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Experiments were carried out in high Reynolds number turbulent boundary layers over rough surfaces of diverse geometries. Roughness configurations varied in element height, distribution (random versus ordered), shape and spacing. Rough surfaces comprising of two superposed element geometries were also tested. All flows were free of transitional effects with
upwards of 40 000 and
ratios above 73. The wall-pressure spectrum and turbulent velocity profiles revealed that the roughness element spacing has the greatest impact on the turbulent structures in the boundary layer. The high-frequency scaling on shear friction velocity,
, (Meyers et al.J. Fluid Mech., vol. 768, 2015, pp. 261–293) was validated and
was shown to be the viscous contribution to the overall surface drag. An empirical formula for the pressure drag on roughness elements was developed to reflect the finding that the pressure drag is a function of only two variables: sparseness ratio
and roughness Reynolds number
. Results also suggest that the viscous contribution to drag approaches a constant non-zero value at high Reynolds numbers, and ‘fully rough-wall flow’ may occur at higher
than previously thought.
Compound-specific radiocarbon (14C) dating often requires working with small samples of < 100 µg carbon (µgC). This makes the radiocarbon dates of biomarker compounds very sensitive to biases caused by extraneous carbon of unknown composition, a procedural blank, which is introduced to the samples during the steps necessary to prepare a sample for radiocarbon analysis by accelerator mass spectrometry (i.e., isolating single compounds from a heterogeneous mixture, combustion, gas purification and graphitization). Reporting accurate radiocarbon dates thus requires a correction for the procedural blank. We present our approach to assess the fraction modern carbon (F14C) and the mass of the procedural blanks introduced during the preparation procedures of lipid biomarkers (i.e. n-alkanoic acids) and lignin phenols. We isolated differently sized aliquots (6–151 µgC) of n-alkanoic acids and lignin phenols obtained from standard materials with known F14C values. Each compound class was extracted from two standard materials (one fossil, one modern) and purified using the same procedures as for natural samples of unknown F14C. There is an inverse linear relationship between the measured F14C values of the processed aliquots and their mass, which suggests constant contamination during processing of individual samples. We use Bayesian methods to fit linear regression lines between F14C and 1/mass for the fossil and modern standards. The intersection points of these lines are used to infer F14Cblank and mblank and their associated uncertainties. We estimate 4.88 ± 0.69 μgC of procedural blank with F14C of 0.714 ± 0.077 for n-alkanoic acids, and 0.90 ± 0.23 μgC of procedural blank with F14C of 0.813 ± 0.155 for lignin phenols. These F14Cblank and mblank can be used to correct AMS results of lipid and lignin samples by isotopic mass balance. This method may serve as a standardized procedure for blank assessment in small-scale radiocarbon analysis.
In January of 2010, North Carolina (NC) USA implemented state-wide Trauma Triage Destination Plans (TTDPs) to provide standardized guidelines for Emergency Medical Services (EMS) decision making. No study exists to evaluate whether triage behavior has changed for geriatric trauma patients.
The impact of the NC TTDPs was investigated on EMS triage of geriatric trauma patients meeting physiologic criteria of serious injury, primarily based on whether these patients were transported to a trauma center.
This is a retrospective cohort study of geriatric trauma patients transported by EMS from March 1, 2009 through September 30, 2009 (pre-TTDP) and March 1, 2010 through September 30, 2010 (post-TTDP) meeting the following inclusion criteria: (1) age 50 years or older; (2) transported to a hospital by NC EMS; (3) experienced an injury; and (4) meeting one or more of the NC TTDP’s physiologic criteria for trauma (n = 5,345). Data were obtained from the Prehospital Medical Information System (PreMIS). Data collected included proportions of patients transported to a trauma center categorized by specific physiologic criteria, age category, and distance from a trauma center.
The proportion of patients transported to a trauma center pre-TTDP (24.4% [95% CI 22.7%-26.1%]; n = 604) was similar to the proportion post-TTDP (24.4% [95% CI 22.9%-26.0%]; n = 700). For patients meeting specific physiologic triage criteria, the proportions of patients transported to a trauma center were also similar pre- and post-TTDP: systolic blood pressure <90 mmHg (22.5% versus 23.5%); respiratory rate <10 or >29 (23.2% versus 22.6%); and Glascow Coma Scale (GCS) score <13 (26.0% versus 26.4%). Patients aged 80 years or older were less likely to be transported to a trauma center than younger patients in both the pre- and post-TTDP periods.
