Temperature Entrainment of Drosophila's Circadian Clock Involves the Gene nocte and Signaling from Peripheral Sensory Tissues to the Brain

Circadian clocks are synchronized by the natural day/night and temperature cycles. Our previous work demonstrated that synchronization by temperature is a tissue autonomous process, similar to synchronization by light. We show here that this is indeed the case, with the important exception of the brain. Using luciferase imaging we demonstrate that brain clock neurons depend on signals from peripheral tissues in order to be synchronized by temperature. Reducing the function of the gene nocte in chordotonal organs changes their structure and function and dramatically interferes with temperature synchronization of behavioral activity. Other mutants known to affect the function of these sensory organs also interfere with temperature synchronization, demonstrating the importance of nocte in this process and identifying the chordotonal organs as relevant sensory structures. Our work reveals surprising and important mechanistic differences between light- and temperature-synchronization and advances our understanding of how clock resetting is accomplished in nature

Using of polypropylene fibers for cleaning of industrial waste water from the fat-soluble organic pollutants

The paper shows the perspective of using methods of ion implantation and microwave irradiation for modifying polypropylene fiber by iron (II), lanthanum (II) and iron metal ions. It was shown that this method is very useful in order to obtain a material with a high photocatalytic activity for extracting liposoluble dyes from non-aqueous media under UV and visible light

The association between experimental and clinical pain measures among persons with fibromyalgia and chronic fatigue syndrome

Evoked or experimental pain is often used as a model for the study of clinical pain, yet there are little data regarding the relationship between the two. In addition, there are few data regarding the types of stimuli and stimulus intensities that are most closely related to clinical pain. In this study, 36 subjects with fibromyalgia (FM), chronic fatigue syndrome (CFS), or both syndromes were administered measures of clinical pain and underwent a dolorimetry evaluation. Subjects also underwent experimental pain testing utilizing heat and pressure stimulation. Stimulation levels evoking low, moderate and high sensory intensity, and comparable levels of unpleasantness, were determined for both types of stimuli using random staircase methods. Clinical pain was assessed using visual analogue ratings and the short form of the McGill Pain Questionnaire (MPQ). Ratings of heat pain sensation were not significantly associated with clinical pain ratings, with the exception of unpleasantness ratings at high stimulus intensities. Pain threshold and tolerance as assessed by dolorimetry were significantly associated with average measures of clinical pain. Both intensity and unpleasantness ratings of pressure delivered using random staircase methods were significantly associated with clinical pain at low, moderate and high levels, and the strength of the association was greater at increasingly noxious stimulus intensities. These findings suggest that random pressure stimulation as an experimental pain model in these populations more closely reflects the clinical pain for these conditions. These findings merit consideration when designing experimental studies of clinical pain associated with FM and CFS.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90175/1/j.ejpain.2006.02.001.pd

Terminus-driven retreat of a major southwest Greenland tidewater glacier during the early 19th century : insights from glacier reconstructions and numerical modelling

Peer reviewedPublisher PD

Tree migration-rates : narrowing the gap between inferred post-glacial rates and projected rates

Faster-than-expected post-glacial migration rates of trees have puzzled ecologists for a long time. In Europe, post-glacial migration is assumed to have started from the three southern European peninsulas (southern refugia), where large areas remained free of permafrost and ice at the peak of the last glaciation. However, increasing palaeobotanical evidence for the presence of isolated tree populations in more northerly microrefugia has started to change this perception. Here we use the Northern Eurasian Plant Macrofossil Database and palaeoecological literature to show that post-glacial migration rates for trees may have been substantially lower (60–260 m yr–1) than those estimated by assuming migration from southern refugia only (115–550 m yr–1), and that early-successional trees migrated faster than mid- and late-successional trees. Post-glacial migration rates are in good agreement with those recently projected for the future with a population dynamical forest succession and dispersal model, mainly for early-successional trees and under optimal conditions. Although migration estimates presented here may be conservative because of our assumption of uniform dispersal, tree migration-rates clearly need reconsideration. We suggest that small outlier populations may be a key factor in understanding past migration rates and in predicting potential future range-shifts. The importance of outlier populations in the past may have an analogy in the future, as many tree species have been planted beyond their natural ranges, with a more beneficial microclimate than their regional surroundings. Therefore, climate-change-induced range-shifts in the future might well be influenced by such microrefugia

