A simple technique to estimate, in situ, population densities of an entomopathogenic nematode (Heterorhabditis indica) in sandy soils

The sandy croplands in the Free State have been identified as one of the main dust sources in South Africa. The aim of this study was to investigate the occurrence and strength of physical soil crusts on cropland soils in the Free State, to identify the rainfall required to form a stable crust, and to test their impact on dust emissions. Crust strength was measured using a fall cone penetrometer and a torvane, while laboratory rainfall simulations were used to form experimental crusts. Dust emissions were measured with a Portable In-Situ Wind Erosion Laboratory (PI-SWERL). The laboratory rainfall simulations showed that stable crusts could be formed by 15 mm of rainfall. The PI-SWERL experiments illustrated that the PM10 emission flux of such crusts is between 0.14% and 0.26% of that of a non-crusted Luvisol and Arenosol, respectively. The presence of abraders on the crust can increase the emissions up to 4% and 8% of the non-crusted dust flux. Overall, our study shows that crusts in the field are potentially strong enough to protect the soil surfaces against wind erosion during a phase of the cropping cycle when the soil surface is not protected by plants.

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Virulence of two entomopathogenic nematode species, Steinernema sp. (strain PQ16) and Heterorhabditis indica (strain KT3987), to nymphs of the coffee cicada Dundubia nagarasingna

Nematology ◽

10.1163/15685411-00003193 ◽

2019 ◽

Vol 21 (1) ◽

pp. 35-44 ◽

Cited By ~ 1

Author(s):

Chau N. Nguyen ◽

Anh T. Do ◽

Phap Q. Trinh ◽

Phuc K. Hoang

Keyword(s):

Biological Control ◽

Entomopathogenic Nematodes ◽

Entomopathogenic Nematode ◽

Nematode Species ◽

Mortality Rates ◽

Coffee Plantations ◽

Heterorhabditis Indica ◽

Inoculation Dose ◽

Pot Trial

Summary The virulence and efficacy of two species of entomopathogenic nematodes, Steinernema sp. (strain PQ16) and Heterorhabditis indica (strain KT3987), against nymphs of the coffee cicada, Dundubia nagarasingna, was evaluated under laboratory and glasshouse conditions. The highest mortality rates of coffee cicada nymphs caused by these two nematode strains were 93.5 and 100%, respectively, at an inoculation dose of 600 infective juveniles (IJ) nymph−1. The virulence (LC50) was established as 137.5 IJ and 149.1 IJ for strains S-PQ16 and H-KT3987, respectively. The highest IJ yields of these nematode strains were 66 × 103 IJ (for S-PQ16) and 134.4 × 103 IJ (for H-KT3987) at a dose of 500 IJ nymph−1. The efficacies of the two nematode strains to coffee cicadas at treated dose of 60 × 103 IJ pot−1 were 84.4 and 88.9% after 30 days, higher than the efficacies at treated dose of 40 × 103 IJ pot−1. The number of IJ in 250 ml of soil at 10, 20 and 30 days after treatment, increased from 0.38 × 103 to 4.80 × 103 IJ in soil treated with a dose of 40 × 103 IJ and from 0.66 × 103 to 5.02 × 103 IJ in soil treated with a dose of 60 × 103 IJ (for S-PQ16). Similarly, for H-KT3987 the number of IJ increased from 0.43 × 103 to 8.99 × 103 IJ and from 0.62 × 103 to 9.64 × 103 IJ, at the respective doses. Based on results of a pot trial from glasshouse modelling, an IJ application dosage for biological control of coffee cicada nymphs in coffee plantations was proposed.

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MHD simulations of the in situ generation of kink and sausage waves in the solar corona by collision of dense plasma clumps

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935539 ◽

2019 ◽

Vol 626 ◽

pp. A53 ◽

Cited By ~ 1

Author(s):

P. Pagano ◽

H. J. Van Damme ◽

P. Antolin ◽

I. De Moortel

Keyword(s):

Solar Corona ◽

Theoretical Study ◽

Simple Technique ◽

Mhd Waves ◽

Mhd Simulations ◽

Wave Guides ◽

2D And 3D ◽

The Waves ◽

Space Description

Context. Magnetohydrodynamic (MHD) waves are ubiquitous in the solar corona where the highly structured magnetic fields provide efficient wave guides for their propagation. While MHD waves have been observed originating from lower layers of the solar atmosphere, recent studies have shown that some can be generated in situ by the collision of dense counter-propagating flows. Aims. In this theoretical study, we analyse the mechanism that triggers the propagation of kink and sausage modes in the solar corona following the collision of counter-propagating flows, and how the properties of the flows affect the properties of the generated waves. Methods. To study in detail this mechanism we ran a series of ideal 2D and 3D MHD simulations where we varied the properties of the counter-propagating flows; by means of a simple technique to estimate the amplitudes of the kink and sausage modes, we investigated their role in the generation and propagation of the MHD waves. Results. We find that the amplitude of the waves is largely dependent on the kinetic energy of the flows, and that the onset of kink or sausage modes depends on the asymmetries between the colliding blobs. Moreover, the initial wavelength of the MHD waves is associated with the magnetic configuration resulting from the collision of the flows. We also find that genuine 3D systems respond with smaller wave amplitudes. Conclusions. In this study, we present a parameter space description of the mechanism that leads to the generation of MHD waves from the collision of flows in the corona. Future observations of these waves can be used to understand the properties of the plasma and magnetic field of the solar corona.

