A cockroach mom shelters her newborn babies. Credit: by Allen Moore Citation: Cockroaches Control Their Breathing to Save Water (2009, September 24) retrieved 18 August 2019 from https://phys.org/news/2009-09-cockroaches.html Explore further Cockroaches can hold their breath for up to seven minutes. Their respiratory system is highly efficient but there are no lungs. Instead, the insects draw in air through external valves called spiracles and transport the air directly to the cells via tubes called trachea. To stop breathing, they simply close the spiracles.The new study, reported in the Journal of Experimental Biology tested the major hypotheses put forward to explain the practice of holding the breath for long periods. One hypothesis is that the insects are trying to build up the carbon dioxide produced during respiration, which makes it easier to expel from the body. Another idea is that they stop breathing to protect themselves from high oxygen concentrations (which can be toxic). The third hypothesis is that the practice aims to regulate water loss.One of the scientists, Dr Craig White, an animal physiologist at the University of Queensland, explained that the trachea do not just carry air inwards to the cells, they also carry water out of the cells. The hypothesis is that when they are resting and have a lower oxygen requirement, they close the spiracles to conserve water.The Australian team of scientists tested the hypotheses by monitoring the breathing of cockroaches over four weeks and under different conditions of humidity, and oxygen and carbon dioxide levels, so some cockroaches spent the four weeks in high humidity, others in low humidity, some with humidity constant but oxygen levels low or high, and so on.The study found that in low humidity the cockroaches held their breath longer, which confirms these insects adapt to dry environments by adjusting their behavior. This ability to adapt to the conditions may be one reason why cockroaches are such a successful group, and why they have survived for so long.More information: Cockroaches breathe discontinuously to reduce respiratory water loss, Journal of Experimental Biology 212, 2773-2780 (2009); doi: 10.1242/jeb.031310© 2009 PhysOrg.com (PhysOrg.com) — Many insects have been known for decades to hold their breath when resting, but the reasons have not been well understood. A new study on cockroaches suggests the insects reduce their breathing to conserve moisture. Breathing easy: When it comes to oxygen, a bug’s life is full of it 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.
More information: Nature doi:10.1038/nature.2013.13441 Discoveries from Planck may mean rethinking how the universe began Journal information: Nature Citation: Researchers detect B-mode polarization in cosmic microwave background (2013, July 26) retrieved 18 August 2019 from https://phys.org/news/2013-07-b-mode-polarization-cosmic-microwave-background.html Scientists believe that approximately half a million years after the Big Bang, the universe began switching from a state of plasma and energy to one where temperatures had dropped to a point where the universe became transparent enough for light to pass through. That light is known as cosmic microwave background (CMB) and is still visible today. Cosmologists studying it have formed the basis of a theory known as inflation—where the universe came to exist as it does today through a process of very rapid expansion just after the Big Bang.In order to prove that the inflation theory is correct, scientists have been studying minute fluctuations in the temperature of the CMB—they revel fluctuations in density of the early universe. They also study fluctuations of the polarization of the CMB which is due, it is believed, to radiation being scattered across the universe by the energy of the Big Bang. Fluctuations in polarization were for a time merely theory, but in 2002, they were actually detected, giving credence to inflation theory. Those fluctuations were given the name E-mode polarizations. Theory has also suggested that there are also B-mode fluctuations in polarization, which are far more subtle—they are thought to describe the rotation of CMB polarization. Finding evidence of them has been extremely difficult, however, as they exist as just one part in ten million in the CMB temperature distribution. But now it appears the team at SPT has done just that, adding further credence to the inflation theory. The researchers report that they were able to detect E-mode polarization due mostly to improvements in detector technology.Adding credence isn’t the same as finding proof of a theory, of course, and that’s why scientists believe the detection of E-mode polarizations is so important. Many believe it will ultimately lead to the detection of primordial gravitational waves—immense ripples in space-time that theory suggests should have come about as a result of the force of inflation. If they can be detected, the theory of inflation would likely become the accepted theory regarding the early formation of the universe. Researchers working at the South Pole Telescope (SPT) have detected tiny fluctuations—known as B-mode polarization—in cosmic background radiation. The team describes their findings in their paper they’ve uploaded to the preprint server arXiv. , arXiv © 2013 Phys.org Explore further 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.
