934 research outputs found
Spatio-temporal patterns in the Diel Vertical Migration of the Copepod Metridia lucens in the Northeast Atlantic derived from the Continuous Plankton Recorder Survey
The archived data set collected over a 45-yr period (1948-1992) by Continuous Plankton Recorders (CPRs) towed in near-surface waters was used to investigate the diel vertical migration of the copepod Metridia lucens in the northeast Atlantic (47-63?N and 10-30?W). Although the CPR sampling intensity was uniform during the day and the night, M. lucens was caught predominantly in samples collected at night, consistent with a normal diel vertical migration pattern involving movement from greater depth during the day to shallower depths at night. The length of time spent near the surface varied seasonally and was closely correlated (r2 = 0.80) with seasonal change in length of night. The residual variation in length of time spent at the surface was nonrandom, with more time being spent at the surface in spring before the onset of the spring bloom, and less time being spent at the surface in autumn, than that predicted from the length of night at these periods. The timing of this enhanced near-surface occupation in spring varied with latitude, occurring a mean of 3.4 d later per degree of latitude
Quantitative proteomics reveals tissue-specific, infection-induced and species-specific neutrophil protein signatures
Neutrophils are one of the first responders to infection and are a key component of the innate immune system through their ability to phagocytose and kill invading pathogens, secrete antimicrobial molecules and produce extracellular traps. Neutrophils are produced in the bone marrow, circulate within the blood and upon immune challenge migrate to the site of infection. We wanted to understand whether this transition shapes the mouse neutrophil protein landscape, how the mouse neutrophil proteome is impacted by systemic infection and perform a comparative analysis of human and mouse neutrophils. Using quantitative mass spectrometry we reveal tissue-specific, infection-induced and species-specific neutrophil protein signatures. We show a high degree of proteomic conservation between mouse bone marrow, blood and peritoneal neutrophils, but also identify key differences in the molecules that these cells express for sensing and responding to their environment. Systemic infection triggers a change in the bone marrow neutrophil population with considerable impact on the core machinery for protein synthesis and DNA replication along with environmental sensors. We also reveal profound differences in mouse and human blood neutrophils, particularly their granule contents. Our proteomics data provides a valuable resource for understanding neutrophil function and phenotypes across species and model systems.</p
Quantitative proteomics reveals tissue-specific, infection-induced and species-specific neutrophil protein signatures
Neutrophils are one of the first responders to infection and are a key component of the innate immune system through their ability to phagocytose and kill invading pathogens, secrete antimicrobial molecules and produce extracellular traps. Neutrophils are produced in the bone marrow, circulate within the blood and upon immune challenge migrate to the site of infection. We wanted to understand whether this transition shapes the mouse neutrophil protein landscape, how the mouse neutrophil proteome is impacted by systemic infection and perform a comparative analysis of human and mouse neutrophils. Using quantitative mass spectrometry we reveal tissue-specific, infection-induced and species-specific neutrophil protein signatures. We show a high degree of proteomic conservation between mouse bone marrow, blood and peritoneal neutrophils, but also identify key differences in the molecules that these cells express for sensing and responding to their environment. Systemic infection triggers a change in the bone marrow neutrophil population with considerable impact on the core machinery for protein synthesis and DNA replication along with environmental sensors. We also reveal profound differences in mouse and human blood neutrophils, particularly their granule contents. Our proteomics data provides a valuable resource for understanding neutrophil function and phenotypes across species and model systems.</p
Novae With Long-Lasting Supersoft Emission That Drive a High Accretion Rate
We identify a new class of novae characterized by the post-eruption quiescent
light curve being more than roughly a factor of ten brighter than the
pre-eruption light curve. Eight novae (V723 Cas, V1500 Cyg, V1974 Cyg, GQ Mus,
CP Pup, T Pyx, V4633 Sgr, and RW UMi) are separated out as being significantly
distinct from other novae. This group shares a suite of uncommon properties,
characterized by the post-eruption magnitude being much brighter than before
eruption, short orbital periods, long-lasting supersoft emission following the
eruption, a highly magnetized white dwarf, and secular declines during the
post-eruption quiescence. We present a basic physical picture which shows why
all five uncommon properties are causally connected. Most novae do not have
adequate accretion for continuous hydrogen burning, but some can achieve this
if the companion star is nearby (with short orbital period) and a magnetic
field channels the matter onto a small area on the white dwarf so as to produce
a locally high accretion rate. The resultant supersoft flux irradiates the
companion star and drives a higher accretion rate (with a brighter
post-eruption phase), which serves to keep the hydrogen burning and the
supersoft flux going. The feedback loop cannot be perfectly self-sustaining, so
the supersoft flux will decline over time, forcing a decline in the accretion
rate and the system brightness. We name this new group after the prototype,
V1500 Cyg. V1500 Cyg stars are definitely not progenitors of Type Ia
supernovae. The V1500 Cyg stars have similar physical mechanisms and
appearances as predicted for nova by the hibernation model, but with this group
accounting for only 14% of novae.Comment: Astronomical Journal, in press, 39 pages, 10 figure
Addressing food insecurity in Papua New Guinea through food safety and sago cropping
