Multiple Small Patches Research Articles

Aberration correction in complex media over multiple isoplanatic patches by exploiting their spatial correlation

Optical imaging in complex media, such as biological tissues, poses significant challenges due to the presence of aberrations and scattering that distort wavefronts and degrade image quality. Wavefront correction has emerged as a crucial technique for mitigating these effects. Recent advances, such as adaptive optics, wavefront shaping, and matrix-based methods, have made significant strides in correcting for wavefront distortions to achieve high-resolution imaging. However, current approaches face challenges when addressing spatially varying distortions and small isoplanatic patches, where the corrections lose reliability due to the rapid spatial variation of distortions. To address this limitation, we introduce a method that exploits the spatial correlation of wavefront distortions across neighboring isoplanatic patches. This approach, termed "inward-outward progression", enables a more reliable wavefront correction across multiple small patches. The process involves two key steps: (1) the inward progression, where a small zone surrounding a pixel is optimized while progressively shrinking the optimized region, and (2) the outward progression, where the wavefront correction phases of the corrected zone serve as the initial guess to optimize adjacent areas, extending the correction from the small zone at the inward progression until the entire field of view is covered. We validate this method by imaging a USAF resolution target under 700-µm-thick chicken breast. Our approach shows a significant improvement in image quality and superior performance over existing techniques, paving the way for noninvasive imaging where conventional methods face substantial limitations due to the spatially varying aberrations and scattering.

Evaluation of historical and future coastal wetland change in the Yellow and Bohai Seas using satellite images and a land use model

Predicting the future distribution of coastal wetlands and characterizing changes in the area of wetlands between historical and future periods are important for the formulation of wetland conservation and management plans. Here, we used a cellular automata–Markov model and satellite images to simulate the future distribution of coastal wetlands under the business-as-usual scenario (BAU) and ecological protection scenario (EP) along the Yellow and Bohai Seas in China; we also explored historical (from 1990 to 2020) and future (from 2020 to 2050) changes in wetlands and the factors driving these changes. We found that the area of tidal flats gradually decreased because of increases in the area of saltpans, and the aquaculture area increased because of land reclamation and the invasion of Spartina alterniflora; most of the tidal flat area was fragmented into multiple small patches. If the current rate of degradation continues (BAU), the area of tidal flats will decrease by 21.25%, and the area of saltpans and aquaculture will increase by 13.83% and 21.25%, respectively. By contrast, under EP, the area of tidal flats will increase by 13.81%, and this increase will mainly stem from the conversion of areas with S. alterniflora (174.49 km2, 33.22%) to aquaculture areas (155.17 km2, 29.54%). Clear differences between historical and future periods were observed among Liaohe Estuary, Bohai Bay, Laizhou Bay, and the Yancheng–Nantong coasts. Land reclamation is the main factor inducing changes in the area of tidal flats, saltpans, and aquaculture in Liaohe Estuary, Bohai Bay, and Laizhou Bay. Land reclamation and the S. alterniflora invasion both affect the distribution of wetlands along the Yancheng–Nantong coasts.

Effect of interactions of two holes on tensile behavior of patch repaired carbon/epoxy woven laminates

The conventional case of patch repair involves bonding a patch over single damage/hole in the laminate. This work investigates the effect of interaction of two holes on the tensile behavior patch repaired carbon epoxy woven laminates. The specimens of [0°/45°/45°/0°] laminates were repaired with adhesively bonded two-ply [45°]2 external patches. Three different cases of drilled specimens were produced with different hole arrangements viz. specimens with single central hole (SH), with two holes aligned along the longitudinal axis (LH) and with two holes along transverse axis (TH). The two-hole specimens were repaired with two different types, i.e. single large patches (SP) and with the two smaller patches (DP) of combined bonding area equal to the single large patches. Digital image correlation (DIC) was employed to capture strain contours. The results reveal the difference in the load transfer through the patches depending upon the arrangement of holes. The TH repaired specimen exhibit significant load recovery (SP-32.75%, DP-34.62%) while the LH specimens result in very marginal (SP- 6.11%, DP-4.10%) recovery compared to their drilled case. The TH specimen failed by crack growing through both the holes beneath the patch, while the LH specimens failed by the failure through only one hole. The use of single large patch over multiple holes and multiple small patches individually over each hole has no significant influence on load recovery.

