Water mass census in the Nordic seas using climatological and observational data sets

We have compared and evaluated the water mass census in the Greenlend-Iceland-Norwegian (GIN) Sea area from climatologies, observational data sets and model output. The four climatologies evaluated were: the 1998 and 2001 versions of theWorld Ocean Atlas (WOA98, WOA01), and the United States Navy’s GDEM90 (Generalized Digital Environmental Model) and MODAS01 (Modular Ocean Data Assimilation System) climatologies. Three observational data sets were examined: the multidecadal (1965-1995) set contained on the National Oceanographic Data Center’s (NODC) WOD98 (World Ocean Data) CD-ROM, and two seasonal data sets extracted from observations taken on six cruises by the SACLANT Research Center (SACLANTCEN) of NATO/Italy between 1986-1989. The model data is extracted from a global model run at 1/3 degree resolution for the years 1983-1997, using the POP (Parallel Ocean Program) model of the Los Alamos National Laboratory. The census computations focused on the Norwegian Sea, in the southern part of the GIN Sea, between 10◦W-10◦E and 60◦N-70◦N, especially for comparisons with the hydrocasts and the model. Cases of such evaluation computations included: a) “short term” comparisons with quasi-synoptic CTD surveys carried out over a 4-year period in the southeastern GIN Sea; b) “climatological” comparisons utilizing all available casts from the WOD98 CD-ROM, with four climatologies; and c) a comparison between the WOA01 climatology and the POP model output ending in 1997. In this region in the spring, the fraction of ocean water that has salinity above 34.85 is ∼ 94%, and that has temperatures above 0◦C is ∼ 33%. Three principal water masses dominated the census: the Atlantic water AW, the deep water DW and an intermediate water mass defined as Lower Arctic Intermediate Water (LAIW). Besides these classes, both the climatologies and the observations exhibited the significant presence of deep water masses with T-S characteristics that do not fall into the “named” varieties, e.g., Norwegian Sea or Greenland Sea deep water (NSDW, GSDW). The seasonal volumetric changes for the Atlantic (AW), intermediate (LAIW) and deep waters (DW) in the GIN Sea are in reasonably good agreement between the climatologies, and with the results of hydrographic census surveys. Typical seasonal changes (spring-summer) involve about 30 × 103 km3 of AW increase and 33 × 103 km3 of LAIW decrease, and a decrease of about 32 × 103 km3 of DW between spring and autumn

Urinary naphthalene and phenanthrene as biomarkers of occupational exposure to polycyclic aromatic hydrocarbons.

OBJECTIVES: The study investigated the utility of unmetabolised naphthalene (Nap) and phenanthrene (Phe) in urine as surrogates for exposures to mixtures of polycyclic aromatic hydrocarbons (PAHs). METHODS: The report included workers exposed to diesel exhausts (low PAH exposure level, n = 39) as well as those exposed to emissions from asphalt (medium PAH exposure level, n = 26) and coke ovens (high PAH exposure level, n = 28). Levels of Nap and Phe were measured in urine from each subject using head space-solid phase microextraction and gas chromatography-mass spectrometry. Published levels of airborne Nap, Phe and other PAHs in the coke-producing and aluminium industries were also investigated. RESULTS: In post-shift urine, the highest estimated geometric mean concentrations of Nap and Phe were observed in coke-oven workers (Nap: 2490 ng/l; Phe: 975 ng/l), followed by asphalt workers (Nap: 71.5 ng/l; Phe: 54.3 ng/l), and by diesel-exposed workers (Nap: 17.7 ng/l; Phe: 3.60 ng/l). After subtracting logged background levels of Nap and Phe from the logged post-shift levels of these PAHs in urine, the resulting values (referred to as ln(adjNap) and ln(adjPhe), respectively) were significantly correlated in each group of workers (0.71 < or = Pearson r < or = 0.89), suggesting a common exposure source in each case. Surprisingly, multiple linear regression analysis of ln(adjNap) on ln(adjPhe) showed no significant effect of the source of exposure (coke ovens, asphalt and diesel exhaust) and further suggested that the ratio of urinary Nap/Phe (in natural scale) decreased with increasing exposure levels. These results were corroborated with published data for airborne Nap and Phe in the coke-producing and aluminium industries. The published air measurements also indicated that Nap and Phe levels were proportional to the levels of all combined PAHs in those industries. CONCLUSION: Levels of Nap and Phe in urine reflect airborne exposures to these compounds and are promising surrogates for occupational exposures to PAH mixtures

Test-Retest Reliability of a 4-Minute All-Out Critical Force Test in Rock Climbers

International Journal of Exercise Science 16(4): 912-923, 2023. The purpose of this study was to assess the test-retest reliability of a 4-minute all-out critical force test in well-trained rock climbers. Thirteen rock climbers (n=4 females) completed a familiarization session and two all-out critical force tests on different days. During each trial, participants completed 24 repetitions of 7s right-handed, maximal effort hangs from a 20mm edge interspersed with 3 s rest. The end-test force (EF; i.e., critical force), impulse above EF (IEF), and peak force achieved durin g the test were analyzed with paired t-tests to determine differences between trials. Intraclass correlation coefficient (ICC), coefficient of variation (CV), and Bland-Altman analysis were performed to quantify the relative and absolute reliability of the measure, respectively. The level of significance for this study was set at p\u3c0.05. There were no significant differences between trials for any of the reported variables (P≥0.455). For EF, IEF, and peak force, ICC was 0.848, 0.820, and 0.938, respectively; and CV was 21.0%, 13.2%, and 5.6%, respectively. Bland-Altman analyses showed a mean relative bias of -2.3%, -2.8%, and -1.3%, with 95% limits of agreement (LoA) of -62.6% to 58.1%, -40.5% to 30.9%, and -17.2% to 14.6% for EF, IEF, and peak force, respectively, however linear regression revealed a significant proportional bias for EF (p = 0.026, R2 = 0.377). The reliability of this protocol was good to excellent for all parameters; however, there was larger intra-individual variability for EF and IEF. This study suggests that when using the 4-min all-out critical force test in rock climbers, coaches and athletes should be aware that there may be a trade-off between the test’s practicality and the precision of its results

Witnessing eigenstates for quantum simulation of Hamiltonian spectra

The efficient calculation of Hamiltonian spectra, a problem often intractable on classical machines, can find application in many fields, from physics to chemistry. Here, we introduce the concept of an "eigenstate witness" and through it provide a new quantum approach which combines variational methods and phase estimation to approximate eigenvalues for both ground and excited states. This protocol is experimentally verified on a programmable silicon quantum photonic chip, a mass-manufacturable platform, which embeds entangled state generation, arbitrary controlled-unitary operations, and projective measurements. Both ground and excited states are experimentally found with fidelities >99%, and their eigenvalues are estimated with 32-bits of precision. We also investigate and discuss the scalability of the approach and study its performance through numerical simulations of more complex Hamiltonians. This result shows promising progress towards quantum chemistry on quantum computers.Comment: 9 pages, 4 figures, plus Supplementary Material [New version with minor typos corrected.