Apparent Longevity Research Articles

Effect of Anesthetic Carrier Gas on In Vivo Circulation Times of Intravenously Administered Phospholipid Oxygen Microbubbles in Rats.

For the treatment of tumor hypoxia, microbubbles comprising oxygen as a majority component of the gas core with a stabilizing shell may be used to deliver and release oxygen locally at the tumor site through ultrasound destruction. Previous work has revealed differences in circulation half-life in vivo for perfluorocarbon-filled microbubbles, typically used as ultrasound imaging contrast agents, as a function of anesthetic carrier gas. These differences in circulation time in vivo were likely due to gas diffusion as a function of anesthetic carrier gas, among other variables. This work has motivated studies to evaluate the effect of anesthetic carrier gas on oxygen microbubble circulation dynamics. Circulation time for oxygen microbubbles was derived from ultrasound image intensity obtained during longitudinal kidney imaging. Studies were constructed for rats anesthetized on inhaled isoflurane with either pure oxygen or medical air as the anesthetic carrier gas. Results indicated that oxygen microbubbles were highly visible via contrast-specific imaging. Marked signal enhancement and duration differences were observed between animals breathing air and oxygen. Perhaps counterintuitively, oxygen microbubbles disappeared from circulation significantly faster when the animals were breathing pure oxygen compared with medical air. This may be explained by nitrogen counterdiffusion from blood into the bubble, effectively changing the gas composition of the core, as has been observed in perfluorocarbon core microbubbles. Our findings suggest that the apparent longevity and persistence of oxygen microbubbles in circulation may not be reflective of oxygen delivery when the animal is anesthetized breathing air.

Pb isotope insight into the formation of the Earth's first stable continents

The formation of stable buoyant continental crust during the Archaean Eon was fundamental in establishing the planet's geochemical reservoirs. However, the processes that created Earth's first continents and the timescales over which they formed are debated. Here, we report the Pb isotope compositions of K-feldspar grains from 52 Paleoarchaean to Neoarchaean granites from the Pilbara Craton in Western Australia, one of the world's oldest and best-preserved granite–greenstone terranes. The Pb isotope composition of the Pilbara K-feldspars is variable, implying the granites were derived from crustal precursors of different age and/or variable time-integrated 238U/204Pb and 232Th/204Pb compositions. Trends to sub-mantle 207Pb/206Pb ratios preclude the influence of 4.3 Ga crustal precursors. In order to estimate crustal residence times we derive equations to calculate source model ages in a linearized Pb isotope evolution system. The best agreement between the feldspar Pb two-stage source model ages and those derived from zircon initial Hf isotope compositions requires crustal precursors that separated from a chondritic mantle source between 3.2 and 3.8 Ga, and rapidly differentiated to continental crust with 238U/204Pb and 232Th/238U ratios of ∼14 and 4.2–4.5, respectively. The preservation of Pb isotope variability in the Pilbara Paleoarchaean granites indicates their early continental source rocks were preserved for up to 500 Ma after their formation. The apparent longevity of these early continental nuclei is consistent with the incipient development of buoyant melt-depleted cratonic lithosphere during the Eoarchaean to Paleoarchaean.

Comparison of long-term changes in size and longevity of bee colonies in mid-west Japan and Maui with and without exposure to pesticide, cold winters, and mites.

