Nutrient Retention in Shallow Reservoirs Using Selected Aquatic Macrophytes

A field experiment was conducted to evaluate the possibility of using shallow reservoirs containing aquatic plants to reduce excess nutrient levels of agricultural drainage effluent from organic soils. The reservoir systems consisted of three small reservoirs in series, containing separate stands of Eichhornia crassipes, Egeria densa and Typha sp., and a single large reservoir containing equal areas of all three aquatic plants. A control reservoir without plants was included. Drainage water from organic soils was pumped through each reservoir at 39.6 l/sec., 6 hours per day, 6 days per week. the major nutrients monitored in theses flow-through systems included nitrate-N, ammonium-N, total-N, ortho-P (soluble reactive phosphorus) and total-P. Temperature, pH, alkalinity, dissolved oxygen, carbon dioxide and turbidity were also monitored at the inflow and outflow of each reservoir system. Standing crop measurements and plant tissue analysis for nitrogen and phosphorus were conducted every 21 days. When a single large reservoir was used, effluent nitrate-N, ammonium-N, ortho-P and total-P concentrations decreased by 65%, 57.9%, 70.3% and 51% respectively, while organic-N concentrations increased by 7.2%. In the a series of small reservoirs the concentrations of nutrients decreased by 80%, 73%, 33%, 74%, and 70% for nitrate-N, ammonium-N organic-N, ortho-P and total-P respectively. The dissolved oxygen increased and turbidity was reduced in both reservoir systems. The bicarbonate and carbonate equilibrium in the series of reservoirs and control reservoir shifted to the carbonate sides as carbon dioxide was reduced. The carbon dioxide in the large reservoir remained at the same concentration throughout the study. The standing crop in both reservoir systems was similar with an average of 11.6 mt/ha grown in R-1 and 11.2 mt/ha grown in the series of reservoirs. The nitrogen retained during the study was 1017 kg/ha and 750 kg/ha in the series and the large reservoir respectively. Phosphorus retained in the series was 249 kg/ha while the large reservoir retained 211 kg/ha of phosphorus. The series of reservoirs was more effective in reducing the nutrient levels of the drainage effluent than the large single reservoir. The results obtained from this study indicated that reservoirs in series can be used to reduce excess nutrient levels of agricultural drainage waters. However, further studies are necessary to increase the efficiency of the system and to accelerate plant removal. The physical, chemical, and biological processes involved in removal of the nitrogen and phosphate should be optimized in future applications

The Multiple Young Stellar Objects of HBC 515: An X-ray and Millimeter-wave Imaging Study in (Pre-main Sequence) Diversity

We present Chandra X-ray Observatory and Submillimeter Array (SMA) imaging of HBC 515, a system consisting of multiple young stellar objects (YSOs). The five members of HBC 515 represent a remarkably diverse array of YSOs, ranging from the low-mass Class I/II protostar HBC 515B, through Class II and transition disk objects (HBC 515D and C, respectively), to the "diskless", intermediate- mass, pre-main sequence binary HBC 515A. Our Chandra/ACIS imaging establishes that all five components are X-ray sources, with HBC 515A - a subarcsecond-separation binary that is partially resolved by Chandra - being the dominant X-ray source. We detect an X-ray flare associated with HBC 515B. In the SMA imaging, HBC 515B is detected as a strong 1.3 mm continuum emission source; a second, weaker mm continuum source is coincident with the position of the transition disk object HBC 515C. These results strongly support the protostellar nature of HBC 515B, and firmly establish HBC 515A as a member of the rare class of relatively massive, X-ray luminous "weak-lined T Tauri stars" that are binaries and have shed their disks at very early stages of pre-MS evolution. The coexistence of two such disparate objects within a single, presumably coeval multiple YSO system highlights the influence of pre- MS star mass, binarity, and X-ray luminosity in regulating the lifetimes of circumstellar, planet-forming disks and the timescales of star-disk interactions.Comment: Accepted for publication in A&A; 11 pages, 5 figure

