V1and V2 Research Articles

Application of sentinel-1 SAR-derived vegetation descriptors for soil moisture retrieval and plant height prediction during the wheat growth cycle

ABSTRACT Soil moisture is the crucialparameter impacting the plant growth during its phenological cycle. The Water Cloud Model (WCM) is one of the most widely used semi-empirical models for retrieval of soil moisture of vegetated lands from synthetic aperture radar (SAR) images. The model considers the effect of soil as well as vegetation on the radar backscatter. The study assesses the applicability of Sentinel-1 SAR-derived vegetation descriptors in the WCM for soil moisture retrieval during the wheat growth cycle. Various combinations of vegetation descriptors (V1and V2), viz. VH polarized backscatter coefficient (σ0 VH), Radar Vegetation Index (RVI) and depolarization ratio (χv), were used in the model. The model performed better when different parameters are used as vegetation descriptors (V1≠V2) in the WCM rather than using the same parameter for both the vegetation descriptors (V1= V2). The best results were observed when σ0 VHwas considered as one of the vegetation descriptors (V1) while either χvor RVI were utilized as the other vegetation descriptor (V2) giving a Pearson correlation coefficient (R) of 0.959 and 0.958 and a root mean square error (RMSE) of 0.499 dB and 0.516 dB respectively. The validation of the model-retrieved soil moisture against the in-situ measured values gave an R value of 0.72 and a RMSE of 0.096m3/m3. The plant height was also predicted by the WCM in which the retrieved soil moisture from SAR data was used as a parameter. The predicted plant height was compared to in-situ measured plant height and an R value of 0.76 and RMSE of 0.214 was obtained as the best result. The study demonstrates the capability of SAR-derived parameters as vegetation descriptors in the WCM for soil moisture retrieval.

Dual‐band frequency‐reconfigurable MIMO PIFA for LTE applications in mobile hand‐held devices

In this study, dual-port dual-frequency tuneable MIMO planar inverted-F antenna (PIFA) is presented for mobile handheld device applications. The proposed MIMO antenna consists of two symmetrical PIFAs with the centre-to-centre distance of 43.0 mm (0.1906λ 0 ). The dual-band tunability is achieved by changing the capacitance (V 1 and V 2 ) of 4.15 pF (0 V)-0.72 pF (15 V). The impedance bandwidth of -6 dB is realised from 0.8 to 0.98 GHz for the lower band and 1.65 to 2.2 GHz for the higher band. The proposed antenna provides the independent frequency tunability without disturbing the frequency bands. It shows the good isolation for both the tuneable bands >20 dB without using any coupling element between the antenna structure. It has a peak realised gain of 3.44 dBi, good efficiency of > 75% and envelope correlation coefficient of 0.007. In addition, the proposed PIFA performance is analysed with total active reflection coefficient, channel capacity, diversity gain, multiplexing efficiency, mean effective gain and specific absorption ratio for the tuneable range of frequencies. The good agreement is obtained between simulation and experimental performances to validate the antenna parameters.

Investigating The Effect of Exposure-Control Strategies on Item Selection Methods in MCAT

This study aims to investigate the effect of different item exposure controlling strategies on item selection methods in the context of multidimensional computerized adaptive testing (MCAT). Additionally, this study aims to examine to what extend the restrictive threshold (RT) and the restrictive progressive (RPG) exposure methods suppress the item exposure rates and increase the exposure rates of underexposed items without losing psychometric precision in MCAT. For this purpose, the performance of four item selection methods with and without exposure controls are evaluated and compared so as to determine how results differ when item exposure controlling strategies are applied with Monte-Carlo simulation method. The four item selection methods employed in this study are D-optimality, Kullback–Leibler information (KLP), the minimized error variance of linear combination score with equal weight (V1), the composite score with optimized weight (V2). On the other hand, the maximum priority index (MPI) method proposed for unidimensional CAT and two other item exposure control methods, that are RT and RPG methods proposed for cognitive diagnostic CAT, are adopted. The results show that: (1) KLP, D-optimality, and V1 performed better in recovering domain scores, and all outperformed V2 with respect to precision; (2) although V1 and V2 offer improved item bank usage rates, KLP, D-optimality, V1, and V2 produced an unbalanced distribution of item exposure rates; (3) all exposure control strategies improve the exposure uniformity greatly and with very little loss in psychometric precision; (4) RPG and MPI perform similarly in exposure control, and outperformed RT exposure control method.