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Estimation of In Situ Strength for Sandy Soils Using CPT Cone Resistance

Deep Foundations and Geotechnical In Situ Testing ◽

10.1061/41106(379)46 ◽

2010 ◽

Author(s):

Junhwan Lee ◽

Doohyun Kyung ◽

Jungmoo Hong

Keyword(s):

Sandy Soils ◽

Cone Resistance

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Breathing straws

The Journal of Laryngology & Otology ◽

10.1017/s0022215109991010 ◽

2009 ◽

Vol 124 (1) ◽

pp. 73-74

Author(s):

G Dhanasekar ◽

D Simmen ◽

H R Briner

Keyword(s):

Endoscopic Surgery ◽

Endoscopic Sinus Surgery ◽

Simple Technique ◽

Sinus Surgery ◽

Poor Sleep ◽

Nasal Cavities ◽

Operative Care ◽

Septal Surgery

AbstractFollowing nasal, septal or endoscopic surgery, it is common practice to insert nasal packs in both nasal cavities to achieve haemostasis, if there has been any bleeding at the end of the procedure. However, such packs make it difficult for patients to breathe, mainly in the first post-operative night which leads to discomfort and poor sleep. To enable patients to breathe better with nasal packs in situ, we describe a simple technique using trimmed straws and wrapped Netcell® packs for post-operative care following septal surgery, rhinoplasty and endoscopic sinus surgery. These packs also assist suction of any blood or mucous from the post-nasal space.

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A simple technique for in situ embedding of monolayer cultures in Lowicryl K4M

Journal of Microscopy ◽

10.1111/j.1365-2818.1988.tb04606.x ◽

1988 ◽

Vol 150 (2) ◽

pp. 161-163 ◽

Cited By ~ 6

Author(s):

G. BOU-Gharios ◽

G. Adams ◽

J. Moss ◽

I. Shore ◽

I. Olscen

Keyword(s):

Simple Technique ◽

Monolayer Cultures ◽

Lowicryl K4m ◽

In Situ Embedding

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Cannibals by night? In situ video monitoring reveals diel shifts in inter- and intra-specific predation on the American lobster

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2013-0099 ◽

2013 ◽

Vol 70 (11) ◽

pp. 1635-1640 ◽

Cited By ~ 12

Author(s):

Noah G. Oppenheim ◽

Richard A. Wahle

Keyword(s):

Video Surveillance ◽

Population Regulation ◽

Gulf Of Maine ◽

Homarus Americanus ◽

Quantitative Information ◽

Video Monitoring ◽

Predatory Fish ◽

American Lobster ◽

Population Densities

We conducted tethering experiments in the field to evaluate day–night differences in the identity and frequency of predators encountered by the American lobster (Homarus americanus) in coastal Maine, USA. Separate daytime and nighttime deployments were conducted using tethered lobsters under infrared-illuminated video surveillance. Supplemental tethering trials without video surveillance provided further quantitative information on diel and size-specific predation patterns. We found crabs to be the most common predators during the day, whereas lobsters prevailed at night. Contrary to expectations, we measured higher predation rates at night than during the day, suggesting that nocturnal interactions with conspecifics may play a more important role in lobster population regulation than previously thought when lobster population densities are high and large predatory fish are rare. As large predatory groundfish have been depleted in the Gulf of Maine, lobster populations have reached historic highs, making density-dependent feedbacks such as cannibalism more likely.

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Diurnal tracking of anthropogenic CO<sub>2</sub> emissions in the Los Angeles basin megacity during spring, 2010

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-12-5771-2012 ◽

2012 ◽

Vol 12 (2) ◽

pp. 5771-5801 ◽

Cited By ~ 12

Author(s):

S. Newman ◽

S. Jeong ◽

M. L. Fischer ◽

X. Xu ◽

C. L. Haman ◽

...

Keyword(s):

Los Angeles ◽

Fossil Fuel ◽

Simple Technique ◽

Anthropogenic Emissions ◽

Fossil Fuel Combustion ◽

Planetary Boundary Layer Height ◽

Los Angeles Basin ◽

Boundary Layer Height ◽

Anthropogenic Component

Abstract. Attributing observed CO2 variations to human or natural cause is critical to deducing and tracking emissions from observations. We have used in situ CO2, CO, and planetary boundary layer height (PBLH) measurements recorded during the CalNex-LA (CARB et al., 2008) ground campaign of 15 May–15 June 2010, in Pasadena, CA, to deduce the diurnally varying anthropogenic component of observed CO2 in the megacity of Los Angeles (LA). This affordable and simple technique, validated by carbon isotope observations, is shown to robustly attribute observed CO2 variation to anthropogenic or biogenic origin. During CalNex-LA, local fossil fuel combustion contributed up to ~50 % of the observed CO2 enhancement overnight, and ~100 % during midday. This suggests midday column observations over LA, such as those made by satellites relying on reflected sunlight, can be used to track anthropogenic emissions.

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