FORCE AND ELECTROMYOGRAPHIC (EMG) RELATIONSHIPS OF LEG EXTENSORS DURING ERGOMETER CONTRACTIONS

'The purpose of this study was to examine the force/EMG relationship during dynamic muscle contractions. Three ergometers (isokinetic dynamometer, adapted leg-only ergometer, standard rowing ergometer) were modified with strain gauges and potentiometers to measure force and displacement. Surface electrodes were used to record EMG of rectus femoris (RF) and vastus lateralis (VL) muscles. Trained rowers (n=ll) performed leg extensions at randomly selected target forces under each condition. There was a strong positive linear correlation between force and EMG amplitude (RF, VL) under constant velocity conditions (r2=.866, .871). Although diminished in strength, this relationship was maintained under leg-only and standard ergometer conditions. The findings support the use of force/EMG analysis during rowing performance

Clarificación de valores en estudiantes de 9° de educación básica. Una experiencia desde la investigación acción participante (IAP)

Este texto se presentó como comunicación al II Congreso Internacional de Etnografía y Educación: Migraciones y Ciudadanías. Universidad Autónoma de Barcelona, Barcelona, 5-8 Septiembre 2008La formación ética y moral del estudiantado es sin duda un compromiso de la educación formal y un deber insoslayable de todo docente. Autores como Payá (1999) sostienen que la educación no es neutra, que educar significa educar en valores. En los últimos años la información sobre educación en valores se ha difundido ampliamente y a todos los niveles. Este proceso implica, además de un período de sensibilización, la puesta en práctica de una serie de metodologías destinadas a facilitar la educación en valores en los distintos niveles del quehacer educativo. Una de las más utilizadas es el Método de Clarificación de Valores, razón por la cual se abordó la presente investigación en el proceso educativo de estudiantes de 9º de educación básica desde la experiencia de investigación acción participante (IAP). El tipo de investigación utilizado fue la etnografía, mediante el diseño metodológico de Investigación Acción Participativa. La información ha sido recogida a través de entrevistas, observación, registro descriptivo y diario de campo. Los insumos se analizaron mediante la técnica de la triangulación, obteniendo resultados que permiten concluir la necesidad de efectuar el proceso educativo centrado en valores, donde los alumnos desarrollen y practiquen los valores que regirán su vida; la apreciación de una actitud reflexiva por parte de los involucrados, durante y después de las actividades desarrolladas así como la adquisición de una herramienta para el abordaje de nuevos valores. Adicionalmente a esta conclusión se resalta el papel que juegan los docentes de todo nivel para la supervivencia de valores cónsonos con el desarrollo de la humanidad, serán ellos lo protagonistas y deberán asumir implícitamente las relaciones simbióticas entre el hombre, sociedad, tecnología, conocimiento y naturaleza y trasladarlas hacia el joven estudiante, se trata de crear a unos jóvenes capaces de resistir la barbarie que ha traído la modernización y con ella el cambio de la escala de los valores de los ciudadanos, en tanto el rol de las instituciones educativas debe estar dirigido hacia la promoción de experiencias significativas que conduzcan a la formación de un ser humano capaz de desarrollarse en la sociedad en la cual estamos inmersos y que de una manera crítica, practique como norma de vida la libertad, la tolerancia, la honestidad, el compañerismo, la cooperación y la justicia, ya que la clave del éxito está en crear una dinámica donde se desarrollen los valores

Evaluating leadership's approach to implementing organizational change across the Naval Aviation Enterprise with a focus on the development of Fleet Readiness Centers

MBA Professional ReportNAVAIR is currently realigning its Aviation Maintenance infrastructure to fall under the overarching umbrella of the newly minted Naval Aviation Enterprise (NAE). This realignment will call for a new enterprise-wide strategy and structure. Hierarchies and relationships are being redefined throughout the enterprise resulting in entirely new organizational structures functionally equivalent to industryb2ss small business units. This realignment will result in the elimination of Intermediate level maintenance as it exists today and presents a myriad of challenges to the Fleet in the terms of achieving business efficiencies and employee relationship management. This MBA Project evaluates, by survey, how effectively the U. S. Navy and Marine Corps have managed the change effort as they continue to realign their Intermediate and Depot level units under the new FRC construct.http://archive.org/details/evaluatingleader1094510097US Navy (USN) authorApproved for public release; distribution is unlimited