Production characteristics of small grains depending on the application of mineral fertilizers with high content of phosphorus and potassium

The aim of this study was to examine the impact of the application of mineral fertilizers with a high content of phosphorus and potassium on the productive characteristics of some small grains grown on pseudogley soils. The research was carried out in the vicinity of Kraljevo during the period 2011/2013. The experiment included wheat, winter barley and triticale and 3 variants of fertilizers (K ? control; V1 ? N80 P60 K60; V2 ? N80 P80 K80 and V3 ? N80 P100 K100). In addition to grain yield, absolute mass and hectoliter mass were observed. The obtained results were analyzed using the analysis of variance. There were no significant differences in yield, absolute mass and hectoliter mass of the grain between small grains. The use of fertilizers with an increased content of phosphorus and potassium led to a significant increase in grain yield, absolute mass and hectoliter mass of small grains compared to control. Among the variants V1 and V2, and V2 and V3 variants, there were no statistically significant differences in the absolute mass and hectoliter mass of the grain. The average values of grain yield of small grains ranged from 1510 kg ha-1 in the control variant up to 3209 kg ha-1 in the variant with the highest dose of phosphorus and potassium fertilizers. Significant differences in grain yield were observed between the variants V1 and V2, as well as between the variants V2 and V3. The application of only mineral fertilizers on acid soils leads to relatively low yields.

Avaliação da resistência da soja a Sclerotinia sclerotiorum em diferentes estádios fenológicos e períodos de exposição ao inóculo

The objectives of this work were to determine the most adequate phenological stage of soybean plants for inoculation of Sclerotinia sclerotiorum and the period of contact between inoculum and plant tissues to detect partial resistance of soybean to the pathogen. Plants of two soybean cultivars, MG/BR-46 (Conquista) and M-SOY 8200 were inoculated at five different phenological stages (V1, V2, V3, V4 and R1). Inoculation involved different periods of contact between culture disks of an isolate of S. sclerotiorum which was selected based on high aggressiveness against soybean. It was observed that disease severity decreased as plants became older and it was concluded that V1and V2(leaves and stems) and V3(leaves) were ideal stages for inoculation during tests aimed at determining levels of resistance in soybean cultivars. Continuous contact of inoculum with plant tissues yielded good results for inoculation of S. sclerotiorum, either onto detached organs or onto organs connected to living plants. Ninety genotypes of soybean were evaluated by placing culture disks in continuous contact with folioles. Only 19 genotypes were moderately resistant and, among these, only two were moderately resistant in inoculation involving whole plants.

When you hear hoofbeats, think of horses and zebras: a 58-year-old man with chest pain and palpitations

Case presentation and primary diagnosisDr. Szkodzinski, Dr. Nowowiejska-Wiewiora: A 58-year-old man presented to the emergency department (ED) withchest pain and palpitations of 2 h duration as well as arapid heart rate (approximately 170 beats/min) and dizzi-ness. The patient reported episodic palpitations within theprior 12 months. His past medical history was negativefor prior surgeries, medications or any drug allergies. Onadmission, the patient was normotensive, normocardicand afebrile. Physical examination was unremarkable. Anelectrocardiogram (ECG) showed a normal sinus rhythmwith slight ST-segment elevation in precordial leads V1and V2, and a rsr’ pattern in V1 (Fig. 1a). Laboratory testsrevealed elevated cardiac marker CK-MB mass 20 ng/mL(upper limit of normal 5 ng/mL) and troponin T 0.4 ng/mL(upper limit of normal 0.1 ng/mL). Based on the clinicalpresentation, elevated cardiac markers and ECG findings, aprimary diagnosis of ST-segment elevation myocardialinfarction (STEMI) was made. The patient received5,000 U of unfractionated heparin IV, 300 mg of aspirinand 600 mg of clopidogrel, and was transferred to cathe-terization laboratory.Final diagnosisDr. Hudzik, Dr. Wozniak: Coronary angiography showednormal coronary arteries. The ECG tracing normalizedafter the procedure (Fig. 1b). Echocardiography revealednormal left and right ventricle functions (left ventricularejection fraction 60%) with no structural heart disease.Inflammatory states were excluded based on negativeinflammation markers [high-sensitivity C-reactive protein0.9 mg/L, erythrocyte sedimentation rate 6 mm/h, normalleukocyte count 6.7 (10

