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For many years, it has been recommended that analysts performing stable isotope analysis of H, C, N, O and/or S prepare their own in-house reference materials (RMS) for daily use. These RMs can be used for calibration/normalization of instrumental data as well as for quality control and/or assurance purposes. In this way, commercially available RMs that are the source of traceability for all isotope delta analyses are preserved, ensuring that the isotope delta scales can be maintained for a longer period of time. Furthermore, in-house RMs can be prepared to supplement those that are commercially available, either by extending the available calibration range in terms of isotope delta values, or by consisting of a matrix which is not yet available from RM producers.Some guidance is available regarding the required nature or properties of an in-house RM including stability, homogeneity, hygroscopicity and other chemical properties [e.g. Dunn & Carter 2018]. There are also a small number of publications providing some guidance on how to prepare in-house RMs for particular applications [e.g. Carter & Fry 2013, Heile & Hillarie-Marcel 2020]. There is, however, far less guidance available regarding the process of assigning an isotope delta value and associated uncertainty to an in-house RM. The guidance available to certified RM producers such as ISO/IEC 17034:2016 tend to have somewhat stricter requirements than those to be met by an in-house RM for QC purposes.Building upon the National Measurement Laboratory’s experience as a CRM producer accredited to ISO/IEC 17034:2016, this presentation will distil the requirements for RM production into simple and clear guidelines for fit-for-purpose production and value-assignment of in-house RMs. This guidance covers five areas: (i) planning and prerequisites; (ii) material selection, preparation and storage; (iii) measurements and assessments; (iv) value assignment and uncertainty estimation; and (v) monitoring and use. Dunn PJH, Carter JF. Good Practice Guide for Isotope Ratio Mass Spectrometry. 2nd ed. FIRMS; 2018. ISBN 978-0-948926-33-4. https://www.forensic-isotopes.org/gpg.htmlCarter JF, Fry B. “Do it yourself” reference materials for δ13C determinations by isotope ratio mass spectrometry. Anal Bioanal Chem. 2013;405(14):4959-4962.Heile J-F, Hillaire-Marcel C. Designing internal reference materials for stable H, C & O isotope measurements in CO2 and H2O. Rapid Commun Mass Spectrom. 2021;35(5)e9008.ISO/IEC 17034:2016. General requirements for the competence of reference material producers. Published online 2016.

The stable HCNOS isotope compositions can be reported in various ways depending on scientific domain and needs. The most common notations are 1) the isotope ratio of two stable isotopes; 2) isotope delta value, and 3) atom fraction of one or more of the isotopes. Frequently recalculations between these notations are required for certain applications, particularly when merging different data sets. All these recalculations require using the absolute isotope ratio for the zero points of the stable isotope delta scales (Rstd). However, several Rstd with very contrasting values have been proposed over time and there is no common agreement on which values should be used word-wide (Skrzypek and Dunn, 2020a).Differences in the selection of Rstdvalue may lead to significant differences between different data sets recalculated from delta value to other notations. These differences in Rstd have a significant influence also on the normalization of raw values but only when the normalization is conducted versus the working standard gas value. We proposed a user-friendly EasyIsoCalculator (http://easyisocalculator.gskrzypek.com) that allows recalculation between the main expressions of isotope compositions using various Rstd and aids for identification of potential inconsistencies in recalculations (Skrzypek and Dunn, 2020b). Skrzypek G., Dunn P. 2020a. Absolute isotope ratios defining isotope scales used in isotope ratio mass spectrometers and optical isotope instruments. Rapid Communications in Mass Spectrometry 34: e8890.Skrzypek G., Dunn P., 2020b. The recalculation of the stable isotope expressions for HCNOS – EasyIsoCalculator. Rapid Communications in Mass Spectrometry 34: e8892.

Arnon Avron has written: “Dunn-McCall logic RM is by far the best understood and the most well-behaved in the family of logics developed by the school of Anderson and Belnap.” I agree. There is the famous saying: “Do not let the perfect become the enemy of the good.” I might say: “good enough.” In this spirit, I will examine the logic R-Mingle, exploring how (in the terminology of Avron) it is only a “semi-relevant logic” but still a paraconsistent logic. I shall discuss the history of RM, and compare RM to Anderson and Belnap’s system R of relevant implication and to classical two-valued logic. There is a “consumer’s guide,” evaluating these logics as “tools,” in the light of my recent work on “Humans as Rational Toolmaking Animals.”

