611 research outputs found
Limited evidence for quantitative contribution of rare and endangered species to agricultural production
Biodiversity underpins ecosystem functions that provide benefits to people, yet the role of rare and endangered species (RES) in supporting ecosystem services is unclear. Thus, it remains controversial whether arguments for conservation that focus on ecosystem services align with the protection of RES. We designed a systematic review protocol to critically assess the evidence for quantitative contributions of RES to terrestrial agricultural production, which is a key driver of biodiversity change and, simultaneously, could suffer from the loss of ecosystem services provided by biodiversity. Our review search criteria required that studies: 1) provide information on RES, 2) focus on an ecosystem service relevant for agriculture; and 3) include a quantitative measure of agricultural production. Surprisingly, we found only four studies that fulfilled these criteria, which was insufficient to perform a meta-analysis of results. Thus, we highlight here the gap in quantitative research, discuss the implications of this knowledge gap for the conservation of RES, and suggest future research directions. We conclude that further quantitative research is urgently needed to better inform conservation and agricultural policies, including research that focuses specifically on RES, incorporates more ecosystem services, and covers a wider range of climatic and socioeconomic contexts
Molecular symmetry group analysis of the low-wavenumber torsions and vibration-torsions in the S1 state and ground state cation of p-xylene: an investigation using resonance-enhanced multiphoton ionization (REMPI) and zero-kinetic-energy (ZEKE) spectroscopy
For the first time, a molecular symmetry group (MSG) analysis has been undertaken in the investigation of the electronic spectroscopy of p-xylene (p-dimethylbenzene). Torsional and vibration-torsional (vibtor) levels in the S1 state and ground state of the cation of p-xylene (p-dimethylbenzene) are investigated using resonance-enhanced multiphoton ionization (REMPI) and zero-kinetic-energy (ZEKE) spectroscopy. In the present work, we concentrate on the 0–350 cm 1 region, where there are a number of torsional and vibtor bands and we discuss the assignment of this region. In an accompanying paper [Tuttle et al. J. Chem. Phys. XXX, xxxxxx (2016)], we examine the 350–600 cm 1 region where vibtor levels are observed as part of a Fermi resonance. The similarity of much of the observed spectral activity to that in the related substituted benzenes, toluene and para-fluorotoluene, is striking, despite the different symmetries. The discussion necessitates a consideration of the MSG of p-xylene, which has been designated G72, but we shall also designate [3,3]D2h and we include the symmetry operations, character table and direct product table for this. We also discuss the symmetries of the internal rotor (torsional) levels and the selection rules for the particular electronic transition of p-xylene investigated here
CCSD(T) Study of CD3-O-CD3 and CH3-O-CD3 Far-Infrared Spectra
From a vibrationally corrected 3D potential energy surface determined with highly correlated ab initio calculations (CCSD(T)), the lowest vibrational energies of two dimethyl-ether isotopologues, 12CH3–16O–12CD3 (DME-d3) and 12CD3–16O–12CD3 (DME-d6), are computed variationally. The levels that can be populated at very low temperatures correspond to the COC-bending and the two methyl torsional modes. Molecular symmetry groups are used for the classification of levels and torsional splittings. DME-d6 belongs to the G36 group, as the most abundant isotopologue 12CH3–16O–12CH3 (DME-h6), while DME-d3 is a G18 species. Previous assignments of experimental Raman and far-infrared spectra are discussed from an effective Hamiltonian obtained after