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In precision farming, weed detection is required for precise weedicide application, and the detection of tobacco crops is necessary for pesticide application on tobacco leaves. Automated accurate detection of tobacco and weeds through aerial visual cues holds promise. Precise weed detection in crop field imagery can be treated as a semantic segmentation problem. Many image processing, classical machine learning, and deep learning-based approaches have been devised in the past, out of which deep learning-based techniques promise better accuracies for semantic segmentation, i.e., pixel-level classification. We present a new method that improves the precision of pixel-level inter-class classification of the crop and the weed pixels. The technique applies semantic segmentation in two stages. In stage I, a binary pixel-level classifier is developed to segment background and vegetation. In stage II, a three-class pixel-level classifier is designed to classify background, weeds, and tobacco. The output of the first stage is the input of the second stage. To test our designed classifier, a new tobacco crop aerial dataset was captured and manually labeled pixel-wise. The two-stage semantic segmentation architecture has shown better tobacco and weeds pixel-level classification precision. The intersection over union (IOU) for the tobacco crop was improved from 0.67 to 0.85, and IOU for weeds enhanced from 0.76 to 0.91 with the new approach compared to the traditional one-stage semantic segmentation application. We observe that in stage I shallower, a smaller semantic segmentation model is enough compared to stage II, where a segmentation network with more neurons serves the purpose of good detection.

Human gait recognition system identifies individuals based on their biometric traits. A human’s biometric features can be grouped into physiologic or behavioral traits. Biometric traits, such as the face [1], ears [2], iris [3], finger prints, passwords, and tokens, require highly accurate recognition and a well-controlled human interaction to be effective. In contrast, behavioral traits such as voice, signature, and gait do not require any human interaction and can be collected in a hidden and non-invasive mode with a camera system at a low resolution. In comparison with other physiological traits, one of the main advantages of gait analysis is the collection of data from a certain distance. However, gait is less powerful than physiological traits, yet it still has widespread application in surveillance for unfavorable situations. From traditional algorithms to deep learning models, a gait survey provides a detailed history of gait recognition.

In this work we present synthesis and extensive characterization of Cerium oxide (CeO2) nanocrystals. Comparison between the properties of as-prepared and air annealed nanoparticles has been carried out, with a goal to clearly identify the effect of oxygen vacancies on crystal, electronic and band structure. Detail crystal and electronic structural analysis was employed to quantify oxygen vacancies. Structural analysis confirmed that the formation of single phase cubic Fluorite structure for both as-prepared and annealed samples. Crystal and electronic structural studies confirmed that Ce ions exists in two oxidation states, Ce+3 and Ce+4. Concentration of oxygen vacancies was larger in as-synthesis nanocrystal. A drastic decrease in oxygen vacancy concentration was observed for the sample annealed in air at 550 °C. For the as-prepared sample, the Raman allowed F2g mode shifted towards lower wavenumber, exhibiting mode softening with broader and asymmetric peak. Observation of absorption edge revealed presence of 4f band within the band gap. Absorption with different band edge, confirmed different energy position of 4f level for the sample possessing oxygen vacancies. Blue shift of the band edge for as-prepared sample has been discussed in terms of increase in lattice parameter, formation of Ce+3 ions, quantum confinement effect etc. Photoluminescence emission studies revealed presence of F-centers with corresponding energy level located below 4f band as a result of oxygen vacancies. It was found that within the measured experimental energy window, transitions associated by the F-center are mainly associated with 4f0 to 4f1, F++ to 4f1 and 4f0 to F+.

A 9-year-old child presented with syncope during exercise. He received a diagnosis of congenital atresia of the left main coronary artery by angiography. He underwent successful coronary artery bypass grafting. On the third postoperative day, he experienced acute, precordial chest pain. An urgent computed tomographic scan showed an unrecognized anomalous origin of the right coronary artery (RCA) with a 1.5-cm intramural course. He was taken back to the operating room to undergo unroofing of the RCA. This case highlights the difficulty involved in making two rare diagnoses that can cause the same exact symptoms in a patient and the surgical challenges associated with it.