We describe an undocumented change in how calm periods in near-surface wind speed (and direction) observations have been encoded in a subset of global datasets of sub-daily data after 2013. This has resulted in the under-estimation of the number of calm periods for meteorological stations across much of Asia and Europe. Hence average wind speeds after 2013 have been over-estimated, affecting the assessment of changes in global stilling and reversal phenomena after this date. By addressing this encoding change we show that globally, since 2010, wind speeds have recovered by around 30% less than previously thought., ZZ was supported by the National Natural Science Foundation of China (grants no. 42071022). CAM was supported by the Spanish Ministry of Science and Innovation (RTI2018-095749-A-I00), the Valencian Regional Government (AICO/2021/023), the Leonardo grant 2021 from the BBVA Foundation, and the Interdisciplinary Thematic Platform PTI-CLIMA. CS was supported by Swedish Formas(2019-00509 and 2017-01408) and VR (2021-02163 and 2019-03954).

The cerium(III) hydroxide chloride Ce(OH)2Cl crystallises directly as a polycrystalline powder from a solution of CeCl3·7H2O in poly(ethylene) glycol (Mn = 400) heated at 240 °C and is found to be isostructural with La(OH)2Cl, as determined from high-resolution synchrotron powder X-ray diffraction (P21/m, a = 6.2868(2) A, b = 3.94950(3) A, c = 6.8740(3) A, β = 113.5120(5)°). Replacement of a proportion of the cerium chloride in synthesis by a second lanthanide chloride yields a set of materials Ce1−xLnx(OH)2Cl for Ln = La, Pr, Gd, Tb. For La the maximum value of x is 0.2, with an isotropic expansion of the unit cell, but for the other lanthanides a wider composition range is possible, and the lattice parameters show an isotropic contraction with increasing x. Thermal decomposition of the hydroxide chlorides at 700 °C yields mixed-oxides Ce1−xLnxO2−δ that all have cubic fluorite structures with either expanded (Ln = La, Gd) or contracted (Ln = Pr, Tb) unit cells compared to CeO2. Scanning electron microscopy shows a shape memory effect in crystal morphology upon decomposition, with clusters of anisotropic sub-micron crystallites being seen in the precursor and oxide products. The Pr- and Tb-substituted oxides contain the substituent in a mixture of +3 and +4 oxidation states, as seen by X-ray absorption near edge structure spectroscopy at the lanthanide LIII edges. The mixed oxide materials are examined using temperature programmed reduction in 10%H2 in N2, which reveals redox properties suitable for heterogeneous catalysis, with the Pr-substituted materials showing the greatest reducibility at lower temperature.

An international comparison study on the accurate determination of the molar mass M(Si) of silicon artificially enriched in 28Si (x(28Si) > 0.9999 mol mol−1) has been completed. The measurements were part of the high level CCQM-P160 pilot study assessing the ability of National Metrology Institutes (NMIs) and Designated Institutes (DIs) to make such measurements at the lowest possible levels of measurement uncertainty and to identify possible difficulties when measuring this kind of sample. This study supports the molar mass measurements critical to disseminating the silicon route to realizing the new definitions for the kilogram and the mole. Measurements were also made by one external research institute and an external company. The different institutes were free to choose their experimental (mass spectrometric) set-ups and equipment, thereby enabling also the comparison of different techniques. The investigated material was a chemically pure, polycrystalline silicon material. The subsequent modified single crystalline secondary product of this material was intended for the production of silicon which was used for two additional spheres in the context of the redetermination of the Avogadro constant NA, required for the revision of the International System of Units (SI) via fundamental constants which came into force from May 2019. The CCQM pilot study was organized by Physikalisch-Technische Bundesanstalt (PTB). Aqueous silicon solutions were shipped to all participating institutions. The data analysis as well as the uncertainty modelling and calculation of the results was predefined. The participants were provided with an uncertainty budget as a GUM Workbench® file as well as a free software license for the duration of the comparison. The agreement of the values of the molar mass (M(Si) = 27.976 942 577 g mol−1) was excellent with ten out of 11 results reported within the range of relative uncertainty of 1 × 10−8 required for the revision of the SI.

In this chapter, we are interested in understanding the nature of information and its value. We focus on information that is used for making decisions, including related activities such as constructing models, performing inferences, and making predictions. Our discussion is mostly qualitative, and it touches on certain aspects of information as related to the sender, receiver, and a possible observer. Although our emphasis is on shedding more light on the concept of information for making decisions, we are not concerned here with the exact details of the decision process, or information processing itself. In addition to discussing information, our expedition takes us through the traditional notions of utility, prices, and risk, all of which, under certain conditions, relate to the value of information. Our main conclusion is that the value of information (used in decision making) is relative and subjective. Since information is relative, it can have more than one value, say a value for the sender, a value for the receiver, or even different values for different senders and receivers, and various values for various “eavesdroppers.” Of course, the value might be zero for any of these. Importantly, that value is inversely related to risk when the information is used for decision making. Although this conclusion is likely expected, we did argue for it in a way that relies on some fundamentals about both value and information.

