Smooth Amaranth Interference with Watermelon and Muskmelon Production

Studies were conducted to determine the critical period of smooth amaranth interference in watermelon (Citrullus lunatus L.) and muskmelon (Cucumis melo L. var. reticulatus). Best-fit linear or exponential regression models were used to predict the maximum period of competition and the minimum weed-free period for 10% yield loss. The maximum period of competition and minimum weed-free period was 0.50 and 2.97 weeks after watermelon emergence, respectively, and 1.0 and 3.9 weeks after muskmelon emergence, respectively. The critical periods of smooth amaranth interference for the crops were between those intervals. In both crops, late emerging smooth amaranth had little effect on total yield. Smooth amaranth introduced at crop emergence reduced total yield. The effect of competition on yield components, i.e., fruit number per hectare and fruit mass, varied by crop. Muskmelon fruit count was more sensitive to smooth amaranth competition than was watermelon fruit count. Conversely, mass per fruit of muskmelon was less sensitive to this competition than was mass per fruit of watermelon.

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Critical Period of Quackgrass (Elytrigia repens) Removal in Potatoes (Solanum tuberosum)

Weed Science ◽

10.1017/s004317450007689x ◽

1994 ◽

Vol 42 (4) ◽

pp. 528-533 ◽

Cited By ~ 13

Author(s):

R. Baziramakenga ◽

Gilles D. Leroux

Keyword(s):

Critical Period ◽

Yield Loss ◽

Field Trials ◽

Quebec City ◽

Critical Periods ◽

Marketable Yield ◽

Elytrigia Repens ◽

Medium Level ◽

High Level ◽

Loss Level

Field trials were carried out in 1989 and 1990 at St-Augustin, near Québec City, Canada, to determine the critical periods of quackgrass control in potato submitted to three levels of infestation. Potato yield losses due to quackgrass interference increased with quackgrass infestation and length of duration of interference. Quackgrass interference influenced marketable tuber yields more than total tuber yields. Duration of the critical period varied depending on the level of quackgrass infestation and year. Based on an arbitrary 5% level of marketable yield loss, the critical period started at ca. 15 days after emergence (DAE) of potato at low level of infestation, and at ca. 3 DAE at medium level of infestation. At high level of infestation, the critical period began prior to the emergence of potato. The end of the critical period of quackgrass removal was extremely variable across quackgrass infestation level and year and ranged from 23 to 68 DAE of potato at a 5 % yield loss level. It appears that onset of interference varied less than the end of it, indicating that early quackgrass control is necessary to prevent yield loss.

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Critical Period of Interference between American Black Nightshade and Triploid Watermelon

Weed Technology ◽

10.1614/wt-d-10-00014.1 ◽

2010 ◽

Vol 24 (3) ◽

pp. 397-400 ◽

Cited By ~ 6

Author(s):

Joshua I. Adkins ◽

William M. Stall ◽

Bielinski M. Santos ◽

Stephen M. Olson ◽

Jason A. Ferrell

Keyword(s):

Critical Period ◽

Yield Loss ◽

Field Trials ◽

Black Nightshade ◽

Maximum Period ◽

American Black ◽

Triploid Watermelon

Field trials were conducted in the spring of 2007 and 2008 to investigate the critical period of interference between American black nightshade and triploid watermelon. To determine the critical period, the maximum period of competition and minimum weed-free period were examined. American black nightshade (2 plants m−2) was established into watermelon plots at watermelon transplanting and removed at 0, 1, 2, 3, 4, and 5 wk after transplanting to determine the maximum period of competition. American black nightshade (2 plants m−2) was established into watermelon plots at 0, 1, 2, 3, 4, and 5 wk after transplanting and remained until watermelon harvest to determine the minimum weed-free period. To avoid yield loss from exceeding 10% of a crop grown weed-free, the maximum period of competition and minimum weed-free period were found to be 3.9 and 3.6 weeks after transplanting, respectively. Therefore, if American black nightshade is controlled at any time during the critical period of 3.6 to 3.9 wk after transplanting, yield loss should not exceed 10% of a crop grown weed-free.

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Safety and efficacy of linuron with or without an adjuvant or S-metolachlor for POST control of Palmer amaranth (Amaranthus palmeri) in sweetpotato

Weed Technology ◽

10.1017/wet.2021.27 ◽

2021 ◽

pp. 1-18

Author(s):

Levi D. Moore ◽

Katherine M. Jennings ◽

David W. Monks ◽

Ramon G. Leon ◽

David L. Jordan ◽

...

