SUMMARY
Complex haploid‐diploid life cycles amongst marine organisms may be maintained by ecological differences in life‐history phases. For red algal species within the Gigartinaceae, such ...differences may be driven, in part, by different cell wall composition and resultant biomechanical strengths of haploid and diploid phases. A field experiment tested the attachment strengths of gametophytes and tetrasporophytes of the isomorphic red alga, Chondrus verrucosus (with comparisons of fertile and vegetative fronds, with and without natural tissue damage across three wave‐exposed sites). Seventy‐nine percent of all fronds broke at the stipe‐holdfast junction. There were significant differences in attachment strength (break force and break stress), but not gross morphology (frond length, number of branch axes, wet weight and cross‐sectional area of fronds that dislodged at the stipe‐holdfast junction) of life‐history phases, with tetrasporophytes exhibiting weaker tissue strength and attachment, and therefore greater susceptibility to dislodgement by waves. However, fertility and tissue damage did not consistently influence dislodgement in pull‐to‐break tests simulating the effects of single waves. The ecological and evolutionary consequences of greater susceptibility to dislodgement of tetrasporophytes (relative to gametophytes) warrant further investigation.
Scanning gate microscopy (SGM) is a valuable scanning probe technique for characterizing electronic transport in mesoscopic systems. However, the interpretation of the method is often limited by many ...experimental challenges. In this work, we propose an empirically-constrained optimization approach based on swarm search and Green’s functions to extract more information from SGM measurements. The approach is applied to a quantum point contact fabricated on an InAlAs/InGaAs/InAlAs quantum well, and the results indicate that the corresponding SGM could be generated, in a weak approximation, by a fluctuating background potential with features with radii in the order of 20 to 30 nm and a correlation length of 5.7 nm. Our method represents a data-driven tool for estimating solutions for inverse problems in mesoscopic physics, and can be used to generate estimates for the potential landscape experienced by free electrons in mesoscopic systems.
Over the past five decades, transitions from kelp beds (or forests) to barrens have occurred as a result of sea urchin overgrazing along the temperate coastlines. The deterioration of mature kelp ...beds has been mainly observed for
Laminaria
,
Saccharina
, and
Macrocystis
in the order Laminariales. In northern Miyagi Prefecture, Japan, the destruction of adult
Ecklonia bicyclis
kelp beds by the overgrazing of
Mesocentrotus nudus
was observed since 2013. In this study, we analyzed the process of deterioration of an
E
.
bicyclis
bed, from the changes in morphology of the thallus, with or without urchin grazing marks and urchin attachment, from video and photographic records. The processes of deterioration followed one of two strategies. In the first strategy, sea urchins climb from the stipes to the branches under calm conditions in winter. Subsequently, the fronds and branches are grazed by these urchins, as shown by large numbers of bare stipes and holdfasts. After the disappearance of the fronds and the branches, sea urchins mainly graze above the stipe bases, as illustrated by the high percentage of stipes with grazing marks. Finally, rigid holdfasts are left on the seafloor. The kelp bed is most likely to be destroyed by this grazing strategy. In the second strategy, urchins aggregate on the holdfasts of the entire plants and graze the stipe bases, particularly in February. The stipes are severely grazed by sea urchins, and the thalli above the stipe bases fall to the seafloor. Urchins aggregated firstly graze the fronds of the detached thalli followed by the branches and the stipes. The results of this study suggest that protection of the stipes from the grazing and climbing of
M
.
nudus
would be desirable for the conservation and restoration of
E
.
bicyclis
kelp beds.
