Friday, September 02, 2022

The scent that could save California’s (& MEXICO) avocado

Scientists search for pheromone to disrupt insect mating

Grant and Award Announcement

UNIVERSITY OF CALIFORNIA - RIVERSIDE

 NEWS RELEASE 

Hoddle in Mexico 

IMAGE: UC RIVERSIDE ENTOMOLOGIST MARK HODDLE ON THE HUNT FOR MEXICAN AVOCADO WEEVILS. view more 

CREDIT: MARK HODDLE/UCR

UC Riverside scientists are on the hunt for a chemical that disrupts “evil” weevils’ mating and prevents them from destroying California’s supply of avocados. 

Avocado weevils, small beetles with long snouts, drill through fruit to lay eggs. The weevil grubs or larvae bore into avocado seeds to feed, rendering everyone’s favorite toast topping inedible. 

“They’re extremely hard to control because they spend most of their time deep inside the fruit, where they’re very well protected from insecticides and natural enemies,” said UCR entomologist Mark Hoddle. 

Not only are the insects reclusive, they are also understudied, making information about them hard to come by. “All books on avocado pest management will tell you these weevils are bad. They’re well recognized, serious pests of avocados, but we know practically nothing about them,” Hoddle said.

One strategy for controlling pests is to introduce other insects that feed on them. However, that is unlikely to work in this case. “Natural enemies of these weevils seem to be extremely rare in areas where this pest is native,” Hoddle said.

To combat avocado weevils in Mexico, an area where they are native, and to prevent them from being accidentally introduced into California, Hoddle is working with Jocelyn Millar, a UCR insect pheromone expert. They are leading an effort to find the weevil’s pheromone, with the goal of using it to monitor these pests and prevent them from mating in avocado orchards. 

Pheromones are chemicals produced and released into the environment by an insect that can be “smelled” by others of its species, and affect their behavior. 

“We could flood avocado orchards with so much pheromone that males and females can’t find each other, and therefore can’t reproduce,” Hoddle said. “This would reduce damage to fruit and enable growers to use less insecticides.” 

Alternative control strategies could include mass trapping, using the pheromone as a lure, or an “attract-and-kill” approach, where the pheromone attracts the weevils to small sources of insecticide.

The work to identify, synthesize and test this pheromone in the field is supported by grants from the California Department of Food and Agriculture, as well as the California Avocado Commission. 

An initial phase of the project sent Hoddle to a base of operations three hours south of Mexico City, an area with large weevil populations. Using a special permit issued by the USDA, Hoddle brought weevils back to UCR’s Insectary and Quarantine facility. 

Hoddle and Sean Halloran, a UCR entomology researcher, captured the chemicals that avocado weevils release into the air. Possible pheromone compound formulas were identified from these crude extracts and are now being synthesized in Millar’s laboratory.  

“Weevil pheromones have complicated structures. When they’re made in a lab, they can have left- or right-handed forms,” said Hoddle. Initially, Millar’s group made a mixture of both forms to see if the blend would work as an attractant, as it is far cheaper to make the blend than the individual left- or right-handed forms. 

Field work in Mexico with the pheromone cocktail by Hoddle, his wife Christina Hoddle, an associate specialist in entomology, and Mexican collaborators did not get a big response from the weevils, suggesting that one of the forms in the blend could be antagonizing the response to the other. 

As the next step, the researchers plan to synthesize the individual forms of the chemicals and test the insects’ response to each in Mexican avocado orchards. 

Because the levels of avocado imports from Mexico are increasing, the risk of an accidental weevil invasion is rising as well. Hoddle is hopeful that the pheromone will be successfully identified and used to lower the risk this pest presents to California’s avocado growers. 

“We’ve been fortunate enough to be awarded these grants, so our work can be implemented in Mexico and benefit California at the same time,” Hoddle said. “The tools we develop now can be used to make sure crops from any exporting country are much safer to import into California.”

CAPTION

Avocado weevil.

CREDIT

Mike Lewis/UCR

  

CAPTION

Weevil damage rendering fruit useless.