refining the ab initio parameters. Because a good agreement between calculated and experimental transition frequencies is reached, new assignments are proposed for various combination bands corresponding to the two deuterated isotopologues and for the 020 → 030 transition of DME-d6. Vibrationally corrected potential energy barriers, structural parameters, and anharmonic spectroscopic parameters are provided. For the 3N – 9 neglected vibrational modes, harmonic and anharmonic fundamental frequencies are obtained using second-order perturbation theory by means of CCSD and MP2 force fields. Fermi resonances between the COC-bending and the torsional modes modify DME-d3 intensities and the band positions of the torsional overtones
RUNX/AML and C/EBP factors regulate CD11a integrin expression in myeloid cells through overlapping regulatory elements
The CD11a/CD18 (leukocyte functionassociated
antigen 1 [LFA-1]) integrin mediates
critical leukocyte adhesive interactions
during immune and inflammatory
responses. The CD11a promoter directs
CD11a/CD18 integrin expression, and its
activity in lymphoid cells depends on a
functional RUNX1/AML-1–binding site
(AML-110) within the MS7 sequence. We
now report that MS7 contains a C/EBPbinding
site (C/EBP-100), which overlaps
with AML-110 and is bound by C/EBP
factors in myeloid cells. C/EBP and RUNX/
AML factors compete for binding to their
respective cognate elements and bind to
the CD11a promoter MS7 sequence in a
cell lineage- and differentiation-dependent
manner. In myeloid cells MS7 is
primarily recognized by C/EBP factors in
proliferating cells whereas RUNX/AMLfactors
(especially RUNX3/AML-2) bind to
MS7 in differentiated cells. RUNX3/AML-2
binding to the CD11a promoter correlates
with increased RUNX3/AML-2 protein levels
and enhanced CD11a/CD18 cell surface
expression. The relevance of the
AML-110 element is underscored by the
ability of AML-1/ETO to inhibit CD11a promoter
activity, thus explaining the low
CD11a/CD18 expression in t(8;21)–containing
myeloid leukemia cells. Therefore,
the expression of the CD11a/CD18
integrin in myeloid cells is determined
through the differential occupancy of the
CD11a proximal promoter by transcription
factors implicated in the pathogenesis
of myeloid leukemia
Ultrathin Oxide Films by Atomic Layer Deposition on Graphene
In this paper, a method is presented to create and characterize mechanically
robust, free standing, ultrathin, oxide films with controlled, nanometer-scale
thickness using Atomic Layer Deposition (ALD) on graphene. Aluminum oxide films
were deposited onto suspended graphene membranes using ALD. Subsequent etching
of the graphene left pure aluminum oxide films only a few atoms in thickness. A
pressurized blister test was used to determine that these ultrathin films have
a Young's modulus of 154 \pm 13 GPa. This Young's modulus is comparable to much
thicker alumina ALD films. This behavior indicates that these ultrathin
two-dimensional films have excellent mechanical integrity. The films are also
impermeable to standard gases suggesting they are pinhole-free. These
continuous ultrathin films are expected to enable new applications in fields
such as thin film coatings, membranes and flexible electronics.Comment: Nano Letters (just accepted
Comparative study of complex N- and O-bearing molecules in hot molecular cores
We have observed several emission lines of two Nitrogen-bearing (C2H5CN and
C2H3CN) and two Oxygen-bearing (CH3OCH3 and HCOOCH3) molecules towards a sample
of well-known hot molecular cores (HMCs) in order to check whether the chemical
differentiation seen in the Orion-HMC and W3(H_2O) between O- and N-bearing
molecules is a general property of HMCs. With the IRAM-30m telescope we have
observed 12 HMCs in 21 bands, centered at frequencies from 86250 to 258280 MHz.
The rotational temperatures obtained range from ~100 to ~150 K in these HMCs.