The cerium(iii) hydroxide chloride Ce(OH)2Cl crystallises directly as a polycrystalline powder from a solution of CeCl3·7H2O in poly(ethylene) glycol (Mn = 400) heated at 240 °C and is found to be isostructural with La(OH)2Cl, as determined from high-resolution synchrotron powder X-ray diffraction (P21/m, a = 6.2868(2) Å, b = 3.94950(3) Å, c = 6.8740(3) Å, β = 113.5120(5)°). Replacement of a proportion of the cerium chloride in synthesis by a second lanthanide chloride yields a set of materials Ce1-xLnx(OH)2Cl for Ln = La, Pr, Gd, Tb. For La the maximum value of x is 0.2, with an isotropic expansion of the unit cell, but for the other lanthanides a wider composition range is possible, and the lattice parameters show an isotropic contraction with increasing x. Thermal decomposition of the hydroxide chlorides at 700 °C yields mixed-oxides Ce1-xLnxO2-δ that all have cubic fluorite structures with either expanded (Ln = La, Gd) or contracted (Ln = Pr, Tb) unit cells compared to CeO2. Scanning electron microscopy shows a shape memory effect in crystal morphology upon decomposition, with clusters of anisotropic sub-micron crystallites being seen in the precursor and oxide products. The Pr- and Tb-substituted oxides contain the substituent in a mixture of +3 and +4 oxidation states, as seen by X-ray absorption near edge structure spectroscopy at the lanthanide LIII edges. The mixed oxide materials are examined using temperature programmed reduction in 10%H2 in N2, which reveals redox properties suitable for heterogeneous catalysis, with the Pr-substituted materials showing the greatest reducibility at lower temperature.

RATIONALE The isotope delta is calculated from the isotope ratio of a sample and the absolute isotope ratio of the zero reference point defining each stable isotope international scale (Rstd ). Therefore, Rstd requires accurate determination. However, the literature contains a large number of Rstd values, and selection of different Rstd may lead to inconsistency in reporting and recalculating stable isotope results. METHODS We reviewed Rstd used in the proprietary software provided by the manufacturers of stable isotope instruments commonly employed for analyses of stable HCNOS compositions. We compared the Rstd values and assessed the potential implications of using different Rstd and the normalization versus tank working gas standard for consistency in reporting stable isotope results. RESULTS Different Rstd values are used by different manufacturers of stable isotope analytical instruments. For R(2 H/1 H)VSMOW two different but very similar values are used, 0.00015575 and 0.00015576; for R(13 C/12 C)VPDB three different values are used, 0.0111802, 0.0112372 and 0.01118028; and for R(15 N/14 N)Air-N2 two values, 0.0036782 and 0.0036765, are used. All manufacturers are using the same value for R(18 O/16 O)VSMOW , 0.00200520, but three different values for R(18 O/16 O)VPDB , 0.002067200, 0.00208835 and 0.002088349. For R(34 S/32 S)VCDT four different Rstd are used, 0.0441509, 0.0441626, 0.044162589 and 0.0441520597. CONCLUSIONS The use of different Rstd values may lead to differences in the isotope delta values obtained if the normalization versus working standard gas is applied. For the range of Rstd used in proprietary software, the potential differences are lowest for oxygen (

Remotely Piloted Aircraft Systems (RPAS) have facilitated new growth in civil aviation. Unlike manned aircraft, however, they are operated without auditory feedback and normally flown under two visual conditions: in direct visual-line-of-sight to the remote pilot (VLOS) and beyond VLOS with first-person-view imagery transmitted via onboard cameras (BVLOS). The present research examined the effectiveness of audiovisual cueing on remote pilot manual flying performance. Eighteen pilots (three female) completed six navigation and 12 spotting tasks. Their flying performance (horizontal accuracy, vertical accuracy and timeliness) was examined under three different visual display types (VLOS (Control), BVLOS-Monitor & BVLOS-Goggles), with and without real-time auditory feedback, and two wind component (no wind and wind) conditions. Horizontal deviation and timeliness improved in the BVLOS-Monitor condition navigation task, while auditory feedback produced nuanced examples of improved and degraded pilot performance. These results indicate how the specificity of the task, combined with different levels of audiovisual feedback influences remote pilot performance. These findings support the rationalisation for the provision of multimodal dynamic sensory cueing in future RPAS. Practitioner summary: Accuracy and timeliness of remote pilot manual flying performance was measured under a combination of audiovisual feedback in calm and wind shear conditions. The inclusion of real-time auditory feedback as an additional sensory cue is uncommon; this study demonstrated nuanced examples of improved and degraded manual flying performance. The provision of dynamic sensory cueing made available to remote pilots in future RPAS should be considered.

