A dense ring of the trans-Neptunian object Quaoar outside its Roche limit.

Planetary rings are observed not only around giant planets1, but also around small bodies such as the Centaur Chariklo2 and the dwarf planet Haumea3. Up to now, all known dense rings were located close enough to their parent bodies, being inside the Roche limit, where tidal forces prevent material with reasonable densities from aggregating into a satellite. Here we report observations of an inhomogeneous ring around the trans-Neptunian body (50000) Quaoar. This trans-Neptunian object has an estimated radius4 of 555 km and possesses a roughly 80-km satellite5 (Weywot) that orbits at 24 Quaoar radii6,7. The detected ring orbits at 7.4 radii from the central body, which is well outside Quaoar's classical Roche limit, thus indicating that this limit does not always determine where ring material can survive. Our local collisional simulations show that elastic collisions, based on laboratory experiments8, can maintain a ring far away from the body. Moreover, Quaoar's ring orbits close to the 1/3 spin-orbit resonance9 with Quaoar, a property shared by Chariklo's2,10,11 and Haumea's3 rings, suggesting that this resonance plays a key role in ring confinement for small bodies.

The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation.

Haumea-one of the four known trans-Neptunian dwarf planets-is a very elongated and rapidly rotating body. In contrast to other dwarf planets, its size, shape, albedo and density are not well constrained. The Centaur Chariklo was the first body other than a giant planet known to have a ring system, and the Centaur Chiron was later found to possess something similar to Chariklo's rings. Here we report observations from multiple Earth-based observatories of Haumea passing in front of a distant star (a multi-chord stellar occultation). Secondary events observed around the main body of Haumea are consistent with the presence of a ring with an opacity of 0.5, width of 70 kilometres and radius of about 2,287 kilometres. The ring is coplanar with both Haumea's equator and the orbit of its satellite Hi'iaka. The radius of the ring places it close to the 3:1 mean-motion resonance with Haumea's spin period-that is, Haumea rotates three times on its axis in the time that a ring particle completes one revolution. The occultation by the main body provides an instantaneous elliptical projected shape with axes of about 1,704 kilometres and 1,138 kilometres. Combined with rotational light curves, the occultation constrains the three-dimensional orientation of Haumea and its triaxial shape, which is inconsistent with a homogeneous body in hydrostatic equilibrium. Haumea's largest axis is at least 2,322 kilometres, larger than previously thought, implying an upper limit for its density of 1,885 kilograms per cubic metre and a geometric albedo of 0.51, both smaller than previous estimates. In addition, this estimate of the density of Haumea is closer to that of Pluto than are previous estimates, in line with expectations. No global nitrogen- or methane-dominated atmosphere was detected.

A ring system detected around the Centaur (10199) Chariklo.

Hitherto, rings have been found exclusively around the four giant planets in the Solar System. Rings are natural laboratories in which to study dynamical processes analogous to those that take place during the formation of planetary systems and galaxies. Their presence also tells us about the origin and evolution of the body they encircle. Here we report observations of a multichord stellar occultation that revealed the presence of a ring system around (10199) Chariklo, which is a Centaur--that is, one of a class of small objects orbiting primarily between Jupiter and Neptune--with an equivalent radius of 124 ± 9 kilometres (ref. 2). There are two dense rings, with respective widths of about 7 and 3 kilometres, optical depths of 0.4 and 0.06, and orbital radii of 391 and 405 kilometres. The present orientation of the ring is consistent with an edge-on geometry in 2008, which provides a simple explanation for the dimming of the Chariklo system between 1997 and 2008, and for the gradual disappearance of ice and other absorption features in its spectrum over the same period. This implies that the rings are partly composed of water ice. They may be the remnants of a debris disk, possibly confined by embedded, kilometre-sized satellites.

Albedo and atmospheric constraints of dwarf planet Makemake from a stellar occultation.

