Deccan volcanism at the Cretaceous-Tertiary boundary

The accuracy with which one can claim that Deccan trap volcanism occurred at the Cretaceous-Tertiary boundary (KTB) over a very short time interval is of key importance in deciding whether a volcanic origin of the KTB events should be taken seriously. In the two years since paleomagnetic, paleontological and geodynamic evidence was published, further data have become available and the case now appears to be well constrained. The Ar-40/Ar-39 results from six labs have yielded some 24 reliable plateau ages that narrow the age range to 65 to 69 Ma. Moreover, it appears that a significant part of this range results from inter-lab spread and possible minor alteration. Paleontology demonstrates that volcanism started in the Maestrichtian, more precisely in the A. mayaroensis zone. Paleomagnetism shows that volcanism spanned only 3 chrons and only one correlation remains possible, that of the main central reversed chron with 29R. Therefore, whereas Ar-40/Ar-39 is able only to restrict the duration of volcanism to some 4 Ma, paleomagnetism restricts it to 0.5 Ma. Using some geochemical indicators such as C-13 as proxy, it is suggested that volcanism actually consists of a few shorter events of unequal magnitude. Extrusion rates may be as high as 100 cu km/yr and fissure lengths as long as several 100 km. Such a scenario appears to be at least as successful as others in accounting for most anomalies observed at the KTB. Particularly important are Iridium and other platinum group elements (PGE) profiles, Sr-87/Sr-86, C-13, 0-18, other exotic geochemical signatures, spherules, soot, shocked minerals, selective and stepwise extinctions. The environmental impact of CO2 possibly released during explosive phases of volcanism, and SO2 released during effusive phases, and the ability of volcanism to ensure worldwide distribution of KTB products are now all addressed. In conclusion, the case for a causal link between internal hotspot activity, birth of the Reunion hotspot itself as the Deccan and KTB events appears to rest on an increasingly stronger basis

Pseudo-Riemannian geodesic foliations by circles

We investigate under which assumptions an orientable pseudo-Riemannian geodesic foliations by circles is generated by an $S^1$-action. We construct examples showing that, contrary to the Riemannian case, it is not always true. However, we prove that such an action always exists when the foliation does not contain lightlike leaves, i.e. a pseudo-Riemannian Wadsley's Theorem. As an application, we show that every Lorentzian surface all of whose spacelike/timelike geodesics are closed, is finitely covered by $S^1\times \R$. It follows that every Lorentzian surface contains a non-closed geodesic.Comment: 14 page

New string vacua from twistor spaces

We find a new family of AdS_4 vacua in IIA string theory. The internal space is topologically either the complex projective space CP^3 or the "flag manifold" SU(3)/(U(1)xU(1)), but the metric is in general neither Einstein nor Kaehler. All known moduli are stabilized by fluxes, without using quantum effects or orientifold planes. The analysis is completely ten--dimensional and does not rely on assumptions about Kaluza--Klein reduction.Comment: 19 pages. v3: published version, further minor correction

A Metric for Gradient RG Flow of the Worldsheet Sigma Model Beyond First Order

Tseytlin has recently proposed that an action functional exists whose gradient generates to all orders in perturbation theory the Renormalization Group (RG) flow of the target space metric in the worldsheet sigma model. The gradient is defined with respect to a metric on the space of coupling constants which is explicitly known only to leading order in perturbation theory, but at that order is positive semi-definite, as follows from Perelman's work on the Ricci flow. This gives rise to a monotonicity formula for the flow which is expected to fail only if the beta function perturbation series fails to converge, which can happen if curvatures or their derivatives grow large. We test the validity of the monotonicity formula at next-to-leading order in perturbation theory by explicitly computing the second-order terms in the metric on the space of coupling constants. At this order, this metric is found not to be positive semi-definite. In situations where this might spoil monotonicity, derivatives of curvature become large enough for higher order perturbative corrections to be significant.Comment: 15 pages; Erroneous sentence in footnote 14 removed; this version therefore supersedes the published version (our thanks to Dezhong Chen for the correction

