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Marine sediment records from the north Icelandic shelf, which rely on tephrochronological age models, reveal an average ΔR (regional deviation from the modeled global surface ocean reservoir age) of approximately 150 yr for the last millennium. These tephra-based age models have not hitherto been independently verified. Here, we provide data that corroborate ΔR values derived from these sediment archives. We sampled the youngest portion (ontogenetic age) of a bivalve shell, Arctica islandica (L.), for radiocarbon analysis, which was collected alive in 2006 from the north Icelandic shelf in ∼80 m water depth. Annual band counting from the sectioned shell revealed that this clam lived for more than 405 yr, making it the longest-lived mollusk and possibly the oldest non-colonial animal yet documented. The 14C age derived from the umbo region of the shell is 951 ± 27 yr BR Assuming that the bivalve settled onto the seabed at AD 1600, the corresponding local value of ΔR is found to be 237 ± 35 yr by comparison of the 14C age with the Marine04 calibration curve (Hughen et al. 2004) at this time. Furthermore, we cross-matched a 287-yr-old, dead-collected, A. islandica shell from AD 1601 to 1656 from the same site with the live-caught individual. 14C analysis from the ventral margin of this shell revealed a ΔR of 186 ± 50 yr at AD 1650. These values compare favorably with each other and with the tephra-based ΔR values during this period, illustrating that 14C from A. islandica can effectively record 14C reservoir changes in the shelf seas.
Marine radiocarbon bomb-pulse time histories of annually resolved archives from temperate regions have been underexploited. We present here series of Δ14C excess from known-age annual increments of the long-lived bivalve mollusk Arctica islandica from 4 sites across the coastal North Atlantic (German Bight, North Sea; Troms⊘, north Norway; Siglufjordur, north Icelandic shelf; Grimsey, north Icelandic shelf) combined with published series from Georges Bank and Sable Bank (NW Atlantic) and the Oyster Ground (North Sea). The atmospheric bomb pulse is shown to be a step-function whose response in the marine environment is immediate but of smaller amplitude and which has a longer decay time as a result of the much larger marine carbon reservoir. Attenuation is determined by the regional hydrographic setting of the sites, vertical mixing, processes controlling the isotopic exchange of 14C at the air-sea boundary, 14C content of the freshwater flux, primary productivity, and the residence time of organic matter in the sediment mixed layer. The inventories form a sequence from high magnitude-early peak (German Bight) to low magnitude-late peak (Grimsey). All series show a rapid response to the increase in atmospheric Δ14C excess but a slow response to the subsequent decline resulting from the succession of rapid isotopic air-sea exchange followed by the more gradual isotopic equilibration in the mixed layer due to the variable marine carbon reservoir and incorporation of organic carbon from the sediment mixed layer. The data constitute calibration scries for the use of the bomb pulse as a high-resolution dating tool in the marine environment and as a tracer of coastal ocean water masses.
Diets rich in fruits and vegetables (FV), which contain (poly)phenols, protect against age-related inflammation and chronic diseases. T-lymphocytes contribute to systemic cytokine production and are modulated by FV intake. Little is known about the relative potency of different (poly)phenols in modulating cytokine release by lymphocytes. We compared thirty-one (poly)phenols and six (poly)phenol mixtures for effects on pro-inflammatory cytokine release by Jurkat T-lymphocytes. Test compounds were incubated with Jurkat cells for 48 h at 1 and 30 µm, with or without phorbol ester treatment at 24 h to induce cytokine release. Three test compounds that reduced cytokine release were further incubated with primary lymphocytes at 0·2 and 1 µm for 24 h, with lipopolysaccharide added at 5 h. Cytokine release was measured, and generation of H2O2 by test compounds was determined to assess any potential correlations with cytokine release. A number of (poly)phenols significantly altered cytokine release from Jurkat cells (P<0·05), but H2O2 generation did not correlate with cytokine release. Resveratrol, isorhamnetin, curcumin, vanillic acid and specific (poly)phenol mixtures reduced pro-inflammatory cytokine release from T-lymphocytes, and there was evidence for interaction between (poly)phenols to further modulate cytokine release. The release of interferon-γ induced protein 10 by primary lymphocytes was significantly reduced following treatment with 1 µm isorhamnetin (P<0·05). These results suggest that (poly)phenols derived from onions, turmeric, red grapes, green tea and açai berries may help reduce the release of pro-inflammatory mediators in people at risk of chronic inflammation.
