No abstract

Ocean surveys show that extremely sharp thermal boundaries have limited the distribution of sockeye salmon (Oncorhynchus nerka) in the Pacific Ocean and adjacent seas over the past 40 years. These limits are expressed as a step function, with the temperature defining the position of the thermal limit varying between months in an annual cycle. The sharpness of the edge, the different temperatures that define the position of the edge in different months of the year, and the subtle variations in temperature with area or decade for a given month probably all occur because temperature-dependent metabolic rates exceed energy intake from feeding over large regions of otherwise acceptable habitat in the North Pacific. At current rates of greenhouse gas emissions, predicted temperature increases under a doubled CO2 climate are large enough to shift the position of the thermal limits into the Bering Sea by the middle of the next century. Such an increase would potentially exclude sockeye salmon from the entire Pacific Ocean and severely restrict the overall area of the marine environment that would support growth.

The detection of wheat heads in plant images is an important task for estimating pertinent wheat traits including head population density and head characteristics such as health, size, maturity stage, and the presence of awns. Several studies have developed methods for wheat head detection from high-resolution RGB imagery based on machine learning algorithms. However, these methods have generally been calibrated and validated on limited datasets. High variability in observational conditions, genotypic differences, development stages, and head orientation makes wheat head detection a challenge for computer vision. Further, possible blurring due to motion or wind and overlap between heads for dense populations make this task even more complex. Through a joint international collaborative effort, we have built a large, diverse, and well-labelled dataset of wheat images, called the Global Wheat Head Detection (GWHD) dataset. It contains 4700 high-resolution RGB images and 190000 labelled wheat heads collected from several countries around the world at different growth stages with a wide range of genotypes. Guidelines for image acquisition, associating minimum metadata to respect FAIR principles, and consistent head labelling methods are proposed when developing new head detection datasets. The GWHD dataset is publicly available at http://www.global-wheat.com/and aimed at developing and benchmarking methods for wheat head detection.

Droplet microfluidics has become a powerful tool in precision medicine, green biotechnology, and cell therapy for single-cell analysis and selection by virtue of its ability to effectively confine cells. However, there remains a fundamental trade-off between droplet volume and sorting throughput, limiting the advantages of droplet microfluidics to small droplets (<10 pl) that are incompatible with long-term maintenance and growth of most cells. We present a sequentially addressable dielectrophoretic array (SADA) sorter to overcome this problem. The SADA sorter uses an on-chip array of electrodes activated and deactivated in a sequence synchronized to the speed and position of a passing target droplet to deliver an accumulated dielectrophoretic force and gently pull it in the direction of sorting in a high-speed flow. We use it to demonstrate large-droplet sorting with ~20-fold higher throughputs than conventional techniques and apply it to long-term single-cell analysis of Saccharomyces cerevisiae based on their growth rate.

The distribution of pelagic elasmobranchs was analyzed using bycatch data from the high seas salmon surveys by research gillnets from 1981 to 1991 in the North Pacific Ocean and the Bering Sea. Five species of sharks and one stingray were reported. Blue and salmon sharks and spiny dogfish were dominant and constituted 98% of the total shark catch. It is considered that the research area includes the southern part of the distribution for spiny dogfish and salmon sharks and the northern part of that for blue, shortfin mako, cookiecutter sharks and pelagic stingrays. These elasmobranchs showed spa tial segregation by species in distribution according to oceanographic conditions. Intraspecific sexual and growth dependent segregations were also confirmed. Length frequency distributions of blue and salmon sharks suggest that their nursery grounds exist around the transitional domain of the subarctic boundary.

SummaryThe lack of knowledge about the mechanism of erythrocyte biogenesis through self-replication makes the in vitro generation of large quantities of cells difficult. We show that transduction of c-MYC and BCL-XL into multipotent hematopoietic progenitor cells derived from pluripotent stem cells and gene overexpression enable sustained exponential self-replication of glycophorin A+ erythroblasts, which we term immortalized erythrocyte progenitor cells (imERYPCs). In an inducible expression system, turning off the overexpression of c-MYC and BCL-XL enabled imERYPCs to mature with chromatin condensation and reduced cell size, hemoglobin synthesis, downregulation of GCN5, upregulation of GATA1, and endogenous BCL-XL and RAF1, all of which appeared to recapitulate normal erythropoiesis. imERYPCs mostly displayed fetal-type hemoglobin and normal oxygen dissociation in vitro and circulation in immunodeficient mice following transfusion. Using critical factors to induce imERYPCs provides a model of erythrocyte biogenesis that could potentially contribute to a stable supply of erythrocytes for donor-independent transfusion.

ABSTRACT-Year-to-year variations in biomass of phytoplankton (surface chlorophyll a concentration) and macrozooplankton (wet weight obtained by NORPAC net operation above 150 m), and abundance of pink salmon (catch per unit effort of pink salmon) from 1985 to 1994 in the subarctic North Pacific in summer were studied. After 1989, phytoplankton biomass and pink salmon abundance showed corresponding yearly patterns, whereas the pattern shown by macrozooplankton biomass was always the inverse of that shown by phytoplankton and salmon. We suggest that macrozooplankton b~omass remained low when pink salmon was abundant due to the intense f e e d~n g impact of pink salmon, which in turn allowed phytoplankton biomass to remain high as a result of the lesser grazing effect of macrozooplankton. The opposite phenomenon probably occurred when pink salmon was not abundant. Prior to 1989, macrozooplankton biomass was at a rather high level while phytoplankton biomass and pink salmon abundance were low. We suggest that macrozooplankton biomass remained high due to a lesser feeding impact of the plnk salmon, and phytoplankton biomass remained low due to the intense grazing effect of macrozooplankton. Our study therefore shows the possib~lity that the feeding effect from the pink salmon controls summer macrozoo-and phytoplankton biomass In the subarctic North Pacific

No abstract