State-wide implementation of a TTDP had no discernible effect on the proportion of patients 50 years and older transported to a trauma center. Under-triage remained common and became increasingly prevalent among the oldest adults. Research to understand the uptake of guidelines and protocols into EMS practice is critical to improving care for older adults in the prehospital environment.
The subglacial hydrologic system exerts strong controls on the dynamics of the overlying ice, yet the parameters that govern the evolution of this system are not widely known or observable. To gain a better understanding of these parameters, we invert a spatially averaged model of subglacial hydrology from observations of ice surface velocity and outlet stream discharge at Kennicott Glacier, Wrangell Mountains, AK, USA. To identify independent parameters, we formally non-dimensionalize the forward model. After specifying suitable prior distributions, we use a Markov-chain Monte Carlo algorithm to sample from the distribution of parameter values conditioned on the available data. This procedure gives us not only the most probable parameter values, but also a rigorous estimate of their covariance structure. We find that the opening of cavities due to sliding over basal topography and turbulent melting are of a similar magnitude during periods of large input flux, though turbulent melting also exhibits the greatest uncertainty. We also find that both the storage of water in the englacial system and the exchange of water between englacial and subglacial systems are necessary in order to explain both surface velocity observations and the relative attenuation in the amplitude of diurnal signals between input and output flux observations.
Along the base of glaciers and ice sheets, the sliding of ice over till depends critically on water drainage. In locations where drainage occurs through Röthlisberger channels, the effective pressure along the base of the ice increases and can lead to a strengthening of the bed, which reduces glacier sliding. The formation of Röthlisberger channels depends on two competing effects: (1) melting from turbulent dissipation opens the channel walls and (2) creep flow driven by the weight of the overlying ice closes the channels radially inward. Variation in downstream ice velocity along the channel axis, referred to as an antiplane shear strain rate, decreases the effective viscosity. The softening of the ice increases creep closure velocities. In this way, even a modest addition of antiplane shear can double the size of the Röthlisberger channels for a fixed water pressure or allow channels of a fixed radius to operate at lower effective pressure, potentially decreasing the strength of the surrounding bed. Furthermore, we show that Röthlisberger channels can be deformed away from a circular cross section under applied antiplane shear. These results can have broad impacts on sliding velocities and potentially affect the total ice flux out of glaciers and ice streams.
The International Law Commission (ILC or the Commission) has a mandate from the United Nations (UN) General Assembly (the UNGA or the General Assembly) to codify and progressively develop international law. During most of the ILC's history, the lion's share of its work product took the form of draft articles adopted by the UNGA as the basis for multilateral conventions. The ILC's activities received their principal legal effect during this period through the UN treaty-making process, rather than directly on the basis of the ILC's analysis of what customary international law (CIL or custom) does or should require.
In recent decades, however, the ILC has self-consciously limited its efforts to codify or progressively develop international law in the form of multilateral conventions. Instead, it has turned to other outputs – such as principles, conclusions, and draft articles, that it does not recommend be turned into treaties. Significantly, the Commission often claims that these outputs reflect CIL. For example, despite recommending that the General Assembly not base a treaty on the Draft Articles on State Responsibility, the ILC as well as many states and commentators assert that the draft articles largely reflect CIL.
This change in behavior presents a puzzle. If the ILC is still engaged in codification and progressive development, why has it changed the form of the work it produces? In this chapter, we argue that increasing political gridlock in the General Assembly – by which we mean a division of views over the substance of international norms and lack of enthusiasm for convening multilateral diplomatic conferences – has led the Commission to modify the form of its work to preserve its influence in shaping the evolution of international law. More specifically, we argue that the reduced likelihood of the General Assembly adopting draft articles as treaties closes off the primary mechanism of ILC influence. In addition, if the UNGA or member states reject an ILC recommendation that its draft articles become treaties, that rejection may suggest that the work product does not reflect existing custom – an alternative mechanism of ILC influence. To avoid these negative outcomes, we expect the ILC to turn to other outputs that allow it to continue to influence CIL without the General Assembly's approval.
This paper describes postrelease monitoring of a population of Jaapiella ivannikovi, a gall-forming midge that was introduced for biological control of Russian knapweed. In 2011 to 2013, from late May to early June through August, we monitored 100 permanent plots at one of the first release sites of J. ivannikovi in central Wyoming. Based on the phenology of gall formation, an appropriate window for collection of galls to distribute to new sites is from early to mid-June through early August. Although J. ivannikovi established successfully, 4 yr after release, the percentage of ramets that were galled remained low (1 to 2%), indicating that J. ivannikovi is not yet having a significant effect on Russian knapweed at the site.
