Primordial r-process Dispersion in Metal-Poor Globular Clusters

Heavy elements, those produced by neutron-capture reactions, have traditionally shown no star-to-star dispersion in all but a handful of metal-poor globular clusters (GCs). Recent detections of low [Pb/Eu] ratios or upper limits in several metal-poor GCs indicate that the heavy elements in these GCs were produced exclusively by an r-process. Reexamining GC heavy element abundances from the literature, we find unmistakable correlations between the [La/Fe] and [Eu/Fe] ratios in 4 metal-poor GCs (M5, M15, M92, and NGC 3201), only 2 of which were known previously. This indicates that the total r-process abundances vary star-to-star (by factors of 2-6) relative to Fe within each GC. We also identify potential dispersion in two other GCs (M3 and M13). Several GCs (M12, M80, and NGC 6752) show no evidence of r-process dispersion. The r-process dispersion is not correlated with the well-known light element dispersion, indicating it was present in the gas throughout the duration of star formation. The observations available at present suggest that star-to-star r-process dispersion within metal-poor GCs may be a common but not ubiquitous phenomenon that is neither predicted by nor accounted for in current models of GC formation and evolution.Comment: Accepted for publication in the Astrophysical Journal Letters (6 pages, 2 figures). v2: references update

Software-Reconfigurable Processors for Spacecraft

A report presents an overview of an architecture for a software-reconfigurable network data processor for a spacecraft engaged in scientific exploration. When executed on suitable electronic hardware, the software performs the functions of a physical layer (in effect, acts as a software radio in that it performs modulation, demodulation, pulse-shaping, error correction, coding, and decoding), a data-link layer, a network layer, a transport layer, and application-layer processing of scientific data. The software-reconfigurable network processor is undergoing development to enable rapid prototyping and rapid implementation of communication, navigation, and scientific signal-processing functions; to provide a long-lived communication infrastructure; and to provide greatly improved scientific-instrumentation and scientific-data-processing functions by enabling science-driven in-flight reconfiguration of computing resources devoted to these functions. This development is an extension of terrestrial radio and network developments (e.g., in the cellular-telephone industry) implemented in software running on such hardware as field-programmable gate arrays, digital signal processors, traditional digital circuits, and mixed-signal application-specific integrated circuits (ASICs)

Magnon bound states vs. anyonic Majorana excitations in the Kitaev honeycomb magnet α\alpha-RuCl3_3

The pure Kitaev honeycomb model harbors a quantum spin liquid in zero magnetic fields, while applying finite magnetic fields induces a topological spin liquid with non-Abelian anyonic excitations. This latter phase has been much sought after in Kitaev candidate materials, such as $\alpha$-RuCl$_3$. Currently, two competing scenarios exist for the intermediate field phase of this compound ($B=7-10$ T), based on experimental as well as theoretical results: (i) conventional multiparticle magnetic excitations of integer quantum number vs. (ii) Majorana fermionic excitations of possibly non-Abelian nature with a fractional quantum number. To discriminate between these scenarios a detailed investigation of excitations over a wide field-temperature phase diagram is essential. Here we present Raman spectroscopic data revealing low-energy quasiparticles emerging out of a continuum of fractionalized excitations at intermediate fields, which are contrasted by conventional spin-wave excitations. The temperature evolution of these quasiparticles suggests the formation of bound states out of fractionalized excitations

Cutaneous Metastasis of Choriocarcinoma : A Case Report

Choriocarcinoma is one of the malignant tumors of trophoblastic cells characterized by the secretion of human chorionic gonadotrophin (hCG) (1-3). Cutaneous metastasis is a rare presentation of choriocarcinoma but a poor prognostic sign because it is associated only with widespread disease (3-5). A 52-yr-old female complaining of dyspnea for 2 months, presented with fingertip sized erythematous nodules on the left side of the neck and the right side of the upper back of 1 month duraton. She has suffered from Behçet's disease since 1999. Microscopic examination of a nodule of upper back demonstrated biphasic pattern of cytotrophoblasts and hCG-positive syncytiotrophoblasts, and the typical histologic features of choriocarcinoma. She was referred to the gynecological oncology department. After 17 cycles of combination chemotherapy, the serum hCG level has fallen from 700,000 to under 2.0 mIU/mL and the skin lesions have almost disappeared. However, after 3 months, total abdominal hysterectomy and bilateral salpingo-oophorectomy were performed due to elevated serum hCG level (4,447.7 mIU/mL), and she is scheduled to receive post-operative adjuvant chemotherapy

