Searching for magnetic monopoles trapped in accelerator material at the Large Hadron Collider

If produced in high energy particle collisions at the LHC, magnetic monopoles could stop in material surrounding the interaction points. Obsolete parts of the beam pipe near the CMS interaction region, which were exposed to the products of pp and heavy ion collisions, were analysed using a SQUID-based magnetometer. The purpose of this work is to quantify the performance of the magnetometer in the context of a monopole search using a small set of samples of accelerator material ahead of the 2013 shutdown.Comment: 11 page

New results on heavy hadron spectroscopy with NRQCD

We present results for the spectrum of b-bbar bound states in the quenched approximation for three different values of the lattice spacing. Results for spin-independent splittings are shown to have good scaling behaviour; spin-dependent splittings are more sensitive to discretisation effects. We discuss what needs to be done to match the experimental spectrum.Comment: 3 pages, contribution to Lattice'9

Introduced Marine Species in the Haida Gwaii (Queen Charlotte Islands) Region, British Columbia

This historical review of a marine area’s introduced species was facilitated by geo-referenced marine species inventories of the Haida Gwaii (Queen Charlotte Islands) region. One plant, 14 invertebrate, and two fish introduced species have been recorded since the early 20th century from the marine waters around Haida Gwaii. Records of species occurrences are listed and mapped, and modes of introduction are discussed. It will be important to continue documenting areas’ introduced species locations to track the progress of invasions that could affect local marine ecosystem well-being. Erratum for figure included

Interventions for the treatment of oral and oropharyngeal cancers: surgical treatment.

BACKGROUND: Surgery is an important part of the management of oral cavity cancer with regard to both the removal of the primary tumour and removal of lymph nodes in the neck. Surgery is less frequently used in oropharyngeal cancer. Surgery alone may be treatment for early stage disease or surgery may be used in combination with radiotherapy, chemotherapy and immunotherapy/biotherapy. There is variation in the recommended timing and extent of surgery in the overall treatment regimens of people with these cancers. OBJECTIVES: To determine which surgical treatment modalities for oral cavity and oropharyngeal cancers result in increased overall survival, disease free survival, progression free survival and reduced recurrence. SEARCH STRATEGY: The following electronic databases were searched: the Cochrane Oral Health Group Trials Register (to 17 February 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 1), MEDLINE via OVID (1950 to 17 February 2011) and EMBASE via OVID (1980 to 17 February 2011). There were no restrictions regarding language or date of publication. SELECTION CRITERIA: Randomised controlled trials where more than 50% of participants had primary tumours of the oral cavity or oropharynx, and which compared two or more surgical treatment modalities or surgery versus other treatment modalities. DATA COLLECTION AND ANALYSIS: Data extraction and assessment of risk of bias was undertaken independently by two or more review authors. Study authors were contacted for additional information as required. Adverse events data were collected from published trials. MAIN RESULTS: Seven trials (n = 669; 667 with cancers of the oral cavity) satisfied the inclusion criteria, but none were assessed as low risk of bias. Trials were grouped into three main comparisons. Four trials compared elective neck dissection (ND) with therapeutic neck dissection in patients with oral cavity cancer and clinically negative neck nodes, but differences in type of surgery and duration of follow-up made meta-analysis inappropriate. Three of these trials reported overall and disease free survival. One trial showed a benefit for elective supraomohyoid neck dissection compared to therapeutic ND in overall and disease free survival. Two trials found no difference between elective radical ND and therapeutic ND for the outcomes of overall survival and disease free survival. All four trials found reduced locoregional recurrence following elective ND.A further two trials compared elective radical ND with elective selective ND and found no difference in overall survival, disease free survival or recurrence. The final trial compared surgery plus radiotherapy to radiotherapy alone but data were unreliable because the trial stopped early and there were multiple protocol violations.None of the trials reported quality of life as an outcome. Two trials, evaluating different comparisons reported adverse effects of treatment. AUTHORS' CONCLUSIONS: Seven included trials evaluated neck dissection surgery in patients with oral cavity cancers. The review found weak evidence that elective neck dissection of clinically negative neck nodes at the time of removal of the primary tumour results in reduced locoregional recurrence, but there is insufficient evidence to conclude that elective neck dissection increases overall survival or disease free survival compared to therapeutic neck dissection. There is very weak evidence from one trial that elective supraomohyoid neck dissection may be associated with increased overall and disease free survival. There is no evidence that radical neck dissection increases overall survival compared to conservative neck dissection surgery. Reporting of adverse events in all trials was poor and it was not possible to compare the quality of life of patients undergoing different surgeries