Soluble Mimetics of Human Immunodeficiency Virus Type 1 Viral Spikes Produced by Replacement of the Native Trimerization Domain with aHeterologous Trimerization Motif: Characterization and Ligand Binding Analysis

The human immunodeficiency virus type 1 (HIV-1) exterior envelope glycoprotein, gp120, mediates binding to the viral receptors and, along with the transmembrane glycoprotein gp41, is a major target for neutralizing antibodies. We asked whether replacing the gp41 fusion/trimerization domain with a stable trimerization motif might lead to a more stable gp120 trimer that would be amenable to structural and immunologic analysis. To obtain stable gp120 trimers, a heterologous trimerization motif, GCN4, was appended to the C terminus of YU2gp120. Biochemical analysis indicated that the gp120-GCN4 trimers were superior to gp140 molecules in their initial homogeneity, and trilobed structures were observable by electron microscopy. Biophysical analysis of gp120-GCN4 trimers by isothermal titration calorimetry (ITC) and ultracentrifugation analyses indicated that most likely two molecules of soluble CD4 could bind to one gp120-GCN4 trimer. To further examine restricted CD4 stoichiometric binding to the gp120-GCN4 trimers, we generated a low-affinity CD4 binding trimer by introducing a D457V change in the CD4 binding site of each gp120 monomeric subunit. The mutant trimers could definitively bind only one soluble CD4 molecule, as determined by ITC and sedimentation equilibrium centrifugation. These data indicate that there are weak interactions between the gp120 monomeric subunits of the GCN4-stabilized trimers that can be detected by low-affinity ligand sensing. By similar analysis, we also determined that removal of the variable loops V1, V2, and V3 in the context of the gp120-GCN4 proteins allowed the binding of three CD4 molecules per trimer. Interestingly, both the gp120-GCN4 variants displayed a restricted stoichiometry for the CD4-induced antibody 17b of one antibody molecule binding per trimer. This restriction was not evident upon removal of the variable loops V1 and V2 loops, consistent with conformational constraints in the wild-type gp120 trimers and similar to those inherent in the functional Env spike. Thus, the gp120-GCN4 trimers demonstrate several properties that are consistent with some of those anticipated for gp120 in the context of the viral spike.

The prevalence, incidence and prognostic value of the Brugada-type electrocardiogram: A population-based study of four decades

OBJECTIVESWe sought to demonstrate the prevalence, incidence and prognostic value of the Brugada-type electrocardiogram (ECG) in a general population.BACKGROUNDThe Brugada syndrome is characterized by evidence of right bundle branch block and ST segment elevation in the right precordial leads, as well as sudden death caused by ventricular fibrillation. However, the natural history of the Brugada-type ECG remains unclear.METHODSWe investigated 4,788 subjects (1,956 men and 2,832 women) who were <50 years old in 1958 and had undergone biennial health examinations, including electrocardiography, through 1999. The Brugada-type ECG was defined as a terminal r′ wave in lead V1and ST segment elevation ≥0.1 mV in leads V1and V2. Unexpected death was defined as sudden death or unexplained accidental death.RESULTSThere were a total of 32 Brugada-type ECG cases; the prevalence and incidence were 146.2 in 100,000 persons and 14.2 persons per 100,000 person-years, respectively. The incidence was nine times higher among men than women, and the average age at presentation was 45 ± 10.5 years. The Brugada-type ECG appeared intermittently in most cases and was found in 26% of subjects who died unexpectedly. Cox survival analysis revealed that mortality from unexpected death was significantly higher in subjects with a Brugada-type ECG than in control subjects (p < 0.01). Unexpected deaths were more frequent among subjects with the Brugada-type ECG who had a history of syncope (p < 0.05).CONCLUSIONSThe Brugada-type ECG is not a very rare condition in the adult Japanese population. Subjects with a Brugada-type ECG have an increased risk of unexpected death.