Prior research has shown that despite an apparent love of sugar, bats do not necessarily always choose a plant with the sweetest nectar, which results in plants that produce diluted nectar in areas frequented by bats. Why this occurs has baffled scientists—logic suggests the opposite would occur. To find the answer, the researchers devised a novel experiment they believed would finally solve the puzzle.The experiment consisted of outfitting 23 artificial flowers (in a part of a Costa Rican rainforest) with sensors and pumps that were able to mix sugar into an artificial nectar and then pump it to the flower. All of the flowers were connected to a computer, which counted the number of bat visits and controlled the concentration of the nectar for each flower. The researchers then routinely captured a number of bats and tagged them with tiny radio transmitters. This setup allowed the researchers to monitor and even influence bat feeding in the wild over a period of six years (and multiple generations of bats) and to see the impact it had on plant evolution.As part of their analysis of the data, the researchers assumed that a bat visit to an artificial flower resulted in the transfer of virtual pollen to another virtual flower, resulting in virtual offspring—this approach allowed the researchers to cause the artificial flowers to evolve at a much higher rate than natural flowers. The team also found that they could manipulate the numbers of bats present in the study by manipulating the nectar, and they found that as a bat population grows, each bat is able to consume less nectar, which made them less discerning concerning sugar concentration and more concerned about finding more to eat—that in turn led the plants to produce less sugar and a diluted nectar. The team also found that the Weber effect may have come into play at certain points—where increases in sweetness led to diminished returns for the plants. 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. © 2017 Phys.org Citation: Clever bat experiment explains why plants tend to produce dilute nectar (2017, January 6) retrieved 18 August 2019 from https://phys.org/news/2017-01-clever-tend-dilute-nectar.html Bees use colour-coding to collect pollen and nectar Big eared townsend bat (Corynorhinus townsendii) Credit: Public Domain (Phys.org)—A clever, exhaustive experiment created and carried out by a combined team of researchers from Germany, the U.K. and the U.S. has explained why some nectar-producing plants produce dilute nectar in spite of a highly sugared preference by bats. In their paper published in the journal Science, the researchers describe their experiment and what they found. Hamilton Farris with the Louisiana State University School of Medicine offers a Perspective piece on the work done by the team in the same journal issue. Journal information: Science Explore further More information: Vladislav Nachev et al. Cognition-mediated evolution of low-quality floral nectars, Science (2017). DOI: 10.1126/science.aah4219AbstractPlants pollinated by hummingbirds or bats produce dilute nectars even though these animals prefer more concentrated sugar solutions. This mismatch is an unsolved evolutionary paradox. Here we show that lower quality, or more dilute, nectars evolve when the strength of preferring larger quantities or higher qualities of nectar diminishes as magnitudes of the physical stimuli increase. In a virtual evolution experiment conducted in the tropical rainforest, bats visited computer-automated flowers with simulated genomes that evolved relatively dilute nectars. Simulations replicated this evolution only when value functions, which relate the physical stimuli to subjective sensations, were nonlinear. Selection also depended on the supply/demand ratio; bats selected for more dilute nectar when competition for food was higher. We predict such a pattern to generally occur when decision-makers consider multiple value dimensions simultaneously, and increases of psychological value are not fully proportional to increases in physical magnitude.