Pluto and Eris are icy dwarf planets with nearly identical sizes, comparable densities and similar surface compositions as revealed by spectroscopic studies. Pluto possesses an atmosphere whereas Eris does not; the difference probably arises from their differing distances from the Sun, and explains their different albedos. Makemake is another icy dwarf planet with a spectrum similar to Eris and Pluto, and is currently at a distance to the Sun intermediate between the two. Although Makemake's size (1,420 ± 60 km) and albedo are roughly known, there has been no constraint on its density and there were expectations that it could have a Pluto-like atmosphere. Here we report the results from a stellar occultation by Makemake on 2011 April 23. Our preferred solution that fits the occultation chords corresponds to a body with projected axes of 1,430 ± 9 km (1σ) and 1,502 ± 45 km, implying a V-band geometric albedo p(V) = 0.77 ± 0.03. This albedo is larger than that of Pluto, but smaller than that of Eris. The disappearances and reappearances of the star were abrupt, showing that Makemake has no global Pluto-like atmosphere at an upper limit of 4-12 nanobar (1σ) for the surface pressure, although a localized atmosphere is possible. A density of 1.7 ± 0.3 g cm(-3) is inferred from the data.

A Pluto-like radius and a high albedo for the dwarf planet Eris from an occultation.

The dwarf planet Eris is a trans-Neptunian object with an orbital eccentricity of 0.44, an inclination of 44 degrees and a surface composition very similar to that of Pluto. It resides at present at 95.7 astronomical units (1 AU is the Earth-Sun distance) from Earth, near its aphelion and more than three times farther than Pluto. Owing to this great distance, measuring its size or detecting a putative atmosphere is difficult. Here we report the observation of a multi-chord stellar occultation by Eris on 6 November 2010 UT. The event is consistent with a spherical shape for Eris, with radius 1,163 ± 6 kilometres, density 2.52 ± 0.05 grams per cm(3) and a high visible geometric albedo, Pv = 0.96(+0.09)(-0.04). No nitrogen, argon or methane atmospheres are detected with surface pressure larger than ∼1 nanobar, about 10,000 times more tenuous than Pluto's present atmosphere. As Pluto's radius is estimated to be between 1,150 and 1,200 kilometres, Eris appears as a Pluto twin, with a bright surface possibly caused by a collapsed atmosphere, owing to its cold environment. We anticipate that this atmosphere may periodically sublimate as Eris approaches its perihelion, at 37.8 astronomical units from the Sun.

Multi-locus HLA class I and II allele and haplotype associations with follicular lymphoma.

Follicular lymphoma (FL) is an indolent, sometimes, fatal disease characterized by recurrence at progressively shorter intervals and is frequently refractive to therapy. Genome-wide association studies have identified single nucleotide polymorphisms (SNPs) in the human leukocyte antigen (HLA) region on chromosome 6p21.32-33 that are statistically significantly associated with FL risk. Low to medium resolution typing of single or multiple HLA genes has provided an incomplete picture of the total genetic risk imparted by this highly variable region. To gain further insight into the role of HLA alleles in lymphomagenesis and to investigate the independence of validated SNPs and HLA alleles with FL risk, high-resolution HLA typing was conducted using next-generation sequencing in 222 non-Hispanic White FL cases and 220 matched controls from a larger San Francisco Bay Area population-based case-control study of lymphoma. A novel protective association was found between the DPB1*03:01 allele and FL risk [odds ratio (OR) = 0.39, 95% confidence interval (CI) = 0.21-0.68]. Extended haplotypes DRB1*01:01-DQA1*01:01-DQB1*05:01 (OR = 2.01, 95% CI = 1.22-3.38) and DRB1*15-DQA1*01-DQB1*06 (OR = 0.55, 95% CI = 0.36-0.82) also influenced FL risk. Moreover, DRB1*15-DQA1*01-DQB1*06 was highly correlated with an established FL risk locus, rs2647012. These results provide further insight into the critical roles of HLA alleles and SNPs in FL pathogenesis that involve multi-locus effects across the HLA region.

