Generalized model of blockage in particulate flow limited by channel carrying capacity

We investigate stochastic models of particles entering a channel with a random time distribution. When the number of particles present in the channel exceeds a critical value $N$, a blockage occurs and the particle flux is definitively interrupted. By introducing an integral representation of the $n$ particle survival probabilities, we obtain exact expressions for the survival probability, the distribution of the number of particles that pass before failure, the instantaneous flux of exiting particle and their time correlation. We generalize previous results for $N=2$ to an arbitrary distribution of entry times and obtain new, exact solutions for $N=3$ for a Poisson distribution and partial results for $N\ge 4$.Comment: 13 pages, 9 figure

Experimental study of granular surface flows via a fast camera: a continuous description

Depth averaged conservation equations are written for granular surface flows. Their application to the study of steady surface flows in a rotating drum allows to find experimentally the constitutive relations needed to close these equations from measurements of the velocity profile in the flowing layer at the center of the drum and from the flowing layer thickness and the static/flowing boundary profiles. The velocity varies linearly with depth, with a gradient independent of both the flowing layer thickness and the static/flowing boundary local slope. The first two closure relations relating the flow rate and the momentum flux to the flowing layer thickness and the slope are then deduced. Measurements of the profile of the flowing layer thickness and the static/flowing boundary in the whole drum explicitly give the last relation concerning the force acting on the flowing layer. Finally, these closure relations are compared to existing continuous models of surface flows.Comment: 20 pages, 11 figures, submitted to Phys. FLuid

Rat control

During the past few years the rat population in Iowa has built up until it is now estimated that there are more than 5 million rats in the state. This rapid increase in population is due primarily to the tremendous volume of corn which is stored in temporary, hastily-constructed cribs that offer easy access to rats and furnish both food and shelter for them. To meet this situation, it is urged that rat control be made an integral part of good farm practice. Since rats move about from farm to farm, especially when they are disturbed by a vigorous control campaign on the part of a few farmers, community cooperation is desired. Rats menace not only our food and our farm animals; from the standpoint of health they threaten both humans and domestic animals, since they may act as reservoirs of infectious jaundice, endemic typhus and bubonic plague in man and trichinosis of hogs

Reliable flow cytometric estimation of nuclear DNA content in coffee trees

La cytométrie en flux a permis d'obtenir des mesures précises de la taille des génomes de deux taxons (#C. liberica dewevrei et #C. pseudozanguebariae). L'iodure de propidium (IP) et le #Petunia hybrida ont été utilisés, respectivement, comme fluorochrome et standard interne. La linéarité de la relation entre la quantité d'ADN et le signal fluorescent digitalisé a été vérifiée. Cinq résultats majeurs ressortent : des conditions expérimentales optimales ont été définies pour l'estimation de la position des pics (moyenne et mode), le temps de coloration (au moins deux minutes), le voltage du photomultiplicateur (557 V) et de la concentration en IP (330 microg/ml) ; les effets du voltage et de la concentration en IP ont été paramétrés ; deux biais dus aux variations de voltage et de concentration en IP ont été décelés dans l'estimation de la quantité d'ADN par noyau. Ces biais ont été minimisés ; les tailles de génome de #C. liberica dewevrei et de #C. pseudozanguebariae$ ont été estimées avec précision (respectivement 2C = 1,421 plus ou moins 0,005 pg et 2C = 1,129 plus ou moins 0,005 pg) ; des variations entre génotypes ont été mises en évidence dans chaque taxon. (Résumé d'auteur