RATIONALE The stable HCNOS isotope compositions can be reported as (a) the isotope ratio of two stable isotopes (R); (b) the isotope delta value (δ); and (c) the atom fraction of the isotopes (x). Recalculations between these different expressions are needed frequently and require the use of the absolute isotope ratio for the zero points of the stable isotope delta scales (Rstd). The inconsistent use of Rstd values may lead to a discrepancy in recalculated results. METHODS We summarised the recalculation procedures between different expressions of the stable isotope compositions and introduced a user-friendly EasyIsoCalculator that allows the recalculation between the main expressions of isotope compositions. We mathematically and empirically evaluated the possible inconsistencies in reporting of the stable isotope data due to the use of different Rstd and different normalisation methods. RESULTS The recalculation between δ-values and other expressions of the stable isotope compositions always involves the use of Rstd. The choice of Rstd will have a significant influence on the recalculated values. The use of different Rstd values has a significant influence also on the normalisation of raw values but only when the normalisation is conducted versus the working standard gas value, causing discrepancy, e.g. for δ(13C/12C) up to ~ 0.3 ‰. CONCLUSIONS Differences in the selection of Rstd value may lead to significant differences among different laboratories. The uncertainty in the calculations originates primarily from the uncertainty in the Rstd determination; however, it is lower than the discrepancy arising from the inconsistent use of Rstd. Consistent use of the same Rstd values is required to eliminate the unnecessary discrepancy if different data sets are recalculated from delta value to other expressions.

An international project developed, quality-tested, and measured isotope−delta values of 10 new food matrix reference materials (RMs) for hydrogen, carbon, nitrogen, oxygen, and sulfur stable isotope-ratio measurements to support food authenticity testing and food provenance verification. These new RMs will enable users to normalize measurements of samples to isotope−delta scales. The RMs span a range of δ2HVSMOW values from −207.4 to −43.3 mUr or ‰, for δ13CVPDB from −30.60 to −13.72 mUr, for δ15Nair from +1.78 to +14.96 mUr, for δ18OVSMOW from +18.20 to +26.33 mUr, and for δ34SVCDT from −20.25 to +17.49 mUr. The RMs include (i) a pair of honeys from Canada and tropical Vietnam, (ii) flours from C3 (rice) and C4 (millet) plants, (iii) four vegetable oils from C3 (olive, peanut) and C4 (corn) plants, and (iv) collagen powders from marine fish and terrestrial mammal origins. After thorough homogenization of the bulk materials, multiple aliquots were sealed in glass under vacuum or noble gas to exclude oxygen and to potentially extend the shelf life to decades when stored at –18 °C in the dark. A total of six laboratories from five countries used various analytical approaches and instrumentation for two- or multiple-point isotopic normalization against international RMs. The use of reference waters and organic liquids in silver tubes allowed direct normalization of δ2H values of organic materials against isotopic reference waters following the principle of identical treatment, minimizing interference from atmospheric moisture. An errors-in-variables regression model that included the uncertainty associated with the measured and assigned values of the RMs was applied centrally to normalize results and obtain consensus values and measurement uncertainties reported here for new RMs USGS82 to USGS91. Because of exchangeable hydrogen and H2O in some RMs (especially in honeys, collagens, and flours), sample loading in contact with laboratory air and different types of pre-treatment can result in significant bulk δ2H variance. Utilization of these new RMs should foster mutual compatibility of δ2H values if harmonized technical/analytical approaches are followed and documented in data reports.

Species-specific Hg isotope ratio data has increasingly become an important tool in understanding biogeochemistry of mercury. Among the plethora of analytical techniques capable of separating Hg species to date only gas chromatography has been used to study natural variations in their isotopic composition. Here, we report new methodology for precise and accurate Hg isotope ratio measurements of methylmercury in fish tissues at environmentally relevant levels using high performance liquid chromatography (HPLC) and cold vapour generation multi-collector inductively coupled plasma mass spectrometry (CVG MC-ICPMS). The chromatographic baseline separation of Hg species such as methylmercury (CH3Hg) and inorganic Hg (iHg) was achieved in isocratic mode using reverse phase HPLC with a mobile phase containing L-cysteine as a complexing agent and without the need for species derivatisation. The signal-to-noise ratio of Hg detection by MC-ICP-MS was improved using a cold vapour generation interface with SnCl2 as reducing agent. Challenges driven by the non-reactivity of CH3Hg with SnCl2 and, interferences caused by the presence of L-cysteine in the mobile phase were efficiently overcome through complete oxidation of isolated Hg species prior to cold vapour generation and species-specific Hg isotope ratio measurements. Combined standard uncertainties of δ199/198Hg, δ200/198Hg, δ201/198Hg and δ202/198Hg values determined from replicated measurements of CH3Hg in fish tissue reference materials BCR 463 and NIST SRM 1947 ranged from 0.10‰ to 0.22‰. The obtained δ-values for the Hg isotope ratios are in very good agreement with indicative values of NIST SRM 1947 and those previously reported for BCR 463 material. The developed technique offers a complimentary measurement method to gas chromatography MC-ICPMS in producing isotopically certified species-specific reference materials for Hg. Furthermore, evidence for Hg isotope fractionation induced by dissociation of CH3Hg and interactions with sulphur compounds in solution is provided here as well.

