1,365 research outputs found
Mesoscale Variability of the California Current
LONG-TERM GOALS: My long-term goal is to understand the kinematics and dynamics of the California Current System. I am particularly interested in the structure of the inshore flow and the interannual, seasonal, and mesoscale variability that occurs off Central California. I feel that this knowledge can be applied to other Eastern Boundary currents and to naval warfare in these regions
Ocean currents above the continental shelf off Oregon as measured with a single array of current meters
Ocean currents were measured with meters moored above the Oregon continental shelf during four periods of about 25 days each----in July, September, and October 1965 and in February 1966. The data are described with histograms and progressive vector diagrams. Velocity variations having a frequency lower than one cycle in two days were associated with similar variations in wind in the alongshore direction...
Aerial Surveys of the Ocean and Atmosphere off Central California
The long-term goal is to enhance our understanding of airsea interaction in the littoral zone by means of applying simple dynamical theories to high-quality observations obtained in the field. The Monterey Bay serves as our natural laboratory for these purposes. The grant is one of a continuing series of programs to study the bay funded by the National Ocean Partnership Program NOPP and the ONR Naval Ocean Modeling and Prediction NOMP Program.Grant #s: N0001403WR20002, N0001403WR20006, N0001403WR2020
Effect of coastal-trapped waves and wind on currents and transport in the Gulf of California
The article of record as published may be located at http://dx.doi.org/10.1002/2013JC009538Subsurface pressure (SsP) observations from stations inside and outside of the Gulf of California
(GC) are used to analyze the relationship between low-frequency currents, temperature, and transport
inside the GC and intraseasonal coastal-trapped waves (CTWs), which propagate poleward along the coast
toward the GC. Correlation functions and coherences of SsP stations were consistent with intraseasonal
CTWs splitting in two at the mouth of the gulf: one part enters the gulf, propagates around the gulf, and
eventually, toward the mouth, and another part that appears to ‘‘jump’’ the mouth of the gulf and travels
poleward along the west coast of the peninsula. The correlation and coherence estimates of SsP at Manzanillo
with currents showed that downwelling CTWs generated along-gulf current anomalies toward the
head of the gulf at the mainland shelf of the mouth, whereas at Ballenas Channel sill (San Lorenzo sill) these
waves generated current anomalies toward the mouth near the surface (bottom). At the San Lorenzo (SL)
sill, downwelling CTWs increased the near-bottom ( 400 m) temperature and reduced the bottom transport
of deep, fresher, and colder water that flows toward the head of the gulf. Cross-Calibrated Multiplatform
winds were used to investigate their relationship with currents. The first empirical orthogonal function
of the along-gulf wind stress showed that wind blowing toward the head of the gulf generated a reduction
of bottom transport toward the head of the gulf through the SL sill, and intensified surface geostrophic current
fluctuations toward the head of the gulf. There was also significant correlation between inflow bottom
transport and outflow surface geostrophic velocities averaged across the gulf, consistent with the exchange
pattern for the Northern Gulf.This work was funded by CONACyT through grants G33464-T, 38797-T, C01-25343, ESE-203401, and through a scholarship to M. O. Guti errez
Temporal variability of downward fluxes of organic carbon off Monterey Bay
17 USC 105 interim-entered record; under review.Sediment traps were deployed at two depths (300 m and 1200 m) off Monterey Bay (36°40′N and 122°25′W, Central California) for 7.3 years (1998–2005). The sediment trap data provided information about the quantity and quality of settling material, and allowed exploration of the relationship of the sinking material with the environmental conditions in this coastal upwelling region. The magnitude and composition of the settling material were highly variable over time. Organic carbon (Corg) fluxes ranged between 4–296 mg C m−2 day−1 and 0.1–142 mg C m−2 day−1 for shallow and deep sediment traps, respectively. The time series of Corg vertical flux was characterized by pulses of intense fluxes that were associated with peaks of primary production, generally during upwelling periods. Despite considerable variability, fluxes varied seasonally with highest values during the upwelling season and the lowest in winter. Attenuation of Corg vertical fluxes with depth (300 m vs. 1200 m) varied between 31% and 24% except for the late upwelling period, when there was an increase with depth likely due to resuspension of material from Monterey Canyon. Calculation of a seasonal vertical budget of organic carbon off Monterey Bay resulted in a transfer between 4.0% and 4.9% of the primary production to the deep ocean, suggesting that coastal upwelling efficiently sequestered CO2.The principal source of support for these measurements was the David and Lucile Packard Foundation. CGC was partially supported by a National Research Council Fellowship at the Naval Postgraduate School.
