Studies of seed production in two Austrodanthonia grass cultivars

2002 ◽  
Vol 53 (11) ◽  
pp. 1197 ◽  
Author(s):  
G. M. Lodge

Studies were conducted in 1993–94 on 2 native grass cultivars, Austrodanthonia richardsonii (Link) H.P.�Linder (syn. Danthonia richardsonii Cashmore) cv. Taranna and A. bipartita (Link) H.P. Linder (syn. D. linkii Kunth) cv. Bunderra, to quantify the important morphological factors affecting seed production (as measured by seed weight, g/plant). Experiments also examined the influence of nitrogen (N) application and investigated the effects of time and method of harvest on seed production and subsequent germination. For both cultivars, inflorescence and floret number accounted for the highest proportion of the variation in seed production per plant (R2 = 0.873 and 0.686 for Taranna and Bunderra, respectively). Although N applied (0, 25, and 50 kg/ha) at the late vegetative or early flowering stage, or split applications at both times, had no significant effect (P > 0.05) on the seed production per plant of Taranna and Bunderra, further studies of N effects are required. In 1993 and 1994, time of inflorescence harvest and method of harvest had no significant effect on inflorescence number and seed production of Taranna and Bunderra and no significant effect on the subsequent germination of Bunderra seed. However, in 1993, harvesting at an early stage of flowering (10% of florets white and fluffy) reduced Taranna seed production by 17% compared with the mean and decreased (P < 0.05) seed germination by about 10%. In 1994, harvesting at early flowering (5% florets white and fluffy) reduced Taranna seed production by a mean of around 55% compared with harvesting at 50% maturity, and subsequent seed germination was also lower (P < 0.05) for the early harvest time. Application of 1 L/ha of paraquat (a.i. 200 g/L of paraquat dichloride) at mid-flowering to desiccate the crop in 1993 had no significant effect on the germination of Taranna and Bunderra caryopses. The implications of these data for commercial seed production are discussed.

1967 ◽  
Vol 7 (24) ◽  
pp. 25 ◽  
Author(s):  
GB Taylor ◽  
RC Rossiter

Seed production and persistence of the Carnamah, Northam A, Dwalganup, and Geraldton strains of subterranean clover (Trifolium subterraneum L.) were examined in undefoliated swards in the wheatbelt of Western Australia. The early flowering characteristic of Carnamah was not always associated with higher seed yields. Only when there was a well-defined, early finish to the growing season, or when flowering was very much earlier in Carnamah (viz., following an early 'break' to the season), did this strain clearly outyield both Northam A and Geraldton. The seed yield of Dwalganup was generally inferior to that of the other strains. Factors affecting regeneration are discussed. Under low rainfall conditions, poorer germination-regulation of Carnamah, compared with Geraldton and Northam A, would be expected to result in poorer persistence unless offset by higher seed yields in the Carnamah strain.


2019 ◽  
Vol 33 (1) ◽  
Author(s):  
Sidra Malik ◽  
Iqra Zaib ◽  
Omer Farooq ◽  
Kanwal Hanif

Objective: To Compare the efficacy of 2 different patching regimens in amblyopic children and highlight the factors affecting compliance. Materials & Methods: The randomized control trial was conducted in Eye OPD SKBZ Hospital Muzaffarabad from September 2017- March 2018. Analysis was limited to children 4 to 16 years of age with unilateral amblyopia. Personal information, visual acuity with and without correction, Cycloplegic refraction & subjective refraction was noted. Children with amblyopic eye acuity of 20/40 to 20/200 (mean 0.56 log MAR, approximately 20/63) and inter ocular acuity difference of 2 or more lines were specified to get either 2 hours (Group A) or 6 hours (Group B) of daily patching, combined with 1 hour of near visual activities per day. Follow up period was 2 weeks, 4 weeks and 3 months. Results:     Out of 72 children 44(61.1%) were males and 28(38.9%) were females. The mean age was 10.25 ± 0.67 years.  Mean visual acuity was 20/63(+0.5 log Mar) in both groups. In group A, 66.7 % and in group B 83.3% of patients showed improvement. The mean difference of BCVA was 2.77 ± 1.28 SD and 3.41±3.16 SD in group ‘A’ and group ‘B’ respectively. Group A and B showed improvement of 3.0 and 2.0 lines respectively. Both groups showed a poor compliance of 11.2 %. Conclusion: 2 hours of patching along with 1 hour of near activity is sufficient to treat amblyopia as compared to 6 hours of patching. Firstly, screening should be done to diagnose amblyopia at early stage. Secondly compliance is found to be a single most important factor to improve outcomes.


