295 research outputs found
Evaluation of Florpyrauxifenbenzyl for the control of Cyperus aromaticus (Navua sedge).
Background:
Cyperus aromaticus (Navua sedge) is a creeping perennial sedge common to tropical environments, currently threatening many agroecosystems and ecosystems in Pacific Island countries and northern Queensland in Australia.
Objective:
A glasshouse study was conducted to evaluate the efficacy of florpyrauxifen-benzyl on C. aromaticus plants with and without established rhizomes.
Methods:
The plants with established rhizomes were treated at three application times being mowed, pre-flowering and flowering growth stages and plants without established rhizomes were treated at seedling, pre-flowering and flowering growth stages. At each application time, plants were treated with four rates of florpyrauxifen-benzyl: 0, 15, 30 and 60 g a.i. ha−1 and control.
Results:
There was no mortality in the plants with established rhizomes. Reduction in the number of tillers was observed at four weeks after treatment (WAT) in plants treated with 30 and 60 g a.i. ha−1 of herbicide, however, there was new growth from the rhizomes and the number of tillers increased at 8 WAT. Conversely, florpyrauxifen-benzyl provided above 95% control in plants without established rhizomes.
Conclusions:
These results indicate florpyrauxifen-benzyl can help manage a new C. aromaticus infestation prior to the establishment of rhizomes. However, it has little to no impact on C. aromaticus plants with established rhizomes, and other management options should be employed to control them
Cumulative assessment:Strategic choices to influence students' study effort
BACKGROUND: It has been asserted that assessment can and should be used to drive students’ learning. In the current study, we present a cumulative assessment program in which test planning, repeated testing and compensation are combined in order to influence study effort. The program is aimed at helping initially low-scoring students improve their performance during a module, without impairing initially high-scoring students’ performance. We used performance as a proxy for study effort and investigated whether the program worked as intended. METHODS: We analysed students’ test scores in two second-year (n = 494 and n = 436) and two third-year modules (n = 383 and n = 345) in which cumulative assessment was applied. We used t-tests to compare the change in test scores of initially low-scoring students with that of initially high-scoring students between the first and second subtest and again between the combined first and second subtest and the third subtest. During the interpretation of the outcomes we took regression to the mean and test difficulty into account. RESULTS: Between the first and the second subtest in all four modules, the scores of initially low-scoring students increased more than the scores of initially high-scoring students decreased. Between subtests two and three, we found a similar effect in one module, no significant effect in two modules and the opposite effect in another module. CONCLUSION: The results between the first two subtests suggest that cumulative assessment may positively influence students’ study effort. The inconsistent outcomes between subtests two and three may be caused by differences in perceived imminence, impact and workload between the third subtest and the first two. Cumulative assessment may serve as an example of how several evidence-based assessment principles can be integrated into a program for the benefit of student learning
Apoptosis is not conserved in plants as revealed by critical examination of a model for plant apoptosis-like cell death
Background: Animals and plants diverged over one billion years ago and evolved unique mechanisms for many cellular processes, including cell death. One of the most well-studied cell death programmes in animals, apoptosis, involves gradual cell dismantling and engulfment of cellular fragments, apoptotic bodies, through phagocytosis. However, rigid cell walls prevent plant cell fragmentation and thus apoptosis is not applicable for executing cell death in plants. Furthermore, plants are devoid of the key components of apoptotic machinery, including phagocytosis as well as caspases and Bcl-2 family proteins. Nevertheless, the concept of plant "apoptosis-like programmed cell death" (AL-PCD) is widespread. This is largely due to superficial morphological resemblances between plant cell death and apoptosis, and in particular between protoplast shrinkage in plant cells killed by various stimuli and animal cell volume decrease preceding fragmentation into apoptotic bodies.Results: Here, we provide a comprehensive spatio-temporal analysis of cytological and biochemical events occurring in plant cells subjected to heat shock at 40-55 degrees C and 85 degrees C, the experimental conditions typically used to trigger AL-PCD and necrotic cell death, respectively. We show that cell death under both conditions was not accompanied by membrane blebbing or formation of apoptotic bodies, as would be expected during apoptosis. Instead, we observed instant and irreversible permeabilization of the plasma membrane and ATP depletion. These processes did not depend on mitochondrial functionality or the presence of Ca2+ and could not be prevented by an inhibitor of ferroptosis. We further reveal that the lack of protoplast shrinkage at 85 degrees C, the only striking morphological difference between cell deaths induced by 40-55 degrees C or 85 degrees C heat shock, is a consequence of the fixative effect of the high temperature on intracellular contents.Conclusions: We conclude that heat shock-induced cell death is an energy-independent process best matching definition of necrosis. Although the initial steps of this necrotic cell death could be genetically regulated, classifying it as apoptosis or AL-PCD is a terminological misnomer. Our work supports the viewpoint that apoptosis is not conserved across animal and plant kingdoms and demonstrates the importance of focusing on plant-specific aspects of cell death pathways