Pure Basaloid Squamous Cell Carcinoma of the Uterine Cervix: A Case Report

Basaloid squamous cell carcinoma of the uterine cervix is an extremely rare malignancy of the female genital tract with a poorer clinical outcome than squamous cell carcinoma of the uterine cervix. We report a case of pure basaloid squamous cell carcinoma of the uterine cervix. A 70-yr-old woman with vaginal bleeding was referred to our institute. A basaloid squamous cell carcinoma of the uterine cervix, of International Federation of Gynecology and Obstetrics (FIGO) stage Ib1, was diagnosed by a loop electrosurgical excision procedure cone biopsy. A radical hysterectomy was performed, along with bilateral salpingo-oophorectomy, pelvic lymph node dissection, and para-aortic lymph node sampling. Pathologic findings were consistent with a basaloid squamous cell carcinoma confined to the cervix without an extracervical tumor. No further treatment was administered and there was no clinical evidence of recurrence during the 12 months of follow-up. Follow-up for the patient is ongoing. Although basaloid squamous cell carcinoma of the uterine cervix is thought to behave aggressively, accumulation of data on these rare tumors is necessary to determine whether their behavior differs significantly from that of conventional cervical squamous cell carcinoma of similar clinical stage. These data would be useful for defining the best diagnosis and treatment for these rare tumors

Light Curves and Period Changes of Type II Cepheids in the Globular Clusters M3 and M5

Light curves in the B, V, and I_c passbands have been obtained for the type II Cepheids V154 in M3 and V42 and V84 in M5. Alternating cycle behavior, similar to that seen among RV Tauri variables, is confirmed for V84. Old and new observations, spanning more than a century, show that V154 has increased in period while V42 has decreased in period. V84, on the other hand, has shown large, erratic changes in period that do not appear to reflect the long term evolution of V84 through the HR diagram.Comment: 28 pages, 12 figure

Supersymmetric black rings and non-linear sigma models

In this paper we investigate the non-linear sigma model arising in the reduction of D = 5 supergravity to D = 3, and present the application of this sigma model to supersymmetric black ring solutions in five-dimensional minimal supergravity. With the ansatz of stationary solutions with $R \times U(1)\times U(1)$ isometry, we obtain a two-dimensional Lagrangian corresponding to geodesic motion of a string-like object on the coset $G_{2(+2)}/SO(4)$, and study the algebra of conserved charges and supersymmetry constraints of supersymmetric black rings. We also obtain the semi-classical wave function of supersymmetric black rings.Comment: 15 page

Amino Alkynylisoquinoline and Alkynylnaphthyridine Compounds Potently Inhibit Acute Myeloid Leukemia Proliferation in Mice

B ackground: Acute myeloid leukemia (AML) remains one of the most lethal, rarely cured cancers, despite decades of active development of AML therapeutics. Currently, the 5-year survival of AML patients is about 30% and for elderly patients, the rate drops to b10%. About 30% of AML patients harbor an activating mutation in the tyrosine kinase domain (TKD) of Fms-Like Tyrosine kinase 3 (FLT3) or a FLT3 internal tandem duplication (FLT3-ITD). In- hibitors of FLT3, such as Rydapt that was recently approved by the FDA, have shown good initial response but pa- tients often relapse due to secondary mutations in the FLT3 TKD, like D835Y and F691 L mutations. Methods: Alkynyl aminoisoquinoline and naphthyridine compounds were synthesized via Sonogashira coupling. The compounds were evaluated for their in vitro and in vivo effects on leukemia growth. Findings: The compounds inhibited FLT3 kinase activity at low nanomolar concentrations. The lead compound, HSN431, also inhibited Src kinase activity. The compounds potently inhibited the viability of MV4–11 and MOLM-14 AML cells with IC50 values b1 nM. Furthermore, the viability of drug-resistant AML cells harboring the D835Y and F691 L mutations were potently inhibited. In vivo efficacy studies in mice demonstrated that the compounds could drastically reduce AML proliferation in mice. Interpretation: Compounds that inhibit FLT3 and downstream targets like Src (for example HSN431) are good leads for development as anti-AML agents

The fraction of second generation stars in Globular Clusters from the analysis of the Horizontal Branch

Most Globular Clusters (GC) show chemical inhomogeneities in the composition of their stars, apparently due to a second stellar generation (SG) in which the forming gas is enriched by hot-CNO cycled material processed in stars belonging to a first stellar generation (FG). We propose to use the horizontal branch (HB) to infer which is today the relative number fraction of ''normal" and anomalous stars in clusters. We assume that the anomalies also include enhanced helium abundance. Helium variations have been recognized to be able to explain several puzzling peculiarities (gaps, RR Lyr periods and period distribution, ratio of blue to red stars, blue tails) in HBs. We extend the analysis to as many clusters as possible. We show that, with few exceptions, 50% or more of the stars belong to the SG. In other cases, where one would think of a simple stellar population, we suggest that the stars might all belong to the SG. We fit the optical and UV data of NGC2808, including a reproduction of the main sequence splittings and an exam of the problem of "blue hook" stars. We also show a detailed fit of the totally blue HB of M13, one among the clusters that are possibly fully made up by SG stars. We conclude that the formation of the SG is a crucial event in the life of GCs. A high fraction of SG stars can be achieved only if the initial cluster was much more massive than the present one and most of the FG low mass stars have been lost. As shown by D'Ercole et al., the mass loss due to type II supernovae of the FG may be the process responsible for triggering the expansion of the cluster, the stripping of its outer layers and the loss of most of the FG low-mass stars.Comment: accepted for publication in MNRA