Four long-term field experiments in mid-west Japan (Shika) made it clear that extinction of colonies exposed to neonicotinoid was much higher than for colonies exposed to organophosphates. The incidence of hive death for of organophosphate-exposed and control (pesticide-free) colonies was similar. We conducted a field experiment in Maui for 271 days using the same pesticides (dinotefuran: 0.2 ppm, clothianidin: 0.08 ppm, fenitrothion: 1 ppm) as used in Shika with the honeybee, Apis mellifera, colonies without mites. Numbers of adult bees, capped brood, mites and other hive parameters were accurately counted on photographs of combs and on the inside of the hives. All six neonicotinoid (dinotefuran & clothianidin)-exposed colonies failed during the experiment. One of three organophosphate (fenitrothion)-exposed colonies and one of the three control colonies also failed. The findings from Maui, where colonies displayed no mites, provides evidence from Shika, with mites, that neonicotinoids are more hazardous to honeybee colonies than organophosphates. The apparent longevity of honeybee colonies on Maui was estimated by numbers of adult bees and capped brood using a mathematical model previously proposed. Seasonal changes in longevity on Maui differ greatly from changes at Shika, the latter showing distinct seasonal variation. Longevity on Maui remains nearly constant throughout the year with wide variations. At Shika, it increases drastically in winter, by six- to ten fold more than the other seasons. Differences seem to depend on the existence of cold winters and the length of flowering seasons. In a perpetually hospitable environment, small changes in conditions can be sensitively reflected in apparent longevity. Examining wide variations in apparent longevity that are seemingly incoherent, we recognized several differences in apparent longevity between neonicotinoid-exposed and organophosphate-exposed colonies: The colony that failed in after organophosphate-exposure colony group exhibited the longest apparent longevity and the fewest number of newly capped brood, as also was the case in control colonies. Extended longevity when few brood are newly produced is reasonable to maintain the colony from a physiological point of view. Extension of apparent longevity is not seen in neonicotinoid-exposed colonies when the number of newly capped brood is fewer. This finding suggests that neonicotinoid pesticides may inhibit normal apian physiology.

A mathematical model to estimate the seasonal change in apparent longevity of bee colony

The longevity of a honeybee colony is far more significant than the lifespan of an individual honeybee, a social insect. The longevity of a honeybee colony is integral to the fate of the colony. We have proposed a new mathematical model to estimate the apparent longevity defined in the upper limit of an integral equation. The apparent longevity can be determined only from the numbers of adult bees and capped brood. By applying the mathematical model to a honeybee colony in Japan, seasonal changes in apparent longevity were estimated in three long-term field experiments. Three apparent longevities showed very similar season-changes to one another, increasing from early autumn, reaching a maximum at the end of overwintering and falling approximately plumb down after overwintering. The influence of measurement errors in the numbers of adult bees and capped brood on the apparent longevity was investigated.

Sustained volcanically-hosted venting at ultraslow ridges: Piccard Hydrothermal Field, Mid-Cayman Rise

At slow spreading mid-ocean ridges sustained submarine venting and the deposition of large seafloor massive sulfide deposits have previously been ascribed to tectonically-controlled hydrothermal circulation unrelated to young volcanic activity. Here, by contrast, we show that the Piccard Hydrothermal Field (PHF), on the ultraslow spreading Mid-Cayman Rise, represents a site of sustained fluid flow and sulfide formation hosted in a neovolcanic setting. The lateral extent and apparent longevity associated with the PHF are comparable to some of the largest tectonically-hosted vent sites known along the slow-spreading Mid-Atlantic Ridge. If such systems recur along all ultraslow ridges, which comprise ∼20% of the ∼55,000 km global ridge crest, potential implications would include (i) a higher probability of locating large, economically valuable, mineral deposits along ultraslow ridges together with (ii) larger fluxes than previously anticipated of chemicals released from high-temperature venting entering the oceans along the Atlantic–Indian Ocean sectors of the deep-ocean thermohaline conveyor.

Making sense of decades of debate on inter-subject comparability in England

This article illustrates how a new framework for conceptualising comparability has the potential to help assessment professionals to understand and to conduct debate on linking theory and practice. The framework was used as a lens through which to study a corpus of research reports, from which a narrative was constructed to characterise the evolution of conceptions of inter-subject comparability in England from the 1960s to the present day. The new framework helped to bring clarity and structure to the trajectory of ideas, from a period before theoretical commitments were clearly articulated to the present day. One dominant underlying conception was identified and characterised as the ‘all causes’ causal definition. Characterising the dominant conception explicitly, in the language of the new framework, revealed clearly its inadequacy in this comparability context, despite its apparent longevity as the de facto paradigm for interpreting inter-subject comparability monitoring research. Although the dominant conception remained largely unchallenged during the twentieth century, the new framework helped to identify how a number of researchers were grappling for alternative conceptions, even from early on. It was not until the turn of the twenty-first century that alternative conceptions began to be articulated explicitly and the focus of the debate changed from methodological adequacy to definitional adequacy.

