Frog embryos associate the smell of predators with danger

first_img(PhysOrg.com) — A new study in the US and Canada has found that frogs can learn to associate the smell of predators with danger, even as embryos. A young wood frog. Credit: Michael Zahniser, via Wikimedia Commons. Citation: Frog embryos associate the smell of predators with danger (2009, November 3) retrieved 18 August 2019 from https://phys.org/news/2009-11-frog-embryos-associate-predators-danger.html The aim of the experiments was to find out if woodfrog (Rana sylvatica) embryos could learn to associate the odor of injured tadpoles with that of their predator, and if they could discriminate between different levels of threat. They also aimed to find out if the time of day would be a factor.In the study, woodfrog egg masses were put into water containing the odor of tiger salamanders (Ambystoma tigrinum) and various concentrations of “injured tadpole” odor between the hours of 1500 and 1700 for five consecutive days. They were then raised for nine days after hatching.The scientists, Dr. Maud Ferarri, from the University of California at Davis, and Douglas Chivers from the University of Saskatchewan, created the olfactory cues by using water previously occupied by a tiger salamander, and water containing varying concentrations of crushed tadpoles. Both chemical cues were added to the water surrounding the frog egg masses.When the eggs hatched, the scientists tested the responses of the tadpoles by placing them in fresh water and measuring how much they moved. They then added water containing the salamander odor, and measured their movements again. They checked the responses at different times. The results revealed that the embryos had learned to associate the predator’s odor with danger.The results ranged from tadpoles swimming normally to freezing for several minutes. Tadpoles that had been exposed as embryos to higher concentrations of injured tadpole odor froze for the longest time, which the scientists say shows they had learned to associate the salamander odor with danger. (Freezing is a common behavior when faced with a threat.) Responses were stronger between 1500 and 1700 hours than they were if the tadpoles were exposed to the odor either earlier or later. The researchers said this type of learning has been found previously in larval amphibians, mosquitoes and fish, but had not been seen in embryos until now.Dr. Ferarri said the embryos presumably “smell” the cues in the water surrounding the eggs. She also said that learning to detect predators at such an early stage makes evolutionary sense and there must be selection for learning to detect predators in this way as it is often the only way they have to recognize them.The findings of the study were published in the Behavioral Ecology and Sociobiology journal.More information: The ghost of predation future: threat-sensitive and temporal assessment of risk by embryonic woodfrogs, Behavioral Ecology and Sociobiology, DOI:10.1007/s00265-009-0870-y© 2009 PhysOrg.com Explore further Time of Day Tempers Tadpoles’ Response to Predators This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Increase in acidity may not be harmful to coral reefs after all

