Category Archives: Peer Reviewed Article Review

global human footprint mapping

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This article in Nature Communications is about detailed global mapping of human impacts on the Earth’s ecosystems.

Sixteen years of change in the global terrestrial human footprint and implications for biodiversity conservation

Human pressures on the environment are changing spatially and temporally, with profound implications for the planet’s biodiversity and human economies. Here we use recently available data on infrastructure, land cover and human access into natural areas to construct a globally standardized measure of the cumulative human footprint on the terrestrial environment at 1 km2 resolution from 1993 to 2009. We note that while the human population has increased by 23% and the world economy has grown 153%, the human footprint has increased by just 9%. Still, 75% the planet’s land surface is experiencing measurable human pressures. Moreover, pressures are perversely intense, widespread and rapidly intensifying in places with high biodiversity. Encouragingly, we discover decreases in environmental pressures in the wealthiest countries and those with strong control of corruption. Clearly the human footprint on Earth is changing, yet there are still opportunities for conservation gains.

hidden parking costs

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Hidden parking costs drive up the cost of rent in U.S. metropolitan areas by an average of 17% according this article. The implication is that people are paying for housing and parking together, and don’t realize it. By separating the two, the cost of housing would be reduced, and people would be free to choose to pay for parking, or use the money saved on other transportation options.

Hidden Costs and Deadweight Losses: Bundled Parking and Residential Rents in the Metropolitan United States

There is a major housing affordability crisis in many American metropolitan areas, particularly for renters. Minimum parking requirements in municipal zoning codes drive up the price of housing, and thus represent an important potential for reform for local policymakers. The relationship between parking and housing prices, however, remains poorly understood. We use national American Housing Survey data and hedonic regression techniques to investigate this relationship. We find that the cost of garage parking to renter households is approximately $1,700 per year, or an additional 17% of a housing unit’s rent. In addition to the magnitude of this transport cost burden being effectively hidden in housing prices, the lack of rental housing without bundled parking imposes a steep cost on carless renters—commonly the lowest income households—who may be paying for parking that they do not need or want. We estimate the direct deadweight loss for carless renters to be $440 million annually. We conclude by suggesting cities reduce or eliminate minimum parking requirements, and allow and encourage landlords to unbundle parking costs from housing costs.

modeling the Maya collapse

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This interesting study included a computer model of how drought and agricultural practices could have combined to destroy the ancient Mayan civilization.

Conceptualizing sociohydrological drought processes: The case of the Maya collapse

With population growth, increasing water demands and climate change the need to understand the current and future pathways to water security is becoming more pressing. To contribute to addressing this challenge, we examine the link between water stress and society through socio-hydrological modeling. We conceptualize the interactions between an agricultural society with its environment in a stylized way. We apply the model to the case of the ancient Maya, a population that experienced a peak during the Classic Period (AD 600-830) and then declined during the ninth century. The hypothesis that modest drought periods played a major role in the society’s collapse is explored. Simulating plausible feedbacks between water and society we show that a modest reduction in rainfall may lead to an 80% population collapse.Population density and crop sensitivity to droughts, however, may play an equally important role. The simulations indicate that construction of reservoirs results in less frequent drought impacts, but if the reservoirs run dry, drought impact may be more severe and the population drop may be larger.

Sense what is using electricity in your home

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This is pretty cool – a device that can learn the patterns and measure the electricity use of individual appliances in your home, all just from being plugged into your fuse box.

The company says it can accurately disaggregate 80 percent of home energy use; it can do things like detect a microwave oven through its very specific startup and operating power “signature,” or sense a washing machine thanks in part to subtly increasing demand on the motor as the drum fills with water. As it identifies garage door openers, toasters, microwave ovens, washing machines, heaters, and refrigerators, it displays them on an app as a newsfeed and a series of labeled bubbles.

Sense—founded by speech-recognition veterans whose technology ended up in Samsung’s S-Voice and Apple’s Siri—consists of a box about the size of an eyeglasses case installed inside or next to an electrical service panel. Two inductive current sensors sense current, and two cables power the box and sense voltage. The box does some onboard processing, and then uses Wi-Fi to send data to the cloud for further analysis and aggregation with data from other users to improve its accuracy.

transportation megaprojects exceed cost estimates by 28%

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According to this Danish study, worldwide transportation “megaprojects” exceed their projected costs by an average of 28%.

