Coulomb-Volkov approach of ionization by extreme ultraviolet laser pulses in the subfemtosecond regime

In conditions where the interaction betweeen an atom and a short high-frequency extreme ultraviolet laser pulse is a perturbation, we show that a simple theoretical approach, based on Coulomb-Volkov-type states, can make reliable predictions for ionization. To avoid any additional approximation, we consider here a standard case : the ionization of hydrogen atoms initially in their ground state. For any field parameter, we show that the method provides accurate energy spectra of ejected electrons, including many above threshold ionization peaks, as long as the two following conditions are simultaneously fulfilled : (i) the photon energy is greater than or equal to the ionization potential ; (ii) the ionization process is not saturated. Thus, ionization of atoms or molecules by the high order harmonic laser pulses which are generated at present may be addressed through this Coulomb-Volkov treatment.Comment: 19 pages including 5 figures and figure caption

Financial stability and the New Basel Accord.

This study outlines how proposed changes to international capital adequacy standards – commonly referred to as “Basel II” – will reinforce financial stability. Basel II is designed to contribute to the prevention of individual bank failures by making minimum capital standards more flexible and aligning them more closely with actual risks and changes in the level of risk. By bringing regulatory capital closer to the concept of economic capital that banks use in their internal management, and by going to the core of banks’ financial information systems, the proposed changes will foster better control of risks. By reducing credit disruptions, the changes should help to limit the severity of macro-economic and sectoral downturns and thereby improve financial stability. Concerns have been expressed about the potential “procyclicality” of the new standards, and the possibility of sharp swings in regulatory capital requirements leading to dramatic shifts in the availability of credit. These concerns, while theoretically appealing, do not appear warranted in practice. The Basel Committee took steps early on to ensure that cyclical effects would be moderated, while still achieving the goal of making capital ratios more risk-sensitive, more closely related to the bank’s management of its “risk-return” tradeoff, and therefore more useful as an internal control tool. In contrast with Basel I, which is external to banks’ methods of management, Basel II incorporates an advanced IRB approach. It can therefore figure as a central element in banks’ strategic planning. The success of the proposed changes will depend on how they are applied by bank managers and on the vigilance of bank supervisors in overseeing their implementation. Numerous contacts and on-site examinations carried out to date are encouraging in this regard. A hoped-for reform in the rules on provisioning, consistent with the new capital standard – factoring in ex ante the impact of expected but unrealized credit losses over the credit cycle instead of concentrating them at the lowest point of the cycle – would contribute significantly to financial stability.

Synchronized flow and wide moving jams from balanced vehicular traffic

Recently we proposed an extension to the traffic model of Aw, Rascle and Greenberg. The extended traffic model can be written as a hyperbolic system of balance laws and numerically reproduces the reverse $\lambda$ shape of the fundamental diagram of traffic flow. In the current work we analyze the steady state solutions of the new model and their stability properties. In addition to the equilibrium flow curve the trivial steady state solutions form two additional branches in the flow-density diagram. We show that the characteristic structure excludes parts of these branches resulting in the reverse $\lambda$ shape of the flow-density relation. The upper branch is metastable against the formation of synchronized flow for intermediate densities and unstable for high densities, whereas the lower branch is unstable for intermediate densities and metastable for high densities. Moreover, the model can reproduce the typical speed of the downstream front of wide moving jams. It further reproduces a constant outflow from wide moving jams, which is far below the maximum free flow. Applying the model to simulate traffic flow at a bottleneck we observe a general pattern with wide moving jams traveling through the bottleneck.Comment: 10 pages, 12 figure

SUPPRESSOR T LYMPHOCYTES IN PREGNANCY

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Adult coloration of the Bearded Vulture (Gypaetus barbatus) in the Pyrenees: relation to sex, mating system and productivity.

Cosmetic coloration is not a common phenomenon among bird species. Adult Bearded Vultures Gypaetus barbatus typically show orange coloration in head, chest, belly and tarsus feathers that is the result of mud baths in ferruginous substrates. Several non-mutually exclusive visual signalling hypotheses can be proposed to explain this phenomenon. Coloration could be used to signal: (1) dominance towards conspecifics, with darker birds being dominant (status signalling hypothesis); (2) sex (gender signalling hypothesis) because females are usually more intensely coloured; (3) individual quality for mate choice (quality signalling hypothesis); or (4) different reproductive strategies between individuals (e.g. in polyandrous trios). Here we report results from systematic monitoring of breeding Bearded Vultures in the pre-laying period in the central and western Pyrenees (Spain and France) between 2016 and 2020, including 162 individuals from 70 reproductive units (48 pairs and 22 trios). We classified individuals as being white, pale, medium or dark, and analysed the relationship with sex, mating system (pair or trios) and average productivity across years. Our results showed that the most common form was medium (67%), then pale (22%), dark (9%) and white (2%) morphs. Overall, females were darker than males, but with a large overlap in coloration. In trios, dominant males were darker than subordinate males, although differences were not statistically significant. The mating system (pair or trio) did not influence female coloration. A multimodel comparison showed that the number of years of territory occupation, mating system and their combination (but not coloration) were the best predictors of average productivity. Our results do not support the gender signalling hypothesis. The reproductive strategy signalling hypothesis might be supported because beta males were, on average, paler than males in pairs, but this topic requires further investigations because our results were inconclusive. Finally, that females (thought to be dominant because of their slightly larger size) were on average darker than males agrees with the status signalling hypothesis, although an experimental approach would be needed to formally test this hypothesis