In patients with failed Fontan circulation, end-stage heart failure can develop or Fontan physiology failure requiring transplantation. Experience with ventricular assist device support for these patients as a bridge to heart transplantation has been limited and often not resulted in successful hospital discharge. We report the successful use of the Berlin Heart EXCOR (Berlin Heart, The Woodlands, TX) ventricular assist device in bridging a child with Fontan circulation and systolic dysfunction to heart transplantation and discharge home.

Thermal annealing behaviour of deep levels in p-GaAs grown by metal-organic chemical-vapor deposition (MOCVD) has been studied by deep level transient spectroscopy (DLTS) technique. Thermal annealing is found to introduce at least six new defects, four majority-carrier emitting deep levels, situated at E v +0.11, E v +0.27, E v +0.44 and E v +0.89 eV in the bandgap, and two minority-carrier emitting defects, at E c −0.49 eV and E c −0.99 eV. The minority-carrier emitting band of deep levels around ∼100 K in the as-grown material has also been found to resolve into two distinct peaks corresponding to deep levels at E c −0.16 eV and E c −0.21 eV, upon isochronal annealing. Four of the annealed-in defects at E v +0.27, E v +0.44, E c −0.16 eV and E c −0.49 eV are identified with previously reported deep levels, while the other four defects cannot be identified with any of the deep levels reported in the literature. Data on the annealing behavior and other characteristics of these annealed-in levels are presented. The thermal annealing behavior of the both inadvertent levels observed at E v +0.55 eV and E v +0.96 eV suggests that these levels are most likely related to arsenic antisite, As Ga , defects.

We report the results of isochronal annealing study of deep levels in Rh-doped n-type GaAs grown by metal-organic vapor phase epitaxy (MOVPE). Deep level transient spectroscopy (DLTS) technique has been employed to study the effects of annealing on deep levels in Rh-doped p + nn + junction samples. A majority-carrier emitting band of deep levels along with a high temperature peak (RhE1), corresponding to deep level energy position E c −0.92 eV and a minority-carrier emitting band of deep levels are identified with Rh-impurity prior to thermal annealing of our samples. In addition to these Rh-related deep levels, the well-known native defect EL2 at E c −0.79 eV is observed in majority-carrier emission spectra and two inadvertent deep-level defects, H1 at E v +0.09 eV and H3 at E v +0.93 eV, usually observed in reference (without Rh) samples, are also detected in the minority-carrier emission spectra of Rh-doped samples. At least one level is found to be introduced at E c −0.13 eV in Rh-doped samples at about the same temperature position as the level E(A)1, observed in reference samples, as a result of isochronal annealing, while the other two levels observed in reference samples could not be seen in annealed Rh-doped samples. Data on the annealing behavior and other characteristics of both Rh-related bands of deep levels observed in majority- and minority-carrier emission DLTS spectra, as well as for the high temperature Rh-related electron-emission peak, are presented. Possible interpretations of these results for the nature and structure of the different deep-level defects are discussed.

Deep-level transient spectroscopy (DLTS) measurements were carried out on low-doped n-silicon before and after irradiation with 5.48MeV @a particles at room temperature with a fluence of ~10^1^[email protected] particles/cm^2. The DLTS measurements on the samples identified three electron levels E"1, E"2 and E"3 before irradiation. The deep-levels characteristic studies include emission rate signatures, activation energies, defect concentrations and capture cross sections. It was found that all pre-existing defects decreased their amplitudes during irradiation. The decrease in activation energy of level E"3 and noticeable suppression of level E"1 was also observed after irradiation. It was clearly seen that the composite peak E"3 (combination of E"2 and E"3) was successfully resolved after irradiating with @a particles. @a-irradiation is seen to lead a significant suppression of the iron interstitial defect, and without causing any change in its room temperature annealing characteristics.

