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Hand pollination to increase seed-set of red helleborine Cephalanthera rubra in the Chiltern Hills, Buckinghamshire, England
In 2007 and in previous years, as part of ongoing attempts to improve red helleborine Cephalanthera rubra seed-set, hand pollination of florets has been undertaken at a small colony of this species in Buckinghamshire, southern England. Natural pollination rarely occurs (one mature pod recorded in 10 years) at this site. In 2007, hand pollination resulted in the production of four seed pods, of which one withered and died. Upon ripening, the three remaining pods were removed for attempted micropropagation of the seeds. Ongoing conservation management has probably benefited the solitary bee Chelostoma campanularum which now appears fairly plentiful at the site, but despite the presence of this red helleborine flower visitor, natural pollination remains virtually unrecorded at this locality; field observations suggest that C.campanularum is in fact probably not large enough to act as an effective red helleborine pollinator as it can slip in and out of the flowers without removing the pollinia, unlike it larger relative C.fuliginosum, absent from the UK but which is a known pollinator of red helleborine in continental Europe
An infrared study of the bi-polar outflow region GGD 12-15
Infrared observations from 1 to 100 microns are presented for the region associated with a bipolar CO outflow source near the nebulous objects GGD 12 to 15. A luminous far-infrared source was found associated with a radio-continuum source in the area. This object appears to be a compact HII region around a nearly main-sequence BO star. A faint 20 micron source was also discovered at the position of an H2O maser 3O deg northwest of the HII region. This object appears to be associated with but not coincident with a 2 micron reflection nebula. This structure serves as evidence for a non-spherically symmetric, possibly disk-like dust distribution around the exciting star for the maser. This object probably powers the bi-polar CO outflow although its luminosity is less than 10% that of the star which excites the compact HII region. A number of other 2 micron sources found in the area are probably members of a recently formed cluster
Far-infrared photometry of compact extragalactic sources: OJ 187 and BL Lac
The 50 and 100 micron emissions of OJ 287 were detected and upper limits for BL Lac were obtained. These first measurements of two BL Lac objects in the far-infrared show them to be similar to the few quasars previously observed in the far-infrared. In particular, there is no evidence for significant dust emission, and the lambda approximately 100 micron flux density fits on a smooth line joining the near-infrared and millimeter continuum fluxes. The implications of the results for models of the sources are discussed briefly
Development of primary invasive pneumococcal disease caused by serotype 1 pneumococci is driven by early increased type I interferon response in the lung
The pneumococcus is the world's foremost respiratory pathogen, but the mechanisms allowing this pathogen to proceed from initial asymptomatic colonization to invasive disease are poorly understood. We have examined the early stages of invasive pneumococcal disease (IPD) by comparing host transcriptional responses to an invasive strain and a noninvasive strain of serotype 1 Streptococcus pneumoniae in the mouse lung. While the two strains were present in equal numbers in the lung 6 h after intranasal challenge, only the invasive strain (strain 1861) had invaded the pleural cavity at that time point; this correlated with subsequent development of bacteremia in mice challenged with strain 1861 but not the noninvasive strain (strain 1). Progression beyond the lung was associated with stronger induction of the type I interferon (IFN-I) response in the lung at 6 h. Suppression of the IFN-I response through administration of neutralizing antibody to IFNAR1 (the receptor for type I interferons) led to significantly reduced invasion of the pleural cavity by strain 1861 at 6 h postchallenge. Our data suggest that strong induction of the IFN-I response is a key factor in early progression of invasive serotype 1 strain 1861 beyond the lung during development of IPD
The Influence of Bureau Scores, Customized Scores and Judgmental Review on the Bank Underwriting Decision-Making Process
In recent years commercial banks have moved toward automated forms of underwriting. This study employs unique bank loan-level data from a scoring lender to determine whether automated underwriting exhibits a potential ‘‘disparate impact’’ across income strata. The findings indicate that strict application of this custom scoring model leads to higher denial rates for low- to moderate-income borrowers when compared with both a naý¨ve judgmental system and a bureau scoring approach. These results suggest that financial regulators should focus more resources on the evaluation and study of customized scoring models.