An interaction between hepatocyte growth factor and its receptor (c-MET) prolongs the survival of chronic lymphocytic leukemic cells through STAT3 phosphorylation: a potential role of mesenchymal cells in the disease

Chronic lymphocytic leukemia cells are characterized by an apparent longevity in vivo which is lost when they are cultured in vitro. Cellular interactions and factors provided by the microenvironment appear essential to cell survival and may protect leukemic cells from the cytotoxicity of conventional therapies. Understanding the cross-talk between leukemic cells and stroma is of interest for identifying signals supporting disease progression and for developing novel therapeutic strategies. Different cell types, sharing a common mesenchymal origin and representative of various bone marrow components, were used to challenge the viability of leukemic cells in co-cultures and in contact-free culture systems. Using a bioinformatic approach we searched for genes shared by lineages prolonging leukemic cell survival and further analyzed their biological role in signal transduction experiments. Human bone marrow stromal cells, fibroblasts, trabecular bone-derived cells and an osteoblast-like cell line strongly enhanced survival of leukemic cells, while endothelial cells and chondrocytes did not. Gene expression profile analysis indicated two soluble factors, hepatocyte growth factor and CXCL12, as potentially involved. We demonstrated that hepatocyte growth factor and CXCL12 are produced only by mesenchymal lineages that sustain the survival of leukemic cells. Indeed chronic lymphocytic leukemic cells express a functional hepatocyte growth factor receptor (c-MET) and hepatocyte growth factor enhanced the viability of these cells through STAT3 phosphorylation, which was blocked by a c-MET tyrosine kinase inhibitor. The role of hepatocyte growth factor was confirmed by its short interfering RNA-mediated knock-down in mesenchymal cells. The finding that hepatocyte growth factor prolongs the survival of chronic lymphocytic leukemic cells is novel and we suggest that the interaction between hepatocyte growth factor-producing mesenchymal and neoplastic cells contributes to maintenance of the leukemic clone.

Potential for clonal animals in longevity and ageing studies

Ageing is defined as a decline in reproductive and/or somatic performance over time, and as such is experienced by most organisms. Evolutionary theories explain ageing as a consequence of reduced selection pressure against mutations and reduced allocation to somatic maintenance in post-reproductive individuals. In addition, the fecundity of younger age-groups makes a more significant contribution than infinite maintenance of the parental body to the production of subsequent generations. However, in clonal animals, as well as in plants that reproduce by agametic cloning, the adult body is itself a reproductive unit that increases its fitness as a function of genet size. Given the apparent longevity of many such clonal organisms, species undergoing agametic cloning are often assumed to be non-ageing and even potentially immortal. Here, we present a brief overview of ageing in organisms undergoing agametic cloning, focusing on animals and molecular investigation. We discuss molecular and evolutionary aspects of ageing or non-ageing with respect to selection in clonal species. Of particular relevance to the search for potential mechanistic processes behind longevity is the notion that clonal organisms are frequently smaller than their obligate sexual counterparts. In conclusion, we find that while clonal animals also commonly age, evolutionary arguments together with empirical evidence suggest that they are likely to be long-lived and stress resistant at the genet level. However, theoretical modeling continues to predict the possibility of immortality, if the contribution from sexual reproduction is low. Future in-depth study of long-lived clones should present an excellent opportunity to discover novel mechanisms for renewal and long-term somatic maintenance and health.