Pela Gandong Sebagai Sarana Penyelesaian Konflik

Penelitian yang berjudul Pela Gandong Sebagai Sarana Penyelesaian Konflik Di Maluku, bertujuan Pertama, untuk mengetahui dan menganalisa peran Pela Gandong dalam tradisi masyarakat Maluku. Kedua, untuk mengetahui dan menganalisa Pela Gandong dilihat dalam konteks Undang-Undang Nomor 7 Tahun 2012. Berdasarkan hasil penelitian dapat disimpulkan bahwa Pertama, konflik merupakan perseteruan dan atau benturan fisik dengan kekerasan antara dua kelompok masyarakat atau lebih, yang berlangsung dalam waktu tertentu dan berdampak luas, yang mengakibatkan ketidakamanan dan disintegrasi sosial sehingga mengganggu stabilitas nasional dan menghambat pembangunan nasional. Ketiga, Pela berarti suatu ikatan, sedangkan Gandong berarti bersaudara, jadi Pela Gandong adalah suatu ikatan persatuan dan saling mengangkat saudara. Ketiga, penyelesaian konflik yang terjadi di Maluku menurut Undang-Undang Nomor 7 Tahun 2012 memberikan porsi bagi pranata adat untuk menyelesaikan konflik tersebut, hasil kesepakatan penyelesaian konflik melalui pranata adat memiliki kekuatan yang mengikat bagi kelompok masyarakat yang terlibat dalam konflik.The research, entitled “Pela Gandong as a Conflict Resolution Tool in Maluku” aims First to know and analyze the role of Pela Gandong in Maluku society tradition. Secondly, to know and analyze Pela Gandong in the context of Law Number 7 Year 2012. Based on the research result, it can be concluded that First, conflict is a feud and/or physical clash with violence between two or more community groups that take place within a certain time and have a wide impact, resulting in insecurity and social disintegration that disrupts national stability and impedes national development. Secondly, Pela means a bond, while Gandong means siblings, so Pela Gandong is a bond of unity and raising one another. Third, the resolution of the conflict in Maluku according to Law No. 7 of 2012 provides a portion for customary institutions to resolve the conflict, the result of the settlement of the conflict through customary institutions has a binding force for the community groups involved in the conflict

A Computational Investigation of Cardiac Caveolae as a Source of Persistent Sodium Current

Recent studies of cholesterol-rich membrane microdomains, called caveolae, reveal that caveolae are reservoirs of “recruitable” sodium ion channels. Caveolar channels constitute a substantial and previously unrecognized source of sodium current in cardiac cells. In this paper we model for the first time caveolar sodium currents and their contributions to cardiac action potential morphology. We show that the β-agonist-induced opening of caveolae may have substantial impacts on peak overshoot, maximum upstroke velocity, and ultimately conduction velocity. Additionally, we show that prolonged action potentials and the formation of potentially arrhythmogenic afterdepolarizations, can arise if caveolae open intermittently throughout the action potential. Our simulations suggest that caveolar sodium current may constitute a route, which is independent of channelopathies, to delayed repolarization and the arrhythmias associated with such delays

The sectional curvature remains positive when taking quotients by certain nonfree actions

We study some cases when the sectional curvature remains positive under the taking of quotients by certain nonfree isometric actions of Lie groups. We consider the actions of the groups $S^1$ and $S^3$ such that the quotient space can be endowed with a smooth structure using the fibrations $S^3/S^1{\simeq}S^2$ and $S^7/S^3\simeq S^4$. We prove that the quotient space carries a metric of positive sectional curvature, provided that the original metric has positive sectional curvature on all 2-planes orthogonal to the orbits of the action.Comment: 26 pages, 1 figure. Changed the spelling of the author's nam

Multivariate assessments of activity-related skeletal changes: Interpreting Bell Beaker specialized male archery and social organization in Central Europe

