Author: admin

  • Constraining The Survival Of HCN During Cometary Impacts

    Constraining The Survival Of HCN During Cometary Impacts

    The peak temperature achieved by all tracer particles in simulations of a 1 km diameter comet impacting at 10 km s−1 (left) and 40 km s−1 (right) in a provenance plot, where the tracers are shown at their initial locations prior to the impact. A solid black line is shown between the two halves of the figure to delineate the difference between the two simulations. The 10 km s−1 impact on the left shows a peak temperature of ∼ 8900 K, whereas the 40 km s−1 impact on the right achieves a peak temperature of ∼ 74 000 K. Although the range of temperatures achieved during the two impacts is vastly different, the distribution of temperatures is similar, with a sharp increase in temperatures at the leading edge and raised temperatures towards the centre of the body. — astro-ph.EP

    Cometary impacts have been invoked as an atmosphere-independent method of stockpiling hydrogen cyanide (HCN), a key prebiotic feedstock molecule, into environments favourable for the onset of prebiotic chemistry on the early Earth.

    This work revisits the prospects for cometary delivery of HCN through new impacts simulations of idealised cometary bodies using the shock physics code iSALE combined with simple chemical modelling.

    Using temperature and pressure profiles for material within spherical, non-porous comets with a high resolution of Lagrangian tracer particles, we assess the survival rate of HCN across a range of impact velocities, sizes and angles, assuming both steady state and equilibrium chemistry.

    We find that HCN survival is extremely limited at impact velocities above the escape velocity of the Earth, unless the impact occurs at extreme obliquity (θ∼15∘). We present a parametrisation of the survival of HCN as a function of impact velocity, angle, and cometary diameter, which provides an upper limit to survival in more realistic scenarios to aid with future studies investigating the role of comets in the origins of life.

    Although successful HCN delivery may be possible in our idealised model, we neglect to consider the effect of atmospheric passage and our results suggest that delivery alone is not likely to be sufficient for the onset of prebiotic chemistry.

    Catriona H. McDonald, Amy Bonsor, Auriol S. P. Rae, Paul B. Rimmer, Richard J. Anslow, Zoe R. Todd

    Comments: 32 pages, 12 figures. Accepted for publication in the Icarus special issue ‘Impact processes and planetary evolution’
    Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
    Cite as: arXiv:2507.08727 [astro-ph.EP] (or arXiv:2507.08727v1 [astro-ph.EP] for this version)
    https://doi.org/10.48550/arXiv.2507.08727
    Focus to learn more
    Journal reference: Icarus, 441, 2025, 116704
    Related DOI:
    https://doi.org/10.1016/j.icarus.2025.116704
    Focus to learn more
    Submission history
    From: Catriona H. McDonald
    [v1] Fri, 11 Jul 2025 16:27:30 UTC (4,459 KB)
    https://arxiv.org/abs/2507.08727

    Astrobiology, Astrochemistry,

    Continue Reading

  • Synthetic Biology For Space Exploration

    Synthetic Biology For Space Exploration

    By efficient use of local extraterrestrial resources and promotion of a more sustainable supply chain, synthetic biology can contribute significantly to human space exploration missions. This is done through incorporating the extraction, processing, and production of raw materials into consumables (A), enhancing recycling ranging from food production to waste management within life support systems (B), supporting radiation and stress protection strategies by producing stable biomolecules to mitigate harmful biological effects within life support systems (C), and engineering customized therapies, nutraceuticals, and biosensors to bolster astronauts’ health (D). CREDIT: Midjourney software. — NPJ Microgravity

    Human space exploration faces different challenges. Topics like Bioregenerative Life Support Systems, In Situ Resource Utilization, and radiation protection, still require for more suitable solutions to be applied in long-term space exploration.

    Synthetic biology could be a powerful tool for enabling human exploration of space and planets.

    This paper explores key topics including resource utilization, life support systems, radiation protection, and human health, providing recommendations for short-, mid-, and long-term advancements in space exploration.

    Synthetic biology for space exploration, NPJ Microgravity (open access)

    Astrobiology

    Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

    Continue Reading

  • legal tender in the digital age

    legal tender in the digital age

    Introductory statement by Piero Cipollone, Member of the Executive Board of the ECB, at the Committee on Economic and Monetary Affairs of the European Parliament

    Brussels, 14 July 2025

    Thank you for inviting me to take part in this exchange of views. I would like to talk about why we need the digital euro – and the cost of not pursuing it.