Simian immunodeficiency virus infection in wild-caught chimpanzees from Cameroon

Simian immunodeficiency viruses (SIVcpz) infecting chimpanzees (Pan troglodytes) in west central Africa are the closest relatives to all major variants of human immunodeficiency virus type 1 ([HIV-1]; groups M, N and O), and have thus been implicated as the source of the human infections; however, information concerning the prevalence, geographic distribution, and subspecies association of SIVcpz still remains limited. In this study, we tested 71 wild-caught chimpanzees from Cameroon for evidence of SIVcpz infection. Thirty-nine of these were of the central subspecies (Pan troglodytes troglodytes), and 32 were of the Nigerian subspecies (Pan troglodytes vellerosus), as determined by mitochondrial DNA analysis. Serological analysis determined that one P. t. troglodytes ape (CAM13) harbored serum antibodies that cross-reacted strongly with HIV-1 antigens; all other apes were seronegative. To characterize the newly identified virus, 14 partially overlapping viral fragments were amplified from fecal virion RNA and concatenated to yield a complete SIVcpz genome (9,284 bp). Phylogenetic analyses revealed that SIVcpzCAM13 fell well within the radiation of the SIVcpzPtt group of viruses, as part of a clade including all other SIVcpzPtt strains as well as HIV-1 groups M and N. However, SIVcpzCAM13 clustered most closely with SIVcpzGAB1 from Gabon rather than with SIVcpzCAM3 and SIVcpzCAM5 from Cameroon, indicating the existence of divergent SIVcpzPtt lineages within the same geographic region. These data, together with evidence of recombination among ancestral SIVcpzPtt lineages, indicate long-standing endemic infection of central chimpanzees and reaffirm a west central African origin of HIV-1. Whether P. t. vellerosus apes are naturally infected with SIVcpz requires further study

Interest of pet imaging in multiple myeloma

The interest of 18Fluoro-deoxyglucose (FDG) positron emission tomography (PET) imaging in the management of patients with multiple myeloma (MM) for the workup at diagnosis and for therapeutic evaluation has recently been demonstrated. FDG-PET is a powerful imaging tool for bone lesions detection at initial diagnosis with high sensitivity and specificity values. The independent pejorative prognostic value on progression-free survival (PFS) and overall survival (OS) of baseline PET-derived parameters (presence of extra-medullary disease (EMD), number of focal bone lesions (FLs), and maximum standardized uptake values [SUVmax]) has been reported in several large independent prospective studies. During therapeutic evaluation, FDG-PET is considered as the reference imaging technique, because it can be performed much earlier than MRI which lacks specificity. Persistence of significant FDG uptake after treatment, notably before maintenance therapy, is an independent pejorative prognostic factor, especially for patients with a complete biological response. So FDG-PET and medullary flow cytometry are complementary tools for detection of minimal residual disease before maintenance therapy. However, the definition of PET metabolic complete response should be standardized. In patients with smoldering multiple myeloma, the presence of at least one hyper-metabolic lytic lesions on FDG-PET may be considered as a criterion for initiating therapy. FDG-PET is also indicated for initial staging of a solitary plasmacytoma so as to not disregard other bone or extra-medullary localizations. Development of nuclear medicine offer new perspectives for MM imaging. Recent PET tracers are willing to overcome limitations of FDG. (11)C-Methionine, which uptake reflects the increased protein synthesis of malignant cells seems to correlate well with bone marrow infiltration. Lipid tracers, such as Choline or acetate, and some peptide tracers, such as (68) Ga-Pentixafor, that targets CXCR4 (chemokine receptor-4, which is often expressed with high density by myeloma cells), are other promising PET ligands. 18F-fludarabine and immuno-PET targeting CD138 and CD38 also showed promising results in preclinical models