Determinants of Family Empowerment in Utilizing Health Services in Kupang, Indonesia: A Cross-Sectional Study
Complications during pregnancy, childbirth, and postpartum are responsible for maternal deaths, however, childbirth in health facilities is far from the Strategic Plan target (88.9%). The majority of Timorese people still live with their parents, so care decisions depend on the parents/relatives. There is a tradition of "Se'i-tatobi), namely that mothers and babies will bathe in hot water and have a fire during the postpartum period. Apart from that, Timorese society is a patriarchal society where women do not have a significant position which can be seen from the weak position of women relative to men. Method. This research uses mixed method research, this research looks for the influence between variables, carried out with a cross-sectional research design. The research target population is families (mother-in-law, biological mother, or other relatives involved) who have pregnant women in the third trimester of pregnancy in Kupang Regency. The number of puskesmas in Kupang Regency is 26 puskesmas. The sample required is relatively large, the minimum required is up to 50 data samples for a predictor (independent) variable. It can select relationships because it uses a non-linear log transformation approach to predict odds so it uses a logistic regression analysis test. Result. Based on the data above, it shows that of the ten independent variables, there are 2 variables, namely parity and husband's job, which do not affect family empowerment, while the variables of mother's age, mother's education, husband's age, husband's education, place of birth of last child, helper, access, birth status are significant. influencing family empowerment. Conclusion Based on the data above, the mother's age, mother's education, husband's age, husband's education, place of birth of the last child, helper, and access also show family empowerment which significantly influences the family's ability to use it
An investigation of the effects of stage of ensilage on Nassella neesiana seeds, for reducing seed viability and injury to livestock
The noxious weed Nassella neesiana is established on a wide range of productive land throughout southeastern Australia. N. neesiana seeds, when mature, are sharp, causing injury to livestock, thus posing a problem in fodder bales. To reduce infestations of agricultural weeds in situ, production of silage from weed-infested pastures is practised as part of integrated weed management (IWM). However, there is little data to demonstrate whether this process is useful to reduce infestations or the harmful properties of N. neesiana. Therefore, the minimum duration of ensilage required to reduce the viability of N. neesiana seeds was investigated, both with and without addition of ensilage inoculants in this process. Also, the decreasing propensity of the seeds to injure livestock, after various times and conditions of ensilage, was assessed. Ensilage inoculant reduced seed germination probability to zero after 35 days. When no inoculant was added, zero viability was achieved after 42 days. A qualitative assessment of the hardness of ensilaged seeds found seed husks were softer (and therefore safer) after 42 days, whether inoculant was used or not. Therefore, we suggest that both the viability of N. neesiana seeds and hardness of seed casings are significantly reduced after 42 days, thereby reducing the risks of seed dispersal and injury to livestock
SPIRO- the automated Petri plate imaging platform designed by biologists, for biologists
Phenotyping of model organisms grown on Petri plates is often carried out manually, despite the procedures being time-consuming and laborious. The main reason for this is the limited availability of automated phenotyping facilities, whereas constructing a custom automated solution can be a daunting task for biologists. Here, we describe SPIRO, the Smart Plate Imaging Robot, an automated platform that acquires time-lapse photographs of up to four vertically oriented Petri plates in a single experiment, corresponding to 192 seedlings for a typical root growth assay and up to 2500 seeds for a germination assay. SPIRO is catered specifically to biologists' needs, requiring no engineering or programming expertise for assembly and operation. Its small footprint is optimized for standard incubators, the inbuilt green LED enables imaging under dark conditions, and remote control provides access to the data without interfering with sample growth. SPIRO's excellent image quality is suitable for automated image processing, which we demonstrate on the example of seed germination and root growth assays. Furthermore, the robot can be easily customized for specific uses, as all information about SPIRO is released under open-source licenses. Importantly, uninterrupted imaging allows considerably more precise assessment of seed germination parameters and root growth rates compared with manual assays. Moreover, SPIRO enables previously technically challenging assays such as phenotyping in the dark. We illustrate the benefits of SPIRO in proof-of-concept experiments which yielded a novel insight on the interplay between autophagy, nitrogen sensing, and photoblastic response
Historical Improvement in Speed Skating Economy
Half the improvement in 1500-m speed-skating world records can be explained by technological innovations and the other half by athletic improvement. It is hypothesized that improved skating economy is accountable for much of the athletic improvement.