    My message is simple. The main reason for issuing a digital euro is to preserve the benefits of cash in the digital era. To do so, we need to complement physical cash with a digital form of cash.

    The inability to use physical cash in online transactions or for digital payments at the point of sale deprives us of a key payment option, reducing resilience, competition, sovereignty and, ultimately, consumers’ freedom to choose how to pay.

    This increases the risks that European consumers, merchants and policymakers face. For a growing number of their transactions, Europeans lack access to central bank money – the money that is backed by the sovereign and has legal tender status, underpinning our monetary union because it is accepted everywhere in the euro area.

    Monetary sovereignty and people’s freedom to pay with legal tender: two sides of the same coin

    The Eurosystem is committed to cash and will continue to issue it.[1] But people’s habits are shifting towards digital payments.

    As the role of online payments has grown, the role of cash in day-to-day transactions has been declining at pace: between 2019 and 2024 its share fell from 68% to 40% in volume terms and from 40% to 24% in value terms.[2]

    This has two important implications.

    First, the role of cash will be significantly reduced if we do not provide a digital equivalent. If we fail to act, we will fail to fulfil our responsibility as a central bank towards the people we serve.

    Second, our monetary sovereignty is eroding. People’s ability to pay across the euro area with sovereign money – cash – and frequently choosing to do so, is a key pillar of monetary sovereignty. A digital form of cash would protect our sovereignty and ensure our monetary union is also a digital monetary union.

    What’s particularly concerning in Europe is that the gap left by declining cash use is being filled by non-European payment solutions. For card payments, only seven out of the 20 euro area countries have a national card scheme. These card schemes cannot be used in other euro area countries and are also losing market share domestically. For e-commerce, European-owned solutions are prevalent in only three euro area countries.[3]

    Strengthening our legal tender to stop the erosion of our monetary sovereignty

    To address this situation, the Single Currency Package protects the rights of those who want to continue to pay with cash, while complementing physical cash with a digital form of the legal tender: the digital euro.

    I believe we are being presented with a false choice: a private pan-euro area payment solution or a public one. First, it is not just about payments; it is about the evolution of the money. And second, it is a historical fact that state-issued money and money issued by private parties have typically coexisted, reinforcing each other.[4]

    The cost of inaction

    Since the start of the euro, we have recognised the need for an integrated retail payments market. This prompted the development of the Single Euro Payments Area (SEPA) to harmonise bank transfers. However, SEPA does not cover key use cases such as payments at the point of sale.

    Over the years, private firms have made several attempts to create a pan-European payment solution, but difficulties in coordinating among market participants prevented those firms from delivering a scalable and unified system.[5] Some 25 years after the launch of the euro, we still have no European payment solution that allows people to pay digitally throughout the euro area in stores, for e‑commerce goods and services and from person to person.

    Let us take a leap of faith. Imagine things would be different this time and that banks would manage to work together to rapidly provide a pan-European private payment solution. Would it still make sense to have the digital euro? The answer is yes.

    First, the digital euro would help preserve money as a public good that is easily accessible to everyone and universally accepted across the euro area. By contrast, private money belongs to the competitive space, so we cannot guarantee its acceptance by all merchants.

    Second, the digital euro would enhance resilience. We would have a reliable fallback in times of crisis, complementing cash. An especially important feature is that the digital euro would also function offline, providing a secure payment method even without an internet connection.[6] Moreover, as is the case with cash, we would be sure that all components of the digital euro remain in European hands.

    Third, the digital euro would prevent market concentration. The availability of legal tender and its wide adoption would put merchants in a stronger position to negotiate fees. In addition, the digital euro would create open standards with a wide acceptance network, making it easier for payment service providers to scale up their solutions. This would result in greater competition and innovation at European level.[7]

    Conclusion

    Let me conclude.

    The Treaty on the Functioning of the European Union entrusts you, the co-legislators, to “lay down the measures necessary for the use of the euro as the single currency.”

    We can together ensure that our currency is fit for the digital age by complementing physical cash and private payment initiatives with digital cash. Indeed, the digital euro is key to preserving the benefits of cash in the digital era.