Headache yesterday in Europe

BACKGROUND: Surveys enquiring about burden of headache over a prior period of time (eg, 3 months) are subject to recall bias. To eliminate this as far as possible, we focused on presence and impact of headache on the preceding day (“headache yesterday”). METHODS: Adults (18-65 years) were surveyed from the general populations of Germany, Italy, Lithuania, Luxembourg and the Netherlands, from a work-force population in Spain and from mostly non-headache patient populations of Austria, France and UK. A study of non-responders in some countries allowed detection of potential participation bias where initial participation rates were low. RESULTS: Participation rates varied between 11% and 59% (mean 27%). Non-responder studies suggested that, because of participation bias, headache prevalence might be overestimated in initial responders by up to 2% (absolute). Across all countries, 1,422 of 8,271 participants (15-17%, depending on correction for participation bias) had headache yesterday lasting on average for 6 hours. It was bad or very bad in 56% of cases and caused absence from work or school in 6%. Among those who worked despite headache, 20% reported productivity reduced by >50%. Social activities were lost by 24%. Women (21%) were more likely than men (12%) to have headache yesterday, but impact was similar in the two genders. CONCLUSIONS: With recall biases avoided, our findings indicate that headache costs at least 0.7% of working capacity in Europe. This calculation takes into account that most of those who missed work could make up for this later, which, however, means that leisure and social activities are even more influenced by headache

The birds of the Loyalty Islands (New Caledonia): census, ecological and biogeographical issues

The avifauna of the Loyalty Islands comprises 62 species, including 14 breeding or erratic seabirds, 5 migratory birds, 7 herons, ducks and rails, 4 birds of prey, 28 indigenous land breeders (belonging to 33 subspecies) and 2 species introduced from the Grande Terre (main island of New Caledonia). Six species are endemic: 3 on the Grande Terre and in the Loyalty Islands (New Caledonian Friarbird Philemon diemenensis, Green-backed White-eye Zosterops xanthochrous, Striated Starling Aplonis striatus) and 3 only found in the Loyalty Islands (Ouvea Parakeet Eunymphicus uvaeensis, Large Lifou White-eye Zosterops inornatus and Small Lifou White-eye Z. minutus). Eunymphicus is an endemic genus of New Caledonia. Eight subspecies are endemic to both the Grande Terre and the Loyalty Islands and 11 are exclusive of the Loyalty Islands. Of the 24 taxa whose geographical origin could be identified, 58% are identical or similar to those on the Grande Terre, 105 km away, and 42% have affinities with birds in Vanuatu, twice as far away (225 km). The paths of cyclones could explain the specific influence of Vanuatu. The correlation between the islands’land area and the number of species that have successfully settled is very close (r = 0.97) and confirms this biogeographical standard. The land breeding species frequencies vary, with rare localized species limited to some islands (Bluefaced Parrotfinch Erythrura trichroa, Ouvea Parakeet), or possibly extinct (Island Thrush Turdus poliocephalus) and others whose frequency varies widely from place to place (Fan-tailed Cuckoo Cacomantis flabelliformis, Gerygone Gerygone flavolateralis, Silvereye Zosterops lateralis), while others show high (Red-bellied Fruit-Dove Ptilinopus greyii), average (Melanesian Flycatcher Myiagra caledonica, Sacred Kingfischer Todiramphus sanctus) or low (Emerald Dove Chalcophaps indica) frequencies that remain comparable between these islands. The species ecology has been determined with some species associated with wide forests, e.g. the Ouvea Parakeet, while others are typical of the open settings. The threats onto this avifauna are mainly linked to habitat destruction and the impact of introduced species. A specific effort should be made to ensure the protection of populations of that species for which there is the greatest concern, i.e. the Ouvea ParakeetL'avifaune des Loyauté comprend 62 espèces, dont 14 marines nicheuses ou erratiques, 5 migratrices, 7 hérons, canards et râles, 4 rapaces/chouette, 28 oiseaux terrestres nicheurs indigènes (appartenant à 33 sous-espèces) et 2 espèces introduites de Grande Terre. Six espèces sont endémiques à l'archipel néo-calédonien: 3 présentes à la fois en Grande Terre et aux Loyauté: Polochion moine Philemon diemenensis, Zostérops à dos vert Zosterops xanthochrous, Stourne des Loyauté Aplanis striatus et 3 pour les seules Loyauté: Perruche d'Ouvéa Eunymphicus uvaeensis, Zostérops de Lifou Zosterops inornatus et Zostérops minute Z. minutus. Eunymphicus est un genre endémique de Nouvelle-Calédonie. Huit sous-espèces sont endémiques à la fois de Grande Terre et des Loyauté et 11 sont exclusives des Loyauté. Sur 24 taxons dont l'origine géographique peut être établie, 58 % sont identiques ou proches de ceux de Grande Terre distante de 105 km, et 42 % ont des affinités avec des oiseaux du Vanuatu, deux fois plus éloigné (225 km). La trajectoire des cyclones pourrait expliquer cette influence ni-vanuatu particulière. La corrélation entre la surface des îles et le nombre d'espèces qui y ont réussi leur implantation est très étroite (r = 0,97) et vérifie bien cette règle de la biogéographie. La fréquence des espèces terrestres nicheuses est variable, avec des espèces rares et localisées, limitées à certaines îles (Diamant de Kittlitz Erythrura trichroa, Perruche d'Ouvéa) et qui ont peut-être disparu (Merle des Iles Turdus poliocephalus), d'autres dont la fréquence est très inégalement répartie (Coucou à éventail Cacomantis flabelliformis, Gérygone Gerygone flavolateralis, Zostérops à dos noir Zosterops lateralis), d'autres enfin aux fréquences élevées (Ptilope de Grey Ptilinopus greyii), moyennes (Monarque Myiagra caledonica, Martin-chasseur Todiramphus sanctus) ou faibles (Colombine turvert Chalcophaps indica), mais comparables entre les îles. L'écologie des espèces a pu être précisée avec des espèces inféodées aux grandes forêts, parmi lesquelles la Perruche d'Ouvéa, et des espèces typiques des milieux ouverts. Les menaces pesant sur cette avifaune sont essentiellement liées aux destructions d'habitat et à l'impact des espèces introduites. Un effort particulier doit être consenti pour sécuriser les populations de l'espèce dont le statut est le plus préoccupant: la Perruche d'Ouvéa

