Constraints on flavor-changing neutral-current HtqHtq couplings from the signal of tHtH associated production with QCD next-to-leading order accuracy at the LHC

We study a generic Higgs boson and a top quark associated production via model-independent flavor-changing neutral-current couplings at the LHC, including complete QCD next-to-leading order (NLO) corrections to the production and decay of the top quark and the Higgs boson. We find that QCD NLO corrections can increase the total production cross sections by about 48.9% and 57.9% for the $Htu$ and $Htc$ coupling induced processes at the LHC, respectively. After kinematic cuts are imposed on the decay products of the top quark and the Higgs boson, the QCD NLO corrections are reduced to 11% for the $Htu$ coupling induced process and almost vanish for the $Htc$ coupling induced process. Moreover, QCD NLO corrections reduce the dependence of the total cross sections on the renormalization and factorization scales. We also discuss signals of the $tH$ associated production with the decay mode t \rightarrow bl^{+}E \slash_{T}, H \rightarrow b\bar{b} and $t\bar{t}$ production with the decay mode \bar{t} \rightarrow H\bar{q}, t\rightarrow bl^{+}E \slash_{T}. Our results show that, in some parameter regions, the LHC may observe the above signals at the $5\sigma$ level. Otherwise, the upper limits on the FCNC $Htq$ couplings can be set.Comment: 28 pages, 14 figures, 5 tables; version published in PR

Gestión cinegética racional ligada a la praxis de la caza y la recolección. ¿Entelequia aristotélica o quimera?

Rational management of hunting and gathering: An Aristotelian entelechy or a chimera? Since the dawn of time, consumption of animal protein has been crucially important to the evolution of humans. Cooperative hunting is an Evolutionarily Stable Strategy from the time when Palaeolithic hunters specialized in the pursuit of large animals. The entire process involves making decisions related to game management, some of which are still used by contemporary hunter-gatherers. In these societies, which still practice subsistence hunting, the composition of their diets and the exploitation techniques employed are explained by the theoretical underpinnings contained in the Optimal Foraging Theory (OFT). In order to test this theory, we have taken into account four decisions involving the adoption of different management strategies by hunter-gatherers: I) what to eat, II) where and how to look for food, III) the most appropriate size and composition of the group of hunter-gatherers and IV) the most efficient guidelines for the handling and distribution of prey. The OFT has been tested several times, and in a high percentage of cases studied, its predictions fit observations made in various hunter-gatherer societies. This means that maximizing catch yields in the short term is their main concern, rather than behaving as ‘cautious predators’ or passively selecting prey according to their size, accessibility and abundance. Such behaviour does not contradict the possibility that hunter-gatherers can act as conservationists, but discards the idea that this is the main focus of their way of life. There is no doubt that indigenous peoples have a wide knowledge of the environment, but it is unclear this knowledge is used to maintain a balance with nature or to be more efficient hunters. It more likely that the presence of sustainable hunting of game is due to low hunting pressure in areas where animal prey is abundant, and is thus an epiphenomenon rather than a deliberate strategy by hunters to conserve prey stocks. On the basis of available data, to continue to uphold the myth of the ‘ecologically noble savage’ is as fallacious as it is dangerous in the face of current and future problems. This misconception stems, in part, from the confusion of what is meant by sustainability and conservation. However, it should be noted that the conclusions drawn in this review are strictly academic and do not justify improper moral judgments about the rights of hunter-gatherers.Gestión cinegética racional ligada a la praxis de la caza y la recolección. ¿Entelequia aristotélica o quimera? Desde los albores de su historia filogenética, el consumo de proteínas de origen animal ha tenido gran relevancia en la evolución de los humanos. La caza cooperativa representa una estrategia evolutiva estable a partir del momento en que los cazadores paleolíticos se especializan en la persecución de grandes animales. Todo este proceso implica la adopción de decisiones relacionadas con la gestión de la caza, algunas de las cuales siguen siendo utilizadas por los cazadores-recolectores contemporáneos. En estas sociedades que todavía practican la caza como medio de subsistencia, la composición de sus respectivas dietas y las técnicas de explotación empleadas son explicables bajo supuestos teóricos contenidos en la Teoría del Forrajeo Óptimo (TFO). Con objeto de poner a prueba dicha teoría, se han tomado en consideración cuatro decisiones que implican la adopción de diferentes estrategias de gestión por parte de los cazadores-recolectores: I) qué comer, II) dónde y cómo buscar el alimento, III) cuáles son el tamaño y composición más adecuados del grupo de cazadores-recolectores y IV) qué pautas de manipulación y reparto de las presas son más eficientes. La TFO se ha puesto a prueba en diversas ocasiones y, en un alto porcentaje de los casos estudiados, sus predicciones se ajustan a lo observado en distintas sociedades cazadoras-recolectoras. Esto significa que la maximización de los rendimientos de captura a corto plazo es su principal preocupación, en lugar de comportarse como “depredadores prudentes” o realizar una selección pasiva de sus presas en función del tamaño, accesibilidad y abundancia de las mismas. Dicho comportamiento no niega que los cazadores-recolectores actúen como conservacionistas pero descarta que esa sea la principal preocupación de su modo de vida. No cabe duda de que los pueblos indígenas tienen un amplio conocimiento del medio, pero no está claro si lo utilizan para mantener un balance con la naturaleza o para ser cazadores más eficientes Es más probable que la extracción sostenible se deba a una baja presión de caza en zonas donde abundan las presas, lo que constituye un epifenómeno en lugar de una estrategia deliberada de conservación. A tenor de los datos disponibles, seguir manteniendo el mito del salvaje ecológicamente noble es tan falaz como peligroso de cara a la solución de sus problemas presentes y futuros. Dicha concepción errónea deriva, en parte, de confundir sostenibilidad y conservación. No obstante, resulta oportuno recordar que las conclusiones derivadas de la presente revisión tienen un valor estrictamente académico y no justifican juicios morales improcedentes respecto a los derechos de los cazadores-recolectores