first_img © 2015 Phys.org More information: K. L. Yeakel et al. Shifts in coral reef biogeochemistry and resulting acidification linked to offshore productivity, Proceedings of the National Academy of Sciences (2015). DOI: 10.1073/pnas.1507021112AbstractOceanic uptake of anthropogenic carbon dioxide (CO2) has acidified open-ocean surface waters by 0.1 pH units since preindustrial times. Despite unequivocal evidence of ocean acidification (OA) via open-ocean measurements for the past several decades, it has yet to be documented in near-shore and coral reef environments. A lack of long-term measurements from these environments restricts our understanding of the natural variability and controls of seawater CO2-carbonate chemistry and biogeochemistry, which is essential to make accurate predictions on the effects of future OA on coral reefs. Here, in a 5-y study of the Bermuda coral reef, we show evidence that variations in reef biogeochemical processes drive interannual changes in seawater pH and Ωaragonite that are partly controlled by offshore processes. Rapid acidification events driven by shifts toward increasing net calcification and net heterotrophy were observed during the summers of 2010 and 2011, with the frequency and extent of such events corresponding to increased offshore productivity. These events also coincided with a negative winter North Atlantic Oscillation (NAO) index, which historically has been associated with extensive offshore mixing and greater primary productivity at the Bermuda Atlantic Time-series Study (BATS) site. Our results reveal that coral reefs undergo natural interannual events of rapid acidification due to shifts in reef biogeochemical processes that may be linked to offshore productivity and ultimately controlled by larger-scale climatic and oceanographic processes. To better understand what might happen with coral reefs if more carbon dioxide makes its way into the oceans due to an increase of the gas in the atmosphere caused by human emissions, the researchers set up monitoring devices along a coral reef offshore from Bermuda—information from the sensors was monitored for five years (2007 to 2012). The team also had access to data from an ocean chemistry monitoring station approximately 80 kilometers from their study site. The combined data offered a unique perspective on coral activity.In studying the data, the researchers noticed that spikes of phytoplankton blooms occurred during 2010 and again in 2011—those blooms made their way to the coral reef offering more food than normal for the coral. The coral responded by growing which caused them to pull more alkaline carbonate from the surrounding water, making it more acidic. Eating more also resulted in the corals emitting more carbon dioxide into the water. The result was a big increase in acidity—to levels higher than have been predicted for the future due to human emissions—yet, the coral continued to flourish.These observations contrast sharply with the prevailing view that an increase in acidity is harmful to coral—leading to death if it goes too far. But the levels seen by the researchers with this new effort suggest that is not the case at all, and therefore muddles theories regarding the impact on the oceans of higher levels of carbon dioxide and warmer temperatures. Another team with Western Australia noted that the results found by this new team appeared to agree with those of a small study they conducted where they put boxes around some coral and piped in carbon dioxide, to no detrimental effect. Carbon dioxide-spewing volcano drives reef from coral to algae This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Journal information: Proceedings of the National Academy of Sciencescenter_img Explore further Citation: Increase in acidity may not be harmful to coral reefs after all (2015, November 10) retrieved 18 August 2019 from https://phys.org/news/2015-11-acidity-coral-reefs.html (Phys.org)—A combined team of researchers affiliated with the Scripps Institution of Oceanography and the Bermuda Institute of Ocean Sciences has found, via a five year study, that increased ocean acidification may not pose the threat to coral reefs that scientists have thought. In their paper published in Proceedings of the National Academy of Sciences, the team describes their study and why they now believe that an increase in green house gas emissions many not have the devastating impact on coral reefs that most in the field have assumed would occur. Close up of polyps are arrayed on a coral, waving their tentacles. There can be thousands of polyps on a single coral branch. Credit: Wikipedialast_img read more

Capturing the never returning moments

first_imgSimply magic, isn’t it? Photographer Sooni Taraporevala feels the same. Her on-going exhibition titled Through a Lens, By a Mirror: The Parsis (1977 – 2013) displays 36 years of her clicking the Parsi community.She has photographed people as they go about their daily lives, successfully narrating emotions of her subjects as they make conversation, at home or in the streets of Mumbai. Taraporevala’s photographs explore the myriad perspectives of her own family and the community. The photographs speak unabatedly  of the charming persona of the Parsis, their eloquent and warm disposition and their passion for life. Also Read – ‘Playing Jojo was emotionally exhausting’About her photographs, the artiste says, “For me, Photographs freeze time and survive death. My grandmother died, so did my grandfather and granduncle and a host of aunts and uncles. But not before I had captured them on celluloid. Their photographs still give me some measure of, perhaps, childish comfort.”The exhibition is organised by National Gallery of Modern Art and  Ministry of Culture.When: Till 3 November 10 am onwardsWhere: National Modern Art Gallerylast_img read more

