Vibrational Dynamics in crystalline 4-(dimethylamino) benzaldehyde: Inelastic Neutron Scattering and Periodic DFT Study

The structure and dynamics of crystalline 4-(dimethylamino) benzaldehyde, 4DMAB, are assessed through INS spectroscopy combined with periodic DFT calculations. The excellent agreement between experimental and calculated spectra is the basis for a reliable assignment of INS bands. The external phonon modes of crystalline 4DMAB are quite well described by the simulated spectrum, as well as the modes involving low-frequency molecular vibrations. Crystal field splitting is predicted and observed for the modes assigned to the dimethylamino group. Concerning the torsional motion of methyl groups, four individual bands are identified and assigned to specific methyl groups in the asymmetric unit. The torsional frequencies of the four methyl groups in the asymmetric unit fall in a region of ca. 190 ± 20 cm−1, close to the range of values observed for methyl groups bonding to unsaturated carbon atoms. The hybridization state of the X atom in X-CH3 seems to play a key role in determining the methyl torsional frequency.

Serpentine crack-seal veins: a unique record of fluid conditions during faulting

<p>Serpentine veins are ubiquitous in hydrated and deformed ultramafic rocks, and have previously been used to track fault kinematics and understand the evolution of environmental conditions during vein formation. However, difficulties in unambiguously identifying and mapping serpentine types at sub-micron to mm scales has limited our understanding of vein precipitation kinetics and growth histories. Using recently developed techniques of Raman spectroscopy mapping, combined with scanning- and transmission-electron microscopy, we describe a new type of mineralogically banded serpentine crack-seal vein in six samples from different settings around the world. In all of the studied samples, individual bands comprise a thin layer (~0.4–2 µm) dominated by chrysotile and a much thicker layer (~0.5–30 µm) dominated by polygonal serpentine/lizardite. Existing field and experimental data suggest that disequilibrium conditions immediately following crack opening may favour rapid precipitation of chrysotile along one of the crack margins. Subsequently, diffusional transport of elements favours slower precipitation of polygonal serpentine/lizardite which leads to crack sealing. The similarities in layer thicknesses and mineralogy exhibited by samples collected from extension and shear veins, dilational jogs, foliation surfaces, and the margins of phacoids, suggest that a common set of processes involving crack opening and sealing are active in a range of different structural sites within serpentinite-dominated shear zones, potentially associated with frequent and repetitive stress drops such as those recorded during episodic tremor and slow slip.</p>

SPECIES DISTRIBUTION MODELING IN FOREST PLANNING OF ANNUAL PRODUCTION UNITS IN THE SOUTHWEST AMAZONIA

ABSTRACT The generally limited resources for forest management and the growing need of forest production regulation requires the optimization of planning approaches for the spatialization of annual production units (APU). An APU planning methodology for forest species of high wood value (Amburana acreana (Ducke) ACSm., Apuleia leiocarpa (Vogel) JF Macbr. and Castilla ulei Warb.) in management area was proposed, using prediction of potential distribution of these species with data from the occurrence of a census forest inventory. It was used sample inventory data simulated in three sampling systems (random, conglomerate systematic, and systematic) and sample intensities (0.5% and 0.8%). As predictive variables, it was used the altitude, vertical distance to the nearest drain, individual bands of the TM sensor on board the Landsat 5, and vegetation index by normalized difference. Eighteen models were obtained, six per species. The test area under the curve (AUC) of the models ranged from 0.517 to 0.804. For all species, the best predictive model was considered the conglomerate system with a sample intensity of 0.8%. Altitude was the predictor variable that most contributed to the models. The AUC values for the Amburana acreana models were significantly different from Apuleia leiocarpa and Castilla ulei (p = 0.0138). For species of lower density, it is recommended greater sampling intensity and sampling systems that provide better spatialization of occurrence records. The use of data from sampling forest inventories in different sampling systems is capable of predicting environmental suitability for forest species and helps to define APUs. Thus, it is possible to strenghten the exploration strategies and management planning of management areas and to contribute to the perpetuation of the activity in the unequal forests of the Amazon region.

Morphological Band Registration of Multispectral Cameras for Water Quality Analysis with Unmanned Aerial Vehicle

Multispectral imagery contains abundant spectral information on terrestrial and oceanic targets, and retrieval of the geophysical variables of the targets is possible when the radiometric integrity of the data is secured. Multispectral cameras typically require the registration of individual band images because their lens locations for individual bands are often displaced from each other, thereby generating images of different viewing angles. Although this type of displacement can be corrected through a geometric transformation of the image coordinates, a mismatch or misregistration between the bands still remains, owing to the image acquisition timing that differs by bands. Even a short time difference is critical for the image quality of fast-moving targets, such as water surfaces, and this type of deformation cannot be compensated for with a geometric transformation between the bands. This study proposes a novel morphological band registration technique, based on the quantile matching method, for which the correspondence between the pixels of different bands is not sought by their geometric relationship, but by the radiometric distribution constructed in the vicinity of the pixel. In this study, a Micasense Rededge-M camera was operated on an unmanned aerial vehicle and multispectral images of coastal areas were acquired at various altitudes to examine the performance of the proposed method for different spatial scales. To assess the impact of the correction on a geophysical variable, the performance of the proposed method was evaluated for the chlorophyll-a concentration estimation. The results showed that the proposed method successfully removed the noisy spatial pattern caused by misregistration while maintaining the original spatial resolution for both homogeneous scenes and an episodic scene with a red tide outbreak.