    Continue Reading

  • Photos: See Lorde at John Proctor is the Villain—And Sadie Sink’s Final Bow

    Photos: See Lorde at John Proctor is the Villain—And Sadie Sink’s Final Bow

    Broadway News

    Photos: See Lorde at John Proctor is the Villain—And Sadie Sink’s Final Bow

    It was a busy weekend for the Kimberly Belflower play on Broadway.


    Lorde and Sadie Sink
    Michaelah Reynolds

    If you’ve seen Kimberly Belflower’s hit Broadway play, John Proctor is the Villain, you will know that the biggest artistic influence in the play isn’t Arthur Miller; It’s New Zealand singer-songwriter Lorde—whose song “Green Light” plays a very important part in the show. 

    Lorde is not officially affiliated with the show, but she did enthusiastically sign off on the usage of her hit pop song after Belflower wrote her a long letter. And on July 11, the musician saw the play, met with the cast, and even signed Playbills at the stage door. And it seemed like she loved the show, according to Belflower: “To share this play with her, to watch her hands dance in the air while her music blasts through the Booth Theatre, to look her in the eye and (attempt to) tell her what she means to me, to see her take such care with everyone who made this production, to hug her, to watch her stage door (!!!?!??) was maybe the most surreal and beautiful night in this entire surreal and beautiful journey. I will never ever ever forget it or get over it.”

    See the photos of Lorde’s visit to the Booth Theatre on Broadway below.

    0
    of

    Photos: Lorde Visits John Proctor is the Villain

    That wasn’t all. On July 13, John Proctor star (and 2025 Tony nominee) Sadie Sink took her final bow in the play. The Stranger Things actor played social outcast Shelby Holcomb—the role will now be played by Chiara Aurelia beginning July 15. See photos of Sink’s final Broadway bow below.

    0
    of

    Photos: Sadie Sink’s Final Curtain Call at John Proctor is the Villain

    John Proctor is the Villain was nominated for seven 2025 Tony Awards, including Best Play, Direction of a Play, Lighting Design of a Play, Sound Design of a Play, and three performance categories, including Leading Actress in a Play for Sink, Featured Actor in a Play for Gabriel Ebert, and Featured Actress in a Play for Fina Strazza.

    The cast also includes Nihar Duvvuri (Romeo + Juliet) as Mason Adams, Tony winner and 2025 Tony nominee Ebert (Matilda) as Carter Smith, Molly Griggs (Hello, Dolly!) as Bailey Gallagher, Maggie Kuntz (The Outsiders) as Ivy Watkins, Hagan Oliveras (Our Town) as Lee Turner, Morgan Scott (Jaja’s African Hair Braiding) as Nell Shaw, 2025 Tony nominee Strazza (Matilda) as Beth Powell, and Amalia Yoo (No Hard Feelings) as Raelynn Nix.

    The production understudies are Noah Pacht, Fiona Robberson, Shian Tomlinson, Garrett Young, and Victoria Vourkoutiotis.

    READ: How To Get $29 Tickets to John Proctor is the Villain

    The work, a modern reexamination of Arthur Miller’s The Crucible set at a rural Georgia high school, was commissioned by The Farm Theater in 2017. Following workshops at Farm Theater and Ojai Playwrights Conference, the play premiered at Centre College in 2018, and has since been produced at Furman University, Rollins College, Washington D.C.’s Studio Theatre, and Boston’s Huntington.

    Danya Taymor directs, with a creative team that includes scenic designer AMP featuring Teresa Williams, costume designer Sarah Laux, lighting designer Natasha Katz, sound designer Palmer Hefferan, projection designer Hannah Wasileski, movement director Tilly Evans-Krueger, hair, wig and make-up design by J. Jared Janas, and intimacy coordinator Ann James. Gigi Buffington serves as voice and dialect coach. Casting is by Taylor Williams.

    Sue Wagner, John Johnson, John Mara Jr., Runyonland, and Eric Falkenstein are producing.


    Continue Reading

  • NASA Rover Breaks Record For Longest Road Trip on Another Planet : ScienceAlert

    NASA Rover Breaks Record For Longest Road Trip on Another Planet : ScienceAlert

    Perseverance is hitting the ‘open road’ on Mars like no other rover.