An understanding of suspended particulate matter (SPM) dynamics is of great importance to design awareness and management strategies of estuaries. Using a Laser In Situ Scattering and Transmissiometry (LISST) instrument, variations in suspended particle size volumetric concentrations (VC) and particle size distributions (PSD) were measured at six sites within Port Curtis estuary (Australia). The port is a macrotidal estuary with significant economic and environmental importance. Observed VC and SPM sizes demonstrated spatial and temporal trends strongly controlled by the variable energy conditions operating on the neap and spring cycle timescale, with a clear trend towards increasing concentrations and decreasing SPM sizes with increasing tidal ranges. Mid-estuary sites were characterized by the greatest depth-averaged VC under transitional and spring conditions. Estuary-wide mean spring tide total water profile concentrations revealed a near 300% increase in comparison to neap tide condition concentrations. In the upper-estuary sites the mean contribution of the combined 2.5–35 µm size classes to the total profile PSDs was greatest during all tidal conditions, whilst within the lower-estuary site the combined 35–130 µm size classes were greatest. Mean contributions of the largest size class (300–500 µm) dominated surface-waters throughout the estuary during the neap tide period, which when compared with the transitional and spring tide conditions, demonstrated changes of −82% to −48% and −82% to −40%, respectively. Overall, the results from this case study provides further evidence of the important influence of neap and spring tidal regimes on SPM dynamics within estuarine settings and the need to observe parameter dynamics on such timescales.

The Oregon Coast landscape displays strong spatial patterns in air temperature, precipitation, and geology, which can confound our ability to detect relationships among land management, instream conditions, and fish at broad spatial scales. Despite this structure, we found that a suite of immutable or intrinsic attributes (e.g., reach gradient, drainage area, elevation, and percent weak rock geology of the catchments draining to each of our 423 study reaches) could explain much of the variation in pool surface area across the landscape and could contribute to an estimate of how many juvenile coho salmon (Oncorhynchus kisutch) one might expect to find in those pools. Further, we found evidence of differences in pool surface area across land ownership categories that reflect differing management histories. Our results also suggest that historical land and river management activities, in particular splash dams that occurred at least 50 years ago, continue to influence the distribution of juvenile coho salmon and their habitats today.

Analytical methods that can identify the source and fate of mercury and organomercury compounds are likely to be useful tools to investigate mercury in the environment. Carbon isotope ratio analysis of methylmercury (MeHg) together with mercury isotope ratios may offer a robust tool to study environmental cycling of organomercury compounds within fish tissues and other matrices.MeHg carbon isotope ratios were determined by gas chromatography/combustion-isotope ratio mass spectrometry (GC/C-IRMS) either directly or following derivatization using sodium tetraethylborate. The effects of a normalization protocol and of derivatization on the measurement uncertainty of the methylmercury δGC/C-IRMS analysis resulted in a δWhile the δ

Prominent philosophers (Bar-Hillel and Carnap, Popper, Floridi) have argued that contradictions contain either too much or too little information to be useful. We dispute this with what we call the “Paradox of the Two Firefighters.” Suppose you are awakened in your hotel room by a fire alarm. You open the door. You see three possible ways out: left, right, straight ahead. You see two firefighters. One says there is exactly one safe route and it is to your left. The other says there is exactly one safe route and it is to your right. While the two firemen are giving you contradictory information, they are also both giving you the perhaps useful information that there is a safe way out and it is not straight ahead. We give two analyses. The first uses the “Opinion Tetrahedron,” introduced by Dunn as a generalization of Audun Josang’s “Opinion Triangle.” The Opinion Tetrahedron in effect embeds the values of the “Belnap-Dunn 4-valued Logic” (Truth, Falsity, Neither, Both) into a context of subjective probability generalized to allow for degrees of belief, disbelief, and two kinds of uncertainty—that in which the reasoner has too little information (ignorance) and that in which the reasoner has too much information (conflict). Josang had only a single value for uncertainty. We also present an alternative solution, again based on subjective probability but of a more standard type. This solution builds upon “linear opinion pooling.” Kiefer had already developed apparatus for assessing risk using expert opinion, and this influences the second solution. Finally, we discuss how these solutions might apply to “Big Data” and the World Wide Web.