Keyword(s):

Nonionic Surfactant ◽

Weed Control ◽

Critical Period ◽

Total Yield ◽

Field Studies ◽

Palmer Amaranth ◽

Amaranthus Palmeri ◽

Foliar Injury ◽

Protoporphyrinogen Oxidase ◽

Safety And Efficacy

Abstract Field studies were conducted to evaluate linuron for POST control of Palmer amaranth in sweetpotato to minimize reliance on protoporphyrinogen oxidase (PPO)-inhibiting herbicides. Treatments were arranged in a two by four factorial where the first factor consisted of two rates of linuron (420 and 700 g ai ha−1), and the second factor consisted of linuron applied alone or in combinations of linuron plus a nonionic surfactant (NIS) (0.5% v/v), linuron plus S-metolachlor (800 g ai ha−1), or linuron plus NIS plus S-metolachlor. In addition, S-metolachlor alone and nontreated weedy and weed-free checks were included for comparison. Treatments were applied to ‘Covington’ sweetpotato 8 d after transplanting (DAP). S-metolachlor alone provided poor Palmer amaranth control because emergence had occurred at applications. All treatments that included linuron resulted in at least 98 and 91% Palmer amaranth control 1 and 2 wk after treatment (WAT), respectively. Including NIS with linuron did not increase Palmer amaranth control compared to linuron alone, but increased sweetpotato injury and subsequently decreased total sweetpotato yield by 25%. Including S-metolachlor with linuron resulted in the greatest Palmer amaranth control 4 WAT, but increased crop foliar injury to 36% 1 WAT compared to 17% foliar injury from linuron alone. Marketable and total sweetpotato yield was similar between linuron alone and linuron plus S-metolachlor or S-metolachlor plus NIS treatments, though all treatments resulted in at least 39% less total yield than the weed-free check resulting from herbicide injury and/or Palmer amaranth competition. Because of the excellent POST Palmer amaranth control from linuron 1 WAT, a system including linuron applied 7 DAP followed by S-metolachlor applied 14 DAP could help to extend residual Palmer amaranth control further into the critical period of weed control while minimizing sweetpotato injury.

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Relationships between test positivity rate, total laboratory confirmed cases of malaria, and malaria incidence in high burden settings of Uganda: an ecological analysis

Malaria Journal ◽

10.1186/s12936-021-03584-7 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Jaffer Okiring ◽

Adrienne Epstein ◽

Jane F. Namuganga ◽

Victor Kamya ◽

Asadu Sserwanga ◽

...

Keyword(s):

Regression Models ◽

Malaria Incidence ◽

Temporal Changes ◽

Linear Regression Models ◽

High Burden ◽

Exponential Regression ◽

Malaria Morbidity ◽

Laboratory Test Results ◽

Combining Data ◽

Catchment Areas

Abstract Background Malaria surveillance is critical for monitoring changes in malaria morbidity over time. National Malaria Control Programmes often rely on surrogate measures of malaria incidence, including the test positivity rate (TPR) and total laboratory confirmed cases of malaria (TCM), to monitor trends in malaria morbidity. However, there are limited data on the accuracy of TPR and TCM for predicting temporal changes in malaria incidence, especially in high burden settings. Methods This study leveraged data from 5 malaria reference centres (MRCs) located in high burden settings over a 15-month period from November 2018 through January 2020 as part of an enhanced health facility-based surveillance system established in Uganda. Individual level data were collected from all outpatients including demographics, laboratory test results, and village of residence. Estimates of malaria incidence were derived from catchment areas around the MRCs. Temporal relationships between monthly aggregate measures of TPR and TCM relative to estimates of malaria incidence were examined using linear and exponential regression models. Results A total of 149,739 outpatient visits to the 5 MRCs were recorded. Overall, malaria was suspected in 73.4% of visits, 99.1% of patients with suspected malaria received a diagnostic test, and 69.7% of those tested for malaria were positive. Temporal correlations between monthly measures of TPR and malaria incidence using linear and exponential regression models were relatively poor, with small changes in TPR frequently associated with large changes in malaria incidence. Linear regression models of temporal changes in TCM provided the most parsimonious and accurate predictor of changes in malaria incidence, with adjusted R2 values ranging from 0.81 to 0.98 across the 5 MRCs. However, the slope of the regression lines indicating the change in malaria incidence per unit change in TCM varied from 0.57 to 2.13 across the 5 MRCs, and when combining data across all 5 sites, the R2 value reduced to 0.38. Conclusions In high malaria burden areas of Uganda, site-specific temporal changes in TCM had a strong linear relationship with malaria incidence and were a more useful metric than TPR. However, caution should be taken when comparing changes in TCM across sites.

