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The Southern Ocean (SO) is highly sensitive to climate change. Therefore, an accurate estimate of phytoplankton biomass is key to being able to predict the climate trajectory of the 21st century. In this study, MODerate resolution Imaging Spectroradiometer (MODIS), on board EOS Aqua spacecraft, Level 2 (nominal 1 km × 1 km resolution) chlorophyll-a (C S a t ) and Particulate Organic Carbon (POC s a t ) products are evaluated by comparison with an in situ dataset from 11 research cruises (2008–2017) to the SO, across multiple seasons, which includes measurements of POC and chlorophyll-a (C i n s i t u ) from both High Performance Liquid Chromatography (C H P L C ) and fluorometry (C F l u o ). Contrary to a number of previous studies, results highlighted good performance of the algorithm in the SO when comparing estimations with HPLC measurements. Using a time window of ±12 h and a mean satellite chlorophyll from a 5 × 5 pixel box centered on the in situ location, the median C S a t :C i n s i t u ratios were 0.89 (N = 46) and 0.49 (N = 73) for C H P L C and C F l u o respectively. Differences between C H P L C and C F l u o were associated with the presence of diatoms containing chlorophyll-c pigments, which induced an overestimation of chlorophyll-a when measured fluorometrically due to a potential overlap of the chlorophyll-a and chlorophyll-c emission spectra. An underestimation of ∼0.13 mg m − 3 was observed for the global POC algorithm. This error was likely due to an overestimate of in situ POC i n s i t u measurements from the impact of dissolved organic carbon not accounted for in the blank correction. These results highlight the important implications of different in situ methodologies when validating ocean colour products.

Data from the Advanced Very High Resolution Radiometer (AVHRR) have been used to create several long-duration data records of geophysical variables describing the atmosphere and land and water surfaces. In the Climate Monitoring Satellite Application Facility (CM SAF) project, AVHRR data are used to derive the Cloud, Albedo, and Radiation (CLARA) climate data records of radiation components (i.a., surface albedo) and cloud properties (i.a., cloud cover). This work describes the methodology implemented for the additional estimation of the Outgoing Longwave Radiation (OLR), an important Earth radiation budget component, that is consistent with the other CLARA variables. A first step is the estimation of the instantaneous OLR from the AVHRR observations. This is done by regressions on a large database of collocated observations between AVHRR Channel 4 (10.8 µm) and 5 (12 µm) and the OLR from the Clouds and Earth’s Radiant Energy System (CERES) instruments. We investigate the applicability of this method to the first generation of AVHRR instrument (AVHRR/1) for which no Channel 5 observation is available. A second step concerns the estimation of daily and monthly OLR from the instantaneous AVHRR overpasses. This step is especially important given the changes in the local time of the observations due to the orbital drift of the NOAA satellites. We investigate the use of OLR in the ERA5 reanalysis to estimate the diurnal variation. The developed approach proves to be valuable to model the diurnal change in OLR due to day/night time warming/cooling over clear land. Finally, the resulting monthly mean AVHRR OLR product is intercompared with the CERES monthly mean product. For a typical configuration with one morning and one afternoon AVHRR observation, the Root Mean Square (RMS) difference with CERES monthly mean OLR is about 2 Wm−2 at 1° × 1° resolution. We quantify the degradation of the OLR product when only one AVHRR instrument is available (as is the case for some periods in the 1980s) and also the improvement when more instruments are available (e.g., using METOP-A, NOAA-15, NOAA-18, and NOAA-19 in 2012). The degradation of the OLR product from AVHRR/1 instruments is also quantified, which is done by “masking” the Channel 5 observations.

After the exponential growth phase, variability in the scattering efficiency of phytoplankton cells over their complete life cycle is not well characterised. Bulk measurements are impacted by senescent cells and detritrus. Thus the analysis of the evolution of the optical properties thanks to their morphological and/or intra-cellular variations remains poorly studied. Using the Cytosense flow cytometer (CytoBuoy b.v., NL), the temporal course of the forward and sideward efficiencies of two phytoplankton species (Thalassiosira pseudonana and Chlamydomonas concordia) were analyzed during a complete life-cycle. These two species differ considerably from a morphological point of view. Over the whole experiment, the forward and sideward efficiencies of Thalassiosira pseudonana were, on average, respectively 2.2 and 1.6 times higher than the efficiencies of Chlamydomonas concordia. Large intra-species variability of the efficiencies were observed over the life cycle of the considered species. It highlights the importance of considering the optical properties of phytoplankton cells as a function of the population growth stage of the considered species. Furthermore, flow cytometry measurements were combined with radiative transfer simulations and biogeochemical and optical measurements. Results showed that the real refractive index of the chloroplast is a key parameter driving the sideward signal and that a simplistic two-layered model (cytoplasm-chloroplast) seems particularly appropriate to represent the phytoplankton cells.