The Oscillation of a System Earth – Moon

Internal links in the Earth-Moon system are determined by gravitational interaction. According to the least compulsion principle of Gauss, the deviation of “free motion” of heliocentric orbits of two material points with Earth and Moon masses is determined by the sum of the products of each material points’ deviation from its free motion and its mass.By solving the minimization problem using the Lagrange multiplier method, Lagrange equations of the first kind were obtained in vector form. With acceptable assumptions (introduction of non-dimensional time τ = nt, where n is the sidereal rotation of the Moon, and the lunar orbit is considered to be circular) the linkage coefficient (Lagrange multiplier) is:where v1and v2 are proper frequencies of the Earth and the Moon and μ is the Moon/Earth mass ratio.

Straight-Line Embeddings of Two Rooted Trees in the Plane

We prove the following theorem: Let T 1 and T 2 be two disjoint rooted trees with roots v 1 and v 2 , respectively, and let P be a set of |T1 $\cup$ T2| points in the plane in general position containing two specified points p 1 and p 2 . Then the union T 1 $\cup$ T 2 can be straight-line embedded onto P such that v 1 and v 2 correspond to p 1 and p 2 , respectively. Moreover, we give a O(n 2 log n) time algorithm for finding such an embedding, where n is the number of vertices contained in T 1 $\cup$ T 2 .

Age and stimulus dependency of visually evoked cerebral blood flow responses.

During visual stimulation, the increased metabolic demand is coupled with an increase of cerebral blood flow velocity (pCBFV) in the posterior cerebral artery (PCA). Investigation of the visually evoked flow responses (VEFR, expressed as percentage of increase from baseline pCBFV values) was suggested for different conditions of vasoneuronal disorders in the absence of any systematic investigation in healthy subjects. We investigated VEFRs from both PCAs to various increasingly complex paradigms (diffuse light, alternating checkerboard patterns, and a color video movie stimulation; 5, 10, 20, and 30-second intervals) in 60 healthy volunteers (mean age, 41.5+/-14.9 years; range, 24 to 80 years; 28 male, 32 female) at different recording sites (P1 versus P2 segments of PCAs). With increasing complexity of stimulation, the VEFRs increased significantly (24.3+/-10.3%, 28.5+/-13.5%, and 43.4+/-10.7%, respectively). Twenty-second stimulation intervals yielded maximal responses (41.5+/-13.2%) compared with 5-, 10-, and 30-second intervals (22.6+/-14.1%, P=0.001; 34.4+/-11.7%, P=0.0042; and 35.5+/-9.9%, P=0.0032, respectively). Significantly higher responses were gained from P2 segments than from P1 segments (42.7+/-7.2% versus 28.2+/-7.1%). Although VEFRs tended to decrease in amplitude with age (mean, 41. 7+/-10.5% [20 to 40 years], 35+/-9.2% [40 to 60 years], and 33.9+/-8.6% [60 to 80 years]); without significant sex-related differences, only the percentage decrement of the pulsatility indices during stimulation were significant (mean, 24+/-10.7% [20 to 40 years], 20+/-7.3% [40 to 60 years], and 13+/-11.2% [60 to 80 years]). For optimal stimulus conditions for maximum VEFRs, a colored video stimulation of 20-second intervals should be used to combine responses not only from the primary visual projection fields (V1 and V2) but also from temporal lobe areas (V3 through V5) often supplied by the PCA.

A PDF description of turbulent plane couette flow

A transport equation for the one‐point velocity probability density function (pdf) of turbulence is derived, modelled and solved. The new pdf equation is obtained by two modeling steps. In the first step, a dynamic equation for the fluid elements is proposed in terms of the fluctuating part of Navier‐Stokes equation. A transition probability density function (tpdf) is extracted from the modelled dynamic equation. Then the pdf equation of Fokker‐Planck type is obtained from the tpdf. In the second step, the Fokker‐Planck type pdf equation is modified by Lundgren’s formal pdf equation to ensure it can properly describe the turbulence intrinsic mechanism. With the new pdf equation, the turbulent plane Couette flow is solved by the direct finite difference method coupled with dimensionality reduction and QUICKER scheme. A simple boundary treatment is proposed such that the near‐wall solution is tractable and then no refined grid is required. The calculated mean velocity, friction coefficient, and turbulence structure are in good agreement with available experimental data. In the region departed from the center of flow field, the contours of isojoint pdf of V1 and V2 is very similar to that of experimental result of channel flow. These agreements show the validity of the new pdf model and the availability of the boundary treatment and QUICKER scheme for solving the turbulent plane Couette flow.