ELBOW FLEXOR MUSCLE FUNCTION AND UPPER ARM GIRTH FOLLOWING CONCURRENT STRENGTH AND ENDURANCE TRAINING IN NON RESISTANCETRAINED FEMALES

The study investigated the effects of eight weeks of concurrent muscular strength and endurance resistance training of the non-dominant elbow flexors on muscular strength, endurance, and upper arm girths of previously non resistance-trained females. Subjects (n=12) were assigned to one of 3 training groups. These groups were Strength (S), Endurance (E), or Combined (C) with pre and post-training tests for arm girths, 1 RM preacher curl, maximal isometric torque, peak isokinetic torque at velocities of 30 and 90" s-', and total work during 25 continuous repetitions at 90"s.'. Significant increases in prepost strength and endurance occurred in both C and S groups, but not E, in the absence of any change in arm girth. Furthermore, C training produced equivalent gains in strength and endurance to the S and E groups, respectively

Disassembly of interchromatin granule clusters alters the coordination of transcription and pre-mRNA splicing

To examine the involvement of interchromatin granule clusters (IGCs) in transcription and pre-mRNA splicing in mammalian cell nuclei, the serine-arginine (SR) protein kinase cdc2-like kinase (Clk)/STY was used as a tool to manipulate IGC integrity in vivo. Both immunofluorescence and transmission electron microscopy analyses of cells overexpressing Clk/STY indicate that IGC components are completely redistributed to a diffuse nuclear localization, leaving no residual structure. Conversely, overexpression of a catalytically inactive mutant, Clk/STY(K190R), causes retention of hypophosphorylated SR proteins in nuclear speckles. Our data suggest that the protein-protein interactions responsible for the clustering of interchromatin granules are disrupted when SR proteins are hyperphosphorylated and stabilized when SR proteins are hypophosphorylated. Interestingly, cells without intact IGCs continue to synthesize nascent transcripts. However, both the accumulation of splicing factors at sites of pre-mRNA synthesis as well as pre-mRNA splicing are dramatically reduced, demonstrating that IGC disassembly perturbs coordination between transcription and pre-mRNA splicing in mammalian cell nuclei

Molecules in the transition disk orbiting T Cha

We seek to establish the presence and properties of gas in the circumstellar disk orbiting T Cha, a nearby (d~110 pc), relatively evolved (age ~5-7 Myr) yet actively accreting 1.5 Msun T Tauri star. We used the APEX 12 m radiotelescope to search for submillimeter molecular emission from the T Cha disk, and we reanalyzed archival XMM-Newton spectroscopy of T Cha to ascertain the intervening absorption due to disk gas along the line of sight to the star (N_H). We detected submillimeter rotational transitions of 12CO, 13CO, HCN, CN and HCO+ from the T Cha disk. The 12CO line appears to display a double-peaked line profile indicative of Keplerian rotation. Analysis of the CO emission line data indicates that the disk around T Cha has a mass (M_disk,H_2 = 80 M_earth) similar to, but more compact (R_disk, CO~80 AU) than, other nearby, evolved molecular disks (e.g. V4046 Sgr, TW Hya, MP Mus) in which cold molecular gas has been previously detected. The HCO+/13CO and HCN/13CO, line ratios measured for T Cha appear similar to those of other evolved circumstellar disks (i.e. TW Hya and V4046 Sgr), while the CN/13CO ratio appears somewhat weaker. Analysis of the XMM-Newton data shows that the atomic absorption $N_H$ toward T Cha is 1-2 orders of magnitude larger than toward the other nearby T Tauri with evolved disks. Furthermore, the ratio between atomic absorption and optical extinction N_H/A_V toward T Cha is higher than the typical value observed for the interstellar medium and young stellar objects in the Orion Nebula Cluster. This may suggest that the fraction of metals in the disk gas is higher than in the interstellar medium. Our results confirm that pre-main sequence stars older than ~5 Myr, when accreting, retain cold molecular disks, and that those relatively evolved disks display similar physical and chemical properties.Comment: Accepted for publication on A&