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Demand Response Coupled with Dynamic Thermal Rating for Increased Transformer Reserve and Lifetime

Energies ◽

10.3390/en14051378 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1378

Author(s):

Ildar Daminov ◽

Rémy Rigo-Mariani ◽

Raphael Caire ◽

Anton Prokhorov ◽

Marie-Cécile Alvarez-Hérault

Keyword(s):

Ambient Temperature ◽

Demand Response ◽

Thermal Model ◽

Critical Period ◽

Optimization Problem ◽

Integrated Management ◽

Critical Periods ◽

Network Access ◽

Maximal Amplitude ◽

Demand Response Program

(1) Background: This paper proposes a strategy coupling Demand Response Program with Dynamic Thermal Rating to ensure a transformer reserve for the load connection. This solution is an alternative to expensive grid reinforcements. (2) Methods: The proposed methodology firstly considers the N-1 mode under strict assumptions on load and ambient temperature and then identifies critical periods of the year when transformer constraints are violated. For each critical period, the integrated management/sizing problem is solved in YALMIP to find the minimal Demand Response needed to ensure a load connection. However, due to the nonlinear thermal model of transformers, the optimization problem becomes intractable at long periods. To overcome this problem, a validated piece-wise linearization is applied here. (3) Results: It is possible to increase reserve margins significantly compared to conventional approaches. These high reserve margins could be achieved for relatively small Demand Response volumes. For instance, a reserve margin of 75% (of transformer nominal rating) can be ensured if only 1% of the annual energy is curtailed. Moreover, the maximal amplitude of Demand Response (in kW) should be activated only 2–3 h during a year. (4) Conclusions: Improvements for combining Demand Response with Dynamic Thermal Rating are suggested. Results could be used to develop consumer connection agreements with variable network access.

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Determining the critical period for weed control in high-yielding cotton using common sunflower as a mimic weed

Weed Technology ◽

10.1017/wet.2019.68 ◽

2019 ◽

Vol 33 (6) ◽

pp. 800-807 ◽

Cited By ~ 3

Author(s):

Graham W. Charles ◽

Brian M. Sindel ◽

Annette L. Cowie ◽

Oliver G. G. Knox

Keyword(s):

Weed Control ◽

Critical Period ◽

Yield Loss ◽

Field Studies ◽

Growing Degree Days ◽

Degree Days ◽

Weed Density ◽

High Level ◽

The Cost ◽

Planting Season

AbstractField studies were conducted over six seasons to determine the critical period for weed control (CPWC) in high-yielding cotton, using common sunflower as a mimic weed. Common sunflower was planted with or after cotton emergence at densities of 1, 2, 5, 10, 20, and 50 plants m−2. Common sunflower was added and removed at approximately 0, 150, 300, 450, 600, 750, and 900 growing degree days (GDD) after planting. Season-long interference resulted in no harvestable cotton at densities of five or more common sunflower plants m−2. High levels of intraspecific and interspecific competition occurred at the highest weed densities, with increases in weed biomass and reductions in crop yield not proportional to the changes in weed density. Using a 5% yield-loss threshold, the CPWC extended from 43 to 615 GDD, and 20 to 1,512 GDD for one and 50 common sunflower plants m−2, respectively. These results highlight the high level of weed control required in high-yielding cotton to ensure crop losses do not exceed the cost of control.

