, and that their loss may have greater consequences than we have imagined

Reversible interconversion of CO2 and formate by a molybdenum-containing formate dehydrogenase.

CO2 and formate are rapidly, selectively, and efficiently interconverted by tungsten-containing formate dehydrogenases that surpass current synthetic catalysts. However, their mechanism of catalysis is unknown, and no tractable system is available for study. Here, we describe the catalytic properties of the molybdenum-containing formate dehydrogenase H from the model organism Escherichia coli (EcFDH-H). We use protein film voltammetry to demonstrate that EcFDH-H is a highly active, reversible electrocatalyst. In each voltammogram a single point of zero net current denotes the CO2 reduction potential that varies with pH according to the Nernst equation. By quantifying formate production we show that electrocatalytic CO2 reduction is specific. Our results reveal the capabilities of a Mo-containing catalyst for reversible CO2 reduction and establish EcFDH-H as an attractive model system for mechanistic investigations and a template for the development of synthetic catalysts.This is the final version. It was first published by ACS at http://pubs.acs.org/doi/abs/10.1021/ja508647