The comparison of natural languages and formal languages has become quite popular of late. The topic was on the program of the last International Congress for Logic, Methodology and Philosophy of Science in Amsterdam, and also on the program of the 1968 New York University Institute of Philosophy. I have read the published results of both meetings [1], and I must say that I am not quite sure what all the fuss is about.

Demonstrating comparability of isotope-delta values between different laboratories by participation in inter-laboratory exercises (ILEs) is a vital component of method validation. Since its inception, the Forensic Isotope Ratio Mass Spectrometry (FIRMS) Network has provided non-accredited ILEs to its members. Provision of an accredited proficiency testing (PT) scheme to ISO/IEC 17043:2010 was not possible until the administration of the scheme was outsourced to an accredited PT provider—in this case LGC Standards. LGC’s FIRMS PT scheme has been operating since 2013 and in 2015 it was included in their scope of accreditation to ISO/IEC 17043:2010 and it remains the only such accredited PT for stable isotopic analyses. Each round of the PT scheme contains two materials that are of interest to forensic scientists. Participants report up to four isotope delta values for each material and the results of the PT scheme are interpreted using z- or z′-scores calculated using a standard deviation of performance assessment (SDPA) that was initially derived from the submitted data, but now have fixed values. This paper presents and discusses results for the FIRMS PT scheme, including inter-laboratory comparability over time not just for individual laboratories but also for particular matrices that have been analysed in multiple rounds. The FIRMS PT scheme has also distributed the same physical material as earlier FIRMS ILEs providing a longer-term view. A number of interesting findings are presented highlighting the value of PT participation together with a discussion of the status of forensic bio-element stable isotope ratio analysis in the light of these outcomes.

Key points Oxygen is vital for life-sustaining aerobic respiration in humans and is arguably the most commonly administered drug in anaesthesia and critical care medicine. Within the mitochondrial inner membrane, oxygen acts as the terminal electron acceptor at the end of the electron transport chain whereby oxidative phosphorylation results in the synthesis of adenosine triphosphate (ATP), the coenzyme that supplies energy to all active metabolic processes. This article will discuss the key physiological concepts underpinning the movement of oxygen within the human body and also highlight some clinical applications that serve as examples of these concepts. With respect to human physiology, oxygen transport can be divided into that occurring through convection and that occurring by diffusion. In this context, convection describes the movement of oxygen within the circulation, occurring through bulk transport. This is an active process requiring energy, in this case derived from the pumping of the heart. On the other hand, diffusion describes the passive movement of oxygen down a concentration gradient, for example, from the microcirculation into the tissues (and ultimately the mitochondria). ### Oxygen uptake into the blood Deoxygenated venous blood becomes oxygenated in the pulmonary capillaries after diffusion down a concentration gradient across the alveolar capillary membrane (see Section 2: diffusive oxygen transport). The …

Pacific harbor seals ( Phoca vitulina richardsi) and belugas ( Delphinapterus leucas ) eat many of the same prey species, occupy the same geographic area, and demonstrate site fidelity in Cook Inlet, Alaska. Although most direct research involving the critically endangered belugas is currently prohibited, studying harbor seals may provide important information about this beluga population. In recent years, harbor seal populations in Alaska have declined for unknown reasons. As part of its stranding program, the Alaska SeaLife Center (ASLC) managed 59 cases of live and dead stranded harbor seals from Cook Inlet between 1997 and 2011. Animals were screened for a variety of diseases and contaminants of concern. Animals were negative by serology to the following diseases: avian influenza, canine distemper virus, dolphin morbillivirus, porpoise morbillivirus, Leptospira canicola, L. grippotyphosa, L. pomona, Neospora caninum , Sarcocystis neurona , and Toxoplasma gondii . Positive titers were found against Brucella spp., phocine distemper virus, seal herpesvirus-1, L. bratislava, L. hardjo, and L. icterohemorrhagiae. All titers were stable or declining except in one animal with an increasing titer for seal herpesvirus-1. Fecal pathogen screenings identified normal flora as well as stable or declining low levels of potentially pathogenic and opportunistic bacteria, though most were of little concern for seal health. In most animals, toxicology screening showed that the majority of tested contaminants were below detectable limits. The level of evidence of exposure to pathogens of concern was low in harbor seals. Although the infectious disease burden and contaminant levels in belugas in Cook Inlet cannot be definitively determined without direct testing, pathogen and contaminant exposure is expected to be similar to that found in harbor seals in this region, as the harbor seals and belugas share the habitat and food resources.