(Phys.org)—A team of researchers from several institutions in Germany has found that middle-age killifish fed the gut contents of younger killifish lived longer than normal. In their paper uploaded to the bioRxiv preprint server, the team describes their experiments with killifish, what they found and where they plan to take their research in the future. More information: Regulation of Life Span by the Gut Microbiota in The Short-Lived African Turquoise Killifish, bioRxiv, biorxiv.org/content/early/2017/03/27/120980AbstractGut bacteria occupy the interface between the organism and the external environment, contributing to homeostasis and disease. Yet, the causal role of the gut microbiota during host aging is largely unexplored. Here, using the African turquoise killifish (Nothobranchius furzeri), a naturally short-lived vertebrate, we show that the gut microbiota plays a key role in modulating vertebrate life span. Recolonizing the gut of middle-age individuals with bacteria from young donors resulted in life span extension and delayed behavioral decline. This intervention prevented the decrease in microbial diversity associated with host aging and maintained a young-like gut bacterial community, characterized by overrepresentation of the key genera Exiguobacterium, Planococcus, Propionigenium and Psychrobacter. Our findings demonstrate that the natural microbial gut community of young individuals can causally induce long-lasting beneficial systemic effects that lead to life span extension in a vertebrate model. © 2017 Phys.org Prior studies have shown that infusing the blood of a young animal into that of an older animal can offer both increased vitality and health benefits to the older animal. Other experiments have suggested that rejuvenating the gut biome of an animal might offer similar benefits. In this new effort, the team in Germany sought to find out if that might be true for the very short lived killifish.Killifish are native to Zimbabwe and Mozambique, living in ponds that accumulate after a heavy rain. They reach maturity at just three weeks and generally die a few months later. Their short lifespan made them ideal subjects for experiments on possible lifespan extension due to gut biome rejuvenation.The experiments by the researchers consisted of killing the gut biome in several middle-aged killifish (age 9.5 weeks) and then putting them in a tank filled with sterilized water. They then dumped the gut contents of young (6-week-old) killifish into the tank. The older fish did not actually eat the material but probed at it using their mouths to figure out if it was food. That was enough to allow the microbes to make their way into their guts. Six weeks later, the gut biome of the older fish was identical to the younger fish that had donated the gut material.In studying the middle-age fish after the gut rejuvenation, the researchers found that they lived on average 37 percent longer than their peers who received no treatment. They also report that those fish with the rejuvenated biomes became more active, behaving like fish just six weeks old. Performing the reverse procedure, giving young fish a middle-aged biome, on the other hand, had no discernible impact.The researchers acknowledge that they do not know how or why rejuvenation of the gut biome in the fish increased both vitality and lifespan, but suggest it might be tied to the immune system. They think it is possible that as fish grow older, their immune systems become less effective at warding off harmful or non-beneficial microbes in the gut. In that case, replacing the biome would mean removing the bad microbes, giving the gut a new start. Nothobranchius furzeri. Credit: Wikipedia, CC BY-SA 3.0 A new model organism for aging research: The short-lived African killifish Explore further Citation: Eating the gut contents of young fish lengthens life of older killifish (2017, April 5) retrieved 18 August 2019 from https://phys.org/news/2017-04-gut-contents-young-fish-lengthens.html 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.
Electrophysiological Evidence for Top-Down Lexical Influences on Early Speech PerceptionLaura M. Getz and Joseph C. Toscano How does information about the meaning of words influence speech perception? Getz and Toscano investigated whether feedback from lexical activation affects listeners’ initial representation of the sound of a word. Participants saw a written word, followed by an auditory target word, and they had to decide which sound the auditory target started with (e.g., /p/, /b/). During this task, participants’ electroencephalographic (EEG) data were collected. When the auditory target (e.g., “potatoes”) was associated with the written word (e.g., “MASHED”), participants were faster at identifying the sound than when the written word had a neutral association (e.g., “FACE”) or when it was a nonword (e.g., “XXXX”). EEG data revealed that the amplitude of N1, a negative potential in the waveform that indexes early acoustic-cue encoding, was smaller when the written word was associated with the target than when it was neutral or a nonword. In another experiment, the word presented before the target changed how ambiguous targets were perceived (e.g., in “park,” the ambiguous first sound /p/ or /b/ was processed more like /p/ when it was preceded by “AMUSEMENT” than it was when preceded by “TEDDY”), as indicated by the N1 amplitude. These results provide evidence for an interactive model of adults’ spoken-word recognition, in which semantic and lexical activation