The cytochrome chain of mitochondria exhibits variable H+/e− stoichiometry

AbstractA study is presented of the ←H+/e− stoichiometry for H+ pumping by the cytochrome chain in isolated rat liver mitochondria under level-flow and steady-state conditions. It is shown that the ←H+/e− stoichiometry for the cytochrome chain varies under the influence of the flow rate and transmembrane ΔμH+. The rate-dependence is shown to be associated with cytochrome c oxidase, whose ←H+/e− ratio varies from 0 to 1, whilst the ←H+/c− ratio for the span covered by cytochrome c reductase is invariably 2

INTEGRAL high energy behaviour of 4U 1812-12

The low mass X-ray binary system 4U 1812-12 was monitored with the INTEGRAL observatory in the period 2003-2004 and with BeppoSAX on April 20, 2000. We report here on the spectral and temporal analysis of both persistent and burst emission. The full data set confirms the persistent nature of this burster, and reveals the presence of emission up to 200 keV. The persistent spectrum is well described by a comptonization (CompTT) model plus a soft blackbody component. The source was observed in a hard spectral state with a 1-200 keV luminosity of 2*10^(36) ergs/s and L/LEdd~1% and no meaningful flux variation has been revealed, as also confirmed by a 2004 RXTE observation. We have also detected 4 bursts showing double peaked profiles and blackbody spectra with temperatures ranging from 1.9 to 3.1 keV.Comment: 6 pages, 4 figures. Accepted for publication by A&

The failed state transition of the ATOLL source GRS 1724-308

The 2004-2012 X-ray time history of the NS LMXB GRS 1724-308 shows, along with the episodic brightenings associated to the low-high state transitions typical of the ATOLL sources, a peculiar, long lasting (about 300 d) flaring event, observed in 2008. This rare episode, characterised by a high-flux hard state, has never been observed before for GRS 1724-308 , and in any case is not common among ATOLL sources. We discuss here different hypotheses on the origin of this peculiar event that displayed the spectral signatures of a failed transition, similar in shape and duration to those rarely observed in Black Hole binaries. We also suggest the possibility that the atypical flare occurred in coincidence with a new rising phase of the 12-years super-orbital modulation that has been previously reported by other authors. The analysed data also confirm for GRS 1724-308 the already reported orbital period of about 90 d.Comment: accepted for publication in MNRA

The first outburst of the black hole candidate MAXI J1836-194 observed by INTEGRAL, Swift, and RXTE

MAXI J1836-194 is a transient black-hole candidate discovered in outburst by MAXI on 30 August 2011. We report on the available INTEGRAL, Swift, and RXTE observations performed in the direction of the source during this event before 55 864 MJD. Combining the broad band (0.6-200 keV) spectral and timing information obtained from these data with the results of radio observations, we show that the event displayed by MAXI J1836-194 is another example of "failed" outburst. During the first ~20 days after the onset of the event, the source underwent a transition from the canonical low/hard to the hard intermediate state, while reaching the highest X-ray flux. In the ~40 days following the peak of the outburst, the source displayed a progressive spectral hardening and a decrease of the X-ray flux, thus it entered again the low/hard state and began its return to quiescence.Comment: Accepted for A&A Letters on 22 Dec. 201

The two INTEGRAL X-ray transients IGR J17091--3624 and IGR J17098--3628: a multi-wavelength long term campaign

IGR J17091-3624 and IGR J17098-3628 are two X-ray transients discovered by INTEGRAL and classified as possible black hole candidates (BHCs). We present here the results obtained from the analysis of multi-wavelength data sets collected by different instruments from 2005 until the end of 2007 on both sources. IGR J17098-3628 has been regularly detected by INTEGRAL and RXTE over the entire period of the observational campaign; it was also observed with pointed observations by XMM and Swift/XRT in 2005 and 2006 and exhibited flux variations not linked with the change of any particular spectral features. IGR J17091-3624 was initially in quiescence (after a period of activity between 2003 April and 2004 April) and it was then detected again in outburst in the XRT field of view during a Swift observation of IGR J17098--3628 on 2007 July 9. The observations during quiescence provide an upper limit to the 0.2-10 keV luminosity, while the observations in outburst cover the transition from the hard to the soft state. Moreover, we obtain a refined X-ray position for IGR J17091-3624 from the Swift/XRT observations during the outburst in 2007. The new position is inconsistent with the previously proposed radio counterpart. We identify in VLA archive data a compact radio source consistent with the new X-ray position and propose it as the radio counterpart of the X-ray transient.Comment: Accepted for publication in Ap

Precision Farming: Barriers of Variable Rate Technology Adoption in Italy

Research dealing with the adoption of various precision agriculture technologies has shown that guidance and recording tools are more widespread than reactive ones (such as variable rate technology), with much lower utilization rates in European case studies. This study aims to analyze the propensity to innovate variable rate technologies among young Italian farmers. A cluster analysis was carried out revealing four groups. The first two groups represent non-adopters who think technological innovation is very complex from a technical point of view, as well as not very accessible as capital-intensive technology. The third and fourth groups represent adopters. The third reports an early level of adoption, still considering the cost of access a major barrier to technology implementation. The fourth, on the other hand, shows a more intensive level and considers the lack of institutional support a major limitation. The cluster with the most intensive adoption is characterized by the youngest age group, the farms with the largest size, and a prevalence of female entrepreneurs. The need for management training in day-to-day business operations upon adoption is detected for all groups. This paper identified relevant drivers and barriers in characterizing the adopting farm of variable rate technologies. Results may offer insights to the policy maker to better calibrate support interventions

Ultrafast force-clamp spectroscopy of single molecules reveals load dependence of myosin working stroke

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Variations in some of the body fluid hormone levels currently used for endocrine monitoring during the third trimester of pregnancy

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