Lithics use at Kansyore sites in East Africa: technological organisation at four recently excavated sites in Nyanza Province, Kenya

Recently a series of active investigations have been launched on aspects of the Kansyore tradition such as ceramics, subsistence and chronology. However, Kansyore lithic assemblages have been little studied and its quartz-based technology has often been simply dubbed as ‘non-descript.’ Here I attempt an overview of the organisation of Kansyore lithic technology based on assemblages from four recently excavated sites in Nyanza Province, Kenya. Kansyore lithics show apparent longevity of use, remaining essentially unchanged between c. 6000 cal. BC and cal. AD 500, despite major changes in ceramics and subsistence economy. Based on the lithics it seems that early Kansyore settlement patterns could have been more mobile, becoming increasingly residentially sedentary over time. However, this was not a complete change, but instead a matter of increasing emphasis on sedentism, since even some early Kansyore sites are indicative of moderate delayed-return subsistence systems and seasonally sedentary settlement patterns. These interpretations based on studying Kansyore stone tool assemblages are also supported by the analyses of other finds from the studied sites.

High-Level Expression of the T Cell Chemokines CCL3 and CCL4 by Chronic Lymphocytic Leukemia B Cells in Nurselike Cell Co-Cultures and in Response to BCR Stimulation.

Despite their apparent longevity in vivo, isolated Chronic Lymphocytic Leukemia (CLL) B cells generally undergo spontaneous apoptosis in vitro when cultured under conditions that support the growth of human B cell lines. This suggests that interactions between CLL cells and a distinct tissue microenvironment in the marrow and the lymphatic tissues, where CLL cells are in close contact with accessory cells (mesenchymal stromal cells, and CD68+ “nurselike cells”/NLC), are critical for the progression of the disease. NLC can be detected in secondary lymphoid tissues from CLL patients and appear to be an integral part of the CLL microenvironment, comparable to lymphoma-associated macrophages in follicular lymphoma. The molecules involved in CLL-NLC cross talk are only partially understood. Therefore, we examined the gene expression profile of purified CLL B cells using Affymetrix U133 Plus 2.0 Arrays to define distinct expression profiles induced in purified CLL B cells by co-culture with NLC. When compared to freshly isolated blood CLL B cells, we found that CLL B cells co-cultured for 14 days with NLC displayed high level expression of two T cell chemoattractants, macrophage inflammatory protein-1a and b (MIP-1 a, MIP-1b, also called CCL3 and CCL4). CCL3 and CCL4 expression levels correlated with ZAP-70 expression by the CLL cells, suggesting that B cell receptor signaling is involved in inducing the expression of these chemokines. Supernatants from CLL-NLC co-cultures harvested 7 and 14 days after initiation of the cultures revealed high CCL3 and CCL4 protein levels (up to >30 ng/ml) by ELISA, predominantly in the same CLL cases that displayed high CCL3, CCL4 and ZAP-70 expression by expression profiling. Moreover, serum samples from CLL patients were tested for CCL3 and CCL4 protein expression by ELISA. These studies demonstrated higher CCL3 and CCL4 serum levels in CLL patients when compared to healthy volunteers. CCL3 and CCL4 serum levels were found to be higher in CLL patients that were CD38+, displayed non-mutated IgVH genes, and b2 microglobulin levels that are > 4 mg/L. In vitro, B cell receptor (BCR) triggering of CLL cells, using anti-IgM antibodies, induced a rapid and robust induction of CCL3 and CCL4 protein production by CLL B cells. In contrast, CD40 triggering did not induce expression of these chemokines. These studies reveal a novel mechanism of cross-talk between CLL B cells and their microenvironment, namely the induction of two T cell chemokines, CCL3 and CCL4, by CLL-NLC interaction. Thus, we provide the first evidence that neoplastic B cells are an important source of T cell chemokines, that can induce recruitment of T cells of helper/effector phenotype to sites of cognate T cell-CLL interactions. Besides inducing the outgrowth of NLC, this is another mechanism how CLL cells actively create a microenvironment that favors their growth and survival. [Display omitted]

