One-Up On L1: Can X-rays Provide Longer Advanced Warning of Solar Wind Flux Enhancements Than Upstream Monitors?

Observations of strong solar wind proton flux correlations with ROSAT X-ray rates along with high spectral resolution Chandra observations of X-rays from the dark Moon show that soft X-ray emission mirrors the behavior of the solar wind. In this paper, based on an analysis of an X-ray event observed by XMM-Newton resulting from charge exchange of high charge state solar wind ions and contemporaneous neutral solar wind data, we argue that X-ray observations may be able to provide reliable advance warning, perhaps by as much as half a day, of dramatic increases in solar wind flux at Earth. Like neutral atom imaging, this provides the capability to monitor the solar wind remotely rather than in-situ.Comment: in press in Adv. Space Research, 7 pages, 6 eps figures, resolution reduced for Astro-ph submission, see http://lena.gsfc.nasa.gov for full versio

Importance of Estrus Expression Before Fixed-time AIon Conception Rates in Beef Cattle

Expression of estrus prior to fixed-time AI has been reported to strongly impact overall pregnancy success. Behavioral estrus is a visual indicator that a cow or heifer’s internal environment is prepared for breeding. Insemination of a cow or heifer after estrus has been expressed will yield greater pregnancy success due to adequate uterine environment, increased fertilization rates, increased accessory sperm numbers, and increased overall embryo survival. It can be difficult to analyze the effects of estrus on pregnancy success across studies due to differences in number of animals and proportion of animals exhibiting estrus per study. In order to accurately analyze such data, a meta-analysis was used to place all studies on an equal level, thus, eliminating study bias. In the present study, a meta-analysis was conducted using data available on 10,116 beef cows and heifers in 26 studies that utilized the 5 most common fixed-time AI protocols to examine the effect of expression of estrus prior to insemination on conception rates. The overall model indicated a positive effect of estrus on conception rates with cows expressing estrus before fixed-time AI having greater conception rates compared with those not exhibiting estrus. There are also numerous management factors that can influence expression of estrus. Data were available on 547 cows that were synchronized with a CIDR based fixed-time AI protocol for estrus for 2 to 4 years. Analysis of these cows indicated that days postpartum did not impact estrus expression. In contrast, Body Condition Score (BCS) influenced estrus expression with cows in a BCS of ≤ 4 having decreased expression of estrus compared to those with a BCS \u3e 4. Initiation of estrous cycles before the breeding season also influenced estrus expression, with anestrous cows having greater expression of estrus compared with estrus-cycling cows. Fixed-time AI protocols offer producers the added benefit of reduced labor needed for heat detection, but the results of this study indicate the importance of detecting an animal in estrus prior to breeding. In conclusion, among all currently recommended fixed-time AI protocols, cows expressing estrus before fixed-time AI had improved conception rates, and BCS and estrus-cycling status had the greatest influence on expression of estrus

Low computational complexity mode division multiplexed OFDM transmission over 130 km of few mode fiber

We demonstrate 337.5-Gb/s MDM-8QAM-OFDM transmission over 130 km of FMF. This confirms that OFDM can significantly reduce the required DSP complexity to compensate for differential mode delay, a key step towards real-time MDM transmission

Herbivores, but not other insects, are scarce on alien plants

Understanding how the landscape-scale replacement of indigenous plants with alien plants influences ecosystem structure and functioning is critical in a world characterized by increasing biotic homogenization. An important step in this process is to assess the impact on invertebrate communities. Here we analyse insect species richness and abundance in sweep collections from indigenous and alien (Australasian) woody plant species in South Africa’s Western Cape. We use phylogenetically relevant comparisons and compare one indigenous with three Australasian alien trees within each of Fabaceae: Mimosoideae, Myrtaceae, and Proteaceae: Grevilleoideae. Although some of the alien species analysed had remarkably high abundances of herbivores, even when intentionally introduced biological control agents are discounted, overall, herbivorous insect assemblages from alien plants were slightly less abundant and less diverse compared with those from indigenous plants – in accordance with predictions from the enemy release hypothesis. However, there were no clear differences in other insect feeding guilds.We conclude that insect assemblages from alien plants are generally quite diverse, and significant differences between these and assemblages from indigenous plants are only evident for herbivorous insects.Centre of Excellence for Invasion Biolog

Landscape corridors: Possible dangers?