A new allele, HLA-B*4212, identified in a Brazilian volunteer bone marrow donors by sequence-based typing.

Here we report the discovery of a novel HLA-B allele, named B*4212 in a Brazilian volunteer bone marrow donor. The new sequence has nucleotide variation at position 496 (T→G) as compared with B*4201. This variation results in a conservative amino acid substitution from valine to glycine at codon 165 of exon 3.

High frequencies of alleles MICA*020 and MICA*027 in Amerindians and evidence of positive selection on exon 3.

MICA is a nonclassical polymorphic MHC molecule. We investigated MICA allelic frequencies and MICA-HLA-B-HLA-C haplotypes in Brazilian Amerindians to describe the polymorphism and to extract information about the evolution of MICA gene. Kaingang is the first population described to have a high frequency of MICA*020, found associated with HLA-B*3505-HLA-Cw*0401. Allele MICA*020 probably originated de novo in South America. The Guarani population had high frequencies of MICA*027. Allele MICA*00801 is common worldwide but rare among Amerindians, occurring only because of gene flow. The analysis of the 64 described MICA alleles revealed that in exons 2 and 4, synonymous substitutions are in excess, a result compatible with purifying selection. The opposite was observed for exons 3 and 6 and the excess of nonsynonymous substitutions was significant for exon 3, indicating positive selection. Few of the alleles described so far had exon 6 sequenced, impeding conclusions for the corresponding portion of the molecule. The analysis of the entire gene is required for a better understanding of the evolution of MICA's polymorphism and its functional consequences. This knowledge is of prime importance in view of the increasing awareness of the functional and medical implications of MICA gene variability.

Major histocompatibility complex class I chain-related gene A polymorphism and linkage disequilibrium with HLA-B alleles in Euro-Brazilians.

Major histocompatibility complex class I chain-related gene A (MICA) was identified within the human leukocyte antigen (HLA) class I region and was located 46 kb centromeric from HLA-B locus. It functions as a ligand for human gammadelta T, CD8 T and natural killer (NK) cells by binding the NKG2D receptor. The aims of the present study were to determine the distribution of MICA alleles and MICA-HLA-B haplotypes in a sample of Euro-Brazilians. Through the combination of three typing methods, polymerase chain reaction (PCR)-sequence-specific oligonucleotide probe, PCR-sequence-specific primer and PCR-restriction fragment length polymorphism, 19 alleles were detected besides a MICA gene deletion in a sample composed by 204 unrelated Euro-Brazilians. The most commonly observed alleles were: MICA*00801 (25.3%), MICA*00201 (17.7%) and MICA*00901 (13.7%). The GCT repeat polymorphism variant A6 was the most commonly found. The most frequent haplotype found in this study was MICA*00901-B*51 (8.1%), followed by haplotypes MICA*00201-B*35 (6.1%) and MICA*00801-B*07 (6.1%). MICA*00801 truncated product, and its low affinity for NKG2D receptor may work as an inhibitor in its putative soluble form. It may also be that selective forces may favor MICA*00801 heterozygosity with NKG2D high affinity MICA alleles enabling activation and inhibition of cytotoxic activity of cells expressing the NKG2D receptor. The possibility of selective neutrality or of balancing selection still provides no explanation for MICA gene polymorphisms. Is it maintained by genetic drift or by the influence of migratory waves? Are there favored alleles while others present the same adaptive value?

Amoebae-resisting bacteria in drinking water: risk assessment and management.

Free-living amoebae have been detected in a large number of man-made water systems, including drinking water distribution systems. Some of these amoebae can host amoebae-resisting bacteria, and thus act potentially as reservoirs and vehicles for a number of pathogens. The objectives of this study were to characterize the amoebae and amoebae-resisting bacteria present in different raw waters used for drinking water production, and to assess the efficiency of different treatments applied for drinking water production in removing or inactivating these amoebae. The preliminary results of this study confirm the presence of amoebae and amoebae-resisting bacteria in raw waters used for drinking water production. Due to their capacity to encyst, most of these amoebae are extremely resistant to disinfection processes. In these conditions, preventing the dissemination of these micro-organisms through drinking water will mainly require their physical removal by clarification and filtration processes. The particular hazard that amoebae-resisting bacteria represent in drinking water production should be taken into account in any risk assessment conducted in the framework of a water safety plan, and control strategies based on physical removal rather than disinfection should be adopted where necessary.

