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Objavljeno v DiRROS: 06.12.2024; Ogledov: 91; Prenosov: 8262
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Povzetek: Although the activities of various tree organs and tissues are under different environmental and internal constraints, they need to be coordinated to ensure whole-tree functioning. Dusart et al. (2024) conducted a heating experiment on branches of Juglans regia saplings during the entire growing season to examine the effect of temperature on primary (bud) and secondary (xylem) growth. They found that primary and secondary meristems responded asynchronously to elevated temperature, which suggests that lack of coordination mechanisms between primary and secondary growth at crown scale could have a potential impact on canopy and tree architecture.
Ključne besede: phloem, wood anatomy, tree growth, angiosperms, bark, meristem, non-structural carbohydrates, primary growth, radial growth, secondary growth, temperature, xylem
Objavljeno v DiRROS: 05.12.2024; Ogledov: 96; Prenosov: 54
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Povzetek: Objective: Parkinson’s patients will experience mobility disturbances with disease progression. Beneficial effects of physical therapy are short-lasting. Novel interventions are needed to maintain these benefits. Methods: Fourteen Parkinson’s patients (71±4.08 years) participated in a randomized controlled examiner-blinded feasibility clinical trial. After 12 physical therapy sessions, the intervention group received a height-adjustable desk that facilitates stepping while standing, for 4 months. Explorative outcome measures included MDS-UPDRS II, III, TUG, 8.5m walking test, PDQ-39, sABC, sFES, DEXA scans, and lower extremity strength. Results: Post-physical-therapy, everyone significantly improved on the MDS-UPDRS II, III, TUG, and 8.5m walking test, and PDQ-39. (p<0.05) After 4 months, the control group regressed towards pre-physical-therapy values. In the intervention group, sedentary behavior decreased beyond desk use, indicating a carry-over effect. MDS-UPDRS II, PDQ-39, sFES, sABC, TUG, 8.5m walking test, activity time, sitting time, hip strength all improved with clinically relevant effect sizes. Conclusion: Postphysical therapy in-home reduction of sedentary behavior was associated with maintenance of physical benefits and additional improvements in mobility, activity time, balance and quality of life
Ključne besede: Parkinson’s disease, physical therapy, sedentarism, sarcopenia, quality of life
Objavljeno v DiRROS: 05.12.2024; Ogledov: 95; Prenosov: 47
Celotno besedilo (1,04 MB)
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Povzetek: Field crickets (Gryllidae) produce sounds by tegminal stridulation, well-studied for its role in female attraction and choice. However, understanding female preferences for their courtship song remains elusive, despite considering additional chemical, visual, and thermal signals. Beyond stridulation, crickets also display vibrational courtship behaviours that remain largely unexplored. Using Acheta domesticus as a model, we conduct the first comprehensive analysis of the entirety of vibroacoustic courtship signals in crickets, including their interaction. Employing audio recording, laser vibrometry, and videorecording, we unveil a complex signal involving simultaneous wing stridulation, body tremulation, and leg drumming against the substrate in a prolonged display, unique among insects. We identify robust correlations, coupling, and coordination between these signal components. We show the tightest coupling between the two types of stridulation pulses, and between tremulation and drumming signals, while drumming-stridulation coupling is less consistent, revealing a constraint on drumming performance. This constraint in the expression of one signal component, without a trade-off, represents a specific case within complex dynamic signalling. In addition, we find no correlation between drumming rate and its accuracy relative to stridulation, challenging common expectations. Our findings indicate that the information conveyed by the complex courtship display in A. domesticus is not simply proportional to that in the song, shedding light on previous ambiguities surrounding its function. Spectral-intensity analysis indicates the closest perceptual connection between stridulation and drumming signals, likely commonly influencing female choice, while proposing another function for tremulation. Further research should delve deeper into the function of this intricate signal.
Ključne besede: male quality, substrate vibration, sound, complex signal, dynamic signal, insects, zoology, biology
Objavljeno v DiRROS: 04.12.2024; Ogledov: 99; Prenosov: 946
Celotno besedilo (5,61 MB)
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Povzetek: Living stumps reported in many tree species were the first, circumstantial evidence of root grafting. Although stump overgrowth has been extensively studied in various tree species, anatomical observations have mainly focused on the xylem part. Here, we investigated the xylem and phloem structure in living stumps of two conifer species: Norway spruce (Picea abies (L.) Karst.) and silver fir (Abies alba Mill.). The mechanism of wound closure was similar in the two species, however, there were differences in the structure of wound tissues in wood and bark. Immediately after the injury, a callus consisting of parenchymal cells was formed, followed by wound-wood with wide increments. In addition, the wood structure and morphology of tracheids were changed. Tracheids lost their typical elongated and tapering structure; instead, numerous crooked and forked tracheids were present. Traumatic resin canals were present in both species but were more abundant in P. abies, which also had normal resin canals. While the structure of the xylem growth rings eventually normalized in both species, the width of the annual xylem increments was diminished. In both species, the typical structure of annual phloem increment was lost in the non-collapsed phloem and sclereids were very abundant in the collapsed phloem. In A. alba, the collapsed phloem was rich in swollen parenchyma cells containing blue-stained contents, while in P. abies, numerous large traumatic resin canals were conspicuous. The study showed that similar patterns of vascular tissue restoration exist in A. alba and P. abies in response to tree felling. However, there are certain species-specific peculiarities in the wood and phloem anatomical response, which might affect long-term stump functioning and survival.
Ključne besede: wood physiology, phloem, xylem, Norway spruce, Picea abies, silver fir, Abies alba
Objavljeno v DiRROS: 03.12.2024; Ogledov: 127; Prenosov: 1387
Celotno besedilo (10,92 MB)
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