Ayurvedic management of vitiligo (Shvitra)

Introduction: Vitiligo is a common autoimmune disorder in which the destruction of melanocytes occurs, resulting in the formation of white spots on the skin. It has a major impact on the quality of life of patients, as they feel distressed and stigmatized by their condition. Treatment available in contemporary medicine has its own limitations and side effects. In Ayurveda, Shvitra is the term employed for the hypopigmentation disorders of the skin. Due to the holistic approach, Ayurveda has the vast potential to treat such autoimmune skin diseases. Here, a case study of chronic vitiligo treated successfully with ayurvedic interventions is reported. Main Clinical Finding: There were white patches measuring about 7x5 cm, 4x3 cm, 3x3 cm and 4x2 cm on right and left arm, neck, chest, forehead region respectively. There were multiple small patches on fingers of hand also. The spots and patches were asymmetric, well defined whitish-pink and without scaling and discharge. Diagnosis: The patches were spread on large area (bahala), colour of patches was white/whitish pink (tvaka vaivarnyata), no secretion from lesion (aparisravi) ,with no itching (kandu) and loss of hair (romavidhvamsha) on affected area, so the case was diagnosed as Shvitra kustha on the bases of observed sign and symptoms. Intervention: The management approach was personalized and holistic in nature incorporating Ahara,vihara and Aushadha. In Sanshamana chikitsa Pitta-kapha shamaka and Vyadhi pratyanika line of treatment including internal administration of Khadira sara, decotition of Amla and Udumbara Chhala and Shashilekha Vati with external application of Chakramarda beeja, Muli beeja and Vakuchi beeja lepa was incorporated. Outcome: After 3 months of interventions, skinny spots appeared between the white patches. After six months, patches of chest, neck and forehead almost disappeared and that of arms significantly decreased with no recurrence. No adverse effect was seen during treatment and in follow up period

Stand-scale responses of forest-floor small mammal populations to varying size, number, and location of retention tree patches

Retention forestry, the practice of maintaining stand legacies in harvested forests, is used to create more complex forest structure and positive biodiversity outcomes in managed forests. However, the relative effectiveness of different retention strategies at increasing forest structural complexity and populations of dependent wildlife species is not well understood. We used an experimental study to evaluate changes in the population density of three small mammal species in response to different size and location (riparian or upland) of retention tree patches within harvested forests in the Pacific Northwest, USA. We further assessed whether small mammal density varied in relation to differences in structural complexity within retention patches among experimental retention stands. Within stands, deer mice (Peromyscus spp.) population density did not differ between retention and harvested areas (β = −0.05, SE = 0.06), Townsend’s chipmunk (Neotamias townsendii) density was higher in retention compared to clearcut areas (β = 1.61, SE = 0.10), and creeping vole (Microtus oregoni) density was highest in clearcut areas (β = −0.68, SE = 0.10). At the stand-scale, deer mouse density and chipmunk density were lowest in stands with large upland patches of retention (mean = 83, SD = 28 trees) and highest in stands with multiple small patches of upland retention (mean = 8, SD = 2 trees). Creeping vole density followed the opposite pattern, highest in stands with large upland patches and lowest in stands with multiple small patches. Densities of each species were intermediate in stands where at least a portion of the retention trees were connected to forested riparian buffers. Relating the density of each species to structural complexity within stands revealed that Townsend’s chipmunk density increased with increasing retention tree blowdown (β = 0.39, SE = 0.08), a proxy for downed wood resources, whereas creeping vole density decreased (β = −0.51, SE = 0.12), and deer mice density did not change consistently (β = 0.00, SE = 0.08). Furthermore, retention tree mortality was highest in the experimental treatment with several small patches and lowest in the treatment with a single large patch. Our results demonstrate that adopting dispersed retention patch patterns increases the abundance of small mammals in managed, early-seral forests in the Pacific Northwest. This relationship is at least partly mediated through higher levels of structural complexity within small retention patches caused by increased retention tree blowdown compared to larger patches.