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Critical periods for functional and anatomical compensation in lateral suprasylvian visual area following removal of visual cortex in cats

Journal of Neurophysiology ◽

10.1152/jn.1984.52.5.941 ◽

1984 ◽

Vol 52 (5) ◽

pp. 941-960 ◽

Cited By ~ 39

Author(s):

L. Tong ◽

R. E. Kalil ◽

P. D. Spear

Keyword(s):

Visual Cortex ◽

Critical Period ◽

Ocular Dominance ◽

Direction Selectivity ◽

Visual Area ◽

Critical Periods ◽

Cortex Lesion ◽

Thalamic Projections ◽

Adult Cats ◽

Visual Cortical

Previous experiments have found that neurons in the cat's lateral suprasylvian (LS) visual area of cortex show functional compensation following removal of visual cortical areas 17, 18, and 19 on the day of birth. Correspondingly, an enhanced retino-thalamic pathway to LS cortex develops in these cats. The present experiments investigated the critical periods for these changes. Unilateral lesions of areas 17, 18, and 19 were made in cats ranging in age from 1 day postnatal to 26 wk. When the cats were adult, single-cell recordings were made from LS cortex ipsilateral to the lesion. In addition, transneuronal autoradiographic methods were used to trace the retino-thalamic projections to LS cortex in many of the same animals. Following lesions in 18- and 26-wk-old cats, there is a marked reduction in direction-selective LS cortex cells and an increase in cells that respond best to stationary flashing stimuli. These results are similar to those following visual cortex lesions in adult cats. In contrast, the percentages of cells with these properties are normal following lesions made from 1 day to 12 wk of age. Thus the critical period for development of direction selectivity and greater responses to moving than to stationary flashing stimuli in LS cortex following a visual cortex lesion ends between 12 and 18 wk of age. Following lesions in 26-wk-old cats, there is a decrease in the percentage of cells that respond to the ipsilateral eye, which is similar to results following visual cortex lesions in adult cats. However, ocular dominance is normal following lesions made from 1 day to 18 wk of age. Thus the critical period for development of responses to the ipsilateral eye following a lesion ends between 18 and 26 wk of age. Following visual cortex lesions in 2-, 4-, or 8-wk-old cats, about 30% of the LS cortex cells display orientation selectivity to elongated slits of light. In contrast, few or no cells display this property in normal adult cats, cats with lesions made on the day of birth, or cats with lesions made at 12 wk of age or later. Thus an anomalous property develops for many LS cells, and the critical period for this property begins later (between 1 day and 2 wk) and ends earlier (between 8 and 12 wk) than those for other properties.(ABSTRACT TRUNCATED AT 400 WORDS)

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Modeling the Competitive Effect of Euphorbia dracunculoides and Astragalus sp. in Zero Input Rainfed Chickpea

Planta Daninha ◽

10.1590/s0100-83582018360100021 ◽

2018 ◽

Vol 36 (0) ◽

Author(s):

R.M. IKRAM ◽

A. TANVEER ◽

R. MAQBOOL ◽

M.A. NADEEN

Keyword(s):

Protein Content ◽

Critical Period ◽

Field Experiments ◽

Seed Protein ◽

Yield Loss ◽

Seed Protein Content ◽

Yield Losses ◽

Competition Period ◽

Crop Competition ◽

Weed Removal

ABSTRACT: Brown chickpea (Cicer arietinum L.) is one of the two chickpea types grown in Pakistan and other countries. The critical period for weed removal in a rainfed chickpea system is an important consideration in devising weed management strategies. Field experiments were conducted in the winter season of 2011 and 2012 to determine the extent of yield loss with different periods of weed crop competition. Seven weed crop competition periods (0, 45, 60, 75, 90, 105 and 160 days after sowing - DAS) were used to identify the critical period for weed removal in rainfed chickpea. Experimental plots were naturally infested with Euphorbia dracunculoides and Astragalus sp. in both years. Individual, composite density and dry weights of E. dracunculoides and Astragalussp. increased significantly with an increase in the competition period. However, yield and yield-contributing traits of chickpea significantly decreased with an increase in the competition period. Chickpea seed yield loss was 11-53% in different weed crop competition periods. Euphorbia dracunculoides and Astragalus sp. removed 39.9 and 36.9 kg ha-1 of N, 9.61 and 7.27 kg ha-1 of P and 38.3 and 36.9 kg ha-1 of K, respectively. Season long weed competition (160 days after sowing) resulted in 19.5% seed protein content compared with 24.5% seed protein content in weed-free chickpea. A Logistic equation was fitted to yield data in response to increasing periods of weed crop competition. The critical timing of weed removal at 5 and 10% acceptable yield losses were 26 and 39 DAS, respectively. The observed critical period suggests that in rainfed chickpea, a carefully timed weed removal could prevent grain yield losses.

