31 research outputs found
Promotoras as Mental Health Practitioners in Primary Care: A Multi-Method Study of an Intervention to Address Contextual Sources of Depression
We assessed the role of promotoras—briefly trained community health workers—in depression care at community health centers. The intervention focused on four contextual sources of depression in underserved, low-income communities: underemployment, inadequate housing, food insecurity, and violence. A multi-method design included quantitative and ethnographic techniques to study predictors of depression and the intervention’s impact. After a structured training program, primary care practitioners (PCPs) and promotoras collaboratively followed a clinical algorithm in which PCPs prescribed medications and/or arranged consultations by mental health professionals and promotoras addressed the contextual sources of depression. Based on an intake interview with 464 randomly recruited patients, 120 patients with depression were randomized to enhanced care plus the promotora contextual intervention, or to enhanced care alone. All four contextual problems emerged as strong predictors of depression (chi square, p < .05); logistic regression revealed housing and food insecurity as the most important predictors (odds ratios both 2.40, p < .05). Unexpected challenges arose in the intervention’s implementation, involving infrastructure at the health centers, boundaries of the promotoras’ roles, and “turf” issues with medical assistants. In the quantitative assessment, the intervention did not lead to statistically significant improvements in depression (odds ratio 4.33, confidence interval overlapping 1). Ethnographic research demonstrated a predominantly positive response to the intervention among stakeholders, including patients, promotoras, PCPs, non-professional staff workers, administrators, and community advisory board members. Due to continuing unmet mental health needs, we favor further assessment of innovative roles for community health workers
The Effects of Increased pCO\u3csub\u3e2\u3c/sub\u3e and Temperature on the North Atlantic Spring Bloom: I. The Phytoplankton Community and Biogeochemical Response
ABSTRACT: The North Atlantic spring bloom is one of the largest annual biological events in the ocean, and is characterized by dominance transitions from siliceous (diatoms) to calcareous (coccolithophores) algal groups. To study the effects of future global change on these phytoplankton and the biogeochemical cycles they mediate, a shipboard continuous culture experiment (Ecostat) was conducted in June 2005 during this transition period. Four treatments were examined: (1) 12°C and 390 ppm CO2 (ambient control), (2) 12°C and 690 ppm CO2 (high pCO2), (3) 16°C and 390 ppm CO2 (high temperature), and (4) 16°C and 690 ppm CO2 (‘greenhouse’). Nutrient availability in all treatments was designed to reproduce the low silicate conditions typical of this late stage of the bloom. Both elevated pCO2 and temperature resulted in changes in phytoplankton community structure. Increased temperature promoted whole community photosynthesis and particulate organic carbon (POC) production rates per unit chlorophyll a. Despite much higher coccolithophore abundance in the greenhouse treatment, particulate inorganic carbon production (calcification) was significantly decreased by the combination of increased pCO2 and temperature. Our experiments suggest that future trends during the bloom could include greatly reduced export of calcium carbonate relative to POC, thus providing a potential negative feedback to atmospheric CO2 concentration. Other trends with potential climate feedback effects include decreased community biogenic silica to POC ratios at higher temperature. These shipboard experiments suggest the need to examine whether future pCO2 and temperature increases on longer decadal timescales will similarly alter the biological and biogeochemical dynamics of the North Atlantic spring bloom
The Effects of Increased pCO\u3csub\u3e2\u3c/sub\u3e and Temperature on the North Atlantic Spring Bloom: I. The Phytoplankton Community and Biogeochemical Response
ABSTRACT: The North Atlantic spring bloom is one of the largest annual biological events in the ocean, and is characterized by dominance transitions from siliceous (diatoms) to calcareous (coccolithophores) algal groups. To study the effects of future global change on these phytoplankton and the biogeochemical cycles they mediate, a shipboard continuous culture experiment (Ecostat) was conducted in June 2005 during this transition period. Four treatments were examined: (1) 12°C and 390 ppm CO2 (ambient control), (2) 12°C and 690 ppm CO2 (high pCO2), (3) 16°C and 390 ppm CO2 (high temperature), and (4) 16°C and 690 ppm CO2 (‘greenhouse’). Nutrient availability in all treatments was designed to reproduce the low silicate conditions typical of this late stage of the bloom. Both elevated pCO2 and temperature resulted in changes in