Quantitative assessment of left ventricular diastolic stiffness in man.

An approach to the quantitative assessment of left ventricular (LV) diastolic stiffness in man has been developed utilizing strip-chart recordings of simultaneous ultrasonic LV dimensions, LV pressure, and electrocardiogram (ECG). In 23 patients without regional abnormalities of contraction, LV pressure, and LV internal diameter (D = distance between endocardial surfaces of LV posterior wall and septum at the plane of the mitral valve) were determined at the onset (P 1 , D 1 ) and peak (P 2 , D 2 ) of left atrial mechanical systole. In addition, left ventricular volumes, V 1 and V 2 , were calculated from D 1 and D 2 using a regression formula for end-diastolic volume previously determined from biplane angiographic studies. This allowed calculation of ΔP/ΔD and ΔP/ΔV associated with the "a" wave of the LV pressure trace, and these ratios were utilized as measures of LV stiffness late in diastole. Patients with LV hypertrophy by standard ECG criteria had much greater late diastolic stiffness (11 patients, ΔP/ΔD = 6.1 ± 1.1 mm Hg/mm, ΔP/ΔV = 1.0 ± 0.2 mm Hg/cc) than those without LV hypertrophy (12 patients, ΔP/ΔD = 1.8 ± 0.2 mm Hg/mm, ΔP/ΔV = 0.29 ± 0.04 mm Hg/cc, P &lt; 0.001 for each ratio). Comparison of the stiffness ratios showed significant variation among patients with different disease states. Thus, late diastolic stiffness was highest in patients with aortic stenosis (three patients, ΔP/ΔD = 8.9 ± 2.9 mm Hg/mm, ΔP/ΔV = 1.5 ± 0.5 mm Hg/cc), lowest in mitral stenosis (four patients, ΔP/ΔD = 1.5 ± 0.5 mm Hg/mm, ΔP/ΔV = 0.23 ± 0.06 mm Hg/cc), and intermediate in patients with aortic regurgitation (three patients, ΔP/ΔD = 4.8 ± 0.7 mm Hg/mm, ΔP/ΔV = 0.83 ± 0.12 mm Hg/cc) and mitral regurgitation (three patients, ΔP/ΔD = 3.2 ± 0.7 mm Hg/mm, ΔP/ΔV = 0.5 ± 0.1 mm Hg/cc). It is concluded that the quantitative evaluation of LV diastolic stiffness obtained by this approach correlates well with the presence or absence of LV hypertrophy and with the underlying pathophysiology.

Stress wave patterns and the size of the non-elastic zones of an explosive source

The travel-time curves of characteristic moments of stress wave patterns were investigated. The arrival time of the onset of stress wavet 0, of the maximum amplitudet 1 and of the moment terminating the pressure part (the first half-wave) of this wavet 2 were taken to be representative. These travel-time curves were used to determine the velocities of propagation of these moments (V 0,V 1 andV 2) as functions of the distance from the source. According to their variations it is possible to appoint the size of the cavity created by the explosion and to determine the distance at which the ‘elastic source surface’ of stress waves is to be found. The radius of the cavity is given by 1.5 times the distance at whichV 1 separates fromV 0. The ‘elastic source surface’ of stress waves is defined by the distance from whichV 0 is constant and at whichV 1 andV 2 have minimum values. These two distances determine the points at which the character of the stress wave pattern changes: from shock wave in gases, through shock wave in a solid medium to a seismic wave.

THE RECOGNITION OF STRICTLY POSTERIOR MYOCARDIAL INFARCTION BY CONVENTIONAL SCALAR ELECTROCARDIOGRAPHY.