Increase of Escherichia coli inoculum doses induces faster innate immune response in primiparous cows

The objective of the current study was to evaluate the dynamics of infection and the immunological response to varying numbers of Escherichia coli injected into the mammary glands of primiparous cows during the periparturient period. Primiparous cows have been shown to be more resistant to intramammary E. coli challenge, and an increase of the inoculum dose by 2 log(10) units induced a more rapid clinical response and clearance of the organisms. Recognition of lipopolysaccharide (LPS) is a key event in the innate immunity response to gram-negative infection and is mediated by the accessory molecules CD14 and LPS-binding protein (LBP). Primiparous cows were inoculated with 1 x 10(4) (Group A; n = 8) or 1 x 10(6) (Group B; n = 8) cfu E. coli P4:O32 in their 2 left quarters during the periparturient period. Clinical examination and analysis of blood and milk parameters, including IL-8, complement fragment 5a (C5a), LBP, and soluble CD14 (sCD14), were performed from d -4 to d +3 relative to infection. Primiparous cows in Group B initiated a more rapid clinical response following intramammary infection (IMI), resulting in typical clinical signs and changes in blood and milk parameters approximately 3 h earlier compared with primiparous cows in Group A. Based on average milk production in the noninfected quarters on d +2 postinoculation, all heifers reacted as moderate responders. Distinct differences in the kinetic patterns of rectal temperature, somatic cell count (SCC), IL-8, C5a, LBP, and sCD14 were observed between both groups during the early phase of inflammation. Both C5a and IL-8 increased before cellular influx into the infected glands, followed by increases in sCD14 and LBP. In conclusion, primiparous cows are able to clear an intramammary E. coli infection efficiently. Moreover, increasing the inoculum dose induces a more rapid inflammatory reaction, mainly because of early activation of the innate host immune response

Proteinuria in apparently healthy elderly dogs : persistency and comparison between free catch and cystocentesis urine

Background: Up to 25% of elderly humans have proteinuria, often associated with underlying lesions. Data concerning the presence of proteinuria in elderly dogs is scarce. Objectives: To describe the presence and persistence of proteinuria and to compare urinary protein:creatinine ratio (UPC) between free catch and cystocentesis urine samples in apparently healthy elderly dogs. Animals: Hundred apparently healthy elderly dogs. Methods: Prospective study. Owners of 100 elderly dogs were asked to collect 2 free catch urine samples. Dogs were considered healthy based on owner's perception and an age chart, based on ideal bodyweight, was used to define dogs as senior or geriatric. UPC of urine collected by free catch and cystocentesis were compared. Overt proteinuria and borderline proteinuria were defined as UPC >0.5 and between 0.2 and 0.5, respectively, if examination of sediment did not explain proteinuria. Proteinuria was considered persistent if present at both sampling times. Results: At baseline, 71 owners succeeded in collecting urine. Eleven percent of dogs had overt proteinuria, 14% were borderline proteinuric, and 75% nonproteinuric. Thirty-seven repeated urine samples, with a median time interval of 31days (range 10-90), were available. Nineteen percent of dogs had a persistently increased UPC (>0.2), with persistent overt proteinuria present in 8%. A strong correlation (=0.88) was found between UPC of urine collected by free catch and cystocentesis. Conclusions and Clinical Importance: As 19% of study dogs had persistent proteinuria, our findings emphasize that measurement of proteinuria should be part of geriatric health screening. For UPC in dogs, free catch urine provides a good alternative to cystocentesis

End-functional styrene-maleic anhydride copolymers via catalytic chain transfer polymerization

Styrene-maleic anhydride copolymers have been successfully synthesized using catalytic chain transfer polymerization employing the low spin [bis(difluoroboryl)dimethylglyoximato]cobalt(II) (COBF) complex. By partially replacing styrene with α-methylstyr