Experiments have been performed on a series of high-Reynolds-number flat-plate turbulent boundary layers formed over rough and smooth walls. The boundary layers were fully rough, yet the elements remained a very small fraction
of the boundary-layer thickness, ensuring conditions free of transitional effects. The wall-pressure spectrum and its scaling were studied in detail. One of the major findings is that the rough-wall turbulent pressure spectrum at vehicle relevant conditions is comprised of three scaling regions. These include a newly discovered high-frequency region where the pressure spectrum has a viscous scaling controlled by the friction velocity, adjusted to exclude the pressure drag on the roughness elements.
Customarily one begins a discussion about the effectiveness of international law by quoting Louis Henkin’s famous remark that “almost all nations obey almost all principles of international law and almost all of their obligations almost all of the time.” For some, this empirical claim supports the notion that international law is a vital tool for furthering international cooperation across a broad range of issue areas. For others, the implicit suggestion that international law’s mere existence might be driving states’ behavior is a calamity of causal inference. Even if Henkin’s claim is empirically correct, effectiveness does not follow from compliance. For a third group, Henkin’s claim may not even be empirically correct. In at least some areas of international law, noncompliance may be relatively high. Deploying the same suspect causal reasoning that the second group worries about, international law skeptics have sometimes suggested that we might infer ineffectiveness on the basis of such noncompliance.
The traditional treaty, conceived of as a contract between states, is in decline. Recent climate change negotiations have produced nonbinding instruments such as the Copenhagen and Cancun Accords; the financial crisis prompted governments to negotiate Basel III, a nonbinding framework for global banking regulation; the nonbinding Organisation for Economic Cooperation and Development’s Guidelines for Multinational Enterprises are developed countries’ primary rules governing the conduct of transnational businesses. Clouds loom on the horizon even in those areas in which the treaty’s prominence continues, such as investment and trade law. The World Trade Organization (WTO) has not reached a major agreement among its members since its founding twenty years ago, and some states have withdrawn from bilateral investment treaties or the Convention on the Settlement of Investment Disputes Between States and National of Other States (better known as the ICSID Convention).
Under what conditions should epistemic institutions (institutions that provide policy-relevant scientific advice) be integrated into international legal institutions – for example, the Conference of the Parties to the United Nations Framework Convention on Climate Change? Following work in law and economics on the theory of the firm, this article argues that where states will not implement environmental policies absent a collective decision to do so, greater hierarchical control of epistemic institutions by legal institutions may be necessary to ensure the credibility and availability of a usable scientific record. Hierarchy creates credibility because it allows all states necessary for cooperation in the legal institution to oversee the production of the scientific record that provides the basis for international legal rules. Hierarchy thus enhances the effectiveness of international law as a coordination tool, even at the expense of the autonomy of the scientific process. By contrast, where collective action is not necessary because states will unilaterally regulate an environmental problem once scientific uncertainty has been reduced, epistemic and legal institutions should be fragmented to ensure the unbiased production and dissemination of scientific information. In such situations, the credibility of the scientific record is demonstrated by decentralized adoption of science-based regulation.
More than 50% of the global population already lives in urban settlements and urban areas are projected to absorb almost all the global population growth to 2050, amounting to some additional three billion people. Over the next decades the increase in rural population in many developing countries will be overshadowed by population flows to cities. Rural populations globally are expected to peak at a level of 3.5 billion people by around 2020 and decline thereafter, albeit with heterogeneous regional trends. This adds urgency in addressing rural energy access, but our common future will be predominantly urban. Most of urban growth will continue to occur in small-to medium-sized urban centers. Growth in these smaller cities poses serious policy challenges, especially in the developing world. In small cities, data and information to guide policy are largely absent, local resources to tackle development challenges are limited, and governance and institutional capacities are weak, requiring serious efforts in capacity building, novel applications of remote sensing, information, and decision support techniques, and new institutional partnerships. While ‘megacities’ with more than 10 million inhabitants have distinctive challenges, their contribution to global urban growth will remain comparatively small.
Energy-wise, the world is already predominantly urban. This assessment estimates that between 60–80% of final energy use globally is urban, with a central estimate of 75%. Applying national energy (or GHG inventory) reporting formats to the urban scale and to urban administrative boundaries is often referred to as a ‘production’ accounting approach and underlies the above GEA estimate.