CREDIT

Mark Hoddle/UCR

COSMOLOGY

VLBA produces first full 3-D view of binary star-planet system

Technique provides details otherwise unavailable

Peer-Reviewed Publication

NATIONAL RADIO ASTRONOMY OBSERVATORY

Two Stars and a Planet 

IMAGE: FROM ABOVE A PLANET ABOUT TWICE THE SIZE OF JUPITER, THIS ARTIST'S CONCEPTION SHOWS THE STAR THAT PLANET IS ORBITING AND THAT STAR'S BINARY COMPANION IN THE DISTANCE. view more 

CREDIT: SOPHIA DAGNELLO, NRAO/AUI/NSF.

By precisely tracing a small, almost imperceptible, wobble in a nearby star's motion through space, astronomers have discovered a Jupiter-like planet orbiting that star, which is one of a binary pair. Their work, using the National Science Foundation's Very Long Baseline Array (VLBA), produced the first-ever determination of the complete, 3-dimensional structure of the orbits of a binary pair of stars and a planet orbiting one of them. This achievement, the astronomers said, can provide valuable new insights on the process of planet formation. 

Though more than 5,000 extrasolar planets have been discovered so far, only three have been discovered using the technique -- called astrometry -- that produced this discovery. However, the feat of determining the 3-D architecture of a binary-star system that includes a planet "cannot be achieved with other exoplanet discovery methods," said Salvador Curiel, of the National Autonomous University of Mexico (UNAM).

"Since most stars are in binary or multiple systems, being able to understand systems such as this one will help us understand planet formation in general," Curiel said.

The two stars, which together are called GJ 896AB, are about 20 light-years from Earth -- close neighbors by astronomical standards. They are red dwarf stars, the most common type in our Milky Way galaxy. The larger one, around which the planet orbits, has about 44 percent of the mass of our Sun, while the smaller is about 17 percent as massive as the Sun. They are separated by about the distance of Neptune from the Sun, and orbit each other once every 229 years.

For their study of GJ 896AB, the astronomers combined data from optical observations of the system made between 1941 and 2017 with data from VLBA observations between 2006 and 2011. They then made new VLBA observations in 2020. The continent-wide VLBA's supersharp resolution -- ability to see fine detail -- produced extremely precise measurements of the stars' positions over time. The astronomers performed extensive analysis of the data that revealed the stars' orbital motions as well as their common motion through space.

Detailed tracing of the larger star's motion showed a slight wobble that revealed the existence of the planet. The wobble is caused by the planet's gravitational effect on the star. The star and planet orbit a location between them that represents their common center of mass. When that location, called the barycenter, is sufficiently far from the star, the star's motion around it can be detectable.

The astronomers calculated that the planet has about twice the mass of Jupiter and orbits the star every 284 days. Its distance from the star is slightly less than Venus' distance from the Sun. The planet's orbit is inclined roughly 148 degrees from the orbits of the two stars. 

"This means that the planet moves around the main star in the opposite direction to that of the secondary star around the main star," said Gisela Ortiz-León, of UNAM and the Max Planck Institute for Radioastronomy. "This is the first time that such dynamical structure has been observed in a planet associated with a compact binary system that presumably was formed in the same protoplanetary disk", she added.

"Additional detailed studies of this and similar systems can help us gain important insights into how planets are formed in binary systems. There are alternate theories for the formation mechanism, and more data can possibly indicate which is most likely," said Joel Sanchez-Bermudez, of UNAM. "In particular, current models indicate that such a large planet is very unlikely as a companion to such a small star, so maybe those models need to be adjusted," he added. 

The astrometric technique will be a valuable tool for characterizing more planetary systems, the astronomers said. "We can do much more work like this with the planned Next Generation VLA (ngVLA)," said Amy Mioduszewski, of the National Radio Astronomy Observatory. "With it, we may be able to find planets as small as the Earth."

The astronomers are reporting their findings in the 1 September issue of the Astronomical Journal.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

IMPACT STUDIES

Crime-scene technique identifies asteroid sites


Peer-Reviewed Publication

UNIVERSITY OF EXETER

Analysing the charred remains of plants can confirm the locations of asteroid strikes in the distant past, new research shows.

Based on estimates of crater-producing asteroid strikes in the last 11,650 years (known as the Holocene), only about 30% of impact sites have been located.

Until now, there has been no way to distinguish between normal land structures and very small asteroid craters unless pieces of iron meteorites were found nearby.

In the new study, an international team of researchers found that charcoal around craters is different from wildfire charcoal – so analysing samples allows scientists to work out the origin of small craters.