The North Korean Positive Hero in The People of the Fighting Village

IntroductionThe People of the Fighting Village by Chon Se Bong (1915-1986) is a socialist realist heroic epic dressed up as a novelette that has apparently withstood the test of time in North Korea. It is a sentimental, stereotyped, and disturbing story set around October to December 1950 during the Korean War. The plot centers on two North Korean villages, Kaean and Kaebak, where peasant dwellers, in coordination with guerrilla partisans, struggle to oust an American occupation force. Notably, the original Korean edition, Ssaunun Maul ui Saramdul, was awarded third prize for the best prose work in 1953 at the Festival of the Fifth Anniversary of the Founding of the Korean People's Army (Chun, 1955). Yet, despite the availability of two Englishlanguage editions published in 1955 and 1986, Chon's narrative has been neglected for half a century in the United States. This, however, does not represent a unique case-it is the fate of all North Korean literature accessible in North America. Having undergone arguably minor alterations and omissions, the translations of The People of the Fighting Village are important political-cultural documents. As both editions suggest, the work has evidently endured several decades of bureaucratic expediencies that condition the Stalinist arts doctrine of socialist realism, which North Korean sources describe as the only valid creative method and style in the country (Korean, 1959, p. 160; Chai and Hyon, 1980, p. 23). That doctrine is now termed Juche or Juche-oriented realism. The apparent longevity and success of Chon's The People of the Fighting Village may be due in part to the characterization of the protagonist Kwon Yong Pil. Central to the tale, he is an ascetic partisan youth and archetypal positive hero molded as an exemplary representative of North Korean nationalist Stalinist ideals, and one who is to be emulated for his uncompromising perseverance, fortitude, and devotion to the North Korean fatherland/motherland.Socialist RealismBefore exploring those qualities that define Kwon Yong Pil as a positive hero, it is necessary to address the question of socialist realism, which underlies his development. In brief, the Bonapartist aesthetic doctrine emerged in Soviet-Stalinist cultural discussion when Ivan Gronsky, chairman of the Organization Committee of the Soviet Writers' Union, introduced the term in 1932. The concept subsequently found its way into colonial-era Korea in 1933. Soon thereafter, it was promulgated and defined by Stalin's cultural lieutenant Andrei Zhdanov at the First Soviet Writers' Congress in 1934. And following the U.S.-Soviet agreements at Yalta and Potsdam, culminating in the occupation and division of the Korean peninsula with the defeat of fascist Japan in i945, socialist realism became the veritable cultural law of the Sovietsponsored northern regime in 1946. (That is also when the North Korean Federation of Literature and Art was established.) To be sure, North Korean literary control policy was thoroughly pervaded by Soviet-Stalinist influence from 1946 to 1950 and formed within the cultural-political structures of Zhadnovism and socialist realism (Lim, 1989). Other scholars such as Gabroussenko (2004), Howard (1996), Kwon (1991; 2003), Pihl (1977), and Pucek (1996) have confirmed the tradition of socialist realism in North Korea. Founded as the Democratic People's Republic of Korea in 1948, North Korea was formed during the height of Zhdanovism (Stalinist cul- tural nationalism) in the Soviet Union, that is, during the blackout of Soviet art and letters that lasted from 1946 to 1953. This was a period that ushered in the notorious anticosmopolitan campaign (a euphemism for anti-Westernism and, to some extent, anti-Semitism) as well as the theory of conflictlessness. Both policies proved especially detrimental in cultural production, cutting off Soviet literature from international influences and rejecting conflict as an integral component of drama and character (Vickery, 1963, pp. …

Constitutive Nuclear p65 NF-kB Expression Predicts for Spontaneous Apoptosis and In Vitro Sensitivity to Fludarabine in CLL Cells.