2000 ◽  
Vol 9 (3) ◽  
pp. 239-251 ◽  
Author(s):  
M. SAHRAMAA ◽  
L. HÖMMÖ

Production of reed canary grass (Phalaris arundinacea L.) seed in Finland may be of interest in the near future. Seed production characters of cultivars Palaton and Venture were studied between 1995 and 1998 at Jokioinen. Effects of harvest time on seed yield, thousand seed weight and seed germination were evaluated for 'Palaton'. Seed yield varied from 2 to 432 kg ha-1, being only 100 kg ha-1 on average. In the years of highest seed yields the optimum harvest time was 15 days after complete anthesis. At that time high seed yield was associated with a low proportion of shattered seeds and high thousand seed weight and good seed germination. In an additional experiment, the effect of storage temperature and storage time on seed germination were investigated for 'Venture'. Storage temperature had no significant influence on final germination, but warmer storage significantly speeded up germination rate as recorded after 7 days of germination. After 7 days the percentage of germinated seeds was also significantly higher for seeds stored for >10 months than with seeds stored for


2020 ◽  
Vol 53 (12) ◽  
pp. 5473-5487 ◽  
Author(s):  
Andrea Rispoli ◽  
Anna Maria Ferrero ◽  
Marilena Cardu

AbstractTunnel boring machine (TBM) performance prediction is often a critical issue in the early stage of a tunnelling project, mainly due to the unpredictable nature of some important factors affecting the machine performance. In this regard, deterministic approaches are normally employed, providing results in terms of average values expected for the TBM performance. Stochastic approaches would offer improvement over deterministic methods, taking into account the parameter variability; however, their use is limited, since the level of information required is often not available. In this study, the data provided by the excavation of the Maddalena exploratory tunnel were used to predict the net and overall TBM performance for a 2.96 km section of the Mont Cenis base tunnel by using a stochastic approach. The preliminary design of the TBM cutterhead was carried out. A prediction model based on field penetration index, machine operating level and utilization factor was adopted. The variability of the parameters involved was analysed. A procedure to take into account the correlation between the input variables was described. The probability of occurrence of the outcomes was evaluated, and the total excavation time expected for the tunnel section analysed was calculated.


Author(s):  
Jinbao Zhang ◽  
Jaeyoung Lee

Abstract This study has two main objectives: (i) to analyse the effect of travel characteristics on the spreading of disease, and (ii) to determine the effect of COVID-19 on travel behaviour at the individual level. First, the study analyses the effect of passenger volume and the proportions of different modes of travel on the spread of COVID-19 in the early stage. The developed spatial autoregressive model shows that total passenger volume and proportions of air and railway passenger volumes are positively associated with the cumulative confirmed cases. Second, a questionnaire is analysed to determine changes in travel behaviour after COVID-19. The results indicate that the number of total trips considerably decreased. Public transport usage decreased by 20.5%, while private car usage increased by 6.4%. Then the factors affecting the changes in travel behaviour are analysed by logit models. The findings reveal significant factors, including gender, occupation and travel restriction. It is expected that the findings from this study would be helpful for management and control of traffic during a pandemic.


Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 314
Author(s):  
Andrew Revill ◽  
Vasileios Myrgiotis ◽  
Anna Florence ◽  
Stephen Hoad ◽  
Robert Rees ◽  
...  