Single Gaussian fits performed to unblended lines show a marginal difference in
the line peak velocities of the C2H5CN and CH3OCH3 lines, indicating a possible
spatial separation between the region traced by the two molecules. On the other
hand, neither the linewidths nor the rotational temperatures and column
densities confirm such a result. By comparing the abundance ratio of the pair
C2H5CN/C2H3CN with the predictions of theoretical models, we derive that the
age of our cores ranges between 3.7 and 5.9x10^{4} yrs. The abundances of
C2H5CN and C2H3CN are strongly correlated, as expected from theory which
predicts that C2H3CN is formed through gas phase reactions involving C2H5CN. A
correlation is also found between the abundances of C2H3CN and CH3OCH3, and
C2H5CN and CH3OCH3. In all tracers the fractional abundances increase with the
H_2 column density while they are not correlated with the gas temperature.Comment: Accepted for publication in A&A, 56 page
UBVRI Light Curves of 44 Type Ia Supernovae
We present UBVRI photometry of 44 type-Ia supernovae (SN Ia) observed from
1997 to 2001 as part of a continuing monitoring campaign at the Fred Lawrence
Whipple Observatory of the Harvard-Smithsonian Center for Astrophysics. The
data set comprises 2190 observations and is the largest homogeneously observed
and reduced sample of SN Ia to date, nearly doubling the number of
well-observed, nearby SN Ia with published multicolor CCD light curves. The
large sample of U-band photometry is a unique addition, with important
connections to SN Ia observed at high redshift. The decline rate of SN Ia
U-band light curves correlates well with the decline rate in other bands, as
does the U-B color at maximum light. However, the U-band peak magnitudes show
an increased dispersion relative to other bands even after accounting for
extinction and decline rate, amounting to an additional ~40% intrinsic scatter
compared to B-band.Comment: 84 authors, 71 pages, 51 tables, 10 figures. Accepted for publication
in the Astronomical Journal. Version with high-res figures and electronic
data at http://astron.berkeley.edu/~saurabh/cfa2snIa
The impact of thickness and thermal annealing on refractive index for aluminum oxide thin films deposited by atomic layer deposition
Abnormal blood flow in the sublingual microcirculation at high altitude
We report the first direct observations of deranged microcirculatory blood flow at high altitude, using sidestream dark-field imaging. Images of the sublingual microcirculation were obtained from a group of 12 volunteers during a climbing expedition to Cho Oyu (8,201 m) in the Himalayas. Microcirculatory flow index (MFI) was calculated from the moving images of microcirculatory red blood cell flow, and comparison was made between the baseline and high altitude measurements. Peripheral oxygen saturation (SpO2) and Lake Louise scores (LLS) were recorded along with MFI. Our data demonstrate that there was a significant reduction in MFI from baseline to 4,900 m in small (less than 25 μm) and medium (26–50 μm) sized blood vessels (P = 0.025 and P = 0.046, respectively). There was no significant correlation between MFI and SpO2 or MFI and LLS. Disruption of blood flow within microcirculatory may explain persistent abnormal oxygen flux to tissues following the normalisation of systemic oxygen delivery that accompanies acclimatisation to high altitude
Orthogonal polarisation spectral imaging as a new tool for the assessment of antivascular tumour treatment in vivo: a validation study
Tumour angiogenesis plays a key role in tumour growth, formation of metastasis, detection and treatment of malignant tumours. Recent investigations provided increasing evidence that quantitative analysis of tumour angiogenesis is an indispensable prerequisite for developing novel treatment strategies such as anti-angiogenic and antivascular treatment options. Therefore, it was our aim to establish and validate a new and versatile imaging technique, that is orthogonal polarisation spectral™ imaging, allowing for non-invasive quantitative imaging of tumour angiogenesis in vivo. Experiments were performed in amelanotic melanoma A-MEL 3 implanted in a transparent dorsal skinfold chamber of the hamster. Starting at day 0 after tumour cell implantation, animals were treated daily with the anti-angiogenic compound SU5416 (25 mg kg bw−1) or vehicle (control) only. Functional vessel density, diameter of microvessels and red blood cell velocity were visualised by both orthogonal polarisation spectral™ imaging and fluorescence microscopy and analysed using a digital image system. The morphological and functional properties of the tumour microvasculature could be clearly identified by orthogonal polarisation spectral™ imaging. Data for functional vessel density correlated excellently with data obtained by fluroescence microscopy (y=0.99x+0.48, r2=0.97, RS=0.98, precision: 8.22 cm−1 and bias: −0.32 cm−1). Correlation parameters for diameter of microvessels and red blood cell velocity were similar (r2=0.97, RS=0.99 and r2=0.93, RS=0.94 for diameter of microvessels and red blood cell velocity, respectively). Treatment with SU5416 reduced tumour angiogenesis. At day 3 and 6 after tumour cell implantation, respectively, functional vessel density was 4.8±2.1 and 87.2±10.2 cm−1 compared to values of control animals of 66.6±10.1 and 147.4±13.2 cm−1, respectively. In addition to the inhibition of tumour angiogenesis, tumour growth and the development of metastasis was strongly reduced in SU5416 treated animals. This new approach enables non-invasive, repeated and quantitative assessment of tumour vascular network and the effects of antiangiogenic treatment on tumour vasculature in vivo. Thus, quantification of tumour angiogenesis can be used to more accurately classify and monitor tumour biologic characteristics, and to explore aggressiveness of tumours
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