EL2 is the ubiquitous native defect in crystalline GaAs grown by a variety of different techniques. It has been proposed to be a doubly charged deep-level center with two states having distinct energy levels in the band gap. While the singly charged state has been the subject of many experimental studies and is, therefore, well established, the doubly charged state has only been occasionally alluded to in the literature. This paper provides evidence for a dominant inadvertent deep level in p-type GaAs most likely to be the doubly charged state of the EL2 center. Deep-level transient spectroscopy (DLTS) has been applied to characterize epitaxial layers of p-type GaAs grown on p + GaAs substrates by low-pressure metal organic chemical vapor deposition (LP-MOCVD). A pronounced peak is observed in the majority carrier (hole) emission deep-level spectra. Thermal emission rate of holes from the corresponding deep level is found to exhibit a strong electric field dependence, showing an increase of more than two orders of magnitude with an increase of the electric field by a factor of ∼2. The thermal activation energy for this level is found to vary from 0.29 to 0.61 eV as the electric field is varied from 2.8×10 5 to 1.4×10 5 V/cm. Direct pulse-filling measurements point to a temperature-dependent behavior of the hole capture cross section of this level. We identify this inadvertent deep-level defect, commonly observed in p-type GaAs grown by a variety of different methods, with the doubly charged state of the well-known As Ga antisite related defect, EL2.

A preliminary study of growth interruption effects on the GaAs/AlGaAs layers is reported. Deep level transient spectroscopy (DLTS) is performed on Al Schottky barrier devices fabricated on Si-doped, isotype GaAs/Al 0.78 Ga 0.22 As heterostructures grown by molecular beam epitaxy (MBE), both with (200 s) and without, growth interruption. Our spectra extending from ∼15 to 300 K show four peaks corresponding to deep level defects with thermal activation energies ( E A ): 0.09, 0.32, 0.42 and 0.52 eV, which are detected in both types of samples (close to and) above liquid nitrogen temperature, although with different relative concentrations. Comparison with reported work on GaAs/Al x Ga 1− x As samples with different compositions ( x ) shows that latter two of these deep levels are counterparts of the levels, P3–P4, earlier observed in MBE grown Al x Ga 1− x As materials with Al content different than that used here. However, the deep level spectra of our samples show dramatic differences for the growth interrupted and uninterrupted samples in the temperature range below 77 K. Whereas the samples prepared without growth interruption show a prominent, hitherto unobserved, positive (majority carrier emission) peak, P0 ( E A =0.029 eV), with shoulders on both higher and lower temperature flanks, the samples with growth interruption show a pronounced negative peak, apparently corresponding to a deep level with E A =0.031 eV, in the same temperature region, under similar measurement conditions. The deep-level characteristics, including emission rate signatures and apparent capture cross-sections, are determined for the observed features using the thermal emission rate data. Some interesting additional features related to depth profiles of deep levels, bias effects and charge-induced metastability effects are also reported.

Results of isochronal annealing up to a temperature of 660 K of n-type GaAs grown by low-pressure metal organic chemical vapor deposition (LP-MOCVD) are reported. Deep-level transient spectroscopy (DLTS) reveals EL2 as the only electron-emitting deep-level defect in our as-grown material, whereas three hole-emitting levels at E v +0.09 eV, E v +0.40 eV and E v +0.93 eV are observed in the minority-carrier injection spectra. While yielding interesting results on the behavior of these pre-existing deep-level defects, thermal annealing is found to introduce at least four new defects, three in the upper half of the band gap at E c −0.13 eV, E c −0.16 eV and E c −0.36 eV, and one in the lower half at E v +0.19 eV. Two of these defects, one at E c −0.16 eV and the other at E c −0.36 eV, are identified with previously reported annealed-in deep levels in n-GaAs, while the other two defects cannot be identified with any of the deep levels reported in the literature. Data on the annealing behavior and other characteristics of these annealed-in levels are presented. All the pre-existing inadvertent deep-level defects in the as-grown material were found to be stable up to 600 K, beyond which the minority-carrier emitting levels start to anneal out, but EL2 tends to show a slight increase with annealing temperature.