Levels of glucose, serum albumin and somatic cells before and during early stages of acute clinical mastitis artificially induced in cows by means of human strains of group-B streptococci (GBS) administered intracisternally

The investigation was performed on 3 cows, sampled repeatedly before and during the initial 48h of artificially induced, acute, clinical mastitis. The results of the investigation both augment and support those of earlier work on the levels and significant correlations of glucose, serum albumin and somatic cells in normal and abnormal secretions monitored before and after the usual milking of healthy lactating cows had been suspended. During acute mastitis, udder secretions from artificially infected quarters showed highly significant escalations of somatic cell counts which coincided with equally significant increases on a high and intermediate level of serum albumin values in both the infected and non-infected quarters. Corresponding glucose values fluctuated from 0,07-0,22 and 0,18-0,32 mM in the former and latter quarters respectively. The selective and elevated transfer of serum albumin in otherwise unaffected quarters of acutely mastitic udders suggests rather specific collateral vascular and epithelial changes of unknown nature and magnitude. The data indicate that marked fluctuations of glucose may occur within and between quarters of individual and different cows respectively. Such variations could significantly affect phagocytosis and killing of bacteria challenging the intramammary leucocytic udder barrier before and particularly during manifestation of mastitis. Hence, udder health, although dependent on specific natural defence mechanisms such as the leucocytes and related systems in milk, may depend even more significantly on the supplies of glucose to and within the bovine mammary gland.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Proton probing of laser-driven EM pulses travelling in helical coils

The ultrafast charge dynamics following the interaction of an ultra-intense laser pulse with a foil target leads to the launch of an ultra-short, intense electromagnetic (EM) pulse along a wire connected to the target. Due to the strong electric field (of the order of $\text{GV m}^{-1}$ ) associated to such laser-driven EM pulses, these can be exploited in a travelling-wave helical geometry for controlling and optimizing the parameters of laser accelerated proton beams. The propagation of the EM pulse along a helical path was studied by employing a proton probing technique. The pulse-carrying coil was probed along two orthogonal directions, transverse and parallel to the coil axis. The temporal profile of the pulse obtained from the transverse probing of the coil is in agreement with the previous measurements obtained in a planar geometry. The data obtained from the longitudinal probing of the coil shows a clear evidence of an energy dependent reduction of the proton beam divergence, which underpins the mechanism behind selective guiding of laser-driven ions by the helical coil targets.</jats:p

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Q fever: new insights, still many queries

Derivatives and Credit Contagion in Interconnected Networks

The importance of adequately modeling credit risk has once again been highlighted in the recent financial crisis. Defaults tend to cluster around times of economic stress due to poor macro-economic conditions, {\em but also} by directly triggering each other through contagion. Although credit default swaps have radically altered the dynamics of contagion for more than a decade, models quantifying their impact on systemic risk are still missing. Here, we examine contagion through credit default swaps in a stylized economic network of corporates and financial institutions. We analyse such a system using a stochastic setting, which allows us to exploit limit theorems to exactly solve the contagion dynamics for the entire system. Our analysis shows that, by creating additional contagion channels, CDS can actually lead to greater instability of the entire network in times of economic stress. This is particularly pronounced when CDS are used by banks to expand their loan books (arguing that CDS would offload the additional risks from their balance sheets). Thus, even with complete hedging through CDS, a significant loan book expansion can lead to considerably enhanced probabilities for the occurrence of very large losses and very high default rates in the system. Our approach adds a new dimension to research on credit contagion, and could feed into a rational underpinning of an improved regulatory framework for credit derivatives.Comment: 26 pages, 7 multi-part figure