Characteristics of physiological responses to +Gx loads in non-professional crew members of short-term missions to the ISS

Analysis of physiological responses to +Gx loads during space flights (SFs) 8–12 days in duration was carried out in ten non-professional crew members of the International Space Station (ISS), many of whom were accepted to participate in SFs while having partial health deficiency. The results were compared to the data on ten apparently healthy crew members of the Mir Orbital Station (OS) who participated in SFs of a similar duration. The age (29–60 years) of the subjects from the ISS crew was older than the age (31–49 years) of the subjects from the Mir OS crew. Objective data showed that subjects from the ISS crew had significantly higher levels of sinus tachycardia and tachypnea during settling into orbit and re-entry than subjects from the Mir OS crew. In some cases, extrasystolic arrhythmias were recorded in subjects from the ISS crew during the pre-launch period. The arrhythmias persisted during the ascent to orbit, and usually became more considerable during the descent to Earth. During the descent to Earth, the subjects from the ISS crew demonstrated, in general, a higher rate of heart rhythm disorders, which were characterized by more pronounced polymorphism and a greater severity. Particularly significant changes in electrocardiograms (ECGs) were observed in two subjects from the ISS crew aged 60 years. These disorders were sporadic in all the cosmonauts. The results of the study show that individual characteristics of cardiac rhythm regulation observed before the start may lead to marked changes in ECG during +Gx loads during the descent from the orbit to Earth. This should be taken into account in preparing individual medical programs for non-professional members of ISS crews in order to minimize health risks. The study has also demonstrated the necessity for stricter criteria of selection for ISS missions for older candidates with partial health deficiency.     

Vanishing native American dog lineages

Background  

Dogs were an important element in many native American cultures at the time Europeans arrived. Although previous ancient DNA studies revealed the existence of unique native American mitochondrial sequences, these have not been found in modern dogs, mainly purebred, studied so far.     

Patterns of Forest Decline and Regeneration Across Scots Pine Populations

To predict future changes in forest ecosystems, it is crucial to understand the complex processes involved in decline of tree species populations and to evaluate the implications for potential vegetation shifts. Here, we study patterns of decline (canopy defoliation and mortality of adults) of four Scots pine populations at the southern edge of its distribution and characterized by different combinations of climate dryness and intensity of past management. General linear and structural equation modeling were used to assess how biotic, abiotic, and management components interacted to explain the spatial variability of Scots pine decline across and within populations. Regeneration patterns of Scots pine and co-occurring oak species were analyzed to assess potential vegetation shifts. Decline trends were related to climatic dryness at the regional scale, but, ultimately, within-population forest structure, local site conditions, and past human legacies could be the main underlying drivers of Scots pine decline. Overall, Scots pine regeneration was negatively related to decline both within and between populations, whereas oak species responded to decline idiosyncratically across populations. Taken together, our results suggest that (1) patterns of decline are the result of processes acting at the plot level that modulate forest responses to local environmental stress and (2) decline of adult Scots pine trees seems not to be compensated by self-recruitment so that the future dynamics of these forest ecosystems are uncertain.     

Performance and Mortality of Rumex obtusifolius and R. crispus in Managed Grasslands are Affected by Nutrient Availability

The reasons for the greater incidence of Rumex obtusifolius in grasslands compared with R. crispus have never been investigated. In a small-plot field experiment in which seedlings of R. obtusifolius and R. crispus were transplanted into a sward dominated by Dactylis glomerata, the growth and survival of seedlings were monitored over three years under control and P, N, NP and NPK fertilizer treatments. The highest plants of R. obtusifolius and R. crispus were generally recorded in the N, NP and NPK treatments and the lowest in the control and P treatment. The maximum recorded heights of R. obtusifolius were 100?cm and of R. crispus 80?cm. The number of leaves per plant, weight of individual plants, cover and fertility were generally higher for R. obtusifolius than for R. crispus. 30% to 80% of transplanted R. obtusifolius plants flowered in the first (seeding) year and this contrasted with no flowering of transplanted R. crispus plants. After cutting, substantially better regrowth of R. obtusifolius was recorded compared to that of R. crispus and surviving R. crispus plants tended to show a gradual reduction in leaf number. The mortality of R. obtusifolius over three years ranged from 0% in the NPK treatment to 13% in the control, with an average of 8% over all treatments. The mortality of R. crispus ranged from 19% in the control to 94% in the NPK treatment with an average of 64% over all treatments. We concluded that R. obtusifolius is better adapted to growing in highly productive temperate grasslands than R. crispus because of its perennial character, larger plant size and higher fertility.