Distinct expression profiles of TGF-β1 signaling mediators in pathogenic SIVmac and non-pathogenic SIVagm infections

BACKGROUND: The generalized T-cell activation characterizing HIV-1 and SIVmac infections in humans and macaques (MACs) is not found in the non-pathogenic SIVagm infection in African green monkeys (AGMs). We have previously shown that TGF-β1, Foxp3 and IL-10 are induced very early after SIVagm infection. In SIVmac-infected MACs, plasma TGF-β1 induction persists during primary infection [1]. We raised the hypothesis that MACs are unable to respond to TGF-β1 and thus cannot resorb virus-driven inflammation. We therefore compared the very early expression dynamics of pro- and anti-inflammatory markers as well as of factors involved in the TGF-β1 signaling pathway in SIV-infected AGMs and MACs. METHODS: Levels of transcripts encoding for pro- and anti-inflammatory markers (tnf-α, ifn-γ, il-10, t-bet, gata-3) as well as for TGF-β1 signaling mediators (smad3, smad4, smad7) were followed by real time PCR in a prospective study enrolling 6 AGMs and 6 MACs. RESULTS: During primary SIVmac infection, up-regulations of tnf-α, ifn-γ and t-bet responses (days 1–16 p.i.) were stronger whereas il-10 response was delayed (4(th )week p.i.) compared to SIVagm infection. Up-regulation of smad7 (days 3–8 p.i.), a cellular mediator inhibiting the TGF-β1 signaling cascade, characterized SIV-infected MACs. In AGMs, we found increases of gata-3 but not t-bet, a longer lasting up-regulation of smad4 (days 1–21 p.i), a mediator enhancing TGF-β1 signaling, and no smad7 up-regulations. CONCLUSION: Our data suggest that the inability to resorb virus-driven inflammation and activation during the pathogenic HIV-1/SIVmac infections is associated with an unresponsiveness to TGF-β1