    On June 19, the six-wheeled explorer officially completed the longest day trip of any robot vehicle on another planet.

    In a single drive, the rover rolled over 411 meters of Mars’ rocky surface (more than a quarter mile).

    Related: Perseverance Found a Zebra-Striped Rock on Mars, And NASA Is Excited

    That may not sound like much, but compared to Curiosity and Opportunity, which inch along at a relative snail’s pace, Percy is a speed demon.

    That’s because Perseverance has self-driving software, which can process and analyze images even while its wheels are turning.

    By contrast, Curiosity and Opportunity need to stop, take images, and then process that information before deciding on a good path forward.

    The ability to drive longer distances in a day opens up new possibilities for scientific studies on Mars.

    Perseverance looks back on a 347.7-meter drive. (Verma et al., Science Robotics, 2023)

    Since Percy landed on the red planet in 2021, and completed its first hesitant test drive a flawless 6.5-meter up-and-back – the rover has come far.

    Its travels include an epic climb up a crater and the longest drive of any vehicle without human review on another planet – 700 meters of pure, ‘wind-in-the-hair’ freedom.

    The reason for its recent long road trip has to do with the rocks that Percy is on a mission to collect.

    Jigging Cove
    Perseverance acquired this image showing the target area for sampling, called “Jigging Cove”, on 27 June 2025. (NASA/JPL-Caltech/ASU)

    For the past month and a half, the rover has searched for clay-bearing rocks on the Krokodillen plateau, which lies on the outer slopes of the Jezero crater rim.

    If samples here are found to contain minerals known as ‘phyllosilicates’, it could mean abundant water may have existed here in the distant past. Phyllosilicates can also preserve remnants of organic materials from billions of years ago.

    “If we find a potential biosignature here, it would most likely be from an entirely different and much earlier epoch of Mars evolution than the one we found last year in the crater with ‘Cheyava Falls’,” said Ken Farley, deputy project scientist for Perseverance, in May.

    “The Krokodillen rocks formed before Jezero Crater was created, during Mars’ earliest geologic period, the Noachian, and are among the oldest rocks on Mars.”

    On some parts of the plateau, however, Perseverance has found clay-bearing rocks that break easily when handled.

    Picking out a solid sample is crucial. Only the best evidence will do.

    “There are seven empty sample tubes remaining and a lot of open road in front of us,” said Perseverance acting project scientist Katie Stack Morgan in May.

    In late June, the NASA team that drives Percy decided to turn the rover around, driving it back to a spot previously sampled, which contains the strongest clay signature of the bunch.

    Hence the long drive.

    Gallant Mars Rover
    Perseverance acquired this image of the target area “Gallants” on 1 July 2025. (NASA/JPL-Caltech)

    Of all the rovers to roam other planets, the Opportunity rover, which has been on Mars since 2004, has racked up the most overall kilometers of driving, more than 40 km.

    But Opportunity can’t move with the same finesse as Perseverance, and neither can Curiosity.

    At this rate, it won’t be long until Perseverance takes the lead. Its current total distance sits at nearly 36 km.

    Continue Reading

  • New WHO guidelines recommend injectable lenacapavir for HIV prevention

    New WHO guidelines recommend injectable lenacapavir for HIV prevention

    The World Health Organization (WHO) released today new guidelines recommending the use of injectable lenacapavir (LEN) twice a year as an additional pre-exposure prophylaxis (PrEP) option for HIV prevention, in a landmark policy action that could help reshape the global HIV response. The guidelines are being issued at the 13th International AIDS Society Conference (IAS 2025) on HIV Science, in Kigali, Rwanda.

    LEN, the first twice-yearly injectable PrEP product, offers a highly effective, long-acting alternative to daily oral pills and other shorter-acting options. With just two doses per year, LEN is a transformative step forward in protecting people at risk of HIV – particularly those who face challenges with daily adherence, stigma, or access to health care.

    While an HIV vaccine remains elusive, lenacapavir is the next best thing: a long-acting antiretroviral shown in trials to prevent almost all HIV infections among those at risk. The launch of WHO’s new guidelines, alongside the FDA’s recent approval, marks a critical step forward in expanding access to this powerful tool. WHO is committed to working with countries and partners to ensure this innovation reaches communities as quickly and safely as possible.”