"The properties of organisms turned into charcoal reflect the conditions in which they were killed," said lead author Dr Ania Losiak, from the Institute of Geological Sciences, Polish Academy of Sciences and the University of Exeter.

"Those conditions, such as the heat the wood was exposed to or the duration of the heating, leave tell-tale signs in the material’s structure.

"For example, charcoal from low-energy surface fires, like burning bushes and leaves, has different properties than charcoal from high-intensity wildfires.

"Impact charcoals are very strange. They all look as if they were formed in much lower temperatures than wildfire charcoals, and they are all very similar to each other, while in a wildfire it is common to find strongly charred wood just next to barely affected branches."

Dr Losiak worked on the research as part of a Marie Sklodowska-Curie Individual Fellowship at the University of Exeter wildFIRE lab, led by Professor Claire Belcher.

The research team dug trenches in rims of four craters (Kaali Main and Kaali 2/8 in Estonia, Morasko in Poland, and Whitecourt in Canada).

"The differences between wildfire charcoal and impact charcoal proved to be dramatic and surprising," said Professor Belcher, part of Exeter's Global Systems Institute.

"While wildfire charcoal is considerably varied in its reflectivity, depending on the local conditions during the fire, impact charcoals showed uniform characteristics despite coming from completely different locations and being formed thousands of years apart.

"This presents an opportunity for geologists looking for unrecognised impact craters."

Professor Chris Herd, from the University of Alberta, said: "This study improves our understanding of environmental effects of small impact crater formation so that in the future, when we discover an asteroid a few metres across or more coming our way only a couple of weeks before the impact, we will be able to more precisely determine the size and type of evacuation zone necessary." 

Dr Losiak added: "Since 1900, two impacts – in Tunguska and Chelyabinsk – caused damage on a massive scale.

"In order to prepare for any future threats, we need to understand how often collisions like that occur.

"And to do that, we need to look to our planet’s recent past."

The paper, published in the journal Geology, is entitled: "Small impact cratering processes produce distinctive charcoal assemblages."

YouTube more likely to direct election-fraud videos to users already skeptical about 2020 election’s legitimacy

New study shows how site’s algorithms perpetuate existing misperceptions

Peer-Reviewed Publication

NEW YORK UNIVERSITY

YouTube was more likely to recommend videos about election fraud to users who were already skeptical about the legitimacy of the 2020 U.S. presidential election, shows a new study examining the impact of the site’s algorithms. 

The results of the research, which is published in the Journal of Online Trust and Safety, showed that those most skeptical of the election’s legitimacy were shown three times as many election-fraud-related videos as were the least skeptical participants—roughly 8 additional recommendations out of approximately 400 videos suggested to each study participant. 

While the overall prevalence of these types of videos was low, the findings expose the consequences of a recommendation system that provides users with the content they want. For those most concerned about possible election fraud, showing them related content provided a mechanism by which misinformation, disinformation, and conspiracies can find their way to those most likely to believe them, observe the authors of the study. Importantly, these patterns reflect the independent influence of the algorithm on what real users are shown while using the platform.

“Our findings uncover the detrimental consequences of recommendation algorithms and cast doubt on the view that online information environments are solely determined by user choice,” says James Bisbee, who led the study as a postdoctoral researcher at New York University’s Center for Social Media and Politics (CSMaP).

Nearly two years after the 2020 presidential election, large numbers of Americans, particularly Republicans, don’t believe in the legitimacy of the outcome. 

“Roughly 70% of Republicans don’t see Biden as the legitimate winner,” despite “multiple recounts and audits that confirmed Joe Biden’s win,” the Poynter Institute’s PolitiFact wrote earlier this year.

While it’s well-known that social media platforms, such as YouTube, direct content to users based on their search preferences, the consequences of this dynamic may not be fully realized. 

In the CSMaP study, the researchers sampled more than 300 Americans with YouTube accounts in November and December of 2020. The subjects were asked how concerned they were with a number of aspects of election fraud, including fraudulent ballots being counted, valid ballots being discarded, foreign governments interfering, and non-U.S. citizens voting, among other questions. 

These participants were then asked to install a browser extension that would record the list of recommendations they were shown. The subjects were then instructed to click on a randomly assigned YouTube video (the “seed” video), and then to click on one of the recommendations they were shown according to a randomly assigned “traversal rule”. For example, users assigned to the “second traversal rule” would be required to always click on the second video in the list of recommendations shown, regardless of its content. By restricting user behavior in these ways, the researchers were able to isolate the recommendation algorithm’s influence on what real users were being suggested in real time. 

