The sensory transduction pathways in bacterial chemotaxis

Bacterial chemotaxis is a useful model for investigating in molecular detail the behavioral response of cells to changes in their environment. Peritrichously flagellated bacteria such as coli and typhimurium swim by rotating helical flagella in a counterclockwise direction. If flagellar rotation is briefly reversed, the bacteria tumble and change the direction of swimming. The bacteria continuously sample the environment and use a temporal sensing mechanism to compare the present and immediate past environments. Bacteria respond to a broad range of stimuli including changes in temperature, oxygen concentration, pH and osmotic strength. Bacteria are attracted to potential sources of nutrition such as sugars and amino acids and are repelled by other chemicals. In the methylation-dependent pathways for sensory transduction and adaptation in E. coli and S. typhimurium, chemoeffectors bind to transducing proteins that span the plasma membrane. The transducing proteins are postulated to control the rate of autophosphorylation of the CheA protein, which in turn phosphorylates the CheY protein. The phospho-CheY protein binds to the switch on the flagellar motor and is the signal for clockwise rotation of the motor. Adaptation to an attractant is achieved by increasing methylation of the transducing protein until the attractant stimulus is cancelled. Responses to oxygen and certain sugars involve methylation-independent pathways in which adaption occurs without methylation of a transducing protein. Taxis toward oxygen is mediated by the electron transport system and changes in the proton motive force. Recent studies have shown that the methylation-independent pathway converges with the methylation-dependent pathway at or before the CheA protein

The Impact of the Coaching Relationship on Pastoral Leaders in the Rocky Mountain Conference

Problem. During the first decade of the 21st century, the Rocky Mountain Conference leaders fostered the professional development of the pastoral workforce. Although periodic seminars and training events were provided, an ongoing model supporting individual growth in ministry deserves further study and implementation. Research indicates that ministerial attrition rates continue to rise in Christian churches, especially among those new in ministry. With the increasing complexities of life and demand for quality pastoral leadership, the intentional development of relationships designed to impact these leaders is vital to strengthen both personal and professional growth. Method. An existing Christian coaching model was chosen and facilitated by the researcher among six pastoral leaders during 2010-2011. Coaching contracts were formed and implemented. The purpose was to realize the impact of these coaching relationships over the course of six months. An instrument was developed which integrated three areas, “knowing, being, and doing.” The success of the coaching relationships was measured by a self-assessment instrument and review questionnaire. Results. All six of the pastoral leaders completed the coaching contract time period. The project focused on the data received from the project assessment tool completed by the participants. The analysis demonstrates the positive impact that the coaching relationship brought to the experience of the participants. Statistically significant (p\u3c.10) positive outcomes for pastoral coaching impact were found in nine of 30 items. These range from p = .004 to p = .093. One statement has statistical significance of p = .004; two statements have a p = .042; five statements have response ratings that result in a p = .076; one statement lists a response value of p = .093. The main weaknesses related to sample size and coach experience of the researcher although positive results were identified. Conclusions. The study demonstrates the value of long-term relationships on pastoral leaders in order to improve satisfaction in their areas of “knowing, being, and doing.” Larger sample studies would be helpful in the future to determine if the results would be similar for other coaching approaches. Long-term studies would additionally prove beneficial in evaluating the positive impact of the coaching relationship. In general, these finding suggest that broad implementation of the coaching relationship would have positive impact mitigating pastoral attrition rates

Comparison of Combustion Efficiency to In-Situ Atmospheric Ammonia Measurements from a Miniature Chemical Ionization Mass Spectrometer in the LA Basin

Atmospheric ammonia (NH3) has been shown to impact the environment and threaten both human and animal health, especially in heavily populated urban areas, yet to date there remains a paucity of direct measurements. Recent studies have suggested that ammonia may be generated as a byproduct of fossil fuel emissions due to highly active catalytic converters in light-duty gasoline vehicles. To investigate this relationship, an airborne miniature Chemical Ionization Mass Spectrometer (miniCIMS) was used to directly measure atmospheric ammonia and combustion reaction products in the Southern California LA Basin, during the 2015 NASA Student Airborne Research Program (SARP). The temporal variability in measured ammonia, and the relationship to combustion efficiency will be compared to mobile ground-based measurements from the NASA DISCOVER-AQ campaign, and implications of the findings will be discussed

Nimbus 7 solar backscatter ultraviolet (SBUV) ozone products user's guide

Three ozone tape products from the Solar Backscatter Ultraviolet (SBUV) experiment aboard Nimbus 7 were archived at the National Space Science Data Center. The experiment measures the fraction of incoming radiation backscattered by the Earth's atmosphere at 12 wavelengths. In-flight measurements were used to monitor changes in the instrument sensitivity. Total column ozone is derived by comparing the measurements with calculations of what would be measured for different total ozone amounts. The altitude distribution is retrieved using an optimum statistical technique for the inversion. The estimated initial error in the absolute scale for total ozone is 2 percent, with a 3 percent drift over 8 years. The profile error depends on latitude and height, smallest at 3 to 10 mbar; the drift increases with increasing altitude. Three tape products are described. The High Density SBUV (HDSBUV) tape contains the final derived products - the total ozone and the vertical ozone profile - as well as much detailed diagnostic information generated during the retrieval process. The Compressed Ozone (CPOZ) tape contains only that subset of HDSBUV information, including total ozone and ozone profiles, considered most useful for scientific studies. The Zonal Means Tape (ZMT) contains daily, weekly, monthly and quarterly averages of the derived quantities over 10 deg latitude zones

Next generation software environments : principles, problems, and research directions

The past decade has seen a burgeoning of research and development in software environments. Conferences have been devoted to the topic of practical environments, journal papers produced, and commercial systems sold. Given all the activity, one might expect a great deal of consensus on issues, approaches, and techniques. This is not the case, however. Indeed, the term "environment" is still used in a variety of conflicting ways. Nevertheless substantial progress has been made and we are at least nearing consensus on many critical issues.The purpose of this paper is to characterize environments, describe several important principles that have emerged in the last decade or so, note current open problems, and describe some approaches to these problems, with particular emphasis on the activities of one large-scale research program, the Arcadia project. Consideration is also given to two related topics: empirical evaluation and technology transition. That is, how can environments and their constituents be evaluated, and how can new developments be moved effectively into the production sector