Compound-specific amino acid carbon-isotope compositions have shown particular promise for elucidating dietary behaviors in complex environmental contexts, and may also be able to mitigate the effect of many of the limitations inherent to palaeodietary reconstructions. Here, we investigate the efficacy of compound-specific amino acid isotopic proxies in characterizing the consumption of different dietary protein sources using amino acid carbon-isotope compositions for humans and fauna from Rössberga (Early to Middle Neolithic), Köpingsvik (Mesolithic and Middle Neolithic), and Visby (Medieval Period), Sweden. We also assess the explanatory capabilities of an isotopic mixing model when used with essential amino acid carbon-isotope compositions of humans and local fauna. All three isotopic proxies distinguished among humans from the three sites consistently and informatively, and were able to enhance the broad interpretations made using bulk isotopic compositions. The mixing model palaeodietary reconstruction revealed considerable diversity in relative protein source contributions among individuals at both Köpingsvik and Visby. Comparing the mixing model for bulk carbon- and nitrogen-isotope compositions to the model for essential amino acid isotopic compositions further demonstrated the likelihood of underestimation and overestimation of marine protein consumption for both aquatic-dominant and mixed marine-terrestrial diets when using bulk isotopic compositions.

Improved methodology for high accuracy Mo isotope amount ratio measurements by multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) using normalisation to an internal standard is presented. It is based on the use of the regression model to correct for instrumental mass discrimination with NIST Standard Reference Material 987, certified for Sr isotope ratios, as the internal standard. Calibration factors for measured Mo isotope ratios were calculated from calibration factors for Sr isotope ratios by using an experimentally established relationship between variations in simultaneously measured Mo and Sr isotope ratios. The novelty of the developed methodology lies in the use of controlled changes in the magnitude of instrumental mass discrimination, achieved by small incremental changes in RF power of the plasma in the measurements, in order to better define a relationship between isotope ratios of the analyte and internal standard. The Mo isotope amount ratios with associated expanded uncertainties (k = 2), as determined for an in-house standard, a high-purity Mo metal rod from Johnson Matthey, were as follows: 92Mo/95Mo = 0.9223(15), 94Mo/95Mo = 0.5790(3), 96Mo/95Mo = 1.0500(6), 97Mo/95Mo = 0.06028(9), 98Mo/95Mo = 1.5278(30), 100Mo/95Mo = 0.6124(25). These values are in excellent agreement with those obtained previously for the same standard using calibration with synthetic isotope mixtures. Overall, the measurement uncertainties obtained by the two calibration approaches are fairly comparable. Performance of the regression model with the improved measurement strategy, in terms of accuracy and precision of Mo isotope amount ratios, was shown to be superior to that of other available models to correct for instrumental mass bias, including the linear, exponential and power models. For the first time in MC-ICPMS, a test of ruggedness of Mo isotope ratio measurements with normalisation to internal standard was performed using a Plackett–Burman factorial design. Full uncertainty budgets for the measurements are presented and identification of the major sources of uncertainty is provided. The developed methodology has been demonstrated to be a promising tool for certification of reference materials for isotopic measurements by offering an independent and less expensive calibration method to the one based on the use of synthetic isotope mixtures.

The first edition of the Forensic Isotope Ratio Mass Spectrometry (FIRMS) Network's Good Practice Guide for Isotope Ratio Mass Spectrometry was published in 2011.1, 2 This document was the result of a collaboration between members of the FIRMS Steering Group and the UK's National Measurement System and was edited by Jim Carter (then Chair of the FIRMS Network) and Vicki Barwick of LGC Limited (formerly the Laboratory of the Government Chemist). Both the FIRMS Network and LGC believe that good practice in isotope ratio analyses is desirable regardless of application, and therefore the first edition of the Guide was made freely available. The Guide has clearly been a valuable resource to the stable isotope community having been downloaded many hundreds of times per year and increasingly being cited in research articles.

Forensic application of carbon isotope ratio measurements of honey and honey protein to investigate the degree of adulteration with high fructose corn syrup or other C4 plant sugars is well established. These measurements must use methods that exhibit suitable performance criteria, particularly with regard to measurement uncertainty and traceability – low levels of adulteration can only be detected by methods that result in suitably small measurement uncertainties such that differences of 1‰ or less can be reliably detected. Inter-laboratory exercises are invaluable to assess the state-of-the art of measurement capabilities of laboratories necessary to achieve such performance criteria. National and designated metrology institutes from a number of countries recently participated in an inter-laboratory assessment (CCQM-K140) of stable carbon isotope ratio determination of bulk honey. The same sample material was distributed to a number of forensic isotope analysis laboratories that could not participate directly in the metrological comparison. The results from these studies have demonstrated that the majority of participants provided isotope delta values with acceptable performance metrics; that all participants ensured traceability of their results; and that where measurement uncertainties were reported; these were fit-for-purpose. A number of the forensic laboratories only reported precision rather than full estimates of measurement uncertainty and this was the major cause of the few instances of questionable performance metrics. Reporting of standard deviations in place of measurement uncertainties is common practice outside metrology institutes and the implications for interpretations of small differences in isotopic compositions are discussed. The results have also highlighted a number of considerations that are useful for organisers of similar inter-laboratory studies in the future.