Wnt Signaling in Zebrafish Fin Regeneration: Chemical Biology Using GSK3b Inhibitors
poster abstractBone growth can be impaired due to disease, such as osteoporosis, and Wnt signaling pathways regulate
bone growth. The parathyroid hormone (PTH) is therapeutic for anabolic bone growth (bone building),
which activates Wnt signaling, leading to bone growth. GSK3b (glycogen synthetase kinase 3 beta)
protein inhibitors activate Wnt signaling, including in bone growth models. Our study utilized a zebrafish
model system to study Wnt activated fin regeneration and bone growth. Wnt signaling is the first
genetically identified step in fin regeneration, and bony rays are the main differentiated cell type in fins.
Thus, zebrafish fin regeneration may be a useful model to study Wnt signaling mediated bone growth. Fin
regeneration experiments were conducted using various concentrations of GSK3b inhibitor compound for
different treatment periods and regenerative outgrowth was measured at 4 and 7 days post amputation.
Experiments revealed continuous low concentration (5-6 nM) treatment to be most effective at increasing
regeneration. Higher concentrations inhibited fin growth, perhaps by excessive stimulation of
differentiation programs. In situ hybridization experiments were performed to examine effects of Gsk3b
inhibitor on Wnt responsive gene expression. Initial experiments show temporal and spatial changes on
individual gene markers following GSK3b inhibitor treatment. Additionally, confocal microscopy and
immunofluorescence labeling data indicated that the Wnt signaling intracellular signal transducer, betacatenin,
accumulates throughout Gsk3b inhibitor treated tissues. Finally, experiments are underway to
quantify phosphohistone-3 staining in regenerating tissue to measure effects of Gsk3b inhibitor on cell
proliferation. Together, these data indicate that bone growth in zebrafish fin regeneration is improved by
activating Wnt signaling. Zebrafish Wnt signaling experiments provide good model to study bone growth
and bone repair mechanisms, and may provide an efficient drug discovery platform
The circulation and water masses in the Gulf of the Farallones
Six ADCP and CTD ship surveys of the continental shelf and slope in the vicinity of the Gulf
of the Farallones, CA, were conducted in 1990}1992. ADCP data provide much more detail on
the structure of the currents over the slope and shelf in the Gulf and reveal a persistent, largely
barotropic poleward #ow with a complex mesoscale #ow "eld superimposed. The directly
measured currents are not well represented by the geostrophic velocity "elds derived from
hydrographic casts. Important upper-ocean circulation features include: a Slope Countercurrent
(SCC), variable shelf circulation, and submesoscale eddy-like features. The SCC was present in
all seasons and is believed due to a strong year-round positive wind-stress curl enhanced by
Point Reyes. Its #ow was poleward throughout the upper 300 m, and often surface intensi"ed.
Poleward transport in the upper 400 m was 1}3 Sv, much greater than previous geostrophic
estimates for the California Current System constrained to a 500 dbar reference level. The shelf
circulation was much more variable than the SCC and generally exhibited a pattern consistent
with classic Ekman dynamics, responding to synoptic wind forcing. Submesoscale vortices, or
eddies, often dominated the general #ow "eld. These eddies are thought to be generated by the
frictional torque associated with current}topography interactions. Their centers typically have
a distinct water type associated with either the SCC or the southward-#owing California
Current. Higher spiciness anomalies, representing a higher percentage of Paci"c Equatorial Water (PEW), were typically found in the core of the SCC or within anticyclonic eddies. Lower
(bland) spiciness anomalies, characteristic of a higher percentage of Paci"c Subarctic Water
(PSAW), were associated with cyclonic eddies. While these circulation features were largely
barotropic, the #ow also adjusted baroclinically to changes in the density "eld, as di!erent
water types were advected by the general #ow "eld or by mesoscale instabilities in the
large-scale boundary currents as they interacted with topography. Despite a seasonal cycle in
regional wind and ocean temperature time series, there is no obvious seasonal pattern in the
circulation. Most of the temporal variability in the current appears to be due to synoptic and
interannual variations in atmospheric forcing. Because of the very dynamic three-dimensional
nature of the regional circulation, the Gulf of the Farallones is likely to be a center for active
mixing and exchange between the coastal and California Current waters, relative to most US
west coast locales
Mutations in the mitochondrial cysteinyl-tRNA synthase gene, CARS2, lead to a severe epileptic encephalopathy and complex movement disorder
Background: Mitochondrial disease is often suspected in cases of severe epileptic encephalopathy especially when a complex movement disorder, liver involvement and progressive developmental regression are present. Although mutations in either mitochondrial DNA or POLG are often present, other nuclear defects in mitochondrial DNA replication and protein translation have been associated with a severe epileptic encephalopathy.