Pulp friction

first_imgThe imminent ‘pulping’ of Wendy Doniger’s The Hindus: An Alternative History sounds an ominous bell. It is really two things at once: one, the relentless political pressure rising from the far-right religious groups, whether they be Hindu, Islamic or Christian; and the other, the shrinking of liberal space via a) censorship and b) self-censorship. The decision to opt for an out-of-court settlement and look for a quiet exit by Penguin, in this light, is no less criminal than Dinanath Batra’s feeling offended by Doniger’s innovative interpretation of Hinduism, particularly by its uncovering of neglected and subaltern histories – those of women, Dalits, Tantric yogis and other practitioners of pleasure and pain that go, strictly speaking, against the ‘bourgeoisie’ Vendantic tradition, favouring all the entrenched divisions and tiers within the religion. So while we feel embarrassed and offended by Batra’s lawsuit that describes Doniger’s ‘factual inaccuracies’, we should feel a million times more let down, and indeed we do, by Penguin India’s pusillanimous stand, its supine succumbing to a little pressure from a tiny group affiliated with the RSS. Also Read – ‘Playing Jojo was emotionally exhausting’Doniger’s tome is not alone in this tragedy of collective ineffectuality. We had A K Ramanujan’s stellar essay Three Hundred Ramayanas scrapped from the Delhi University’s MA English curriculum only three years back. Other works of historical reinterpretation, say Joseph Lelyveld’s Great Soul, based on M K Gandhi’s stint in South Africa, was dubbed unreadable and insulting for its frank explorations of sexuality. We have, of course, the epic case of book banning and burning in The Satanic Verses, the hounding flames of which still reach for the NYC-dwelling Salman Rushdie, making his India tours a matter of great political and public consternation. We also have Taslima Nasreen, whose books keep facing the axe at the same pace at which she pens them, choosing still to go with the gut rather than opting for safer thematic havens. Among artists, we have the grand catastrophe and historical blunder in the maestro, the late M F Hussain, picking exile in Qatar over the ‘creative chaos’ of India as a result of Shiv Sena’s constant vandalisation of his works, his nude Saraswatis and Mother Indias. Also Read – Leslie doing new comedy special with NetflixNo matter how we wish to look at it – whether as a grand dance of democracy which throws to the surface the obscene but often sidelined voices of the neo-natives, the hardline cultural nationalists, the patriarchal patriots, mostly all easily offended, or as a muzzling of truly liberal and radical voices, not just those dressed in seminar English and political correctness of the day, but those digging deep and excavating lost or buried tropes, shedding new light on the subterranean tunnels of history, politics and literature – there’s little joy in seeing a book waiting for the gallows. Much like capital punishment, pulping or burning of books reeks of an extreme punitive approach to dissent, to difference and to the other. It’s uncomfortable with non-conformity; hence perennially threatened. It’s rarely the exact occasion that ensues this angry bird’s hawkish ire – it’s more a mouldy and partisan convenience, whether of relevance or reiteration, that sets off the triggers, resulting in violence, intellectual, physical and cultural. It is in fact the same state-society complex that punishes people and ostracises them for thinking and expressing differently, say in their choice of sexual partners, or in their interlacing of words with loaded sexuality, particularly of the dissident variety, also goes for the theory of banishment – of ideas, of people, of lives. Hence, whether Doniger’s book is an erudite work of scholarly brilliance or a puerile mass of unsubstantiated conjectures is not the question. The real question is: why can’t Doniger’s book exist, be read, shared and critiqued, stirring, as the Chicago University-based ‘Indologist’ hoped, ‘creative controversy’? Why must debate be sacrificed at the altar of sameness, or interpretations that have ossified and exploited millions for thousands of years thwart ones that are new and contentious?  And, in this context, why can’t a publisher, one of the oldest and biggest, with liberal pretensions and self-aggrandising tone and tenor, also a global shark really with the latest merger with Random House, stand up to a small, literally insignificant tributary of the RSS stream?These are strange times. If world cities and mega malls have no room for libraries and if we run out of reading material, if we stop ourselves from coming out and reclaiming the streets, the bedrooms, the pages, the ink, the mind and the bodies, what good would that be? Perhaps, the mantra ‘publish or perish’ has a new meaning now.Is the Chicken listening?last_img read more