    Dr. Tedros Adhanom Ghebreyesus, WHO Director-General

    The new guidelines come at a critical moment as HIV prevention efforts stagnate with 1.3 million new HIV infections occurring in 2024 – with disproportionate impact among key and priority populations, including sex workers, men who have sex with men, transgender people, people who inject drugs, people in prisons, and children and adolescents. WHO’s recommendation on LEN signals a decisive move to expand and diversify HIV prevention, giving people more options to take control over their health with choices that fit their lives.

    Simplified testing: a major barrier removed

    As part of these guidelines, WHO has recommended a public health approach to HIV testing using HIV rapid tests to support delivery of long-acting injectable PrEP, including LEN and cabotegravir (CAB-LA). The simplified testing recommendation removes a major access barrier by eliminating complex, costly procedures and enabling community-based delivery of long-acting PrEP through pharmacies, clinics, and tele-health.

    Next steps: call for implementation

    LEN joins other WHO-recommended PrEP options, including daily oral PrEP, injectable cabotegravir and the dapivirine vaginal ring, as part of a growing arsenal of tools to end the HIV epidemic. While access to LEN outside clinical trials remains limited at the moment, WHO urges governments, donors and global health partners to begin rolling out LEN immediately within national combination HIV prevention programmes – while collecting essential data on uptake, adherence and real-world impact.

    Additional WHO recommendations at IAS 2025

    For the first time, WHO’s treatment guidelines include a clear recommendation for the use of long-acting injectable cabotegravir and rilpivirine (CAB/RPV) as an alternative switching option for antiretroviral therapy (ART) for adults and adolescents who have achieved full viral suppression on oral ART and do not have active hepatitis B infection. This approach is designed to support people living with HIV facing adherence challenges to oral regimens.

    Updated guidelines on service delivery integration include recommendations to integrate HIV services with noncommunicable diseases (NCDs) such as hypertension and diabetes, as well as mental health care for depression, anxiety and alcohol use disorders into HIV services, alongside interventions to support ART adherence. Additionally, new guidelines on management of asymptomatic STIs recommend screening of gonorrhoea and/or chlamydia in key and priority populations.

    For people living with HIV who have mpox and are either ART naive or have experienced prolonged ART interruption, rapid initiation of ART is strongly recommended. Additionally, early HIV testing is advised for individuals presenting with suspected or confirmed mpox infection. WHO’s standard operating procedures further emphasize HIV and syphilis testing for all individuals with suspected or confirmed mpox.

    In response to the broader challenges facing HIV programmes, WHO has also issued new operational guidance on sustaining priority HIV services in a changing funding landscape. The guidance aims to provide a stepwise framework to help countries prioritize services, assess risks, monitor disruptions, and adapt systems to protect health outcomes and preserve progress.

    “We have the tools and the knowledge to end AIDS as a public health problem,” said Dr. Meg Doherty, Director of WHO’s Department of Global HIV, Hepatitis and STI Programmes and incoming Director of Science, Research, Evidence and Quality for Health. “What we need now is bold implementation of these recommendations, grounded in equity and powered by communities.”

    HIV remains a major global public health issue. By the end of 2024, an estimated 40.8 million people were living with HIV with an estimated 65% in the WHO African Region. Approximately 630 000 people died from HIV-related causes globally, and an estimated 1.3 million people acquired HIV, including 120 000 children. Access to ART continues to expand, with 31.6 million people receiving treatment in 2024, up from 30.3 million in 2023.

    At a time of reduced funding for HIV and health, WHO’s new and updated guidelines offer practical, evidence-based strategies to sustain momentum. By expanding prevention and treatment options, simplifying service delivery and promoting integration with broader health services, they support more efficient, equitable, and resilient HIV responses. Now is the moment for bold implementation to ensure these gains translate into real-world impact.