Rudolf Carnap is a curious figure in twentieth-century philosophy. His principal reputation is as a leading exponent of logical positivism (or logical empiricism), a school of thought that, according to lore, is notably rigid and technical as well as dismissive of other ways of doing philosophy. One of Carnap's most-read essays (Carnap, 1932d/ 1959) argues, for example, for the elimination or overcoming of metaphysics based on strict adherence to syntactic and verificationist strictures on meaningfulness. W. V. Quine's most famous essay - arguably, the single most famous essay in analytic philosophy - “Two Dogmas of Empiricism” (1951/1980) singles out Carnap as its most important target and uses the notion of “dogma ” to characterize the key commitments of his version of empiricism. Quine’s essay begins with the bold claim that “modern empiricism has been conditioned in large part by two dogmas” – dogmas his readers would at the time closely associate with Carnap – and then argues that embracing an empiricism without these dogmas has two principal effects:
One effect of abandoning [the dogmas] is, as we shall see, a blurring of the supposed boundary between speculative metaphysics and natural science. Another effect is a shift toward pragmatism.
If there is a movement or school that epitomized or typified analytic philosophy in the middle of the twentieth century, it was, by all odds, logical empiricism. Logical empiricists such as Hans Reichenbach, Rudolf Carnap, Carl G. Hempel, and Herbert Feigl had, by 1950, influenced the major fields of analytic philosophy. They had been instrumental in creating a scientifically and technically informed philosophy of science, in establishing mathematical logic as a topic in and a tool for philosophy, and in creating the project of formal semantics. Logical empiricism provided an importantly new understanding of the nature of empiricism and a new rejection of metaphysics. Accounts of analytic philosophy written in the middle of the twentieth century give logical empiricism a central place in the project, often repeating for analytic philosophy the revolutionary rhetoric of early logical empiricism. Because of this importance of logical empiricism in establishing the project of analytic philosophy, philosophical innovations both within and outside the analytic tradition in the 1960s and 1970s often were at pains to distance themselves from one aspect or another of logical empiricism.
If there is a movement or school that epitomizes analytic philosophy in the middle of the twentieth century, it is logical empiricism. Logical empiricists created a scientifically and technically informed philosophy of science, established mathematical logic as a topic in and tool for philosophy, and initiated the project of formal semantics. Accounts of analytic philosophy written in the middle of the twentieth century gave logical empiricism a central place in the project. The second wave of interpretative accounts was constructed to show how philosophy should progress, or had progressed, beyond logical empiricism. The essays survey the formative stages of logical empiricism in central Europe and its acculturation in North America, discussing its main topics, and achievements and failures, in different areas of philosophy of science, and assessing its influence on philosophy, past, present, and future.
In the twenty-first century, no one is a logical empiricist. There are, to be sure, more than a few philosophers whose work resembles in important ways the work of the logical empiricists, indeed, whose work, if it had been done in the 1950s, would be logical empiricist work. But, no one presents such work under the rubric “logical empiricism.” Nor, really, could anyone plausibly attempt to do so - being a logical empiricist really is not a live option for a twenty-first century philosopher.
It is a matter of some historical and philosophical interest to think about why and how logical empiricism came to lose its status as a philosophical project to be pursued. After all, as this volume amply demonstrates, logical empiricism was a leading project in analytic philosophy in the not too distant past and, indeed, the preeminent project within certain branches of philosophy, such as philosophy of science. Something substantial must have happened for such a project to decline so importantly in influence that even the most technical work in areas such as confirmation theory or philosophy of physics cannot today be said to be examples of logical empiricist philosophy of science.