The bulk backscattering ratio ( b b p ˜ ) is commonly used as a descriptor of the bulk real refractive index of the particulate assemblage in natural waters. Based on numerical simulations, we analyze the impact of modeled structural heterogeneity of phytoplankton cells on b b p ˜ . b b p ˜ is modeled considering viruses, heterotrophic bacteria, phytoplankton, organic detritus, and minerals. Three case studies are defined according to the relative abundance of the components. Two case studies represent typical situations in open ocean, oligotrophic waters, and phytoplankton bloom. The third case study is typical of coastal waters with the presence of minerals. Phytoplankton cells are modeled by a two-layered spherical geometry representing a chloroplast surrounding the cytoplasm. The b b p ˜ values are higher when structural heterogeneity is considered because the contribution of coated spheres to light backscattering is higher than homogeneous spheres. The impact of heterogeneity is; however, strongly conditioned by the hyperbolic slope ξ of the particle size distribution. Even if the relative abundance of phytoplankton is small (<1%), b b p ˜ increases by about 58% (for ξ = 4 and for oligotrophic waters), when the heterogeneity is taken into account, in comparison with a particulate population composed only of homogeneous spheres. As expected, heterogeneity has a much smaller impact (about 12% for ξ = 4 ) on b b p ˜ in the presence of suspended minerals, whose increased light scattering overwhelms that of phytoplankton.

Objective A growing body of literature documents high rates of burnout, depression, and suicidal ideation among physicians and medical students. Barriers to seeking mental health treatment in this group include concerns about time, stigma, confidentiality, and potential career impact. The authors describe a 4-year trial of the Healer Education Assessment and Referral (HEAR) program, designed to increase mental health services utilization (MHSU) and decrease suicide risk (SR) as assessed by an Interactive Screening Program (ISP)at one US medical school. Methods Over a 4-year period, medical students were engaged in face-to-face, campus-wide, educational group programs and were invited to complete an individual, online, and anonymous survey. This survey contained the 9-item Patient Health Questionnaire (PHQ-9) scale to assess depression and items to identify suicidal thoughts and behaviors, substance use, distressing emotional states, and the use of mental health treatment. Students who engaged in this ISP by corresponding electronically with a counselor after completing the survey were assessed and when indicated, referred to further treatment. Results The HEAR program was delivered to 1,008 medical students. Thirty-four percent (343/1,008) completed the online screening portion. Almost 8 % of respondents met the criteria for high/significant SR upon analysis of the completed screens. Ten out of 13 of the students with SR who dialogued with a counselor were not already receiving mental health treatment, indicating that this anonymous ISP identified a high proportion of an untreated, at risk, and potentially suicidal population. MHSU among medical students who completed the survey was 11.5 % in year 1 and 15.0 % by year 4. SR among medical students was 8.8 % in year 1 and 6.2 % in year 4 as assessed by the ISP. Conclusions This novel interventional program identified at risk, potentially suicidal medical students at one institution. Based on this single-site experience, we suggest that future multisite studies incorporate a comparison group, acquire baseline (prematriculation) data regarding MHSU and SR, and use an individualized yet anonymous identification system to measure changes in individual participants’ mental health status over time.

Burnout, depression and suicide are rampant amongst health care professionals. Current evidence shows the problem is worsening. In the aftermath of physician suicides, the Physician Wellbeing Committee created the UC San Diego Healer Education Assessment and Referral (HEAR) Program in 2009 in collaboration with the American Foundation for Suicide Prevention (AFSP). This article chronicles the HEAR program from inception through June 2017. Initially created to address medical students, residents and faculty physician duress, HEAR has now expanded to embrace pharmacists, nurses and clinical staff within UC San Diego Health. HEAR operates through two mechanisms: 1) a program of ongoing education and outreach, and 2) encouragement of all personnel to annually engage in the online, anonymous, interactive screening program, created by the AFSP (known as SDSQ at UC San Diego Health). Since inception in May 2009 through June 2017, 1,537 UC San Diego health care personnel have been screened, 320 individuals have dialogued with a counselor either in person, by phone or electronically, and more than 300 have been referred confidentially for evaluation and treatment by a mental health professional, usually a community psychiatrist. While tracking death by suicide remains challenging, we have reason to believe that the prevalence of suicide has diminished during this time. The UC San Diego HEAR Program is one cost-effective model for addressing this current crisis in U.S. health care. This AFSP model has been adopted by many other schools of medicine and is now ready for use with clinicians of all disciplines.

In November 2011, the Coalition for Physician Enhancement (CPE) and the University of California, San Diego, Physician Assessment and Clinical Education (PACE) Program held a conference on the issue of physician aging and its potential impact on clinical performance and quality of care. Speakers and attendees from the United States and Canada reviewed a variety of topics and trends related to aging. Data reviewed during the conference reveal that average physician age is increasing, and while a variety of positive aspects of aging can provide a professional benefit, some studies associate a decrease in physician performance with increasing age. Among the factors that can affect physician performance include solo practice, lack of American Board of Medical Specialties (ABMS) Board Certification, practicing outside the scope of training, high clinical volume and health issues. Conference attendees examined Canadian experiences with age-based competency screening and participated in a survey of opinion regarding age-based screening. The majority favored age-based screening beginning at the age of 70, using a system that would include assessments of physical and mental health and a cognitive screen. Competency screening could include peer review and practice evaluation methods. The authors propose further study of age-based screening and encourage physicians to think carefully about the timing of appropriate modifications to and retirement from practice.