    Source:

    The World Health Organization

    Continue Reading

  • Yuki Kawamura is stealing the show at Summer League – NBA

    Yuki Kawamura is stealing the show at Summer League – NBA

    1. Yuki Kawamura is stealing the show at Summer League  NBA
    2. Yuki Kawamura weighs in on departure from Memphis Grizzlies, missing Ja Morant  The Commercial Appeal
    3. Grizzlies renounced the rights to two Japanese superstars  BasketNews.com
    4. ‘Heart over height:’ Yuki Kawamura searches for place in NBA during summer league stint with Chicago Bulls  Chicago Tribune
    5. Yuki Kawamura Reacts To Ja Morant’s Latest Post  Sports Illustrated

    Continue Reading

  • How to Get AI Out of Your Google Search Results • The Revelator

    How to Get AI Out of Your Google Search Results • The Revelator

    Three simple keystrokes will deliver search results that consume less energy and water — and probably contain better information.

    A few weeks ago, I wrote an editorial discouraging environmentalists from using generative AI programs like ChatGPT due to their extraordinary energy and water consumption. If you care about the planet, I argued, you shouldn’t use such climate-damaging systems.

    Most people responded to the editorial positively, but one follow-up question kept coming up: “How do I get AI completely out of my life?”

    That’s a broad question, and it’s a tough one to answer because artificial intelligence has been wrapped into so many aspects of our daily lives, from cell phones, use of Microsoft Word, customer-service inquiries and, of course, search engines.

    That last one bothered a lot of you, who complained about Google presenting AI answers to every search, well before any websites that might contain the same (or better) answers.

    Now, search results that present AI-generated answers don’t carry quite the same environmental cost as full-fledged generative AI queries — like asking ChatGPT to “write” a full essay — but some research suggests AI search results will use four to five times as much energy as the old non-AI searches we used to enjoy. That’s not nothing, and in the battle against climate change, every watt counts.

    Luckily, it turns out there’s an easy way to get AI out of your Google search results. Simply type these three keys after your search term: -AI

    (That’s the minus sign immediately followed by the letters AI, with no space between them.)

    Here’s an example: I Googled the phrase “why are tigers endangered” and got this result, leading with an AI-generated overview:

    I tried it again with “-AI” at the end of the search phrase and got these results, which start with an authoritative source. Google still includes an overview pulled from the pages, but it doesn’t appear to have been generated by AI:

    A second example: I searched for information on data centers and noise pollution (another problem of AI) and got this AI-generated search result:

    But I added “-AI” to the search and got a reputable source first. Google still included a few lines from that source, but that’s the point: It was sourced in the first place. A lot of AI-generated texts don’t present their sources, so you can’t judge their veracity.

    Google is obviously the king of search, but it’s not the only game in town. I tried this on a variety of other search engines and got similar — but imperfect — results.

    A normal search on Bing delivered a detailed AI answer from its Copilot AI system.

    Using “-AI” on Bing delivered a search result with a space for Copilot, but that space didn’t populate.

    A normal search on Yahoo delivered an AI summary.

    Using “-AI” on Yahoo still generated an AI answer, although it appeared after an authoritative source. (This earns Yahoo a failing grade, in my book.)

    DuckDuckGo presented an AI “assist” on my first search (which, quite interestingly, included a warning about its possible lack of accuracy).

    Adding “-AI” to the search on that platform delivered AI-free results. This made DuckDuckGo today’s winner. (It’s worth noting that DuckDuckGo also receives high marks from security specialists because it doesn’t track your search results.)

    None of these results are perfect, and these search engines are likely to modify their systems at any time. But as of this writing using “-AI” seems like a simple and efficient way to reduce the carbon footprint of your online searches — which, as a journalist who searches for stuff dozens of times a day, is something I appreciate.

    Credit where credit is due: I got this tip about Google from a video posted by ABC News chief meteorologist Ginger Zee. Watch her video below, and her Climate A to Zee series on YouTube:

    Do you have other questions about reducing your carbon footprint or helping wildlife? Or do you have tips to share? Write to us at [email protected].

    Republish this article for free! Read our reprint policy.
    Subscribe to our weekly newsletter. Scan the QR code, or sign up here.

    Why The Revelator Banned AI Articles and Art


    is the editor of The Revelator. An award-winning environmental journalist, his work has appeared in Scientific American, Audubon, Motherboard, and numerous other magazines and publications. His “Extinction Countdown” column has run continuously since 2004 and has covered news and science related to more than 1,000 endangered species. He is a member of the Society of Environmental Journalists and the National Association of Science Writers. John lives on the outskirts of Portland, Ore., where he finds himself surrounded by animals and cartoonists.


