1,025 research outputs found
Touch-sensitive glandular trichomes: a mode of defence against herbivorous arthropods in the Carboniferous
This is the publisher's version, also available electronically from http://www.evolutionary-ecology.com/issues/v04n05/mmar1431.pdf.We present evidence that the capitate glandular trichomes of Blanzyopteris praedentata, a lianescent seed fern from the Upper Carboniferous of France, possessed a specialized, touchsensitive mechanism that triggered the opening of the secretory cell by contact. The trichomes are interpreted as functionally similar to those of some modern flowering plants, which release a sticky exudate when touched and ruptured that functions to disable plant-feeding arthropods
Comparison of a Continuous and Discontinuous GXT on VO2 in Resistance-Trained and Endurance-Trained Males
International Journal of Exercise Science 15(4): 414-422, 2022. Traditional graded exercise testing to assess maximal oxygen uptake (VO2max) may not well represent resistance-trained athletes due to their unfamiliarity with continuous exercise. For this reason, it is possible discontinuous exercise protocols may better represent the maximum capacity for aerobic metabolism in resistance-trained athletes, in order to provide a more valid assessment of VO2max and risk of developing cardiovascular disease. Purpose: The purpose of this experiment was to compare VO2peak during a continuous and discontinuous modified Bruce protocol in both highly resistance-trained and endurance-trained males. Methods: 19 college-aged males (age: 20.6 ± 1.9 yr, height: 176.5 ± 7.6 cm, weight: 85.0 ± 25.6 kg) of intermediate resistance- or endurance-trained status were recruited for this study. Participants completed a continuous and discontinuous modified Bruce protocol on two visits separated by seven days. Results: A 2x2 one-way ANOVA revealed a significant group main effect for VO2peak (p = 0.004) in which endurance athletes achieved significantly higher VO2peak values compared to resistance-trained athletes. A significant group main effect for RPE was found (p = 0.045) in which endurance-trained reported significantly higher RPE values than the resistance-trained. A significant main effect for protocol for heart rate (p = 0.033) was found in which individuals achieved higher heart rates during the continuous protocol compared to the discontinuous. Conclusion: Although a discontinuous protocol with rest periods between stages is comparable to the exercise mode familiar to resistance-trained athletes, it did not provide any additional benefit to VO2peak values
Coprolites in a Middle Triassic cycad pollen cone: evidence for insect pollination in early cycads?
This is the publisher's version, also available electronically from http://www.evolutionary-ecology.com/issues/v07n03/kkar1828.pdf.Question: What evidence is there for cycad–insect interactions in the fossil record?
Organism: The pollen cone Delemaya spinulosa Klavins, Taylor, Krings et Taylor.
Locality: Fremouw Formation (Middle Triassic), Fremouw Peak, Central Transantarctic
Mountains, Antarctica.
Methods: We document the presence of pollen-laden coprolites in pollen sacs of a Middle
Triassic cycad.
Conclusions: These coprolites are comparable with fecal pellets of modern arthropods and we suggest that they were produced by beetles. This provides the oldest unequivocal evidence for a cycad–insect interaction and may represent a precursory stage in the establishment of a more complex cycad–pollinator relationship
Photocatalytic degradation of diclofenac in wastewater using ironceramic composites
The photocatalytic degradation of diclofenac in model aqueous solution is investigated. The surface of composites were correlated with photocatalytic activity. Adsorption activity of the composites is related to the presence of surface active sites. The degradation under UV irradiation and photo-Fenton process using ironceramic composites is more effective than direct photolysis
Effects of time window size and placement on the structure of aggregated networks
Complex networks are often constructed by aggregating empirical data over
time, such that a link represents the existence of interactions between the
endpoint nodes and the link weight represents the intensity of such
interactions within the aggregation time window. The resulting networks are
then often considered static. More often than not, the aggregation time window
is dictated by the availability of data, and the effects of its length on the
resulting networks are rarely considered. Here, we address this question by
studying the structural features of networks emerging from aggregating
empirical data over different time intervals, focussing on networks derived
from time-stamped, anonymized mobile telephone call records. Our results show
that short aggregation intervals yield networks where strong links associated
with dense clusters dominate; the seeds of such clusters or communities become
already visible for intervals of around one week. The degree and weight
distributions are seen to become stationary around a few days and a few weeks,
respectively. An aggregation interval of around 30 days results in the stablest
similar networks when consecutive windows are compared. For longer intervals,
the effects of weak or random links become increasingly stronger, and the
average degree of the network keeps growing even for intervals up to 180 days.
The placement of the time window is also seen to affect the outcome: for short
windows, different behavioural patterns play a role during weekends and
weekdays, and for longer windows it is seen that networks aggregated during
holiday periods are significantly different.Comment: 19 pages, 11 figure
Urban Gravity: a Model for Intercity Telecommunication Flows
We analyze the anonymous communication patterns of 2.5 million customers of a
Belgian mobile phone operator. Grouping customers by billing address, we build
a social network of cities, that consists of communications between 571 cities
in Belgium. We show that inter-city communication intensity is characterized by
a gravity model: the communication intensity between two cities is proportional
to the product of their sizes divided by the square of their distance
The use of 4D-CTA in the diagnostic work-up of brain arteriovenous malformations
Neuro Imaging Researc
Partial “targeted” embolisation of brain arteriovenous malformations
The treatment of pial arteriovenous brain malformations is controversial. Little is yet known about their natural history, their pathomechanisms and the efficacy and risks of respective proposed treatments. It is known that only complete occlusion of the AVM can exclude future risk of haemorrhage and that the rates of curative embolisation of AVMs with an acceptable periprocedural risk are around 20 to 50%. As outlined in the present article, however, partial, targeted embolisation also plays a role. In acutely ruptured AVMs where the source of bleeding can be identified, targeted embolisation of this compartment may be able to secure the AVM prior to definitive treatment. In unruptured symptomatic AVMs targeted treatment may be employed if a defined pathomechanism can be identified that is related to the clinical symptoms and that can be cured with an acceptable risk via an endovascular approach depending on the individual AVM angioarchitecture. This review article gives examples of pathomechanisms and angioarchitectures that are amenable to this kind of treatment strategy
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