Climate, nitrogen (N) and leaf area index (LAI) are key determinants of crop yield. N additions can enhance yield but must be managed efficiently to reduce pollution. Complex process models estimate N status by simulating soil-crop N interactions, but such models require extensive inputs that are seldom available. Through model-data fusion (MDF), we combine climate and LAI time-series with an intermediate-complexity model to infer leaf N and yield. The DALEC-Crop model was calibrated for wheat leaf N and yields across field experiments covering N applications ranging from 0 to 200 kg N ha−1 in Scotland, UK. Requiring daily meteorological inputs, this model simulates crop C cycle responses to LAI, N and climate. The model, which includes a leaf N-dilution function, was calibrated across N treatments based on LAI observations, and tested at validation plots. We showed that a single parameterization varying only in leaf N could simulate LAI development and yield across all treatments—the mean normalized root-mean-square-error (NRMSE) for yield was 10%. Leaf N was accurately retrieved by the model (NRMSE = 6%). Yield could also be reasonably estimated (NRMSE = 14%) if LAI data are available for assimilation during periods of typical N application (April and May). Our MDF approach generated robust leaf N content estimates and timely yield predictions that could complement existing agricultural technologies. Moreover, EO-derived LAI products at high spatial and temporal resolutions provides a means to apply our approach regionally. Testing yield predictions from this approach over agricultural fields is a critical next step to determine broader utility.


Author(s):  
Andrea Petetta ◽  
Massimo Virgili ◽  
Stefano Guicciardi ◽  
Alessandro Lucchetti

AbstractStock overexploitation, bycatch, discards and gear impacts on the environment are outstanding issues for Mediterranean fisheries. The adoption of alternative fishing gears is an appealing solution to ensure a more sustainable exploitation of resources. We discuss the pros and cons of pots as alternative gears by reviewing their main designs, spatial distribution and target species in the Mediterranean basin. We assessed the technical factors affecting the catch efficiency of the different pot designs for four target species: spiny lobster, Palinurus elephas; Norway lobster, Nephrops norvegicus; common octopus, Octopus vulgaris and pandalid shrimps, Plesionika spp. We found that pot volume is important to catch Octopus; mesh size to catch Nephrops and Plesionika; entrance surface to catch Octopus, Nephrops and Plesionika; pot shape/colour and entrance shape/position to catch Octopus and Plesionika; and bait type to catch Octopus and Nephrops. The literature review shows that pot fisheries have several considerable advantages over conventional gears, especially in terms of discards, bycatch, seabed impacts (particularly compared with bottom trawls and passive set nets), size and species selectivity, gear depredation, catch quality and gear cost, besides saving time and labour. Disadvantages hampering their wider diffusion include ghost fishing, a low catch of finfish species, the narrow range of species targeted by each pot design and the current early stage of research. These data make a clear case for using pots as alternative gears to traditional ones in the Mediterranean Sea in some areas and seasons to catch certain target species.


Cancers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1161
Author(s):  
Lidia Delrieu ◽  
Liacine Bouaoun ◽  
Douae El Fatouhi ◽  
Elise Dumas ◽  
Anne-Deborah Bouhnik ◽  
...  

Breast cancer (BC) remains complex for women both physically and psychologically. The objectives of this study were to (1) assess the evolution of the main sequelae and treatment two and five years after diagnosis in women with early-stage breast cancer, (2) explore patterns of sequelae associated with given sociodemographic, clinical, and lifestyle factors. The current analysis was based on 654 localized BC patients enrolled in the French nationwide longitudinal survey “vie après cancer” VICAN (January–June 2010). Information about study participants was collected at enrollment, two and five years after diagnosis. Changes over time of the main sequelae were analyzed and latent class analysis was performed to identify patterns of sequelae related to BC five years after diagnosis. The mean age (±SD) of study participants at inclusion was 49.7 (±10.5) years old. Six main classes of sequelae were identified two years and five years post-diagnosis (functional, pain, esthetic, fatigue, psychological, and gynecological). A significant decrease was observed for fatigue (p = 0.03) and an increase in cognitive sequelae was reported (p = 0.03). Two latent classes were identified—functional and esthetic patterns. Substantial sequelae remain up to five years after BC diagnosis. Changes in patient care pathways are needed to identify BC patients at a high risk.


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