Methods: and results We identified a proband with an epileptic encephalopathy, complex movement disorder and a combined mitochondrial respiratory chain enzyme deficiency. The child presented with neurological regression, complex movement disorder and intractable seizures. A combined deficiency of mitochondrial complexes I, III and IV was noted in liver tissue, along with increased mitochondrial DNA content in skeletal muscle. Incomplete assembly of complex V, using blue native polyacrylamide gel electrophoretic analysis and complex I, using western blotting, suggested a disorder of mitochondrial transcription or translation. Exome sequencing identified compound heterozygous mutations in CARS2, a mitochondrial aminoacyl-tRNA synthetase. Both mutations affect highly conserved amino acids located within the functional ligase domain of the cysteinyl-tRNA synthase. A specific decrease in the amount of charged mt-tRNACys was detected in patient fibroblasts compared with controls. Retroviral transfection of the wild-type CARS2 into patient skin fibroblasts led to the correction of the incomplete assembly of complex V, providing functional evidence for the role of CARS2 mutations in disease aetiology.
Conclusions: Our findings indicate that mutations in CARS2 result in a mitochondrial translational defect as seen in individuals with mitochondrial epileptic encephalopathy
Seasonal variation of the temperature and salinity at the entrance to the Gulf of California, Mexico
The article of record as published may be found at http://dx.doi.org/10.7773/cm.v26i4.621Se describe la variabilidad estacional en la entrada al Golfo de California utilizando datos de CTD en
una sección a través de la entrada al golfo, la cual fue ocupada en ocho ocasiones entre 1992 y 1998. Se
encontró que la variabilidad decrece rápidamente debajo de los 100 dbar; las desviaciones estándar
mayores que 0.5ºC y 0.05 para temperatura y salinidad, respectivamente, fueron confinadas a la capa
superior de 150 dbar. El campo medio de salinidad fue asimétrico, con aguas de menor salinidad
(S 34.8) arriba de 50 dbar y
entre 100 y 150 dbar cerca de Baja California. En la capa superior de 50 dbar se observó una termoclina
estacional sobre la cual las temperaturas superficiales cambiaron de 21ºC en febrero a 31ºC en agosto.
Debajo de los 100 dbar, la temperatura a una presión dada fue tÃpicamente más frÃa en el centro de la
sección, indicando flujo ciclónico (flujo de entrada al golfo cerca de Sinaloa y de salida del golfo cerca de
Baja California). El enfriamiento subsuperficial en la mitad de la sección del golfo (flujo ciclónico) fue
más fuerte durante el invierno y la primavera, época cuando el intercambio de calor entre el golfo y el
Océano PacÃfico es mayor. No se observó el calentamiento subsuperficial en la parte media de la sección
que corresponde a un flujo anticiclónico. La distribución temporal y espacial de las masas de agua de
mayor salinidad sugieren que los intercambios de calor se dan por la alternancia de flujos de entrada y
salida de masas de agua de mayor temperatura (superficial) y menor temperatura (subsuperficial). Durante el evento de El Niño 1997–1998 se observó un hundimiento de 50 dbar en la termoclina en
noviembre de 1997, asà como una disminución de 0.1 a 0.2 de la salinidad de las aguas arriba de la
termoclina.Seasonal variability at the entrance to the Gulf of California is described using high resolution CTD
data from a section across the entrance to the gulf that was occupied eight times between 1992 and 1998.
Variability decreased rapidly below 100 dbar, so that standard deviations exceeding 0.5ºC and 0.05 for
temperature and salinity, respectively, were confined to the upper 150 dbar. The mean salinity field
wasasymmetric, with fresher waters (S < 34.6) between 25 and 75 dbar next to Sinaloa and saltier waters
(S > 34.8) above 50 dbar and between 100 and 150 dbar near Baja California. A seasonal thermocline
developed in the upper 50 dbar, increasing from 21ºC in February surface temperatures to 31ºC in August.
Below 100 dbar, temperature at a given pressure was typically colder in the center of the section,
indicating cyclonic flow (flow into the gulf next to Sinaloa and out of the gulf next to Baja California).
The subsurface mid-gulf cooling (cyclonic flow) was strongest during winter and spring when the
exchange of heat between the gulf and the Pacific Ocean is large. Subsurface mid-gulf heating
(corresponding to anticyclonic flow) was not observed. Temporal and spatial distribution of saline water
masses suggests that heat exchanges take place by alternating the inflow and outflow of warm (surface)
and cold (subsurface) water masses. The 1997–1998 El Niño resulted in a 50 dbar deepening of the
thermocline in November 1997, as well as a freshening of 0.1 to 0.2 of waters above the thermocline.CONACYTUABCOceanographer of the Navy (US)Naval Postgraduate SchoolSecretarÃa de MarinaUNAM (Mexico)26653-T4271P-T9601400940151076-T920
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