Ctr Invas Bio

Origin of Life

The evolution of life has been a big enigma despite rapid advancements in the fields of biochemistry, astrobiology, and astrophysics in recent years. The answer to this puzzle has been as mind-boggling as the riddle relating to evolution of Universe itself. Despite the fact that panspermia has gained considerable support as a viable explanation for origin of life on the Earth and elsewhere in the Universe, the issue remains far from a tangible solution. This paper examines the various prevailing hypotheses regarding origin of life like abiogenesis, RNA World, Iron-sulphur World, and panspermia; and concludes that delivery of life-bearing organic molecules by the comets in the early epoch of the Earth alone possibly was not responsible for kick-starting the process of evolution of life on our planet.Comment: 32 pages, 8 figures,invited review article, minor additio

Age‐related changes in the biophysical and morphological characteristics of mouse cochlear outer hair cells

Outer hair cells (OHCs) are electromotile sensory receptors that provide sound amplification within the mammalian cochlea. Although OHCs appear susceptible to ageing, the progression of the pathophysiological changes in these cells is still poorly understood. By using mouse strains with a different progression of hearing loss (C57BL/6J, C57BL/6NTac, C57BL/6NTacCdh23+ , C3H/HeJ), we have identified morphological, physiological and molecular changes in ageing OHCs (9–12 kHz cochlear region). We show that by 6 months of age, OHCs from all strains underwent a reduction in surface area, which was not a sign of degeneration. Although the ageing OHCs retained a normal basolateral membrane protein profile, they showed a reduction in the size of the K+ current and non‐linear capacitance, a readout of prestin‐dependent electromotility. Despite these changes, OHCs have a normal V m and retain the ability to amplify sound, as distortion product otoacoustic emission thresholds were not affected in aged, good‐hearing mice (C3H/HeJ, C57BL/6NTacCdh23+ ). The loss of afferent synapses was present in all strains at 15 months. The number of efferent synapses per OHCs, defined as postsynaptic SK2 puncta, was reduced in aged OHCs of all strains apart from C3H mice. Several of the identified changes occurred in aged OHCs from all mouse strains, thus representing a general trait in the pathophysiological progression of age‐related hearing loss, possibly aimed at preserving functionality. We have also shown that the mechanoelectrical transduction (MET) current from OHCs of mice harbouring the Cdh23ahl allele is reduced with age, highlighting the possibility that changes in the MET apparatus could play a role in cochlear ageing

Reconstructing the 3-D Trajectories of CMEs in the Inner Heliosphere

A method for the full three-dimensional (3-D) reconstruction of the trajectories of coronal mass ejections (CMEs) using Solar TErrestrial RElations Observatory (STEREO) data is presented. Four CMEs that were simultaneously observed by the inner and outer coronagraphs (COR1 and 2) of the Ahead and Behind STEREO satellites were analysed. These observations were used to derive CME trajectories in 3-D out to ~15Rsun. The reconstructions using COR1/2 data support a radial propagation model. Assuming pseudo-radial propagation at large distances from the Sun (15-240Rsun), the CME positions were extrapolated into the Heliospheric Imager (HI) field-of-view. We estimated the CME velocities in the different fields-of-view. It was found that CMEs slower than the solar wind were accelerated, while CMEs faster than the solar wind were decelerated, with both tending to the solar wind velocity.Comment: 17 pages, 10 figures, 1 appendi

Training teachers for the multimedia age: developing teacher expertise to enhance online learner interaction and collaboration

This article considers the skills that enable teachers to foster interaction and collaboration in online language learning. Drawing on Hampel and Stickler’s (2005) skills pyramid for online language learning and teaching, it presents the pre-service and in-service training programme that associate lecturers in the Department of Languages at the Open University undergo in the context of teaching languages with the help of online communication tools. Two projects are presented that shed more light on the expertise required to teach languages in virtual learning environments. The first project highlights the skills that are needed to teach in a complex online environment; the second one, a teacher training study, aimed to examine distance teachers’ experience of facilitating online group work, identify development needs, try out the potential of specific asynchronous and synchronous tools to support collaborative learning and trial possible development activities. The paper concludes by describing the kind of training programme that tutors require in order to acquire the skills identified

MET currents and otoacoustic emissions from mice with a detached tectorial membrane indicate the extracellular matrix regulates Ca2+ near stereocilia

The tectorial membrane (TM) is an acellular structure of the cochlea that is attached to the stereociliary bundles of the outer hair cells (OHCs), electromotile cells that amplify motion of the cochlear partition and sharpen its frequency selectivity. Although the TM is essential for hearing, its role is still not fully understood. In Tecta/Tectb−/− double knockout mice, in which the TM is not coupled to the OHC stereocilia, hearing sensitivity is considerably reduced compared with that of wild‐type animals. In vivo, the OHC receptor potentials, assessed using cochlear microphonics, are symmetrical in both wild‐type and Tecta/Tectb−/− mice, indicating that the TM does not bias the hair bundle resting position. The functional maturation of hair cells is also unaffected in Tecta/Tectb−/− mice, and the resting open probability of the mechanoelectrical transducer (MET) channel reaches values of ∼50% when the hair bundles of mature OHCs are bathed in an endolymphatic‐like Ca2+ concentration (40 μM) in vitro. The resultant large MET current depolarizes OHCs to near –40 mV, a value that would allow optimal activation of the motor protein prestin and normal cochlear amplification. Although the set point of the OHC receptor potential transfer function in vivo may therefore be determined primarily by endolymphatic Ca2+ concentration, repetitive acoustic stimulation fails to produce adaptation of MET‐dependent otoacoustic emissions in vivo in the Tecta/Tectb−/− mice. Therefore, the TM is likely to contribute to the regulation of Ca2+ levels around the stereocilia, and thus adaptation of the OHC MET channel during prolonged sound stimulation