B-cell chronic lymphocytic leukemia (CLL) is characterized by the accumulation of monoclonal B-cells in the blood, secondary lymphoid tissues, and bone marrow. The leukemia cells primarily are arrested in the G0/G1 phase of the cell cycle and appear resistant to programmed cell death. Despite their apparent longevity in vivo, CLL cells typically undergo spontaneous apoptosis in vitro although there is considerable heterogeneity in the timing and extent of this process. In this study we investigated the degree of this apoptosis in vitro, and its association with constitutive nuclear p65 NF-kB expression (n = 25). Apoptosis was measured by annexin V / propidium iodide labeling using flow cytometry and nuclear NF-kB expression was evaluated using electrophoretic mobility shift assay and quantified using a p65 ELISA. In contrast to previous reports, we found constitutive NF-kB activity varied in our patient cohort with a trend towards higher expression in samples with unmutated VH genes, high CD38 expression and high ZAP-70 expression. Importantly, we demonstrated an inverse correlation between the percentage of Annexin V-positive cells and nuclear p65 NF-kB expression (r2 = − 0.21; P = 0.02) suggesting that high levels of p65 NF-kB are cytoprotective in CLL cells. We then investigated the relationship between p65 NF-kB and in vitro response to fludarabine. Sensitivity to fludarabine was evaluated using LD50 values calculated from sigmoidal dose-response curves. These LD50 values positively correlated with nuclear p65 NF-kB activity (r2 = 0.25; P = 0.006) indicating that in vitro drug resistance to fludarabine may be mediated, at least in part, through the transcriptional effects of NF-kB. Taken together, our data indicate that NF-kB is a key regulator of both spontaneous and drug induced apoptosis in CLL cells and is therefore a promising therapeutic target for the treatment of this incurable condition.

The contribution of epidemiology to the study of traumatic stress

Post-traumatic stress disorder (PTSD) has been a controversial construct because of the complex set of factors that have been hypothesized to influence its onset and prevalence, such as compensation and withdrawal from combat duty. Epidemiology has done much to objectively clarify these controversies in the study of stratified population samples. The symptoms characterizing PTSD have been repeatedly described in large population samples where compensation is not a confounding issue and this has done much to support the validity of the construct. Epidemiology has also highlighted that the prevalence of exposure to traumatic events is far greater than was previously estimated. Emphasizing the importance of these events is accounting for the major burden of disease. Kessler (2000) has suggested the socio-economic effects of PTSD represent a burden of disease not dissimilar to that associated with depression. Traumatic events provide a unique opportunity to implement a preventative and public health approach to the management of psychiatric morbidity. Of particular importance is the apparent longevity of the influence that these events have on psychological adjustment.

No Evidence for a Genetic Relationship between Alzheimer’s Disease and Longevity

Objective: Late onset Alzheimer’s disease (AD) is frequent in subjects who have reached an age above the average life expectancy. AD and life expectancy are both influenced by genetic factors. Consequently, a possible genetic relationship between AD and longevity was investigated using family study data. Methods: First-degree relatives of patients with AD (n = 645) and of non-demented controls (n = 1,106) were examined by direct interview or by family history in the case of already deceased or unavailable subjects. Survival of subjects with an assumed familial load for AD (i.e. first-degree relatives of AD patients) and of controls was compared using the Kaplan-Meier analysis and log-rank statistics. Results: Relatives with AD reached higher ages than other family members. However, there was no significant co-aggregation of AD and longevity in first-degree relatives of AD patients in comparison with those of controls. This applied to all diseased as well as non-demented relatives. Conclusions: Longevity is an independent prerequisite for the development of the disease, but is not genetically related to AD. The apparent longevity in relatives with AD is likely to result from the selection of subjects fulfilling this prerequisite.

How long can diamonds remain stable in the continental lithosphere?