Objectives The Bell Beaker period witnessed the rise of individual inhumations with “wealthy” burial contexts containing archery-related grave goods, leading archaeologists to label the individuals in these tombs as “archers.” This study looks to (1) compare the skeletons from male “archer” burials with those from male “non-archer” burials—those not having archery-related grave goods—in order to assess a possible link between burial context and physical activity, and (2) apply a biomechanics profile to evaluate whether the individuals associated with these “archer” burials practiced specialized archer activity. Materials and Methods The corpus (males only) included 46 “archers” and 40 “non-archers” from Bell Beaker individual inhumations. Osteological data included measurements, scores of entheseal changes, and a diagnosis of certain pathologies. Data analyses involved visual observations, hypothesis tests, dimension reduction, and MANOVA, with approaches aimed at exploring the treatment of data missingness. Results Measurement data revealed no differences between the two groups. Evaluations of entheseal changes found that “non-archers” had consistently more instances of bone surface modifications than “archers.” Individual assessments of specialized archer occupation identified 11 possible specialized archers. Discussion These findings indicate a possible labor differentiation represented through the presence of a probably prestigious “archer” burial context. This suggests a link between grave good presence and labor, but not between a Bell Beaker archery occupation and an “archer” burial context. Data analyses support the application of biomechanics to osteological analyses in order to assess specialized activity on the skeleton

Scarf osteotomy versus metatarsophalangeal arthrodesis in forefoot first ray disorders: Comparison of functional outcomes

SummaryIntroductionScarf osteotomies of the first metatarsal and metatarsophalangeal arthrodesis are the two most frequent surgical forefoot reconstructive procedures.HypothesisWe compared functional results of isolated arthrodesis of the first metatarsophalangeal joint with an isolated Scarf osteotomy of the first metatarsal.Materials and methodsThis was a retrospective, observational, continuous study of patients operated between 1993 and 2008. After patients who had undergone a procedure on the lateral rays, extremely elderly patients, lost to follow-up patients and those with incomplete questionnaires had been excluded, there remained two comparable groups of 25 patients. Mean age was 60 in the arthrodesis group [41–70] and 59.8 in the Scarf group [47–71]. The Scarf group included 25 hallux valgus (100%) compared to 16 hallux valgus (64%) and nine hallux rigidus (36%) in the arthrodesis group. Complications were recorded. Evaluation of functional results was based on the most recent functional or quality of life scores (AOFAS, FFI, FAAM, SF 36) and a questionnaire on physical and athletic ability.ResultsThere was no significant difference in the rate of complications between the two groups. There was no difference in pain according to the AOFAS score with 35.6/40 (±6.5) in the Scarf group and 34.5 (±5.9) in the arthrodesis group. Global satisfaction was also similar between the Scarf and arthrodesis groups: 91.4% and 90% of very satisfied or satisfied patients, respectively. The FFI score was higher in the Scarf group than in the arthrodesis group: 8.6 (±20.1) and 19.8 (±17.7) respectively. Functional results were better in the Scarf group than in the arthrodesis group with a FAAM Daily Activity score of 80.2 (±12.1) compared to 68 (±7.2), a FAAM Sports Activity score of 29.7 (±6.7) compared to 25.2 (±7.6) and a FAAM Global Function score of 94% (±10.8) compared to 87% (±15.7), respectively. The Global SF36 score was higher in the Scarf group than in the arthrodesis group: 70.9% (±14.1) and 62.3% (±20.6) respectively, which was due to a higher Mental Health score in the Scarf group: 68.7% (±14.2) and 60.4% (±19.3) respectively. In the area of sports activities the Scarf group practiced more hiking than the arthrodesis group (74% versus 42% respectively). There was no difference for other activities.Discussion and conclusionThis study provides detailed information on the level of physical and sports activities that are practiced following these procedures, so that the patient can be better informed.Level of evidenceLevel III. Comparative retrospective