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Extent and mechanism of sealing in transected giant axons of squid and earthworms
Transected axons are often assumed to seal at their cut
ends by the formation of continuous membrane barriers that
allow for the restoration of function in the axonal stumps.
We have used several electrophysiological measures (membrane
potential, input resistance, injury current density) and
several morphological measures (phase-contrast, video-enhanced
differential interference contrast, light, and electron
microscopies) of living and fixed material to assess the extent
and mechanism of sealing within hours after transecting
giant axons of squid (Loligo pealeiand Sepioteuthis lessoniana)
and earthworms (Lumbricus terrestris). Our electrophysiological
data suggest that the proximal and distal ends
of transected squid giant axons do not completely seal within
2.5 hr in physiological saline. In contrast, the same set of
measures suggest that proximal and distal ends of transected
earthworm giant axons seal within 1 hr in physiological
saline. Our morphological data show that the cut ends
of both squid and earthworm axons constrict, but that a 20-
70-am-diameter opening always remains at the cut end that
is filled with vesicles. Axonal transection induces the formation
of vesicles that are observed in the axoplasm within
minutes in standard salines and that rapidly migrate to the
cut ends. These injury-induced vesicles are loosely packed
near the cut ends of squid giant axons, which do not functionally
seal within 2.5 hr of transection. In contrast, vesicles
formed a tightly packed plug at the cut ends of earthworm
medial giant axons, which do functionally seal within 1 hr of
transection in physiological saline. Since we detect no single
continuous membrane that spans the cut end, sealing does
not appear to occur by the fusion of constricted axolemmal
membrane or the formation of a membranous partition at the
cut end. Rather, our data are consistent with the hypothesis
that a tightly packed vesicular plug is responsible for sealing
of earthworm giant axons.This work was supported in part by NIH Grant NS31256 and ONR Grant N00014-90-J-1137 to H.M.F., an NIAAA fellowship to T.L.K., and an ATP grant to G.D.B.Neuroscienc
Characterization of 1.55-μm pulses from a self-seeded gain-switched Fabry-Pérot laser diode using frequency-resolved optical gating
The intensity and frequency chirp of picosecond pulses from a self-seeded gain-switched Fabry-Perot laser diode have been directly measured using the technique of frequency-resolved optical gating. Measurements over an output sidemode suppression ratio (SMSR) range of 15-35 dB show that higher SMSR's are associated with an increasingly linear frequency chirp across the output pulses. This complete pulse characterization allows the conditions for optimum pulse compression to be determined accurately, and indicates that transform-limited, pedestal free pulses can be obtained at an SMSR of 35 dB
Image restoration and superresolution as probes of small scale far-IR structure in star forming regions
Far-infrared continuum studies from the Kuiper Airborne Observatory are described that are designed to fully exploit the small-scale spatial information that this facility can provide. This work gives the clearest picture to data on the structure of galactic and extragalactic star forming regions in the far infrared. Work is presently being done with slit scans taken simultaneously at 50 and 100 microns, yielding one-dimensional data. Scans of sources in different directions have been used to get certain information on two dimensional structure. Planned work with linear arrays will allow us to generalize our techniques to two dimensional image restoration. For faint sources, spatial information at the diffraction limit of the telescope is obtained, while for brighter sources, nonlinear deconvolution techniques have allowed us to improve over the diffraction limit by as much as a factor of four. Information on the details of the color temperature distribution is derived as well. This is made possible by the accuracy with which the instrumental point-source profile (PSP) is determined at both wavelengths. While these two PSPs are different, data at different wavelengths can be compared by proper spatial filtering. Considerable effort has been devoted to implementing deconvolution algorithms. Nonlinear deconvolution methods offer the potential of superresolution -- that is, inference of power at spatial frequencies that exceed D lambda. This potential is made possible by the implicit assumption by the algorithm of positivity of the deconvolved data, a universally justifiable constraint for photon processes. We have tested two nonlinear deconvolution algorithms on our data; the Richardson-Lucy (R-L) method and the Maximum Entropy Method (MEM). The limits of image deconvolution techniques for achieving spatial resolution are addressed
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