  • In 9 out of 10 transportation infrastructure projects, costs are underestimated.
  • For rail projects, actual costs are on average 45% higher than estimated costs (sd=38).
  • For fixed-link projects (tunnels and bridges), actual costs are on average 34% higher than estimated costs (sd=62).
  • For road projects, actual costs are on average 20% higher than estimated costs (sd=30).
  • For all project types, actual costs are on average 28% higher than estimated costs (sd=39).
  • Cost underestimation exists across 20 nations and 5 continents; it appears to be a global phenomenon.
  • Cost underestimation appears to be more pronounced in developing nations than in North America and Europe (data for rail projects only).
  • Cost underestimation has not decreased over the past 70 years. No learning that would improve cost estimate accuracy seems to take place.
  • Cost underestimation cannot be explained by error and seems to be best explained by strategic misrepresentation, i.e., lying.
  • Transportation infrastructure projects do not appear to be more prone to cost underestimation than are other types of large projects.

biodiversity and ecosystem services in decisions

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Here’s an “open-source software tool for integrating biodiversity and ecosystem services into impact assessment and mitigation decisions“.

Governments and financial institutions increasingly require that environmental impact assessment and mitigation account for consequences to both biodiversity and ecosystem services. Here we present a new software tool, OPAL (Offset Portfolio Analyzer and Locator), which maps and quantifies the impacts of development on habitat and ecosystem services, and facilitates the selection of mitigation activities to offset losses. We demonstrate its application with an oil and gas extraction facility in Colombia. OPAL is the first tool to provide direct consideration of the distribution of ecosystem service benefits among people in a mitigation context. Previous biodiversity-focused efforts led to redistribution or loss of ecosystem services with environmental justice implications. Joint consideration of biodiversity and ecosystem services enables targeting of offsets to benefit both nature and society. OPAL reduces the time and technical expertise required for these analyses and has the flexibility to be used across a range of geographic and policy contexts.

everyday chemicals and the developing brain

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This is a disturbing article about the effects of common chemicals on childrens’ developing brains. I don’t get too alarmed when I hear this stuff from hte anti-vaccine and anti-GMO crowd, but this article is signed by dozens of scientists who study the brain.

Children in America today are at an unacceptably high risk of developing neurodevelopmental disorders that affect the brain and nervous system including autism, attention deficit hyperactivity disorder, intellectual disabilities, and other learning and behavioral disabilities. These are complex disorders with multiple causes—genetic, social, and environmental. The contribution of toxic chemicals to these disorders can be prevented…These include chemicals that are used extensively in consumer products and that have become widespread in the environment. Some are chemicals to which children and pregnant women are regularly exposed, and they are detected in the bodies of virtually all Americans in national surveys conducted by the U.S. Centers for Disease Control and Prevention. The vast majority of chemicals in industrial and consumer products undergo almost no testing for developmental neurotoxicity or other health effects.

To me, there is a difference between chemicals used in industry and agriculture, and chemicals found in everyday household products. We should be looking for truly safe and nontoxic substitutes for all of them, but the latter are particularly important both because the public is exposed to them directly, and because in some cases they are just not necessary. When I read the label on a bottle of shampoo I can’t help wondering if the chemical soup that is in there is really necessary to cleanse my hair, and even if were, cleansing my hair is not a matter of life and death.

gene circuits

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Here’s another article on the idea of designed biological circuits.

Synthetic mixed-signal computation in living cells

Living cells implement complex computations on the continuous environmental signals that they encounter. These computations involve both analogue- and digital-like processing of signals to give rise to complex developmental programs, context-dependent behaviours and homeostatic activities. In contrast to natural biological systems, synthetic biological systems have largely focused on either digital or analogue computation separately. Here we integrate analogue and digital computation to implement complex hybrid synthetic genetic programs in living cells. We present a framework for building comparator gene circuits to digitize analogue inputs based on different thresholds. We then demonstrate that comparators can be predictably composed together to build band-pass filters, ternary logic systems and multi-level analogue-to-digital converters. In addition, we interface these analogue-to-digital circuits with other digital gene circuits to enable concentration-dependent logic. We expect that this hybrid computational paradigm will enable new industrial, diagnostic and therapeutic applications with engineered cells.

more on the new cancer treatments

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The BBC has a bit more on the leading edge in cancer research and treatment:

Cancer is entering a “new era” of personalised medicine with drugs targeted to the specific weaknesses in each patient’s tumour, say doctors…

The idea of precision medicine is to test every patient’s tumour, find the mutations that have become essential for it to survive and then select a targeted drug to counter-act the mutation – killing the tumour…

a revolution in genetics – allowing scientists to rapidly and cheaply interrogate a cancer’s corrupted DNA – is leading to huge excitement about a new generation of precision drugs.