play a role in the early processing of word sounds. Read about the latest research published in Psychological Science: Where Does Time Go When You Blink?Shany Grossman, Chen Gueta, Slav Pesin, Rafael Malach, and Ayelet N. Landau When humans blink, they lose brief moments of vision, yet they rarely notice these gaps. But could blinks change time perception? This research suggests that when humans spontaneously blink, they underestimate time passing. While eye movements were recorded by an eye tracker, participants either saw a white disc or heard a white noise during an interval of time between 0.6 and 2.8 s, and they estimated whether the duration had been closer to the short interval (0.6 s) or to the long interval (2.8 s). To increase the probability of blinks occurring during the task, the researchers first asked participants to perform a visual task in which they saw colored squares and had to decide how may red squares they had seen. In the main task, when a blink occurred during the estimated time interval, participants’ time estimates were reduced when the interval was filled by visual information (the white disc) but not when it was filled by auditory information (the white noise). Moreover, the size of their underestimate depended on the blink duration. These results suggest that (a) unconscious loss of visual input, via spontaneous blinks, may be related to a compression of subjective time and (b) one’s subjective sense of time might be informed by the ongoing processing of sensory information. Intentional Binding Without Intentional ActionKeisuke Suzuki, Peter Lush, Anil K. Seth, and Warrick Roseboom Experiencing agency over one’s actions and their consequences has been measured by intentional binding, which is the perceived compression of the time interval between an intentional action (e.g., pressing a button) and an outcome (e.g., an auditory tone). However, a person can also perceive time compression when perceiving a causal unintentional relationship between events (causal binding). To investigate whether intentional action or causal binding contributes to time-binding effects, Suzuki et al. used a virtual-reality task in which participants pressed a button, observed it being pressed by a virtual hand, or saw it pressing in on its own. When the button was pressed, it lit up and participants felt a vibration and then heard a sound. Participants were asked to estimate the time between the button being pressed and hearing the sound. The time estimates were shorter when participants pressed the button themselves or saw another hand pressing it. However, participants reported higher agency when they actively pressed the button than when they observed the hand doing it, indicating that the perception of time compression may not depend on agency but rather reflect causal binding. Therefore, future studies that relate binding effects to agency should provide evidence for effects beyond causal binding, Suzuki et al. suggest.
A new name marks its entry in the list of fine diners in the city. The all new Lebanese and Moroccan specialty Rrala’s Habibi, located in the heart of South Delhi has joined the race to tell its inimitable story of Arabic food and culture. Through a colourful and flavourful palette of the Lebanese and Moroccan cuisine, the taste of Arab is brought together by Chef Ratib Al Ghriwati.Exotic indoor and outdoor ambience spells magic complimented with a menu set to perfection, variety of signature cocktails and mocktails adding to an ethereal experience laced with great live entertainment. Also Read – ‘Playing Jojo was emotionally exhausting’Ala Madhu and Rajan Madhu (promoters) played the perfect hosts to celebrate the launch of the diner on Friday.Madhu says ‘We are overwhelmed to launch Rrala’s Habibi, a Lebanese and Moroccan venue in Delhi offering a delightful Arabic experience with an extensive authentic palette of food. A special Arabian cuisine is being introduced with a celebrated Chef and his team in Delhi to begin with, only to accomplish its presence in the other parts of the country’.
To promote the eclectic range of mangoes produced in West Bengal and to exhibit its vibrant culture, the state government organised a cultural soiree on Saturday at Dilli Haat. The cultural evening saw performers from Gorbhanga village in Nadia district of Bengal singing some vibrant Bengali folk songs. Traditional Bangla sufi qawwali performed by Fakeer singers were also a major attraction of the evening. The government of West Bengal has organised the second edition of Bengal mango festival called Mango Mela at Dilli Haat INA which will continue till 30 June. The mela also exhibits delectable varieties of mangoes from the state’s Malda and Murshidabad districts such as Langra, Fazli, Himsagar, and Laxmanbhog. For the first time, Amrapali mangoes from Bankura, successfully grown under a convergence programme with MGNREGS, will be available towards the end of the mela. The project for creation of 163 big mango orchards in Bankura under MGNREGS won a special award from the Union Rural Development Ministry in February this year. Visitors can also enjoy cultural evenings on every Saturday while relishing the delicious mangoes. The mela also displays select handloom and handicrafts from Bengal, such as Nakshi Kantha (traditional needlework), Shantiniketan embossed leather goods, Shantipuri sarees, terracotta costume jewellery, wooden masks and clay dolls. Processed mango products such as juice and pickles are also the special attraction of the fair.
