Archive for 'Research News'

Magic Sand and Degradation, at the Shi-Ting River

Friday, November 15th, 2019

Degradation, over long periods of time, is a worry to some scientists, as is evident in this new study:

Can magic sand cause massive degradation of a gravel-bed river at the decadal scale? Shi‑ting River, China,” Chenge An, Gary Parker, Marwan A. Hassan, and Xudong Fu, Geomorphology, vol. 327, February 15, 2019, pp. 147-158. (Thanks to Tom Gill for bringing this to our attention.) The authors, at Tsinghua University, Beijing, China; the University of Illinois, USA; and the University of British Columbia, Canada, report:

Massive bed degradation (20 m in 7 years) has been observed in the Shi‑ting River, Sichuan Province, China, since the 2008 Wenchuan Ms. 8.0 earthquake. The reason for the massive bed degradation has not been well understood. A hypothesis has been proposed that relates bed degradation to the augmentation of sand supply after the earthquake. The effect of sand on gravel mobility (magic sand effect) has long been observed in laboratory experiments. In this paper, we study whether the augmentation of sand supply and its magic sand effect can lead to the observed massive degradation at decadal scales….

Our simulation results also indicate that despite the fact that magic sand effects are not explicitly included in most sediment transport relations, they are at least partly built in via the hiding function that is contained in most sediment transport relations for gravel-sand mixtures.

The insect sex research adventures of Yoshitaka Kamimura

Wednesday, November 13th, 2019

This insect-sex-reversal-centric profile of 2017 Ig Nobel Biology Prize co-winner Yoshitaka Kamimura appeared a year ago in the Keio Times:

Sex-Role Reversal Research in Insects Wins Ig Nobel Prize for Keio Professor Yoshitaka Kamimura

…In 2012, Prof. Kamimura was first invited to join a research team led by Kazunori Yoshizawa, an associate professor at Hokkaido University, whose award-winning research focuses on cave-dwelling species of insect from Brazil that belongs to the genus Neotrogla. In most insects, the male penetrates the female reproductive organ to transfer seminal fluid, but for Neotrogla, it is the female that has a penis, which it uses to penetrate the male in order to receive seminal fluid and nutritional substances.

“Neotrogla are small, 3mm-long insects that inhabit caves in Brazil. Our first face-to-face encounter with these fascinating creatures was in 2016, when we donned headlamps and explored the caves in search of them. The caves they inhabit are quite dry and food is scarce, which forces them to rely on bat guano and mouse droppings to survive….”

 

 

The entomologist who seduced malaria mosquitoes with cheese

Tuesday, November 12th, 2019

“Bart Knols, the entomologist who seduced the mosquito mosquito with cheese” says the headline of this Telemetro [Panama] profile of Ig Nobel Prize winner Bart Knols and his innovations against malaria.

The 2006 Ig Nobel Prize for biology was awarded to Bart Knols (of Wageningen Agricultural University, in Wageningen, the Netherlands; and of the National Institute for Medical Research, in Ifakara Centre, Tanzania, and of the International Atomic Energy Agency, in Vienna Austria) and Ruurd de Jong (of Wageningen Agricultural University and of Santa Maria degli Angeli, Italy) for showing that the female malaria mosquito Anopheles gambiae is attracted equally to the smell of limburger cheese and to the smell of human feet.

Their Ig-winning research is documented in several publications:

REFERENCE: “On Human Odour, Malaria Mosquitoes, and Limburger Cheese,” Bart. G.J. Knols, The Lancet, vol. 348 , November 9, 1996, p. 1322.

REFERENCE: “Behavioural and electrophysiological responses of the female malaria mosquito Anopheles gambiae (Diptera: Culicidae) to Limburger cheese volatiles,” Bulletin of Entomological Research, B.G.J. Knols, J.J.A. van Loon, A. Cork, R.D. Robinson, et al., vol. 87, 1997, pp. 151-159.

REFERENCE: “Limburger Cheese as an Attractant for the Malaria Mosquito Anopheles gambiae s.s.,” B.G,J. Knols and R. De Jong, Parasitology Today, yd. 12, no. 4, 1996, pp. 159-61.

REFERENCE: “Selection of Biting Sites on Man by Two Malaria Mosquito Species,” R. De Jong and B.G.J. Knols, Experientia, vol. 51, 1995, pp. 80–84.

The dynamics of hula-hooping

Friday, November 8th, 2019

Hole Assessment by Finger and Tongue [research study]

Wednesday, November 6th, 2019

A markedly penetrating report, involving fingers, tongues, and holes:

Differences in the oral size illusions produced by cross-modality matching of peg and hole stimuli by the tongue and fingers in humans,” Bruce Melvin and Robin Orchardson, Archives of Oral Biology, vol. 46, no. 3, March 2001, pp. 209-13. The authors, at the University of Glasgow, Scotland, report:

“Individuals overestimate the diameter of 1-mm-deep stimulus holes presented to the tongue when they use their fingers to select a hole of matching diameter. The aim here was to determine whether the oral size illusion evident for 1-mm-deep holes would also occur with 1-mm-high pegs of similar diameters. The illusion was studied in 24 individuals who were blindfolded during the trials. The two sets of test stimuli were (a) 5 cylindrical pegs (1 mm high) and (b) five circular holes (1 mm deep), each of 2.5, 5.0, 7.5, 10.0, 12.5 mm dia. The stimuli were held to the mouth with one hand, while the fingers of the free hand were used to select a matching object from a comparator series of either 1-mm-deep holes or 1-mm-high pegs ranging from 2.0 to 18 mm dia…. Regardless of the nature of the stimulus (‘hole’ or ‘peg’), a mismatch between the stimulus and comparator was consistently seen only when the fingers probed comparator holes. The oral size illusion is not due to any intrinsic differences in the sensitivities of the tongue or fingers. Rather, the illusion is due to the inability of the fingertip to access small comparator holes.”

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