Diagnostic value of combined nucleic acid and antibody detection in suspected COVID-19 cases

ObjectivesNucleic acid testing is the gold standard method for the diagnosis of coronavirus disease 2019 (COVID-19); however, large numbers of false-negative results have been reported. In this study, nucleic acid detection and antibody detection (IgG and IgM) were combined to improve the testing accuracy of patients with suspected COVID-19. Study designThe positive rate of nucleic acid detection and antibody detection (IgG and IgM) were compared in suspected COVID-19 patients. MethodsA total of 71 patients with suspected COVID-19 were selected to participate in this study, which included a retrospective analysis of clinical features, imaging examination, laboratory biochemical examination and nucleic acid detection and specific antibody (IgM and IgG) detection. ResultsThe majority of participants with suspected COVID-19 presented with fever (67.61%) and cough (54.93%), and the imaging results showed multiple small patches and ground-glass opacity in both lungs, with less common infiltration and consolidation opacity (23.94%). Routine blood tests were mostly normal (69.01%), although only a few patients had lymphopenia (4.23%) or leucopenia (12.68%). There was no statistical difference in the double-positive rate between nucleic acid detection (46.48%) and specific antibody (IgG and IgM) detection (42.25%) (P = 0.612), both of which were also poorly consistent with each other (kappa = 0.231). The positive rate of combined nucleic acid detection and antibody detection (63.38%) was significantly increased, compared with that of nucleic acid detection (46.48%) and that of specific antibody (IgG and IgM) detection (42.25%), and the differences were statistically significant (P = 0.043 and P = 0.012, respectively). ConclusionsNucleic acid detection and specific antibody (IgG and IgM) detection had similar positive rates, and their combination could improve the positive rate of COVID-19 detection, which is of great significance for diagnosis and epidemic control.

Linear-slip discrete fracture network model and multiscale seismic wave simulation

We propose a method to design a discrete fracture network (DFN) model for seismic wave simulations that eliminates complex meshing requirements and poor mesh design. An ant-tracking volume is generated from the original seismic to capture the global fracture geometry. A mesh structure is specified prior to adding fractures. Fractures are then specified on the mesh in the form of small fracture patches following the trend of ant-tracking signals in the previously defined mesh. In the proposed method, the implementation of the DFN model is thus independent of the mesh structure. Also, fracture clusters in the final DFN model are composed of multiple small patches, and each small patch is represented by the linear slip model in the form of a discontinuity of the displacement field. We also performed wave simulations to validate the proposed method of DFN model building, and investigated the wave behavior in the given fracture structure. For efficient implementation of wave modeling, we employed the generalized multiscale finite element method to discretize the elastic wave equation with explicit fractures. The wave simulation results show that a small fracture segment could be ignored when the wavelength is long enough; however, fracture clusters can induce large displacement discontinuities and wave scattering, and these effects become obvious as we apply high source frequency.

Coupled-layer based visual tracking via adaptive kernelized correlation filters

Part-based visual model is particularly useful when the target appearance undergoes partial occlusion or deformation. The existing reliable patches tracking (RPT) method has achieved better result by identifying and exploiting the reliable patches that can be tracked correctly, yet it tends to fail in some challenging scenes since it ignores the holistic information of target completely, while, in fact, the target’s holistic appearance provides more discriminative features than local patches with low resolution. Based on the existing RPT and kernelized correlation filters tracking method, in this paper, we propose a coupled-layer visual model based tracker by combining the target’s global and local appearance in a coupled way. The global layer provides the holistic information and is treated as an approximation of the target. The local layer is composed of multiple small patches that are randomly initialized in the first frame. During tracking, the global tracker detects the target itself; its detection result is employed in the local layer to exploit the reliable patches and to estimate the target position corresponding to each patch. The exploited reliable patches are employed to estimate the target scale and to vote the current target location. Finally, both global and local models are updated with carefully designed updating mechanisms. Experiments conducted on 80 challenging benchmark sequences clearly show that our tracker improves the RPT tracker significantly both in overall and individual performance yet without obvious speed cost. Also, our tracker outperforms all the state-of-the-art trackers in overall datasets and eight independent datasets.