Papua New Guinea (PNG) is known to have a large resource base of sago with over 1 million ha, as well as a high number of germplasm types of the Metroxylon species. The country’s food security status is very low and is primarily dependent on subsistence fresh garden produce as practiced by 85% of the population who are rural dwellers. Postharvest losses can be as high as 40% with little to no postharvest technology nor processing of foods done. Sago provides well for food security and sustains life in rural communities during disasters such as droughts, floods, and cyclones. The dilemma of sago being an underutilized crop in PNG is exacerbated by the introduction of new food crops, cash crops, and limited accessibility to cash to purchase other foods. Over the last 50 years, sago consumption has diminished as one of the major traditional food staples, from 16% to less than 10%. Neglect of sago is further due to food safety concerns about traditionally processed sago, in particular, the risk from sago hemolytic disease (SHD). For over30 years, SHD has been a food safety issue since it was first reported in 1973.Investigations on SHD highlight the serious need to improve on the hygiene and sanitation of the traditional postharvest processing and storage methods of sago starch in PNG. A set of hazard analysis and critical control point (HACCP) protocols has been developed for traditional processing of sago as a food safety measure to improve food safety for food security. While commercial cultivation is nonexistent, there is increased planting of the larger hapaxanthic, non-soboliferous sagospecies, Metroxylon salomonense Becc., in some nontraditional sago-consuming areas as a low-cost raw material source for roof thatching and other building materials. It is however a wasted opportunity for food security in these areas as the starch from the palm is not utilized. Current work in these areas promotes sago as a potential food source that can be harvested or processed into flour. This is to improve the food security status in areas of high population density, like island communities where land is scarce
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Influence of healthy candidate bias in assessing clinical effectiveness for implantable cardioverter-defibrillators: cohort study of older patients with heart failure
Objective: To assess the potential contribution of unmeasured general health status to patient selection in assessments of the clinical effectiveness of implantable cardioverter-defibrillator (ICD) therapy. Design: Retrospective cohort study. Setting: Linked data from an ICD registry, heart failure registry, and Medicare claims data for ICDs implanted in 2005 through 2009. Participants: 29 426 patients admitted to hospital with heart failure aged 66 years or older and eligible for ICD therapy for primary prevention. Main outcome measures Non-traumatic hip fracture, admission to a skilled nursing facility, and 30 day mortality—outcomes unlikely to be improved by ICD therapy. Results: Compared with 17 853 patients without ICD therapy, 11 573 patients with ICD therapy were younger and had lower ejection fraction and more cardiac admissions to hospital but fewer non-cardiac admissions to hospital and comorbid conditions. Patients with ICD therapy had greater freedom from unrelated events after adjusting for age and sex: hip fracture (hazard ratio 0.77, 95% confidence interval 0.64 to 0.92), skilled nursing facility admission (0.53, 0.50 to 0.55), and 30 day mortality (0.12, 0.10 to 0.15). Conclusions: Lower risks of measured outcomes likely reflect unmeasured differences in comorbidity and frailty. The findings highlight potential pitfalls of observational comparative effectiveness research and support physician consideration of general health status in selecting patients for ICD therapy
Automated Control Systems and Methods for Underground Crop Harvesters
Methods and devices for automated adjustment of a digging implement during harvest of underground crops are described. Utilizing the devices, a digging implement, e.g., a blade, can be located and maintained at a desired depth as a harvester travels across a field. During use, the digging implement depth controls can be varied as the harvester travels within a single field under different operating conditions, e.g., different soil friability, consistency, etc., thereby preventing crop loss and improving crop yield
The Behavior of Novae Light Curves Before Eruption
In 1975, E. R. Robinson conducted the hallmark study of the behavior of
classical nova light curves before eruption, and this work has now become part
of the standard knowledge of novae. He made three points; that 5 out of 11
novae showed pre-eruption rises in the years before eruption, that one nova
(V446 Her) showed drastic changes in the variability across eruptions, and that
all but one of the novae (excepting BT Mon) have the same quiescent magnitudes
before and after the outburst. This work has not been tested since it came out.
We have now tested these results by going back to the original archival
photographic plates and measuring large numbers of pre-eruption magnitudes for
many novae using comparison stars on a modern magnitude scale. We find in
particular that four out of five claimed pre-eruption rises are due to simple
mistakes in the old literature, that V446 Her has the same amplitude of
variations across its 1960 eruption, and that BT Mon has essentially unchanged
brightness across its 1939 eruption. Out of 22 nova eruptions, we find two
confirmed cases of significant pre-eruption rises (for V533 Her and V1500 Cyg),
while T CrB has a deep pre-eruption dip. These events are a challenge to
theorists. We find no significant cases of changes in variability across 27
nova eruptions beyond what is expected due to the usual fluctuations seen in
novae away from eruptions. For 30 classical novae plus 19 eruptions from 6
recurrent novae, we find that the average change in magnitude from before the
eruption to long after the eruption is 0.0 mag. However, we do find five novae
(V723 Cas, V1500 Cyg, V1974 Cyg, V4633 Sgr, and RW UMi) that have significantly
large changes, in that the post-eruption quiescent brightness level is over ten
times brighter than the pre-eruption level.Comment: 91 pages (preprint), AJ accepte
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