Govt pushes civic bodies for antilarvae drives

first_imgKolkata: The state government has asked all the civic bodies to conduct anti-larvae drives seriously.In the meeting of the nodal body, comprising representatives of the state Health, Fisheries and Urban Development departments, along with representatives of all the municipal corporations and municipalities, which was held at Sasthya Bhavan on Tuesday, senior officials have urged the civic bodies to launch the drives seriously. Particular emphasis has been laid on cleaning of garbage and house-to-house visit. Also Read – Heavy rain hits traffic, flightsIt may be mentioned that Chief Minister Mamata Banerjee, in all the administrative review meetings held recently, had asked the civic bodies to launch the drives seriously. The state government has given Rs 4 crore to Kolkata Municipal Corporation (KMC), to launch campaigns in this regard and buy equipment to spray mosquito repellants.Accordingly, all the municipalities and corporations have taken initiatives to combat dengue and malaria. Some municipalities have released Gappi fishes in drains, as they eat mosquito larvae. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedSteps have been taken by all the civic bodies to launch massive awareness campaigns in this regard. Through posters, billboards and tableaus, the awareness drives are being conducted. People have been urged to cooperate with the civic bodies as without their support, mosquito-borne diseases cannot be controlled.The KMC has set up 15 dengue detection centres, where blood samples are examined and medicines are given free of cost. The Health department workers are visiting houses to inspect the underground reservoirs and overhead tanks. Actions are being taken against the owners who are found not maintaining the water tanks properly.South Dum Dum Municipality has chalked out elaborate plans to combat dengue and malaria, while Bidhannagar Municipal Corporation is conducting anti-larvae drives throughout the year.Senior state government officials said that as the dengue-carrying mosquitoes have changed their breeding season because of global warming, it is absolutely essential to conduct the drives throughout the year.last_img read more

Independence Day celebrations Kalimpong gets ready for gala event

first_imgDarjeeling: While places like Kolkata can boast of Durga Puja celebrations and Mumbai of Ganesh puja, Kalimpong can safely boast of a unique Independence Day celebration. This two-day affair in the hill town is nothing short of Dussehra or Diwali celebrations.”What Dussehra is in some places and Diwali in others, Independence Day celebrations is the same in Kalimpong. It heralds in the festive season. From early days, Kalimpong has been known for the two-day long celebrations,” stated Binay Ghising, Convenor of the Independence Day Celebration Committee. Also Read – Rain batters Kolkata, cripples normal lifeFrom restaurants to garment stores, everything remains packed as Kalimpong gears up to celebrate Independence day.”Earlier locals used to stitch new clothes and tailors remained busy well in advance. Now, it’s the ready-made garment stores. Earlier, hotels used to remain packed as people from Bhutan, Sikkim and even Nepal arrived in Kalimpong to witness the two-day long celebrations,” stated Kailash Bagdas, a local.Independence day is brisk business. “It is not just about celebrations. The local economy also gets a major boost owing to the celebrations. Many buy new clothes for the Independence Day,” stated Sanju Gupta, owner of a garment shop. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedPreparations are on in full swing for the mega event. A total of 21 schools are taking part in this year’s parade. “They will present the salute on the Mela Ground in Kalimpong following which they will take Dal Bahadur Giri road, popular as the Main Road,” added Ghising.Binay Tamang, Chairman, Board of Administrators, Gorkhaland Territorial Administration, will grace the ocassion as the Chief Guest and will take the salute.The Main road will be devoid of traffic on August 15. Thousands of people line up on either side of the road and occupy roof tops to watch the parade. Food Stalls will be put up all along the route. March past is the main attraction of the day, along with the final of the Independence Day football tournament.On August 16, drill display and marching band display competitions; cultural shows will be held along with the football tournament.”This year we are felicitating three ladies for their social contributions. Sova Chettri, social worker, Sister Subheshna Thapa, who works in mitigating child labour, and traffic police Geetu Tamang,” added Ghising.Darjeeling too will witness parades, drill display and cultural shows at the programme organised by the Information and Cultural Department, Gorkhaland Territorial Administration. On the eve of the Independence Day, the Striking Lion Division of the Indian Army put up a marching pipe band display and Khukhuri dance display at Darjeeling Chowrasta on Tuesday.last_img read more