phytoplankton community structure. Increased temperature promoted whole community photosynthesis and particulate organic carbon (POC) production rates per unit chlorophyll a. Despite much higher coccolithophore abundance in the greenhouse treatment, particulate inorganic carbon production (calcification) was significantly decreased by the combination of increased pCO2 and temperature. Our experiments suggest that future trends during the bloom could include greatly reduced export of calcium carbonate relative to POC, thus providing a potential negative feedback to atmospheric CO2 concentration. Other trends with potential climate feedback effects include decreased community biogenic silica to POC ratios at higher temperature. These shipboard experiments suggest the need to examine whether future pCO2 and temperature increases on longer decadal timescales will similarly alter the biological and biogeochemical dynamics of the North Atlantic spring bloom
Impact of ocean acidification on phytoplankton assemblage, growth, and DMS production following Fe-dust additions in the NE Pacific high-nutrient, low-chlorophyll waters
Ocean acidification (OA) is likely to have an effect on the fertilizing
potential of desert dust in high-nutrient, low-chlorophyll oceanic regions,
either by modifying iron (Fe) speciation and bioavailability or by altering
phytoplankton Fe requirements and acquisition. To address this issue, short
incubations (4 days) of northeast subarctic Pacific waters enriched with
either FeSO<sub>4</sub> or dust and set at pH 8.0 (in situ) and 7.8 were conducted
in August 2010. We assessed the impact of a decrease in pH on dissolved Fe
concentration, phytoplankton biomass, taxonomy and productivity, and the
production of dimethylsulfide (DMS) and its algal precursor
dimethylsulfoniopropionate (DMSP). Chlorophyll <i>a</i> (chl <i>a</i>) remained
unchanged in the controls and doubled in both the FeSO<sub>4</sub>-enriched and
dust-enriched incubations, confirming the Fe-limited status of the plankton
assemblage during the experiment. In the acidified treatments, a significant
reduction (by 16–38 %) in the final concentration of chl <i>a</i> was
measured compared to their nonacidified counterparts, and a 15 %
reduction in particulate organic carbon (POC) concentration was measured in
the dust-enriched acidified treatment compared to the dust-enriched
nonacidified treatment. FeSO<sub>4</sub> and dust additions had a fertilizing
effect mainly on diatoms and cyanobacteria as estimated from algal pigment
signatures. Lowering the pH affected mostly the haptophytes, but pelagophyte
concentrations were also reduced in some acidified treatments. Acidification
did not significantly alter DMSP and DMS concentrations. These results show
that dust deposition events in a low-pH iron-limited northeast subarctic
Pacific are likely to stimulate phytoplankton growth to a lesser extent than
in today's ocean during the few days following fertilization and point to a
low initial sensitivity of the DMSP and DMS dynamics to OA
Effects of increased pCO2 and temperature on the North Atlantic spring bloom. I. The phytoplankton community and biogeochemical response
International audienceThe North Atlantic spring bloom is one of the largest annual biological events in the ocean, and is characterized by dominance transitions from siliceous (diatoms) to calcareous (coccolithophores) algal groups. To study the effects of future global change on these phytoplankton and the biogeochemical cycles they mediate, a shipboard continuous culture experiment (Ecostat) was conducted in June 2005 during this transition period. Four treatments were examined: (1) 12°C and 390 ppm CO2 (ambient control), (2) 12°C and 690 ppm CO2 (high pCO2), (3) 16°C and 390 ppm CO2 (high temperature), and (4) 16°C and 690 ppm CO2 ('greenhouse'). Nutrient availability in all treatments was designed to reproduce the low silicate conditions typical of this late stage of the bloom. Both elevated pCO2 and temperature resulted in changes in phytoplankton community structure. Increased temperature promoted whole community photosynthesis and particulate organic carbon (POC) production rates per unit chlorophyll a. Despite much higher coccolithophore abundance in the greenhouse treatment, particulate inorganic carbon production (calcification) was significantly decreased by the combination of increased pCO2 and temperature. Our experiments suggest that future trends during the bloom could include greatly reduced export of calcium carbonate relative to POC, thus providing a potential negative feedback to atmospheric CO2 concentration. Other trends with potential climate feedback effects include decreased community biogenic silica to POC ratios at higher temperature. These shipboard experiments suggest the need to examine whether future pCO2 and temperature increases on longer decadal timescales will similarly alter the biological and biogeochemical dynamics of the North Atlantic spring bloom