MADX – a simple technique for source detection and measurement using multiband imaging from the Herschel–ATLAS survey

ABSTRACT We describe the method used to detect sources for the Herschel–ATLAS (Herschel Astrophysical Terahertz Large Area Survey) survey. The method is to filter the individual bands using a matched filter, based on the point spread function (PSF) and confusion noise, and then form the inverse variance-weighted sum of the individual bands, including weights determined by a chosen spectral energy distribution. Peaks in this combined image are used to estimate the source positions. The fluxes for each source are estimated from the filtered single-band images, interpolated to the exact subpixel position. We test the method by creating simulated maps in three bands with PSFs, pixel sizes, and Gaussian instrumental noise that match the 250, 350, and 500 μm bands of Herschel–ATLAS. We use our method to detect sources and compare the measured positions and fluxes to the input sources. The multiband approach allows reliable source detection a factor 1.2–3 lower in flux compared to single-band source detection, depending on the source colours. The false detection rate is reduced by a factor between 4 and 10, and the variance of the source position errors is reduced by about a factor 1.5. We also consider the effect of confusion noise and find that the appropriate matched filter gives a further improvement in completeness and noise over the standard PSF filter approach. Overall the two modifications give a factor of 1.5–3 improvement in the depth of the recovered catalogues compared to a single-band PSF filter approach.

RP-HPLC and UV Spectrophotometric Analysis of Paracetamol, Ibuprofen, and Caffeine in Solid Pharmaceutical Dosage Forms by Derivative, Fourier, and Wavelet Transforms: A Comparison Study

Different signal-transforming algorithms were applied for UV spectrophotometric analysis of paracetamol, ibuprofen, and caffeine in ternary mixtures. Phosphate buffer pH 7.2 was used as the spectrophotometric solvent. Severe overlapping spectra could be resolved into individual bands in the range of wavelengths 200–300 nm by using Savitzky–Golay smoothing and differentiation, trigonometric Fourier series, and mother wavelet functions (i.e., sym6, haar, coif3, and mexh). To optimize spectral recoveries, the concentration of various types of divisors (single, double, and successive) was tested. The developed spectrophotometric methods showed linearity over the ranges 20–40 mg/L for paracetamol, 12–32 mg/L for ibuprofen, and 1–3.5 mg/L for caffeine (R2 > 0.990). They could be successfully applied to the assay and dissolution test of paracetamol, ibuprofen, and caffeine in their combined tablets and capsules, with accuracy (99.1–101.5% recovery) and precision (RSD < 2%). For comparison, an isocratic RP-HPLC analysis was also developed and validated on an Agilent ZORBAX Eclipse XDB–C18 (150 × 4.6 mm, 5 µm) at an ambient temperature. A mixture of methanol : phosphate buffer 0.01 M pH 3 (30 : 70 v/v) was used as the mobile phase delivered at 2 mL/min, and the effluent was monitored at 225 nm. It was shown that spectrophotometric data were statistically comparable to HPLC p>0.05, suggesting possible interchange between UV spectrophotometric and HPLC methods for routine analysis of paracetamol, ibuprofen, and caffeine in their solid pharmaceutical dosage forms.

Chronic venous insufficiency and interest of adjustable compression wrap devices

Adjustable compression wrap devices (ACWD) are a heterogenic group which makes it difficult to match them to individual patient in their best way, we tried to characterize these products by their technical features. We bought four different ACWD and compared them regarding construction and handling. ACWD show obvious advantages including self-management, self-application, re-adjustability and standardization of the compression therapy. Basically, all systems are one or more low stretch bandages that encircle the lower leg and adhere to itself with velcro. Some allow for a selective adjustment during the course of the application because in these systems the individual bands mutually intermesh. In others, the bandages must always be opened from proximal to distal in order to retighten individual segments. In addition only one enables the user to control the compression pressure of each segment by a built-in-pressure system. Different technical features of the four ACWDs make it difficult to compare them. For effective compression easy handling, selective adjustments and a reliable pressure control seem to be the most important aspects.

Structure of Centers of Matrix Emission of the Undoped and RE-Doped Scheelite-Type Lead Tungstate Crystals

The paper reports the investigation of a structure of luminescence spectra of PbWO4 (PWO) crystals. The doping of the samples with rare earth (RE) impurities is used in order to obtain more information about the composition of spectra of the PWO matrix emission and the structure of its luminescence centers. The decomposition of the emission spectra onto individual bands has shown that 5 bands contribute to the total spectra of all the undoped and RE-doped samples at 10 K. The maxima of the obtained bands are 1.95, 2.2, 2.45, 2.7, and 3.0 eV. Effects of the RE-doping and the annealing on relative intensities of these bands are considered. The nature of luminescence and the structure of the centers involved in the excitation and emission processes responsible for each of the separated bands are discussed.