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The ex-illiterate brain: The critical period, cognitive reserve and HAROLD model

Dementia & Neuropsychologia ◽

10.1590/s1980-57642009dn30300008 ◽

2009 ◽

Vol 3 (3) ◽

pp. 222-227 ◽

Cited By ~ 4

Author(s):

Maria Vania Silva Nunes ◽

Alexandre Castro-Caldas ◽

Dolores Del Rio ◽

Fernado Maestú ◽

Tomás Ortiz

Keyword(s):

Recognition Test ◽

Cognitive Skills ◽

Critical Period ◽

Cognitive Reserve ◽

Brain Activity ◽

High Educational Level ◽

Critical Periods ◽

Language Recognition ◽

Regular Time ◽

The Brain

Abstract The lifelong acquisition of cognitive skills shapes the biology of the brain. However, there are critical periods for the best use of the brain to process the acquired information. Objectives: To discuss the critical period of cognitive acquisition, the concept of cognitive reserve and the HAROLD (Hemispheric Asymmetry Reduction in Older adults) model. Methods: Seven women who learned how to read and to write after the age of 50 (ex-illiterates) and five women with 10 years of regular schooling (controls) were submitted to a language recognition test while brain activity was being recorded using magnetoencephalography. Spoken words were delivered binaurally via two plastic tubs terminating in ear inserts, and recordings were made with a whole head magnetometer consisting of 148 magnetometer coils. Results: Both groups performed similarly on the task of identifying target words. Analysis of the number of sources of activity in the left and right hemispheres revealed significant differences between the two groups, showing that ex-illiterate subjects exhibited less brain functional asymmetry during the language task. Conclusions: These results should be interpreted with caution because the groups were small. However, these findings reinforce the concept that poorly educated subjects tend to use the brain for information processing in a different way to subjects with a high educational level or who were schooled at the regular time. Finally, the recruiting of both hemispheres to tackle the language recognition test occurred to a greater degree in the ex-illiterate group where this can be interpreted as a sign of difficulty performing the task.

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APPLICATION RESULTS OF CUCUMBER GRAFTING ON DIFFERENT ROOTSTOSKS OF PUMPKIN

VEGETABLE CROPS OF RUSSIA ◽

10.18619/2072-9146-2018-6-31-33 ◽

2018 ◽

pp. 31-33

Author(s):

G. S. Martirosyan

Keyword(s):

Vitamin C ◽

Total Yield ◽

Growth Conditions ◽

Summer Period ◽

High Increase ◽

Fruit Setting ◽

The World ◽

Growth Development ◽

Fruit Mass ◽

Female Flowers

At present it is very actual in vegetable growing the development of highly effective and ecologically safe methods for increasing yields and plant resistance to unfavorable growth conditions. One of these methods is grafting. The goal of the study was to learn the influence of the rootstock on the characteristics of the growth, development and yield of cucumber. Research was conducted in 2015-2016 in greenhouse in spring-summer period in Armenia. As a scions was used cucumber variety Nazrvan, which was grafted on 5 pumpkin rootstocks (VI033637, VI03338, VI03364, VI040903, VI056328) from the collection of the World Vegetable Center (WVC). The grafting was carried out according to the standard method. When the VI033637 rootstock was used, flowering started 5 days earlier than the ungrafted plants, while when grafted on VI040903, the fruits ripened 6.2 days earlier. High increase of early yield (33.3%) received when used both above mentioned rootstocks. VI033638 – 4.1 kg/m2 and VI033664- 9.9 kg/m2 samples provided high increase of the total yield. For all the types of rootstocks the grafted plants of cucumber surpass the non-grafted ones by height from 4.7 % to 21.7%, by marketability of fruits from 5% to 14% and by fruit mass from 15 gr to 45 g. At the beginning of fruit-setting of cucumber plants the number of female flowers increased from 27% to 63% depending on the rootstock sample. The amount of dry substances in all grafted plants has increased by 4.4-8.8% and the amount of vitamin C by 1.8-9.2%. As a result of research carried out by us, perspective rootstocks (VIO33638 and VIO33664) are identified by a set of economically valuable characteristics which are recommended for applying in the further investigation and breeding activities and in production of grafted plants.

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