Purpose - To determine skating economy in contemporary athletes and to evaluate the change in economy over the years.
Methods - Contemporary skaters of the Dutch national junior team (n=8) skated 3 bouts of 6 laps at submaximal velocity, from which skating economy was calculated (in mL O2·kg-1·km-1). A literature search provided historic data of skating velocity and submaximal VO2 (in mL·kg-1·min-1), from which skating economy was determined. The association between year and skating economy was determined using linear regression analysis. Correcting the change in economy for technological innovations resulted in an estimate of the association between year and economy due to athletic improvement.
Results An average (±SD) skating economy of 73.4±6.4 mL O2·kg-1·km-1 was found in contemporary athletes. Skating economy improved significantly over the historical timeframe (-0.57 mL O2·kg-1·km-1 per year, 95% confidence interval [-0.84, -0.31]). In the final regression model for the klapskate era, with altitude as confounder, skating economy improved with a non-significant -0.58 mL O2·kg-1·km-1 each year ([-1.19, 0.035]).
Conclusions Skating economy was 73.4±6.4 mL O2·kg-1·km-1 in contemporary athletes and improved over the past ~50 years. The association between year and skating economy due to athletic improvement, for the klapskate era, approached significance, suggesting a possible improvement in economy over these years
MLP: a MATLAB toolbox for rapid and reliable auditory threshold estimation
In this paper, we present MLP, a MATLAB toolbox enabling auditory
thresholds estimation via the adaptive Maximum Likelihood procedure proposed
by David Green (1990, 1993). This adaptive procedure is particularly appealing for
those psychologists that need to estimate thresholds with a good degree of accuracy
and in a short time. Together with a description of the toolbox, the current text
provides an introduction to the threshold estimation theory and a theoretical
explanation of the maximum likelihood adaptive procedure. MLP comes with a
graphical interface and it is provided with several built-in, classic psychoacoustics
experiments ready to use at a mouse click
Characterising and improving the deteriorating trends in soil physical quality under banana
Deterioration in soil physical quality under intensive tillage practices is a norm rather than an exception. The objectives of this study were to (i) evaluate total porosity (TP) as an indicator parameter to assess the impact of banana cropping on compaction and infiltration in soils, and (ii) assess the effectiveness of different interrow grass-covers in minimising the deteriorating trends. Depth-incremented TP under banana rows and interrows from 4 sites, corresponding forest sites, and from 3 interrow grass-cover treatments were computed from bulk density measurements. The TP results show the compacted depth ranged from 0.35 to 0.45m in banana rows and from 0.35 to 1.0m in the interrows. The TP in 0.10m depth increments decreased in the order: forest > rows > interrows, and was positively correlated with soil organic C (OC) and negatively with wheel traffic stress (WTS). The multiple regression analysis showed that 77% of the variability in TP was accounted for by clay + silt, OC, and WTS. We show that a threshold compaction index (DIt) of 0.81-0.83 can be estimated from TP regardless of the soil type. Depending on the soil type and the cultural practices followed, infiltration decreased from 0.75 mm/s in rainforest to 0.23 mm/s under banana in 1 soil type compared with 2.55 mm/s in forest and 0.85 mm/s under banana in another. After 18 months of interrow grass-covers we found the deterioration in TP was minimum under the indigenous grass-cover but not under the 2 improved species. We conclude the interrow grass-covers were effective in minimising WTS associated compaction and reduction in infiltration
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