This one’s for the art lovers. A solo show titled Play – A Series of the Captured Moments that displays paintings and prints by Priyanka Dua has been organised in the Capital that started off on 1 November at Vivanta by Taj. The paintings on display are a series of some significant moments Dua had which she’s playing as a reel of her real life. Dua says, ‘There are endless ideas which run through my mind with every new moment. Some of them stay with me and I start working on them reliving the experience. Every piece of work ever done by me stands for an emotion felt which started as an inspiration for me to create it’.She added, ‘Every new moment comes with a new emotion. I try and capture those emotions which all of us experience but are unaware of them consciously. I personally love capturing positive emotion as they make us aware of all the happiness around us. Regardless of gender, living or non-living, colour or black and white, my paintings are purely me and my way of expressing and sharing thoughts with the rest of the world.
Kolkata: Mystery shrouds the death of a couple whose bodies were found inside their house in Narayandari area of Tamluk in East Midnapore on Monday morning. The incident triggered tension in the area. Police said the victims are Moloy Maity (32) and Sharmistha Maity (26). Moloy Maity was a primary school teacher. Maity was found inside the kitchen while his wife was spotted lying in the bed inside her room. Both the victims had injury marks around their neck. According to police, they got married four years ago and they have a two-year-old son. Police are interrogating the family members of the victims and some locals as well. Also Read – Heavy rain hits traffic, flightsThe husband’s family members told police that Maity might have killed his wife by strangulating her inside the room and later committed suicide by hanging himself from the ceiling. The woman’s family members, however, cried foul behind the death of the couple. They alleged that both the victims were murdered.As the news spread, some of locals started gathering outside the house. After being informed, the police reached the spot and removed the curious onlookers from the area. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedThey recovered the bodies and sent them to Tamluk district hospitals for post-mortem. The investigators also collected samples from the house. No suicide note was, however, recovered in this incident. Police are yet to confirm if the victims committed suicide or there was any foul play behind the death of the couple.Police are, however, not ruling out the possibility of the husband committing suicide after killing his wife. They have started a detailed probe in this regard. Police are investigating into all possible angles. They are waiting for the post-mortem report which might throw some light on the death of the couple.
Kolkata: As many as ten passengers have been injured when two private buses collided head on in Mahishadal area of East Midnapore on Tuesday morning.The injured victims, who were travelling in those two buses, have been admitted to a nearby hospital. Later some of them were shifted to a city hospital as their conditions deteriorated.According to police, the accident took place on Haldia-Mecheda State Highway.Locals staged a protest demonstration on the spot against rash driving of vehicles. The demonstration was later lifted after the intervention of senior police officers in the district. Also Read – Rain batters Kolkata, cripples normal lifeThe incident had caused traffic congestion on the busy road for nearly an hour in the morning.Police said it was raining in the area when a Mecheda-bound private bus from Haldia, with around 30 passengers on board, hit another private bus coming from the opposite direction.According to police, there were around 25 passengers on the other bus that was going towards Haldia from Kolaghat.A preliminary investigation suggests that both vehicles were running at a high speed at the time of the accident. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedThe exact cause of the accident is yet to be ascertained by the district police. Both the bus drivers fled the spot immediately after the accident.Some locals heard a loud thud and reached the spot.They rescued the injured victims from the vehicles and rushed them to hospital. The other passengers who were inside the two buses were traumatised.Some of the passengers, who were travelling on the Mecheda bound bus told police that they had repeatedly urged the bus driver to slow down but he turned a deaf ear to their appeal.While taking a sharp bend near Mahishadal, the driver lost control over the vehicle and collided head on with the other vehicle.A probe has been initiated. Raids are being conducted to nab the bus drivers.