We examined the early life stage process of the kelp
Ecklonia cava
from zoospore settlement to juvenile sporophyte in the field. The microspatial genetic structure of an
E. cava
population in a 4 m × ...4 m area was analyzed using microsatellite markers to evaluate the spatial distribution of individuals. Within this area, 169 adults and 87 juveniles were analyzed, and the distributional pattern was aggregated for juveniles, uniform for adults, and random for all individuals. The kinship coefficient decreased with increasing distance and reached zero at approximately 2 m. Using a parentage analysis, the parents of 8 and 46 juveniles in the study area were identified at the 95% and 80% confidence levels, respectively. Among the juveniles, selfing was confirmed in 3 and 7 individuals at the 95% and 80% confidence levels, respectively. Although the selfing juveniles that survived appeared to grow normally, the frequent occurrence of selfing may drive the distributional change between juveniles and adults. Most of the parents had two or fewer juvenile offspring within 2.5 m in the study area. Although the stipe length of the parents did not affect the dispersal distance of the zoospores, each parent appeared to release zoospores in a specific direction. In
E. cava
, the local population may be maintained by the short dispersal distance of most spores and the occurrence of selfing, and the rare zoospore settlement in distant areas may allow low levels of gene flow among local populations.
The roles of the rice sucrose transporter, OsSUT1, have previously been examined in filling grain, germination, and early seedling growth. In the current work, the role that OsSUT1 plays in the ...transport of assimilate along the entire long-distance pathway, from the flag leaf blade to the base of the filling grain, was investigated. OsSUT1 promoter::GUS (β-glucuronidase) reporter gene analysis and immunolocalization revealed that both OsSUT1 promoter::GUS activity and OsSUT protein were present in the mature phloem of all the vegetative tissues involved in the long-distance assimilate transport pathway during grain filling. In addition, expression was observed in the flag leaf blade and sheath prior to heading. The OsSUT1 promoter::GUS activity appeared to be largely confined to the companion cells within the phloem, whereas the protein localized to both the sieve tubes and the companion cells. RT-PCR analysis confirmed that the OsSUT1 transcript is expressed in the uppermost internode of the rice plant (internode-1). These OsSUT localization data were related to measurements of starch and soluble sugar content of these tissues, and localization of the carbohydrate reserves stored in the stem. Results from dye feeding experiments, to examine cellular connections, revealed a symplastic continuity between the phloem and surrounding parenchyma in the flag leaf blade, sheath, and internode-1 tissues. It is proposed that OsSUT1 may primarily play a role in phloem loading of sucrose retrieved from the apoplasm along the transport pathway.
Abstract
Offshore windfarms are a key renewable solution to help supply global energy needs. However, implementation has its challenges, including intense pile driving sound produced during ...constructions, which can affect marine life at the individual level, yet impacts at the group level remain poorly studied. Here, we exposed groups of longfin squid (Doryteuthis pealeii) in cages at multiple distances from consecutive pile driving events and sought to quantify responses at both individual and group levels. Pile driving induced short-term alarm responses at sound levels (in zero-peak) of 112–123 dB re 1 µm s−2 that were similar to those measured at kilometre scale from offshore windfarm constructions. The rate of individual alarm responses quickly decreased both within and across consecutive pile driving events, a result consistent with previous laboratory studies. Despite observing dramatic behavioural changes in response to initial pile driving sound, there were no significant differences in squid shoaling areas before and during exposure, showing no disruption of squid collective behaviours. Our results demonstrate rapid habituation of squid to pile driving sound, showing minimal effects on this ecologically and commercially key taxon. However, future work is now needed to assess responses of wild squid shoals in the vicinity of offshore windfarm constructions.
Introduction
The care relationships of physicians and nurses with patients with Covid-19 had pointed to a scenario explorable from a psychological point of view due to the peculiarities of this ...pandemic. How do clinicians feel, when caring for their co-workers, in a context that was not so common to see colleagues occupy the patient’s place? What emotional experiences arise from this reality? The results of the present study sought to point out how to handle this caring relationship, in an exceptional context.
Objectives
To interpret emotional meanings reported by physicians and nurses on their experiences of working at COVID-19 intensive care units during the height of the pandemic.