Do Archean ages obtained for diamonds from many of the world’s cratons constitute a strong constraint on the thermal state of the Archean continental lithosphere? The apparent longevity of diamonds obtained from cratonic kimberlites [Boyd et al., Nature 315 (1985) 387–389; Richardson et al., Nature 310 (1984) 198–202] has been used to infer the physical and chemical isolation of cratonic roots from the convecting mantle since 3 Ga. This would also provide an extremely strong constraint on the thermal history of the lithospheric mantle – requiring low temperatures at depth for its entire history. Recent evidence suggests, however, that the published ‘diamond’ ages may not represent the ages of the diamonds themselves, but significantly pre-date them [Shimizu and Sobolev, Nature 375 (1995) 308–311; Spetsius et al., Earth Planet. Sci. Lett. 199 (2002) 111–126]. We use a particle-in-cell finite element code to model the thermal stability of the continental lithosphere in a convecting mantle. The continental crust modulates the thermal conditions of the underlying mantle lithosphere, increasing the depth of the thermal boundary layer beneath the continent and providing a mechanism for stabilizing the sub-continental thermal field. If diamonds have survived in cratonic roots since the Archean, the conditions necessary for diamond stability must have existed in the Archean continental lithosphere, and those conditions must have remained relatively unperturbed for ∼3 Gyr [Boyd et al., Nature 315 (1985) 387–389]. Here, the longevity of the diamond stability field is explored for systems with chemically distinct continental crust and a strongly temperature-dependent mantle viscosity. Such models frequently produce the temperature conditions needed to form diamonds within the Archean lithosphere, but the temperature fluctuations experienced within the modeled mantle lithosphere are generally able to destroy these diamonds within 1 Gyr. Increasing the distance to active margins has only a marginal effect on the longevity of the diamond stability field. Convectively stable cratonic roots extend the lifetime of the diamond stability field in those regions. However, while the residence time of diamonds approaches the order of magnitude required (284–852 Myr), extremely fortuitous mantle conditions are required to explain Archean diamonds.

When knowledge adds up to nothing

Knowledge management has been around for many years now, but is its apparent longevity automatically representative of universal success? Charles Lucier, Chief Knowledge Officer at international management and technology consulting firm Booz‐Allen and Hamilton would argue not. He has suggested that up to 84 percent of all knowledge management programs fail.

1995 eruptions of Cerro Negro volcano, Nicaragua, and risk assessment for future eruptions

Cerro Negro volcano, Nicaragua, continued a 147-yr-long duration of cinder-cone activity with a major eruption in 1995. Small, phreatically driven eruptions began in May 1995 and continued for 79 days. Following a 95 day repose, the main eruption produced 8 × 106 m3 of basalt from Cerro Negro over 13 days of activity and deposited 5 mm of ash in the city of Leon. Although the damage from the 1995 eruptions was fortunately minor, previous tephra falls from Cerro Negro have produced significant crop damage and multiple deaths through building collapse. In spite of its apparent longevity for a historically active cinder cone, Cerro Negro has mass-flow rates typical of arc-related basaltic cinder cone volcanoes. Volcanic hazards beyond 3 km from Cerro Negro consist of tephra falls. Few models are available to calculate tephra-fall risks from basaltic volcanoes such as Cerro Negro, and none have been applied to dispersive cinder cone eruptions. A convective-dispersive model of Suzuki is modified and evaluated using detailed data from the 1995 Cerro Negro eruption and is found to reasonably calculate tephra-fall thickness between 8 and 30 km from the vent. This model is used with detailed data from previous Cerro Negro eruptions in a tephra-fall hazard assessment. Cerro Negro also appears to have had a steady-state eruption rate since about A.D. 1900, which is used to estimate the timing of the next eruption as before A.D. 2006. The potential tephra fall from Cerro Negro in Leon, Nicaragua, is calculated as 2.2 mm/yr until 2006, with 95% confidence that deposits will be <11 cm thick.

Prolonged residence times for the youngest rhyolites associated with Long Valley Caldera: 230Th— 238U ion microprobe dating of young zircons