Development and implementation of an expert system to improve the control of nitrification and denitrification in the Vic wastewater treatment plant.

Wastewater treatment plants employ various physical, chemical and biological processes to reduce pollutants from raw wastewater. One of the most important is the biological nitrogen removal process through nitrification and denitrification steps taking place in various sections of the biological reactor. One of the most extensively used configurations to achieve the biological nitrogen removal is an activated sludge system using oxidation ditch or extended aeration. To improve nitrogen removal in the wastewater treatment plant (WWTP) of Vic (Catalonia, NE Spain), the automatic aeration control system was complemented with an Expert System to always provide the most appropriate aeration or anoxia sequence based on the values of ammonium and nitrates given by an automatic analyzer. This article illustrates the development and implementation of this knowledge-based system within the framework of a Decision Support System, which performs SCADA functions. The paper also shows that the application of the decision support system in the Vic WWTP resulted in significant improvements to the biological nitrogen removal.

Conocimiento del farmacéutico comunitario sobre el asma y el control del paciente asmático / Community pharmacist's knowledge of asthma and asthma patient management

Introducción: el asma es una patología que afecta a casi 3 millones de españoles. A día de hoy existen datos preocupantes en cuanto a la patología asmática, con un infradiagnóstico del 50 % y un mal control del paciente asmático de un 60-70 %. Además, varios estudios muestran que el propio paciente no tiene una percepción real de su enfermedad o hace un mal uso de su tratamiento; hecho del que no escapan los propios profesionales sanitarios que atienden a estos pacientes.Objetivo: evaluar los conocimientos de los farmacéuticos comunitarios sobre la patología asmática y su tratamiento además de explorar posibles opciones de mejora a través de una formación adecuada y actualizada y de acciones coordinadas con atención primaria.Resultados: se obtuvieron un total de 566 respuestas. De ellas, los porcentajes de respuestas acertadas según la temática fueron: prevalencia 51.59 %, diagnóstico 59.01 %, evolución 80,57 %, mortalidad 20,67 %, etiología 40,46 %, control 30,45 % y tratamiento 48,35 %. Además, queda patente la disponibilidad para llevar a cabo tareas en las que cooperar con los médicos de atención primaria y acciones que podrían implementarse en la farmacia comunitaria sin grandes dificultades.Conclusiones: el estudio refleja la falta de formación de los farmacéuticos comunitarios en las áreas de prevalencia, diagnóstico, mortalidad, etiología, control y tratamiento del asma; haciéndose imprescindible un estudio riguroso de la falta de conocimientos antes de emprender intervenciones educativas y formativas. Las propuestas de mejora más valoradas han sido comunicación directa con el médico, medidas higiénico-dietéticas y la integración de la farmacia comunitaria en el sistema de salud. (AU)

Human leukocyte antigen allelic groups and haplotypes in a brazilian sample of volunteer donors for bone marrow transplant in Curitiba, Paraná, Brazil.

Bone Marrow Transplant (BMT) is a lifesaving procedure for several diseases. Histocompatibility between host and donor is crucial for the success of this therapy. Since human leukocyte antigen (HLA) genes are the most polymorphic in humans, a foreknowledge of their frequencies and a vast register of volunteer donors are important for patients who need an unrelated donor. This research evaluated data from 3500 HLA-typed donors using PCR-SSP (One Lambda ABDRX kits, low/medium resolution). The allele and haplotype frequencies were calculated from the donor HLA typings. Among the total sample we observed that the allelic groups HLA-A*02, -B*35, and -DRB1*11 had frequencies of 0.228, 0.112, and 0.125, respectively. The haplotype HLA-A*01-B*08-DRB1*03 was the most frequent (0.024). We also compared our results with another study conducted in a Northeastern Brazilian population. The identification of the most common allelic groups and haplotypes is of great interest, not only to know the HLA composition of the population but also to search for the best HLA match for a transplant. However, the search for the perfect match depends on the eventual registration of every specific donor in the national registers for bone marrow donation.