Statistics of Echoes From a Directional Sonar Beam Insonifying Finite Numbers of Single Scatterers and Patches of Scatterers

When a sonar beam sweeps across a field of scatterers and insonifies a different set of scatterers in each ping, the echoes can fluctuate significantly from ping to ping. For a homogeneous spatial distribution of scatterers in which there are a large number of scatterers in each sonar resolution cell, the echoes tend to be Rayleigh distributed. However, the echoes can be strongly nonRayleigh when there is a small number of scatterers in the sonar resolution cell-a condition that can occur with a narrow beam sonar. For scatterers randomly distributed in the sonar beam, the corresponding random weighting associated with the beampattern also significantly contributes toward a non-Rayleigh distribution when the number of scatterers is small. In this paper, a general formulation for echo statistics is developed by combining equations derived by Ehrenberg etal. [Proc. Conf. Eng. Ocean Environ., vol. 1, pp. 61-64,1972 and J. Acoust. Soc. Amer., vol. 69, pp. 955-962, 1981] and Barakat [Optica Acta, vol. 21, pp. 903-921,1974] to account for a directional sonar beam involving an arbitrary finite number of scatterers, each with an arbitrary echo probability density function (pdf), each randomly located in the beam, and each correspondingly randomly weighted by the beampattern. Theoretical predictions are made, along with numerical simulations for validation, for a range of cases including: 1) a range of number of scatterers each randomly located in the beam and 2) several different echo pdfs of the scatterers. Here, a single scatterer could be a patch of scatterers whose overall dimensions are much smaller than the resolution cell of the sonar beam and multiple scatterers could be multiple small patches. Although the application is intended for volumetric patches, the formulation could be applied to areal patches under appropriate conditions. The formulation applies directly to the geometry of the short-range direct-path sonar in which there are no reflections due to boundaries such as the seafloor and sea surface.

Fusarium Wilt of Strawberry Caused by Fusarium oxysporum in California.

Beginning in 2006 and continuing into 2009, an apparently new disease of strawberry (Fragaria × ananassa) affected commercial plantings (cvs. Albion, Camarosa, and others) in coastal (Ventura and Santa Barbara counties) California. Symptoms consisted of wilting of foliage, drying and withering of older leaves, stunting of plants, and reduced fruit production. Plants eventually collapsed and died. Internal vascular and cortical tissues of plant crowns showed a brown-to-orange-brown discoloration. Differences in cultivar susceptibility were not recorded. Internal crown and petiole tissues, when placed on acidified corn meal agar, consistently yielded Fusarium isolates having similar colony morphologies. No other pathogens were isolated. The Fusarium isolates were subcultured on carnation leaf agar and observed to be producing macroconidia and microconidiophores that are diagnostic of Fusarium oxysporum (1). For two of these isolates, the internal transcribed spacer region comprising ITS1, ITS2, and 5.8S rRNA was amplified using primers ITS-1 and ITS-4 (3). On the basis of a comparison of 515 bp, both isolates had the identical sequence, which was a 100% match for 30 accessions of F. oxysporum in GenBank. This comparison included several formae speciales of F. oxysporum, but F. oxysporum f. sp. fragariae, a previously described pathogen of strawberry (4), was not included. The isolates are archived in the Department of Plant Pathology at UC Davis and are available on request. Both sequenced isolates plus four others were tested for pathogenicity on strawberries. For these tests, spore suspensions of 1 × 105 conidia/ml were prepared separately for six isolates. Roots of strawberry transplants (12 plants of cv. Camino Real) were cut and soaked in spore suspensions for 10 min. Plants were potted in soilless, peat moss-based medium in containers. Control strawberry plants were soaked in water prior to planting. All plants were then grown in a shadehouse. After 8 weeks, inoculated plants began to show wilting and decline of foliage and internal crown tissue was lightly discolored. F. oxysporum was isolated from all inoculated plants. Control plants did not exhibit any disease symptoms and crown tissue was symptomless. To our knowledge, this is the first report of Fusarium wilt of strawberry in California. This disease has been reported from a number of other countries including Argentina, Australia, China, South Korea, Spain, and Japan (2). Since 2006, Fusarium wilt of strawberry has increased in incidence and severity in California. Initial problems in 2006 consisted of multiple small patches (2 to 4 beds wide × 3 to 10 m long) of diseased plants; in these patches disease incidence could range from 80 to 100%. By 2009, in some fields, the disease affected large sections that ran the length of the field.