This paper presents an overview of the pioneering contributions of Larisa Maksimova to relevance logics. She is one of the first researchers who set out to methodically study systems of relevance logics, initially, focusing on Ackermann’s \(\varPi '\) of “Rigorous Implication,” and then extending her work to Anderson and Belnap’s systems E of Entailment and R of Relevant Implication, and other related logics. Not only did she develop an algebraic semantics for E, but also we find that a semantic definition of entailment via a ternary accessibility relation appears — the very first time — in an abstract by her.

Of central importance to palaeodietary reconstruction is a clear understanding of relative contributions of different terrestrial (i.e., C3 vs. C4 plants) and aquatic (i.e., freshwater vs. marine) resources to human diet. There are, however, significant limitations associated with the ability to reconstruct palaeodiet using bulk collagen stable isotope compositions in regions where diverse dietary resources are available. Recent research has determined that carbon-isotope analysis of individual amino acids has considerable potential to elucidate dietary protein source where bulk isotopic compositions cannot. Using δ13CAA values for human and faunal remains from Zvejnieki, Latvia (8th – 3rd millennia BCE), we test several isotopic proxies focused on distinguishing freshwater protein consumption from both plant-derived and marine protein consumption. We determined that the Δ13CGly-Phe and Δ13CVal-Phe proxies can effectively discriminate between terrestrial and aquatic resource consumption, and the relationship between essential δ13CAA values and the Δ13CGly-Phe and Δ13CVal-Phe proxies can differentiate among the four protein consumption groups tested here. Compound-specific amino acid carbon-isotope dietary proxies thus enable an enhanced understanding of diet and resource exploitation in the past, and can elucidate complex dietary behaviour.

RATIONALE Natural stable carbon (δ(13)C) and nitrogen isotope ratios (δ(15)N) of humans are related to individual dietary habits and environmental and physiological factors. In forensic science the stable isotope ratios of human remains such as hair and nail are used for geographical allocation. Thus, knowledge of the global spatial distribution of human δ(13)C and δ(15)N values is an essential component in the interpretation of stable isotope analytical results. METHODS No substantial global datasets of human stable isotope ratios are currently available, although the amount of available (published) data has increased within recent years. We have herein summarised the published data on human global δ(13)C andδ(15)N values (around 3600 samples) and added experimental values of more than 400 additional worldwide human hair and nail samples. In order to summarise isotope ratios for hair and nail samples correction factors were determined. RESULTS The current available dataset of human stable isotope ratios is biased towards Europe and North America with only limited data for countries in Africa, Central and South America and Southeast Asia. The global spatial distribution of carbon isotopes is related to latitude and supports the fact that human δ(13)C values are dominated by the amount of C4 plants in the diet, either due to direct ingestion as plant food, or by its use as animal feed. In contrast, the global spatial distribution of human δ(15)N values is apparently not exclusively related to the amount of fish or meat ingested, but also to environmental factors that influence agricultural production. CONCLUSIONS There are still a large proportion of countries, especially in Africa, where there are no available data for human carbon and nitrogen isotope ratios. Although the interpretation of modern human carbon isotope ratios at the global scale is quite possible, and correlates with the latitude, the potential influences of extrinsic and/or intrinsic factors on human nitrogen isotope ratios have to be taken into consideration.

Thyroid hormones play a critical physiologic role in regulating protein synthesis, growth, and metabolism. To date, because no published compilation of baseline values for thyroid hormones in beluga whales (Delphinapterus leucas) exists, assessment of thyroid hormone concentrations in this species has been underused in clinical settings. The purpose of this study was to document the concentrations of total thyroxine (tT4) and total triiodothyronine (tT3) in healthy aquarium-maintained and free-ranging beluga whales and to determine the influence of age, sex, and season on the thyroid hormone concentrations. Archived serum samples were collected from healthy aquarium-maintained (n=43) and free-ranging (n=39) belugas, and serum tT4 and tT3 were measured using chemiluminescence immunoassay. The mean tT4 concentration in aquarium-maintained belugas was 5.67±1.43 μg/dl and the mean tT3 concentration was 70.72±2.37 ng/dl. Sex comparisons showed that aquarium-maintained males had significantly greater tT4 and tT3 (9.70±4.48 μg/dl and 92.65±30.55 ng/dl, respectively) than females (7.18±2.82 μg/dl and 77.95±20.37 ng/dl) (P=0.004 and P=0.013). Age comparisons showed that aquarium-maintained whales aged 1-5 yr had the highest concentrations of tT4 and tT3 (8.17±0.17 μg/dl and 105.46±1.98 ng/dl, respectively) (P=0.002 and P