    Continue Reading

  • Google Gemini Bug Turns Gmail Summaries into Phishing Attack – PCMag

    1. Google Gemini Bug Turns Gmail Summaries into Phishing Attack  PCMag
    2. Google urges caution as Gmail AI tools face new threats  Digital Watch Observatory
    3. Google Gemini for Workspace Vulnerability Lets Attackers Hide Malicious Scripts in Emails  CyberSecurityNews
    4. Google Gemini flaw hijacks email summaries for phishing  BleepingComputer
    5. Google’s Gmail Warning—If You See This, You’re Being Hacked  Forbes

    Continue Reading

  • Microbial N2O Reduction in Sulfidic Waters: Implications For Proterozoic Oceans

    Microbial N2O Reduction in Sulfidic Waters: Implications For Proterozoic Oceans

    Normalized nosZ transcript abundance in metatranscriptomes of marine (red) and lacustrine (green) euxinia. Shown is the ratio of nosZ to rplF transcripts for comparison across 245 datasets with different sequencing depths. Estimates of sulfide concentrations in Proterozoic oceans are shown with dotted vertical lines, with recent estimates in pelagic regions around 2-5 µM (Ozaki et al., 2018). biorxiv.org

    Throughout Earth’s history, shifts in ocean redox influenced the bioavailability of trace metals, shaping the activity of microorganisms.

    In Proterozoic oceans, the precipitation of copper (Cu) with sulfide was hypothesized to limit the bioavailability of Cu. This limitation may have suppressed microbial reduction of nitrous oxide (N2O), due to the Cu dependency of nitrous oxide reductase (Nos). It is thought that without this critical microbial sink, Proterozoic oceans were a significant net source of N2O.

    Here, we revisit this paradigm in light of recently derived ∼20-fold lower estimates for sulfide in Proterozoic seawater and an empirical evaluation of the potential for microbial N2O reduction under sulfidic conditions. Leveraging publicly available environmental metatranscriptomes, we infer active N2O reduction from the detection of nosZ transcripts in multiple marine and lacustrine systems in which sulfide and Cu concentrations are analogous to those of the Proterozoic.

    In controlled culture experiments, we demonstrate that the purple non-sulfur bacterium Rhodopseudomonas palustris can reduce N2O at sulfide concentrations up to 100 µM, well above levels predicted for Proterozoic oceans. Based on trace metal speciation modeling, we suggest that Cu remains bioavailable under Proterozoic-like conditions as a dissolved CuHS0 complex.

    Using phylogenetics, we infer that early N2O reducers were probably anoxygenic phototrophs and performed N2O reduction as dark metabolism. Collectively, these observations suggest microbial N2O reduction occurs under euxinic conditions, implying that Proterozoic marine N2O emissions were substantially lower than previously proposed.

    Our conclusions inform our understanding of the microbial ecology in sulfidic waters, the early climate, and the search for extraterrestrial life.

    Unrooted maximum likelihood phylogenetic tree of NosZ protein sequences. The phylogeny includes 595 nosZ sequences collected from genomes obtained from Zhu et al. (2019). Clade I (purple) and clade II (blue) nosZ sequences show distinct clade separation in the tree. Branch tips are colored by taxonomy at the level of phylum. Four phyla (Pseudomonadota, 360 Bacteroidota, Bacillota, and Euryarchaeota—boxed in the legend) forming large, notable clades within the tree are further distinguished by shading beyond branch tips. Metadata is shown for specific taxa with genomes represented in the tree. These include, phototrophy (phototrophs vs non-phototrophs), oxygen status (aerobes, anaerobes, facultative organisms, and microaerophiles), and presence or absence of nitrite reductase genes nirS and nirK in the 365 corresponding genomes. Halobacterium species are distinguished within the “phototrophy” category due to previous characterization of photobiology within the aerobic archaeon Halobacterium salinarum NRC-1 (DasSarma et al., 2001). Note that nirK, like nosZ, is a Cuusing enzyme and is distinguished in the tree. — biorxiv.org

    Microbial N2O reduction in sulfidic waters: Implications for Proterozoic oceans, biorxiv.org

    Astrobiology,

    Continue Reading