Gangrene of the fingertips after bleomycin and methotrexate.

The increased use of cytostatic drugs, which are sometimes used in combination chemotherapy, may result in new and unusual cutaneous side effects. We describe a 57-year-old man with acral erythrocyanosis progressing to acute digital ischemia and gangrene that developed after combined chemotherapy (bleomycin and methotrexate) used to treat a metastatic squamous cell carcinoma of the hypopharynx. A leukocytoclastic vasculitis was found in both the acute phase and in the amputated fingertips. This supports the well-reported potential of bleomycin to trigger acral vascular toxicity.

Aerobic bacterial spores as process indicators for protozoa cysts in water treatment plants.

The possibility of using aerobic spores as indicators (surrogates) of water treatment efficiency for the removal of Giardia cysts and Cryptosporidium oocysts was evaluated in a water treatment plant that supplies the Barcelona area of Spain. The water treatment consists of pre-chlorination, flocculation-sedimentation, double filtration (sand and granular activated carbon, GAC) with intermediate ozonation and post-chlorination. Aerobic spores significantly increased after GAC filtration, which indicated an active propagation of aerobic spore-formers. However, anaerobic (Clostridium) spores could be a good surrogate for Cryptosporidium oocysts, especially if their detection in samples at low concentrations was improved.

[Stillbirth as a perinatal health indicator]. / A natimortalidade como indicador de saúde perinatal.

The authors carried out a literature review of the subject "stillbirth", with special emphasis on its conceptual and epidemiological features, aimed at highlighting its importance as a perinatal health indicator.

[Incidence of typhoid fever in our environment. Analysis in Guipúzcoa]. / Incidencia de la fiebre tifoidea en nuestro medio. Análisis en Guipúzcoa.

Based in 184 cases of Typhoid Fever bacteriologically demonstrated in the past 14 years (greater than 90% of all cases registered in the whole province), we have observed that, with the exception of some epidemic outbreaks, the disease has been constantly present during all these years, with a higher incidence between August and November. Salmonella typhi infected primarily young adults, its distribution being similar to the one among the general population. 49% of cases were males. The estimated incidence rate of the disease during this period was 2-3 per 100,000 population. A seroepidemiological study among healthy women with ages between 20 and 40 years showed a seroprevalence of anti-H:d antibodies greater than or equal to 1/40 of 1%. Although the epidemiological situation of Typhoid fever in our environment is not as bad as it has been referred in reports and textbooks, an effort is needed to situate the problem at the appropriate level, given our geographical situation and our economical development.

[Efficacy and safety of dotarizine vs. cinnarizine in the symptomatic treatment of acute balance disorders (common vertigo)]. / Eficacia y seguridad de dotarizina frente a cinarizina en el tratamiento sintomático de los trastornos agudos del equilibrio (vértigo común).

One hundred and ten adult patients suffering from peripheral vertigo were treated in a multifactorial double-blind randomized clinical trial with dotarizine (50 mg b.i.d.) or cinnarizine (75 mg b.i.d.). There was a 60 days clinical follow-up. Results showed that dotarizine was significantly active against the vertigo attacks and its associated symptoms (mainly neurovegetative). The global superiority of dotarizine was confirmed by statistically significant differences between treatments in the improvement of the severity of vertigo, hearing loss in audiometries, global relief of symptoms, disability produced by crises and global assessment by the investigators themselves. No clinically significant unwanted effects were seen in either group on blood pressure, heart rate or analytical parameters. No serious adverse effects to dotarizine were reported. This study confirms the value of dotarizine in the treatment of peripheral vertigo.