Ecology of Sleeping: The Microbial and Arthropod Associates of Chimpanzee Beds

The indoor environment created by the construction of homes and other buildings is often considered to be uniquely different from other environments. It is composed of organisms that are less diverse than those of the outdoors and strongly sourced by, or dependent upon, human bodies. Yet, no one has ever compared the composition of species found in contemporary human homes to that of other structures built by mammals, including those of non-human primates. Here we consider the microbes and arthropods found in chimpanzee beds, relative to the surrounding environment (n = 41 and 15 beds, respectively). Based on the study of human homes, we hypothesized that the microbes found in chimpanzee beds would be less diverse than those on nearby branches and leaves and that their beds would be primarily composed of body-associated organisms. However, we found that differences between wet and dry seasons and elevation above sea level explained nearly all of the observed variation in microbial diversity and community structure. While we can identify the presence of a chimpanzee based on the assemblage of bacteria, the dominant signal is that of environmental microbes. We found just four ectoparasitic arthropod specimens, none of which appears to be specialized on chimpanzees or their structures. These results suggest that the life to which chimpanzees are exposed while in their beds is predominately the same as that of the surrounding environment

The diet of open-habitat chimpanzees (Pan troglodytes schweinfurthii) in the Issa valley, western Tanzania

Comparative data on the diets of extant primates inform hypotheses about hominin resource use. Historically, data describing chimpanzee diets stem primarily from forest-dwelling communities, and we lack comparative data from chimpanzees that live in mosaic habitats that more closely resemble those reconstructed for Plio-Pleistocene hominins. We present data on the diet of a partially-habituated community of open habitat chimpanzees (Pan troglodytes schweinfurthii) from the Issa valley, western Tanzania, collected over a four-year period. Based mostly on macroscopic faecal analysis, Issa chimpanzees consumed a minimum of 69 plant species. There was no relationship between plant consumption and either fruit availability or feeding tree density; the most frequently consumed plant species were found in riverine forests, with woodland species consumed more frequently during the late dry season. We conclude by contextualising these findings with those of other open-habitat chimpanzee sites, and also by discussing how our results contribute towards reconstructions of early hominin exploitation of mosaic landscapes

Crystal Structure of the Pre-fusion Nipah Virus Fusion Glycoprotein Reveals a Novel Hexamer-of-Trimers Assembly.

Nipah virus (NiV) is a paramyxovirus that infects host cells through the coordinated efforts of two envelope glycoproteins. The G glycoprotein attaches to cell receptors, triggering the fusion (F) glycoprotein to execute membrane fusion. Here we report the first crystal structure of the pre-fusion form of the NiV-F glycoprotein ectodomain. Interestingly this structure also revealed a hexamer-of-trimers encircling a central axis. Electron tomography of Nipah virus-like particles supported the hexameric pre-fusion model, and biochemical analyses supported the hexamer-of-trimers F assembly in solution. Importantly, structure-assisted site-directed mutagenesis of the interfaces between F trimers highlighted the functional relevance of the hexameric assembly. Shown here, in both cell-cell fusion and virus-cell fusion systems, our results suggested that this hexamer-of-trimers assembly was important during fusion pore formation. We propose that this assembly would stabilize the pre-fusion F conformation prior to cell attachment and facilitate the coordinated transition to a post-fusion conformation of all six F trimers upon triggering of a single trimer. Together, our data reveal a novel and functional pre-fusion architecture of a paramyxoviral fusion glycoprotein

Untargeted lipidomics uncovers lipid signatures distinguishing severe versus moderate forms of acutely decompensated cirrhosis