The subjects then proceeded through a sequence of YouTube recommended videos, allowing the researchers to observe what the YouTube algorithm suggested to its users. Bisbee and his colleagues then compared the number of videos about election fraud in the 2020 U.S. presidential election that were recommended to participants who were more skeptical about the legitimacy of the election to those recommended to participants who were less skeptical. These results showed that election skeptics were recommended an average of eight additional videos about possible fraud in the 2020 US election, relative to non-skeptical participants (12 vs. 4).

“Many believe that automated recommendation algorithms have little influence on online ‘echo chambers’ in which users only see content that reaffirms their preexisting views,” observes Bisbee, now an assistant professor at Vanderbilt University. “Our study, however, suggests that YouTube's recommendation algorithm was able to determine which users were more likely to be concerned about fraud in the 2020 U.S. presidential election and then suggested up to three times as many videos about election fraud to these users compared to those less concerned about election fraud. This highlights the need for further investigation into how opaque recommendation algorithms operate on an issue-by-issue basis."

The paper’s other authors were Joshua A. Tucker and Jonathan Nagler, professors in NYU’s Department of Politics, and Richard Bonneau, a professor in NYU’s Department of Biology and Courant Institute of Mathematical Sciences, as well as Megan A. Brown, the senior research engineer at CSMaP, and Angela Lai, an NYU doctoral student. Tucker and Nagler are co-directors of CSMaP.

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The American Association of Feline Practitioners and EveryCat Health Foundation Announce Feline Infectious Peritonitis (FIP) Diagnosis Guidelines

New Guidelines provide veterinarians with essential information to diagnose FIP

Peer-Reviewed Publication

SAGE

BRIDGEWATER, NJ; WYCKOFF, NJ; September 1, 2022 – The American Association of Feline Practitioners (AAFP) and EveryCat Health Foundation have released the 2022 AAFP/EveryCat Feline Infectious Peritonitis Diagnosis Guidelines. These landmark Guidelines are published in the Journal of Feline Medicine and Surgery and will provide veterinarians with the essential information necessary to provide a FIP diagnosis in cats. FIP is a viral disease that can affect any organ in the body and is caused by a feline coronavirus (FCoV).

“First recognized over 50 years ago, feline infectious peritonitis has been one of the most important infectious diseases and causes of death in cats, especially affecting young cats less than two years old,” said Vicki Thayer, DVM, DABVP (Feline), Task Force Co-chair. “Further, FIP can be challenging to diagnose in some cases and is often considered an enigma by the veterinary profession. Today, diagnosis relies upon evidence from signalment, history, physical examination findings, and diagnostic testing. The 2022 AAFP/EveryCat Feline Infectious Peritonitis Diagnosis Guidelines serve as a critical resource for veterinary practitioners diagnosing FIP in their cat patients.”

Given the fact that FIP is fatal when untreated and nearly every small animal veterinary practitioner will see FIP cases, the ability to obtain a correct diagnosis is critical. FIP can be challenging to diagnose due to the lack of clinical signs or laboratory changes, especially when no physical symptoms are present. These Guidelines will provide veterinarians with essential information to assist their ability to recognize cats presenting with FIP. “These Guidelines were
written with the intent of providing the most current knowledge available in one comprehensive format combined with extensive supplemental resources all in one location,” adds Susan Gogolski, DVM, DABVP (Canine/Feline), Task Force Co-chair. “The Guidelines will be an invaluable resource to veterinary teams around the world as a clinician builds the index of suspicion of FIP brick by brick.”

The 2022 AAFP/EveryCat Feline Infectious Peritonitis Diagnosis Guidelines were developed by a Task Force of experts in feline clinical medicine. Helpful tips, images and tables, and algorithms are included throughout the document. In addition, the Guidelines feature 16 valuable supplemental resources that appear online such as videos, figures, instructions, and a questionnaire.

The AAFP and EveryCat Health Foundation thank Boehringer Ingelheim Animal Health USA Inc. for supporting these Guidelines and resources through an educational grant.

Download the FIP Diagnosis Guidelines at the AAFP or EveryCat Health Foundation website. Resources for cat caregivers can be found at catfriendly.com/FIP.