Carbon-rich dust production in metal-poor galaxies in the Local Group

We have observed a sample of 19 carbon stars in the Sculptor, Carina, Fornax, and Leo I dwarf spheroidal galaxies with the Infrared Spectrograph on the Spitzer Space Telescope. The spectra show significant quantities of dust around the carbon stars in Sculptor, Fornax, and Leo I, but little in Carina. Previous comparisons of carbon stars with similar pulsation properties in the Galaxy and the Magellanic Clouds revealed no evidence that metallicity affected the production of dust by carbon stars. However, the more metal-poor stars in the current sample appear to be generating less dust. These data extend two known trends to lower metallicities. In more metal-poor samples, the SiC dust emission weakens, while the acetylene absorption strengthens. The bolometric magnitudes and infrared spectral properties of the carbon stars in Fornax are consistent with metallicities more similar to carbon stars in the Magellanic Clouds than in the other dwarf spheroidals in our sample. A study of the carbon budget in these stars reinforces previous considerations that the dredge-up of sufficient quantities of carbon from the stellar cores may trigger the final superwind phase, ending a star's lifetime on the asymptotic giant branch.Comment: ApJ, in press, 21 pages, 12 figures. Replaced Fig 12, corrected two reference

A Post-AGB Star in the Small Magellanic Cloud Observed with the Spitzer Infrared Spectrograph

We have observed an evolved star with a rare combination of spectral features, MSX SMC 029, in the Small Magellanic Cloud (SMC) using the low-resolution modules of the Infrared Spectrograph on the Spitzer Space Telescope. A cool dust continuum dominates the spectrum of MSX SMC 029. The spectrum also shows both emission from polycyclic aromatic hydrocarbons (PAHs) and absorption at 13.7 micron from C2H2, a juxtaposition seen in only two other sources, AFGL 2688 and IRAS 13416-6243, both post-asymptotic giant branch (AGB) objects. As in these sources, the PAH spectrum has the unusual trait that the peak emission in the 7-9 micron complex lies beyond 8.0 micron. In addition, the 8.6 micron feature has an intensity as strong as the C-C modes which normally peak between 7.7 and 7.9 micron. The relative flux of the feature at 11.3 micron to that at 8 micron suggests that the PAHs in MSX SMC 029 either have a low ionization fraction or are largely unprocessed. The 13-16 micron wavelength region shows strong absorption features similar to those observed in the post-AGB objects AFGL 618 and SMP LMC 11. This broad absorption may arise from the same molecules which have been identified in those sources: C2H2, C4H2, HC3N, and C6H6. The similarities between MSX SMC 029, AFGL 2688, and AFGL 618 lead us to conclude that MSX SMC 029 has evolved off the AGB in only the past few hundred years, making it the third post-AGB object identified in the SMC.Comment: 4 figures, Fig. 4 color; to appear in the 20 November 2006 Astrophysical Journal Letter

Growth and Structure of Stochastic Sequences

We introduce a class of stochastic integer sequences. In these sequences, every element is a sum of two previous elements, at least one of which is chosen randomly. The interplay between randomness and memory underlying these sequences leads to a wide variety of behaviors ranging from stretched exponential to log-normal to algebraic growth. Interestingly, the set of all possible sequence values has an intricate structure.Comment: 4 pages, 4 figure