Methods
Clinical-qualitative design of Turato. Data collection with semi-directed interviews with open-ended questions in-depth applied to a sample of six professionals, closed by theoretical information saturation according to Fontanella, in a Brazilian university general hospital. Trigger question: “Talk about the psychological meanings of your experience in face of management of patients with COVID-19 at ICU”. Data treatment by the Seven Steps of the Clinical-Qualitative Content Analysis of Faria-Schützer. Theoretical framework from Medical Psychology using Balintian concepts.
Results
We raised initially 4 categories. Three categories were presented preliminarily in this congress, version last year. In this opportunity, we show this special category of analysis that emerged during the deepened discussion of the final results: “The feeling of insecurity: from technique to affective dimension”.
Conclusions
The care relationships between the health professional and the patient hospitalized in the Covid-19 ICU pointed to peculiar transference and countertransference psychodynamic mechanisms between both. Before the pandemic, the care relationship seemed pragmatic and protocolar. During the pandemic, this relationship seemed “more subjective”, building a strongly emotional dimension, as health professionals also began to care for their colleagues in the profession. The egoic defense mechanisms, such as projective and introjective identification were reported as intense.
Disclosure of Interest
None Declared
Objectives Multidrug-resistant Pseudomonas aeruginosa (MDRP) is becoming a serious problem in hospitals, especially in patients on ventilators. Recent data demonstrate that colistin may be effective ...for these patients, although limited in vitro and in vivo data are available. Our aim was to identify further characteristics of colistin for the therapy of pneumonia caused by MDRP. Methods The effects of colistin on clinical strains of MDRP were examined by susceptibility test, time–kill assay, lipopolysaccharide (LPS)-blocking assay and a mouse pneumonia model, alone or in combination with other antibiotics. For the pneumonia model, mice were intranasally infected with bacteria and kept in hyperoxic conditions to mimic ventilator-associated pneumonia. Results As a single agent, colistin exhibited the strongest activity of the antimicrobial agents tested. In combination, maximum synergy was observed with colistin plus rifampicin. As expected, co-incubation of bacterial culture supernatants with colistin significantly reduced LPS activities with an associated decrease in cellular cytotoxicity. In the pneumonia model, intranasal, but not intravenous, colistin combined with rifampicin produced maximum survival protection. Pharmacokinetic analysis of colistin demonstrated the superiority of intranasal administration, judging from the compartmentalized high concentration and the long half-life in the lungs. Moreover, colistin therapy significantly decreased both production of inflammatory cytokines and LPS activity, even at a dose effecting no change in the bacterial burden in the lung. Conclusions These data strongly suggest that colistin may be an important option for combination therapy against critical MDRP infections. For pneumonia especially, intranasal colistin with rifampicin may be beneficial not only for synergistic antibacterial activity, but also for blocking LPS.
Highlights • We investigated the neural circuits downstream from the IMM for imprinting. • The IMHA region is critical not only for imprinting acquisition, but also for recall. • The IMHA region ...works for imprinting downstream from T3 action in the IMM. • We revealed the neural connections from the IMM to the IMHA.
Recognition of the wide diversity of organisms that maintain complex haploid–diploid life cycles has generated interest in understanding the evolution and persistence of such life cycles. We ...empirically tested the model where complex haploid–diploid life cycles may be maintained by subtle/cryptic differences in the vital rates of isomorphic haploid–diploids, by examining the ecophysiology of haploid tetraspores and diploid carpospores of the isomorphic red alga Chondrus verrucosus. While tetraspores and carpospores of this species did not differ in size or autofluorescence, concentrations of phycobiliproteins of carpospores were greater than that of tetraspores. However, tetraspores were more photosynthetically competent than carpospores over a broader range of photosynthetic photon flux densities (PPFDs) and at PPFDs found at both the depth that C. verrucosus is found at high tide and in surface waters in which planktonic propagules might disperse. These results suggest potential differences in dispersal potential and reproductive success of haploid and diploid spores. Moreover, these cryptic differences in ecological niche partitioning of haploid and diploid spores contribute to our understanding of some of the differences between these ploidy stages that may ultimately lead to the maintenance of the complex haploid–diploid life cycle in this isomorphic red alga.
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