This study was undertaken in order to determine whether the standard scalar electrocardiogram contains sufficient information to permit the recognition of strictly posterior myocardial infarction. Sixteen patients were selected on the basis of vectorcardiographic evidence and four on the basis of autopsy evidence. One hundred normal adult electrocardiograms served as controls. The data indicate that strictly posterior infarction causes (1) R waves of 0.04 second in V 1 and in contiguous right anterior chest leads with upright T waves and, in the acute phase, ST-segment depressions, (2) Q waves of 0.04 second in an area posteriorly between the spine and the left scapula, (3) R/S ratios equal to or greater than one in V 1 and V 2 , (4) slurring of the descending limb of the R wave in lead V 1 due to abrupt change in QRS direction, and (5) no pathologic Q waves in the standard 12 leads unless diaphragmatic or lateral infarction coexists. Extra chest leads derived from the right anterior and left posterior thorax serve principally to corroborate the diagnoses. R waves of 0.04 second or R/S ratios equal to or greater than one in lead V 1 were also found in the normal child, complete right bundle-branch block, the Wolff-Parkinson-White syndrome with an anteriorly directed delta wave, right ventricular hypertrophy, and an occasional normal adult especially with vertical frontal plane electrical axis. Attention to these differential diagnoses and to the foregoing manifestations of strictly posterior infarction facilitate its recognition by conventional scalar electrocardiography.

Atrial infarction of the heart.

Six cases of atrial infarction associated with ventricular infarction are presented. All cases were diagnosed during life and were confirmed by autopsy. A clinical diagnosis of atrial infarction should be suspected in patients with ventricular myocardial infarction having any form of atrial arrhythmia. Frequent electrocardiograms should be obtained, especially if sinus rhythm has just been re-established after episodes of supraventricular tachycardia or atrial fibrillation. The major electrocardiographic criteria for the diagnosis of atrial infarction are as follows: elevation of the P-Ta segment of over 0.5 mm. in V 5 ; and V 6 with reciprocal depression of the same segment in V 1 and V 2 ; elevation of the P-Ta segment of over 0.5 mm. in lead I and its depression in leads II or III; depression of the P-Ta segment of more than 1.5 mm. in precordial leads and 1.2 mm. in leads I, II, and III in the presence of any form of atrial arrhythmia. The minor electrocardiographic criteria in making the diagnosis of atrial infarction are as follows: abnormal P waves: M-shaped, W-shaped, irregular or notched; depression of the P-Ta segment of small amplitude without elevation of this segment in other leads cannot be regarded by itself as positive evidence of atrial infarction. A diagnosis of atrial infarction can sometimes be made when the presence of ventricular myocardial infarction cannot be definitely established by electrocardiogram. The treatment of atrial infarction is similar to that of ventricular infarction. Attention should be directed to the control of atrial arrhythmias and to the prevention of mural thrombi.

New experiments upon the combustion of well-dried carbon monoxide and oxygen mixtures.—Part II

For this third series of experiments a special form of apparatus (shown diagrammatically “in plan” in fig. 1) was set up, whereby the ignitibilities of 2CO + O 2 mixtures, whose components had been thoroughly dried (after compression) over re-distilled phosphoric anhydride in small steel cylinders, could be tested in a nickel-steel bomb with a 1-in. diameter cylindrical explosion chamber at various initial pressures up to 20 atmospheres. The whole system and its connections had been previously thoroughly dried out by continuously circulating P 2 O 5 -dried nitrogen round it day and night for several months together. The following is a detailed description of the apparatus :— Apparatus . The nickel-steel cylindrical bomb A* (with explosion chamber 8 inches long by 1 inch diameter, capacity 103 c. c.) was clamped horizontally to a special iron casting, which permitted of the bomb being rocked as and when required. This was bolted down to the experimental table, on to which were also fixed all the other items of the installation. The outside of the bomb, whose overall dimensions were 16 inches by 5 inches diameter, was wound with nichrome wire, so that it could be heated electrically to a temperature of 150° C. or more to facilitate the drying of it. It was fitted with a specially designed firing plug P, consisting of a central electrode (5 inches long by 1/8 inch diameter nickel-steel rod), which was wrapped round with an insulating packing of compressed mica to a thickness of 5/16 inch, in such a manner as to make a perfectly gastight joint even at high explosion pressures. It should be particularly noted that no organic substance whatever was employed in “packing” the firing piece, or indeed in any other part of the bomb or apparatus. The electrode of the firing piece projected about 3½ inches out of the body of the bomb in order to allow of a sufficiently high voltage being applied when a mixture had to be fired under high pressure. The bomb was closed at each end by the high-pressure steel valves V 1 and V 2 , respectively.