Observation of an Exotic Baryon with S=+1 in Photoproduction from the Proton

The reaction $\gamma p \to \pi^+K^-K^+n$ was studied at Jefferson Lab using a tagged photon beam with an energy range of 3-5.47 GeV. A narrow baryon state with strangeness S=+1 and mass $M=1555\pm 10$ MeV/c$^2$ was observed in the $nK^+$ invariant mass spectrum. The peak's width is consistent with the CLAS resolution (FWHM=26 MeV/c$^2$), and its statistical significance is 7.8 $\pm$ 1.0 ~$\sigma$. A baryon with positive strangeness has exotic structure and cannot be described in the framework of the naive constituent quark model. The mass of the observed state is consistent with the mass predicted by a chiral soliton model for the $\Theta^+$ baryon. In addition, the $pK^+$ invariant mass distribution was analyzed in the reaction $\gamma p\to K^-K^+p$ with high statistics in search of doubly-charged exotic baryon states. No resonance structures were found in this spectrum.Comment: 5 pages, 5 figures, add reference

Exclusive Photoproduction of the Cascade (Xi) Hyperons

We report on the first measurement of exclusive Xi-(1321) hyperon photoproduction in gamma p --> K+ K+ Xi- for 3.2 < E(gamma) < 3.9 GeV. The final state is identified by the missing mass in p(gamma,K+ K+)X measured with the CLAS detector at Jefferson Laboratory. We have detected a significant number of the ground-state Xi-(1321)1/2+, and have estimated the total cross section for its production. We have also observed the first excited state Xi-(1530)3/2+. Photoproduction provides a copious source of Xi's. We discuss the possibilities of a search for the recently proposed Xi5-- and Xi5+ pentaquarks.Comment: submitted to Phys. Rev.

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Basel–Tuscany, a long-lasting link

A significant contribution of Burkart Engesser to fieldsurveys and palaeontological studies is undoubtedly on theLate Miocene faunas from Maremma in southern Tuscany,especially the celebrated Baccinello basin in the Grossetodistrict. This is not just a coincidence, but is the continu-ation of a long tradition.The interest of successive Palaeontologists of theNaturhistorisches Museum Basel (NMB) in Tuscan fossilsand fossiliferous localities has a long history that datesback to the second half of the nineteenth century. Thisstarted with Ludwig Ru¨timeyer (1825–1895) who was theprofessor of Zoology and Comparative Anatomy at theUniversity of Basel in 1855. Ru¨timeyer was mainly inter-ested in the natural history of Tertiary mammal species,and a number of specimens from Italy (as well as fromother countries in Europe, especially France) were acquiredby the NMB during his period of activity.The interest in the Tuscan mammal fossil record becameparticularly strong thanks to the activity of CharlesImmanuel Forsyth Major (1843–1923), a physician ofScottish origin who grew up in Switzerland. He graduatedin Medicine in Basel in 1868 and started his professionalpractice in Florence (Italy) where he stayed for about adecade. As many nineteenth century medical doctors,however, he was fascinated by natural history and devotedmuch of his spare time to the study of fossil mammals. Hisinterest in extinct vertebrates exceeded his dedication tomedicine, so that he finally decided to cease practising inthe mid 1880s. Forsyth Major was a correspondent ofCharles Darwin (Cioppi & Dominici, 2010), and his nameappears three times in the second edition of The Descent ofMan (a much improved edition, published in 1874) aboutsexual dimorphisms in fossil pigs tusks, about the occur-rence of fossil apes in Europe, and about a bovid skull''wholly without horns'' from Upper Valdarno, believed tobe that of a ''Bos etruscus'' female. The latter is an issuethat re-addresses us to the story of the Basel-Florenceexchanges. About this specimen (housed in the collectionof the Florence Museum), Forsyth Major (1874, 1890) wasin disagreement with ''the leading authority in the field ofTertiary Ruminants'', i.e. Ru¨timeyer. The eminent palae-ontologist from Basel (Ru¨timeyer, 1878) described thisspecimen as type of a new species (Leptobos strozzii), lateron formally synonymzed to L. etruscus by Forsyth Major(1890). Forsyth Major's main interests were especiallyPrimates and, more generally speaking, Plio-Pleistocenemammals (e.g. among others, Forsyth Major, 1872,1875–1877, 1890). His entire scientific production clearlyshows how deep his attention was for Tuscan vertebratefossils, and whilst he was active in Florence, he system-atically searched for new material, mainly in Tuscany butalso in other Italian regions (Sardinia, Calabria, Sicily),bringing hundreds of specimens to the Florence Museum.Forsyth Major had intensive relationships with colleaguesand institutions across Europe and in Basel too. Samplescollected during his Italian field surveys are now housed inseveral museums, amongst others in the Natural History,London, in the Colle`ge Gaillard in Lausanne (Switzerland),and in the Naturhistorisches Museum Basel.Other Tuscan material (namely from Upper Valdarno)kept in Basel from the Plio-Pleistocene of Italy was boughtby another eminent Basel palaeontologist, Hans GeorgStehlin (1870–1941). He was the president of the board ofthe Naturhistorisches Museum from 1920 to 1940 and astudent of Ludwig Ru¨timeyer at the University of Basel