We describe a new ion microprobe method for dating magmatic zircon growth that is based on in situ measurement of the magnitude of 238U— 230Th disequilibrium. Our results support independent inferences that zircon can remain suspended for long periods (> 100 ka) in the convecting potions of the magma from which it crystallizes. Because the crystallization ages date when the magma cooled to its zircon saturation temperature, even when the zircons have long magmatic residence times, 238U— 230Th zircon dating can be used to constrain the thermochemical evolution of silicic magmas. 238U— 230Th ages have been determined for individual zircons from rhyolites associated with the Long Valley magmatic system of eastern California. The samples are from Deer Mountain, an 115 ± 3 ka low-silica moat rhyolite, and from the coarsely porphyritic, low-silica rhyolite of South Deadman dome, one of the ∼ 0.6 ka Inyo domes. Previous investigations have suggested that the two lavas were derived from the same magma reservoir. A few of the zircon model ages, calculated with respect to the isotopic characteristics of the whole rocks, are within error of that for eruption of the Deer Mountain rhyolite. However, the majority of zircons from both lavas cluster around an age of ∼ 230 ka. This common interval of zircon nucleation and growth, for petrologically similar lavas, suggests that the younger Inyo dome lava may have tapped the same magma body from which the Deer Mountain rhyolite erupted more than 100 ka before. On the other hand, most of the zircon model ages are younger than previous episodes of silicic volcanism in the Long Valley Caldera, suggesting that the rhyolites may have been generated during development of a silicic upper crustal magma chamber in the western portion of Long Valley caldera. Zircon saturation temperatures for the rhyolites studied (795–810°C) are the same as those obtained from coexisting Fe—Ti oxides (809 ± 4°C), showing that the magma cooled to <815°C more than 200 ka ago. The surprising consequence of these temperatures is the apparent longevity of the shallow magma reservoir from which relatively small (< 1 km 3) volume magmas erupted. The magma reservoir could have remained molten because of the regular influx and differentiation of mafic magma, resulting in accumulation of a much larger volume of magma than that erupted.

The cock, the dog, the serpent, and the monkey. Reception and transmission of a Roman punishment, or historiography as history

Thepoena cullei originated as a Roman capital punishment imposed for parricide: the culprit was drowned in a leather sack together with a cock, a dog, a serpent, and a monkey. This punishment was last imposed in Germany during the 18th century. After its disappearance from written legislation, it continued to attract much scholarly attention. In the course of the 19th century thepoena cullei turned from a legal curiosity into a key issue in debates about the long-term development from ritual sacrifice to public punishment. This article investigates the apparent longevity of thepoena cullei tries to come to grips with the problem of the historical continuity of this bizarre phenomenon, and argues that the history and historiography of this ‘phantom punishment’ are inextricably intertwined.

Bacteria, fungi and biokarst in Lechuguilla Cave, Carlsbad Caverns National Park, New Mexico

Lechuguilla Cave is a deep, extensive, gypsumand sulfur-bearing hypogenic cave in Carlsbad Caverns National Park, New Mexico, most of which (>90%) lies more than 300 m beneath the entrance. Located in the arid Guadalupe Mountains, Lechuguilla's remarkable state of preservation is partially due to the locally continuous Yates Formation siltstone that has effectively diverted most vadose water away from the cave. Allocthonous organic input to the cave is therefore very limited, but bacterial and fungal colonization is relatively extensive: (1)Aspergillus sp. fungi and unidentified bacteria are associated with iron-, manganese-, and sulfur-rich encrustations on calcitic folia near the suspected water table 466 m below the entrance; (2) 92 species of fungi in 19 genera have been identified throughout the cave in oligotrophic (nutrient-poor) “soils” and pools; (3) cave-air condensate contains unidentified microbes; (4) indigenous chemoheterotrophicSeliberius andCaulobacter bacteria are known from remote pool sites; and (5) at least four genera of heterotrophic bacteria with population densities near 5×105 colony-forming units (CFU) per gram are present in ceiling-bound deposits of supposedly abiogenic condensation-corrosion residues. Various lines of evidence suggest that autotrophic bacteria are present in the ceiling-bound residues and could act as primary producers in a unique subterranean microbial food chain. The suspected autotrophic bacteria are probably chemolithoautotrophic (CLA), utilizing trace iron, manganese, or sulfur in the limestone and dolomitic bedrock to mechanically (and possibly biochemically) erode the substrate to produce residual floor deposits. Because other major sources of organic matter have not been detected, we suggest that these CLA bacteria are providing requisite organic matter to the known heterotrophic bacteria and fungi in the residues. The cavewide bacterial and fungal distribution, the large volumes of corrosion residues, and the presence of ancient bacterial filaments in unusual calcite speleothems (biothems) attest to the apparent longevity of microbial occupation in this cave.