12,609 research outputs found
Recommended from our members
Developmental changes in the germinability, desiccation tolerance, hardseededness, and longevity of individual seeds of Trifolium ambiguum
Background and Aims: Using two parental clones of outcrossing Trifolium ambiguum as a potential model system, we examined how during seed development the maternal parent, number of seeds per pod, seed position within the pod, and pod position within the inflorescence influenced individual seed fresh weight, dry weight, water content, germinability, desiccation tolerance, hardseededness, and subsequent longevity of individual seeds.
Methods: Near simultaneous, manual reciprocal crosses were carried out between clonal lines for two experiments. Infructescences were harvested at intervals during seed development. Each individual seed was weighed and then used to determine dry weight or one of the physiological behaviour traits.
Key Results: Whilst population mass maturity was reached at 33â36 days after pollination (DAP), seed-to-seed variation in maximum seed dry weight, when it was achieved, and when maturation drying commenced, was considerable. Individual seeds acquired germinability between 14 and 44 DAP, desiccation tolerance between 30 and 40 DAP, and the capability to become hardseeded between 30 and 47 DAP. The time for viability to fall to 50 % (p50) at 60 % relative humidity and 45 °C increased between 36 and 56 DAP, when the seed coats of most individuals had become dark orange, but declined thereafter. Individual seed f. wt at harvest did not correlate with air-dry storage survival period. Analysing survival data for cohorts of seeds reduced the standard deviation of the normal distribution of seed deaths in time, but no sub-population showed complete uniformity of survival period.
Conclusions: Variation in individual seed behaviours within a developing population is inherent and inevitable. In this outbreeder, there is significant variation in seed longevity which appears dependent on embryo genotype with little effect of maternal genotype or architectural factors
Combining marine ecology and economy to roadmap the integrated coastal management: A systematic literature review
Integrated coastal management (ICM) relies on the inclusion of economic issues within marine ecology. To assess the progress of this integration, we applied topic modelling and network analysis to explore the pertinent literature (583 Isi-WoS, and 5459 Scopus papers). We classified the topics of interest (i.e., concepts, approaches, and sectors) that combined ecological and economic issues within marine science, we aggregated these topics in fields pertinent to ICM, and tracked the knowledge-exchange between these fields by using an information-flow network. Main findings were: (i) the high trans-disciplinary fashion of studies about marine protection and of those about commercial fisheries, (ii) the weak interaction between studies focusing on potential biohazards and those about environmental management, (iii) the isolation, in the overall information-flow, of studies about ecotourism and aquaculture. We included in a roadmap all the integration routes we detected within ICM, based on the combination of ecological and economic issues. We conclude that, to improve integration, ICM should: (i) Exploit marine protection as a bridge between ecological and economic concepts and approaches, and between maritime economy sectors, (ii) employ systems ecology to pursue trans-disciplinary investigations, (iii) complement systems ecology with citizen science by means of inclusive economic initiatives, such as ecotourism
Respiratory infections in children:an appropriateness study of when parents should home care or seek medical help
Testing Einstein's time dilation under acceleration using M\"ossbauer spectroscopy
The Einstein time dilation formula was tested in several experiments. Many
trials have been made to measure the transverse second order Doppler shift by
M\"{o}ssbauer spectroscopy using a rotating absorber, to test the validity of
this formula. Such experiments are also able to test if the time dilation
depends only on the velocity of the absorber, as assumed by Einstein's clock
hypothesis, or the present centripetal acceleration contributes to the time
dilation. We show here that the fact that the experiment requires -ray
emission and detection slits of finite size, the absorption line is broadened;
by geometric longitudinal first order Doppler shifts immensely. Moreover, the
absorption line is non-Lorenzian. We obtain an explicit expression for the
absorption line for any angular velocity of the absorber.
The analysis of the experimental results, in all previous experiments which
did not observe the full absorption line itself, were wrong and the conclusions
doubtful. The only proper experiment was done by K\"{u}ndig (Phys. Rev. 129
(1963) 2371), who observed the broadening, but associated it to random
vibrations of the absorber. We establish necessary conditions for the
successful measurement of a transverse second order Doppler shift by
M\"{o}ssbauer spectroscopy. We indicate how the results of such an experiment
can be used to verify the existence of a Doppler shift due to acceleration and
to test the validity of Einstein's clock hypothesis.Comment: 11 pages, 4 figure
Oregon Psychologists on Prescriptive Authority: Divided Views and Little Knowledge
With over half of all states having considered legislating prescriptive authority, an immense amount of time and money has been invested. The literature is limited in terms of understanding if opinions toward prescriptive authority are grounded in knowledge and what implications that has for altering these opinions. Following a veto of a prescriptive authority bill in Oregon, 399 licensed Oregon clinical psychologists were surveyed regarding their attitudes and knowledge. In terms of knowledge, only 6.5% knew which three states/territories currently have prescriptive authority and 70.4% were unfamiliar with any of the prerequisites for postdoctoral training in psychopharmacology. Reflecting division, 43.4% were in favor, 25.4% were undecided, and 31.2% were in opposition to broadening privileges for psychologists. Further, only 15.2% expressed interest in pursuing training or 6.7% in becoming prescribers. Data on access, training, and legislative costs were presented to participants in the education condition. These participants showed significant gains in their knowledge across all domains and their opinions shifted only in these specific areas leaving their general stance on the issue unchanged. In contrast to ardent supporters who argue that their âdata should provide reassurance to psychologists spearheading legislative initiativesâ because of high approval ratings (Sammons et al., 2000, p. 608), our data suggest disagreement amongst a group of professionals who are not particularly well-informed, nor interested in becoming prescribers. Future work should investigate whether expanding the data relevant to other facets of the argument contributes to further targeted change or an overall change in opinion toward prescriptive authority
Intersecting Ecosystem Services Across the Aquatic Continuum: From Global Change Impacts to Local, and Biologically Driven, Synergies and Trade-Offs
The study of ecosystem services requires the integration of different observational points. This is particularly true in Water, as this element continuously cycles, increasing chances of interaction among services originating in different ecosystems. However, aquatic scientists historically approached the study of inland/freshwater and open/marine waters in different ways and this cultural division potentially hampers integrative approaches. Herein, we explored the literature pertaining to ecosystem services across the last 23 years, analysing 4,590 aquatic papers. By aggregating and intersecting topics included in this papersâ collection using text-mining and topical network approaches, we saw that the study of local environmental conditions (e.g., river estuary management) and synergies and trade-offs between services (e.g., carbon sequestration and water purification) can display several potential conceptual links between freshwater and marine sciences. Our analyses suggest that to intersect ecosystem services across the aquatic continuum, the conceptual integration between marine and freshwater science must be reinforced, especially at the interface between different âsalinity realms.â Such integration should adopt a âsystem thinkingâ perspective, in which the focus is on multiple socio-ecological processes giving rise to interactions that are (i) biologically mediated, (ii) potentially conflicting, and (iii) entangled within networks
Mobile Communications Technologies in Tree Time: The Listening Wood
This article presents a practice-led investigation by a cross-disciplinary team of artists and computer scientists into the potential for mobile and digital communications technologies to engage visitors to Londonâs Hampstead Heath with the histories of its veteran urban trees. Focusing on the application of Internet of Things (IoT) technologies within the arboreal environment for the digital poetic walk, The Listening Wood, it considers the reciprocal impact of âtree timeâ on the development of âslow techâ
- âŠ