Background The purpose of this study was to examine early and late outcome of tricuspid valve repair for Ebstein's anomaly in young children. Methods Between October 1974 and November 2003, 52 children (25 boys) underwent tricuspid valve repair and annuloplasty for Ebstein's anomaly. Mean age was 7.1 ± 3.9 years (range, 5 months to 12 years). Concomitant procedures included atrial septal defect closure (n = 46), division of accessory conduction pathways (n = 4), ventricular septal defect closure (n = 3), and other (n = 7). Results Early mortality was 5.8% (3 of 52 patients; no mortality since 1984, n=31). Risk factors were age younger than 2.5 years ( p = 0.03) and weight less than 10.7 kg ( p = 0.03). Morbidity included transient atrial (n = 11) and ventricular arrhythmias (n = 5), and early reoperation in 3 patients. There was no need for a permanent pacemaker. Mean follow-up was 12.2 ± 7.4 years (maximum, 24.3 years). Actuarial survival at 5, 10, and 15 years was 92.3% ± 3.7%, 89.9% ± 4.3%, and 89.9% ± 4.3%, respectively. Freedom from all reoperations at 5, 10, and 15 years was 91.0% ± 4.3%, 76.9% ± 6.8%, and 61.4% ± 8.8%, respectively. Moderate (grade II) or more tricuspid regurgitation on dismissal echocardiogram was the only risk factor for reoperation ( p = 0.04). Tricuspid stenosis did not occur in any patient. At late follow-up, 89% of patients were in New York Heart Association class I or II. Conclusions Ebstein's anomaly in young children can now be repaired with low mortality and good tricuspid valve durability. Tricuspid regurgitation at the completion of operation should be mild or less to minimize need for reoperation. Tricuspid valve repair and annuloplasty did not result in stenosis despite somatic growth. Most patients enjoy an excellent quality of life.

Background . Increases in blood flow support oxygen (O 2 ) delivery with hemodilution. However, with α-stat management, the cerebral response to hemodilution is blunted. We tested the hypothesis that carbon dioxide (CO 2 ) management is a primary determinant of the cerebral blood flow (CBF) response to hemodilution during hypothermic bypass. Methods . Following Animal Care Committee approval, 15 dogs underwent bypass at 18°C (pH-stat, n=7 or α-stat, n=8). Measurements were obtained after progressive hemodilution, and cerebral blood flow was determined by sagittal sinus outflow. Arterial pressure was maintained at 60 to 70 mm Hg. The CBF response to hemodilution and cerebral metabolic rate were compared in the two groups of animals. Results . In both groups, hemodilution increased CBF. At every hematocrit, CBF and O 2 delivery in the pH-stat group exceeded that of α-stat group, although O 2 demand did not differ between groups. While absolute CBF in the pH-stat group was greater at every hematocrit, the relative change in CBF from control and the slope of the CBF-Hct relationship did not differ between groups. Conclusions . pH-stat management is associated with a greater absolute CBF and a greater ratio of cerebral O 2 supply to demand for any degree of hemodilution. However, over the range of hematocrits common in practice, CO 2 management per se does not determine the cerebral response to hemodilution.

Background . Embolization during cardiopulmonary bypass probably alters cerebral autoregulation. Therefore, using laser Doppler flowmetry we investigated the cerebral blood flow velocity changes in response to changes in arterial pressure, before and after embolization in a canine bypass model. Methods . After Institutional Animal Care and Use Committee approval, 8 anesthetized dogs had a laser Doppler flow probe positioned over the temporoparietal dura. During 37° C cardiopulmonary bypass, the cerebral blood flow velocity response to changing mean arterial pressure (40 to 85 mm Hg in random order) was assessed before and after systemic embolization of 100 mg of 97-μm latex microspheres. Results . Before embolization, cerebral blood flow velocity increased 39% as mean arterial pressure increased from 40 to 85 mm Hg. Following embolization, a 94% increase in cerebral blood flow velocity was demonstrated over the same mean arterial pressure range. The slopes of the curves relating cerebral blood flow velocity to mean arterial pressure were 0.21 ± 0.74 and 1.31 ± 0.87, before and after embolization ( p = 0.016) respectively. Conclusions . Regional cerebral blood flow autoregulation may be impaired by microembolization known to occur during cardiopulmonary bypass, increasing the dependence of cerebral blood flow on mean arterial pressure.