Chaos on campus had no impact on emergency services NRS principal

first_imgKolkata: The principal of NRS Medical College and Hospital has written to the Director of Medical Education (DME) at Swasthya Bhavan on Monday stating that emergency health services were never stopped at the hospital following the clash that broke out between junior doctors and relatives of a patient who died there on Sunday morning.A college council meeting was held at NRS on Monday discussing Sunday’s incident.Senior officials of NRS Medical College spoke to the interns and junior doctors to get information about the violence that took place at the emergency ward after the patient dies. Also Read – Rain batters Kolkata, cripples normal lifeThe interns and junior doctors have urged the hospital authorities to put in place adequate security arrangements inside the campus. In previous occasions, junior doctors had been heckled by the family members of patients but the authorities have failed to check such incidents.In his letter to the senior health official, the principal said though some doctors were taking part in the agitation, it did not have any impact on the emergency health services of the hospital. However, there was some delay in the admission of patients due to the chaos that broke out on the hospital campus, the principal clarified. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedThe hospital authorities on Sunday lodged an FIR with the local police station on the basis of which police have arrested five persons for triggering violence.The trouble broke out on the hospital campus after a patient, Pervej Hossain, a resident Topsia died at the hospital.He was taken to NRS after he complained of severe chest pain. The patient was admitted to the hospital but there was a slight delay in conducting a CT scan on the patient. The family members of the victim brought charges of medical negligence against the hospital and clashed with some junior doctors.last_img read more

Drug racket busted in Kolkata three arrested

first_imgKolkata: The Narcotics Control Bureau (NCB) has busted an international drugs racket here by seizing more than 3,000 tablets of psychotropic substances and arresting three persons, a senior NCB official said on Thursday. According to the official, the gang was involved in online trading of drugs in the US and Canada. “The NCB Kolkata team seized 3,161 tablets of six psychotropic substances valued at Rs 10-15 lakh from drug dealers Ganesh Pan and Sunil Agarwal who were arrested on Wednesday,” NCB Kolkata unit Zonal Director Dilip Kumar Srivastava said. “The drugs were sold to customers in the US and Canada through a city-based call centre Dream Advent Services and delivered via courier. Clement Phillips, the call centre owner, was also arrested,” he said. The official said that the seized drugs were procured in Kolkata as they can be sold in India but are illegal in the two foreign countries.last_img read more

All govt depts asked to submit details of employees 2 yrs ahead

first_imgKolkata: In a bid to ensure quick disposal of pension cases, all departments of the state government have been directed to submit details of employees 24 months ahead of the date of their retirement.The departments have also been asked to submit the “pension cases” to the offices of Accountant General (A&E) six months before the date of retirement of an employee.It has also been directed in the communiqué in this connection to all departments, to “furnish the reports or returns on a regular basis.” Also Read – Rain batters Kolkata, cripples normal lifeIt may be mentioned that a report has to be filed in a prescribed format. The report can also be sent in a CD by post or through e-mail. It has also been directed to “be prompt in re-submission of the cases of pension or family pension, etc. to the office of the AG (A&E) that has been returned,” without finalisation of the case.The direction to take the prompt action has been given to avoid unnecessary delay and harassment to the pensioners that compel them “to resort to file Right to Information applications, court cases, etc.”According to a senior official of the state government, it will be of great benefit for the state government employees as they won’t have to faceany difficulty in getting their pension soon after their retirement.Submission of all documents 24 months ahead of the date of retirement of the employees will help in preparation of retirement profile and the disposal of the future pension cases.last_img read more

Shami asked to appear in court on Jan 15 over cheque bounce

first_imgKolkata: A court here on Wednesday directed Indian pacer Mohammed Shami to appear before it on January 15 in connection with a complaint of cheque bounce filed by his wife, with whom he is embroiled in a marital dispute case. Alipore Judicial Magistrate Md Zafar Parwej, in-charge of the chief judicial magistrate court on this day, said that failure to appear personally may invite a warrant of arrest against Shami. His wife Hasin Jahan filed the case under NI Act after the cricketer had alleg- Also Read – Rain batters Kolkata, cripples normal lifeedly stopped payment of a cheque which he had given to her for monthly expenses after a marital dispute arose between the two, following which they were residing separately. The CJM had directed Shami to appear before the court on Wednesday after he had failed to appear on an earlier date in October. But the cricketer was not present in the court on Wednesday either. His lawyer Sk Salim Rahaman pleaded before judge Parwej that Shami be allowed to appear through the counsel. The judge, however, said that the law was the same for everyone and directed Shami to appear personally on January 15, 2019. The court said that failure on the part of Shami to appear before the court on the said date may invite issuance of arrest warrant against him.last_img read more