Multiple vibrissae sensory regions in rat cerebellum: A (14C) 2‐deoxyglucose study

Repetitive tactile sensory stimulation of the right mystacial vibrissae (whiskers) was performed in awake, adult rats. Regions of increased (14C) 2-deoxyglucose (2DG) uptake were mapped autoradiographically in cerebellum. Predominantly ipsilateral activation of multiple discrete granule cell regions occurred in paramedian lobule, crus 2, crus 1, lobulus simplex, and anterior lobe hemisphere. Bilateral and contralateral activation of cerebellum did occur. Multiple small patches, as well as large granule cell regions, were activated. Mossy fiber afferents from the spinal trigeminal nuclei (particularly interpolaris), principal trigeminal sensory nucleus, and superior colliculus could account for metabolic activation of the granular layer. The slight metabolic activation of the molecular layer could have occurred from climbing or parallel fibers. Comparisons of the paramedian lobule granule cell regions activated during repetitive sensory stimulation of the vibrissae (RSSV) to those activated during vibrissae motor cortex stimulation (VMIS) showed regions only activated by RSSV, regions only activated by VMIS, and regions activated by both RSSV and VMIS. The granule cell regions activated during RSSV and VMIS were usually adjacent to or overlapping each other. Regions only activated during RSSV or only during VMIS could represent technical problems in trying to compare vibrissae motor and sensory pathways in two different groups of animals. Alternatively, cerebellar regions activated only during RSSV could process vibrissae tactile inputs. Regions activated only during VMIS could process vibrissae motor and perhaps proprioceptive sensory input. Regions activated during both RSSV and VMIS might process vibrissae proprioceptive sensory input and/or might represent loci where vibrissae motor, proprioceptive sensory, and tactile sensory convergence occur. The results raise the possibility that vibrissae motor, proprioceptive sensory, and tactile sensory pathways could be processed in separate granule cell patches in parts of cerebellum and in the same granule cell patches in other parts of cerebellum.

Regression of Pulmonary Metastases from Mammary Carcinoma Following Inactivation of Ovaries by Irradiation

It has been well established that certain mammary carcinomas recede definitely following the withdrawal of ovarian hormonal stimulation. Beatson (2), in 1896, reported shrinkage of primary tumors, regression of metastases, and improvement in the general condition of patients following oophorectomy. Wintz (8) appears to have first used roentgen castration as an adjuvant in the treatment of carcinoma of the breast. Ahlbom (1) reported the treatment of 163 cases with rather indeterminate results. Martin (4), Dresser (3), Smith (5), and Taylor (6) have reported regression of metastases in bone following roentgen castration and have given excellent reviews of the literature. Dresser observed regression of skeletal metastases in 30 per cent of cases, clinical improvement without evident regression in 43.3 per cent, and no response in 26.6 per cent of a total of 30 cases under 45 years of age. Pulmonary metastases from carcinoma of the breast present a dismal and distressing picture. The progressive, intractable symptoms of cough, pain, and dyspnea harass the patient and confound the physician. Treves (7) has recently shown that administration of radiotherapy to the lungs is deleterious rather than beneficial to the patient. Dresser (3) reported regression of pulmonary metastases in one case following 600 roentgens to the pelvis through anterior and posterior ports. We have observed striking and unexpected regression of pulmonary metastases with relief of symptoms in two cases following inactivation of ovaries by irradiation. Case Reports Case 1. V. S. Nebraska Methodist Hospital. Referred by C. R. Kennedy, M.D., on Feb. 3, 1933. Housewife, aged 35. A radical mastectomy had been done five years previously for a Grade III adenocarcinoma of the right breast. She entered the hospital with a history of gradually increasing unproductive cough, pain in the back, failing vision, and loss of 30 pounds in weight during four months. Examination showed numerous hard lymph nodes in the left axilla and dullness over the right chest. She was unable to count fingers at two feet with the left eye and an ophthalmoscopic study showed edema of the optic disc and congestion of the retinal veins. Roentgenographic study of the chest on Feb. 3, 1933 (Fig. I-A) showed infiltration through the upper two-thirds of the right pulmonic field with multiple small patches of deposit through each lung. There was extensive destruction of the ribs and lumbar vertebræ. The skull showed multiple metastases (Fig. 2-A). Therapy consisted of 475 roentgens anteriorly and posteriorly over the pelvis, 200 kv.p., through 0.5 mm. Cu and 2 mm. A1, 60 cm. distance, 20 × 20 cm. port. Also, 475 roentgens were delivered anteriorly and posteriorly to the spine and chest and 475 roentgens laterally to the skull. Pain in the back was relieved within a few days, vision gradually improved, and the cough was alleviated after six or eight weeks.