We report a comprehensive study of deep levels in the entire band gap of alpha-irradiated n-type GaAs, grown by metal-organic vapor phase epitaxy (MOVPE), over a wide temperature scan range of 12–475 K. Deep level transient spectroscopy (DLTS) reveals the presence of, at least, seven radiation-induced deep level defects at energy positions E c −0.05 eV, E c −0.14 eV, E c −0.19 eV, E c −0.34 eV, E c −0.38 eV, E c −0.59 eV and E c −0.69 eV in the upper-half of the band gap, while two radiation-induced defects at energy positions E v +0.54 eV and E v +0.77 eV were observed in the lower-half band gap. Some significant differences have been observed with respect to the published work on Schottky barrier diodes. Detailed data on the emission rates, capture cross-sections and introduction rates of the radiation-induced defects are presented. The majority carrier emitting levels at E c −0.05 eV and E c −0.14 eV have been found to have electric-field-dependent emission rate signatures.

Deep-level transient spectroscopy (DLTS) has been used to investigate deep levels in n-type Ru-doped GaAs grown by low-pressure metal-organic chemical-vapor deposition (LP-MOCVD). DLTS scans over a wide temperature range (12–470 K) reveal two prominent deep-level peaks associated with Ru, when compared with control samples with no deliberate Ru-doping. The well-known mid-gap defect EL2 is also observed in these scans. The Ru-related deep levels, Ru1 and Ru2, correspond to energy positions Ec−0.46 eV and Ec−0.57 eV in the upper-half-bandgap of GaAs. No prominent deep levels associated with Ru are observed in the lower half-bandgap in the injection DLTS spectra; only the three inadvertent levels already present in the as-grown, control material are observed in these spectra. Although a possible Ru-related peak may be present with a rather small concentration in these injection DLTS spectra, it is difficult to clearly identify this peak also present in the control (as-grown, without Ru) samples at a closely similar position. Interestingly, doping with Ru reveals an interesting significant suppression of the pre-existing deep levels, including EL2. Detailed emission rate signatures are presented for the Ru-related deep levels and analyzed to obtain the relevant deep-level characteristics. Both Ru1 and Ru2 are found to show strong dependence on electric field, as demonstrated by the shift in the corresponding DLTS peak positions with the applied reverse bias during electron emission.

s S37 IL; 3University of Alabama at Birmingham, Birmingham, AL; 4Primary Children’s Medical Center, Salt Lake City, UT; 5Children’s Hospital of Wisconsin, Milwaukee, WI; 6Great Ormond Street Hospital, London, United Kingdom; 7Medical University of South Carolina, Charleston, SC; 8Children’s Healthcare of Atlanta, Atlanta, GA. Purpose: Current knowledge of antibody-mediated rejection (AMR) after heart transplantation (HT) stems largely from adult data with only a few small single-center pediatric studies. Using the multi-institutional Pediatric Heart Transplant Study (PHTS) database, we aimed to report the incidence of AMR, describe contemporary treatment, and evaluate outcomes for treated AMR in children after HT. Methods: We queried the PHTS database for patients < 18 yrs undergoing primary HT between 1/10 12/13. An AMR episode was defined as either a biopsy (bx) with histology and/or complement staining consistent with pathologic AMR or a rejection event attributed to donor specific antibodies based on immunotherapy augmentation directed against antibody production. Biopsy data, treatment strategies, and survival were analyzed. Results: AMR was reported in 118/1217 (10%) HT recipients and accounted for 142/467 (30%) rejection episodes. AMR was diagnosed by bx in 108 episodes and by Ab-directed therapy in 27 with negative bx and 7 with no bx performed. 106 episodes had concurrent acute cellular rejection (ACR) by bx. 91% and 88% of patients were free from AMR at 1 and 3 years, respectively. AMR therapies included IVIG (n= 81, 57%), plasmapheresis (n= 61, 43%), rituximab (n= 55, 39%), bortezomib (n= 16, 11%), and eculizumab (n= 1, 1%). 19 patients (16%) died after developing AMR. Mortality did not differ between the AMR, AMR+ACR, and no AMR groups. (Fig. 1) The 1 and 3 year patient survival after initial AMR diagnosis was 89% and 72%, respectively. Conclusion: This is the largest multi-institutional assessment to date of AMR in pediatric HT recipients. AMR was common and often occurred concurrently with ACR. This study highlights wide variability in both the diagnosis and treatment of AMR. The outcomes of those with AMR were comparable to those with rejection not due to AMR. Ongoing collaborative studies are needed to better characterize AMR and determine treatment effects specific to pediatric HT.