BACKGROUND AND AIM: Acutely decompensated of cirrhosis is a heterogeneous clinical entity associated with moderate mortality. In some patients, this condition develops quickly into a more often deadly acute-on-chronic liver failure (ACLF), in which other organs such as the kidneys or brain fail. The aim of this study was to characterize the blood lipidome in a large series of patients with cirrhosis and identify specific signatures associated with acute decompensation and ACLF development. METHODS: Serum untargeted lipidomics was performed in 561 patients with acutely decompensated (AD) cirrhosis (518 without and 43 with ACLF) (discovery cohort) and in 265 AD patients (128 without and 137 with ACLF) in whom serum samples were available to perform repeated measurements during the 28-day follow-up (validation cohort). Analyses were also performed in 78 AD patients included in a therapeutic albumin trial, 43 patients with compensated cirrhosis and 29 healthy subjects. RESULTS: The circulating lipid landscape associated with cirrhosis was characterized by a generalized suppression, which was more manifest during acute decompensation and in non-surviving patients. By computing discriminating accuracy and the variable importance projection score for each of the 223 annotated lipids, we identified a sphingomyelin fingerprint specific for AD cirrhosis and a distinct cholesteryl ester and lysophosphatidylcholine fingerprint for ACLF. Liver dysfunction, mainly, and infections were the principal net contributors to these fingerprints, which were dynamic and interchangeable between AD patients whose condition worsened to ACLF and those who improved. Notably, blood lysophosphatidylcholine levels increased in these patients after albumin therapy. CONCLUSIONS: Our findings provide insights into the lipid landscape associated with decompensation of cirrhosis and ACLF progression and identify unique noninvasive diagnostic biomarkers of advanced cirrhosis. LAY SUMMARY: Analysis of lipids in blood from patients with advanced cirrhosis reveals a general suppression of their levels in the circulation of these patients. A specific group of lipids known as sphingomyelins are useful to distinguish compensated from decompensated patients with cirrhosis. Another group of lipids designated cholesteryl esters further distinguish patients with decompensated patients who are at risk of developing organ failures

A Large Scale Double Beta and Dark Matter Experiment: GENIUS

The recent results from the HEIDELBERG-MOSCOW experiment have demonstrated the large potential of double beta decay to search for new physics beyond the Standard Model. To increase by a major step the present sensitivity for double beta decay and dark matter search much bigger source strengths and much lower backgrounds are needed than used in experiments under operation at present or under construction. We present here a study of a project proposed recently, which would operate one ton of 'naked' enriched GErmanium-detectors in liquid NItrogen as shielding in an Underground Setup (GENIUS). It improves the sensitivity to neutrino masses to 0.01 eV. A ten ton version would probe neutrino masses even down to 10^-3 eV. The first version would allow to test the atmospheric neutrino problem, the second at least part of the solar neutrino problem. Both versions would allow in addition significant contributions to testing several classes of GUT models. These are especially tests of R-parity breaking supersymmetry models, leptoquark masses and mechanism and right-handed W-boson masses comparable to LHC. The second issue of the experiment is the search for dark matter in the universe. The entire MSSM parameter space for prediction of neutralinos as dark matter particles could be covered already in a first step of the full experiment - with the same purity requirements but using only 100 kg of 76Ge or even of natural Ge - making the experiment competitive to LHC in the search for supersymmetry. The layout of the proposed experiment is discussed and the shielding and purity requirements are studied using GEANT Monte Carlo simulations. As a demonstration of the feasibility of the experiment first results of operating a 'naked' Ge detector in liquid nitrogen are presented.Comment: 22 pages, 12 figures, see also http://pluto.mpi-hd.mpg.de/~betalit/genius.htm

Immunohistochemical and transcriptional expression of Matrix Metalloproteinases in full-term human umbilical cord and Human Umbilical Vein Endothelial Cells

Matrix metalloproteinases (MMPs) are extracellular zinc-dependent endopeptidases involved in the degradation and remodelling of extracellular matrix in physiological and pathological processes. MMPs also have a role on cell proliferation, migration, differentiation, angiogenesis and apoptosis. Umbilical cord is a special organ subjected to many changes during pre-natal life and whose cells can maintain a certain degree of plasticity also in post-natal period; for example recently they have been used as a source of stem cells. In this work we investigated the expression of MMPs in human umbilical cord and Human Umbilical Vein Endothelial Cells (HUVEC) though immunohistochemistry, RT-PCR and gelatin zymography. MMP-2 protein is expressed in the amniotic epithelium of human umbilical cord and in few sub-epithelial fibroblasts, while MMP-3 and MMP-10 only in the umbilical epithelium. MMP-8, MMP-9 and MMP-13 immunoreactivity is localised in the epithelium and in Wharton\u2019s jelly mesenchymal cells. Immunocytochemistry also revealed protein expression for MMP-2, 3, 8, 9 and 10 in cultured HUVEC. In agreement with immunohistochemical data, RT-PCR analysis performed on samples of whole umbilical cord confirmed the transcriptional expression for the genes encoding all the six matrix metalloproteinases investigated, while in HUVEC only the expression of MMP-2, 3, 9, 10 and 13 mRNAs was detected. Gelatin zymograpgy showed a clear MMP-2 and MMP-9 enzymatic activity in the conditioned medium of HUVEC at different culture passages, suggesting that HUVEC secrete gelatinases, that afterwards undergo extracellular activation, and this ability is not affected by passage number

Ecological implications of a flower size/number trade-off in tropical forest trees

Peer reviewedPublisher PD