504 research outputs found
The role of part structure in the perceptual localization of a shape
No full textThe process of object localization may be accomplished with respect to a particularreference location, such as the center of gravity, COG (eg Vishwanath and Kowler, 2003 VisionResearch 43 1637-1653). Here, we investigated how part structure affects an object's referencelocation. The reference location was evaluated with a measure of the illusory displacement of an internal target element embedded within a larger object (Morgan et al, 1990 Vision Research 30 1793-1810). To examine whether the reference location is different for shapes with part structure, two shapes were tested: circle (small and large; no part structure) and bell (shape with two parts, one larger than the other). Results were examined with respect to two predictions: either the location of an object is based on its shape as a whole, disregarding part structure (ie a single, overall COG), or the parts are processed separately (different COGs).With the circles, the results showed a systematic illusory displacement of the internal target toward the COG. With the bell, the illusion was significantly weaker than with both circles--even though the main part of the bell had the same size as the small circle, and its horizontal axis had the same extent as the large circle. Moreover, the distance judgments for the bell were consistent with a (weaker) reference point being located at the COG of the larger part, rather than at the COG of the entire bell. These results show that the part structure of a shape plays a role in the representation of its location, and that for complex shapes the perceived location of an embedded element depends more on the parts within which it is embedded, rather than on the whole shape.Supported by the Air Force Office of Scientific Research, Grant AF 49620- 02-1-0112, Life Sciences Directorate to Eileen Kowler, and by NSF, Grant BCS-0216944 to Manish Singh.AF 29620-02-1-0112; to Eileen KowlerNSF BCS-0216944; to Manish SinghDenisova, Kristina, Manish Singh, Eileen Kowler, 2006. The definitive, peer-reviewed and edited version of this article is published in Perception, 35, 1073-1087, DOI:10.1068/p5518
Dynamic modeling and forecasting algorithms for financial data systems
No full textIt is a valid question that why a Control Systems Engineer would be interested in dealing with financial instruments. Financial instruments involving option theory are very elegant, math oriented and practical. These mathematical tools have created a new industry known as 'Derivative Industry' or 'Hedge-Fund Industry' or so called 'Risk-Management Industry'. This thesis is aimed at developing investment strategies involving the decision making needs via control system techniques. The problem, in general, is computationally challenging particularly when investment of many securities is involved resulting in a high dimensional computational framework. Furthermore, complications may arise due to realistic restrictions and non-linearities. The various areas of financial engineering are very fertile for the application of the system methodology and control theory techniques. Modeling, optimization, identification and computational methods used in the Systems Engineering can be successfully applied to the financial instruments. The ideas developed in this thesis are more about the scientific reasoning involving financial instruments rather than specific situations alone. Major contribution of this thesis is the time series optimal prediction filter and the development of the Dynamic Modeling and Forecasting Algorithm (DMFA). The proposed algorithm predicts the next data point of the financial time series while dynamically computing the parameters from existing data. The computation of the parameters is optimized by use of the recursive matrix inversion algorithm. The system is solved via an innovative technique of inversion such that it avoids explicit inversion of more than a 2 X 2 matrix and computation of higher dimensional determinants and co-factors. This results in new contributions to computation finance and numerical methodology along with arbitrage decision and hedging strategies under market uncertainties as well as robust control applications. The minimum mean-square algorithm used assures system stability via poles within the unit circle. The DMFA method is a superior auto regression (AR) model as a general system of time-series realizations in-order to calculate the coefficients that fit the model for a better prediction. Theoretical modeling and market specific volatility models, updated volatility computation are derived from the observation data.Ph.D.Includes bibliographical referencesIncludes vitaby Manish Mahaja
Should I add orthobiologics to my knee osteotomy practice? A systematic review
No full textImportance: Orthobiologics has seen a renaissance over the last decade as an adjunct therapy during osteotomy due to the limited inherent regenerative potential of damaged intraarticular tissues. Aim or objective: This systematic review aims to present the latest evidence regarding using orthobiologics with simultaneous high tibial osteotomy (HTO) for knee osteoarthritis. The results of this study may guide surgeons to improve their clinical results and clear the air regarding confusion over whether or not to add orthobiologics to HTO in clinical practice backed by scientific evidence. Evidence review: According to PRISMA guidelines a systematic search for relevant literature was performed in the PubMed (MEDLINE), Scopus, EMBASE, and Cochrane Library databases of all studies published in English from January 1990 to May 2023. The following search terms were entered into the title, abstract, and keyword fields: "knee" or "osteotomy" AND "valgus" or "varus" AND "regenerative medicine" or "PRP" or "mesenchymal stem cells" or "stem cells" or "BMAC" or "bone marrow" or "growth factors" or "umbilical cord blood-derived mesenchymal stem cell" or "stromal vascular fraction". The AMSTAR-2 checklist was used to confirm the quality of the systematic review. Randomised controlled trials (RCTs), prospective and retrospective comparative cohort studies, case-control studies, and case series were included. Studies that reported clinical outcomes in patients treated with knee osteotomy for varus/valgus knee with concomitant adjunction of regenerative treatment [Platelet-rich plasma (PRP), Adipose-derived stem cells (ADSC), Human Umbilical Cord Blood-Derived (HUCBD), Mesenchymal Stem Cells (MSC), bone marrow aspirate concentrate (BMAC), stromal vascular fraction (SVF)] were included. The outcome measures extracted from the studies were the KOOS score, Lysholm score, Subjective IKDC, WOMAC Score, KSS, Tegner, HSS, radiographic tibiofemoral angle, posterior tibial slope and complications. The current systematic review is registered in the PROSPERO Registry (CRD42023439379). Findings: Osteotomy for unicompartmental arthritis with adjunction of orthobiologics such as PRP, ADSC, HVCBD, MSC, BMAC, and SVF presents a consistent statistically significant clinical improvement compared to preoperative scores regardless of the treatment modality used and there were no notable complications associated with the use of these novel agents. Conclusions and relevance: Orthobiologics and knee osteotomies could improve outcomes in patients with knee osteoarthritis desiring Knee preservation surgeries. However, only a few studies are available on the topic to conclude anything with certainty, the patients included in the studies could not be disintegrated based on the grade of osteoarthritis (OA), type, dosage and frequency of administration of orthobiologic and type of additional surgical procedures used. Therefore, better-structured RCTs are required to implement this finding into routine Orthopaedic practice. Level of evidence: Level 4
Both Hamstring and Quadriceps Tendon Autografts Offer Similar Functional Outcomes After Arthroscopic Anterior Cruciate Ligament Reconstruction in Patients Aged 50 Years or Older
No full textPurpose: To compare the outcomes of hamstring tendon (HT) and quadriceps tendon (QT) autografts for anterior cruciate ligament (ACL) reconstruction in patients aged 50 years or older in terms of patient-reported functional outcomes, graft failure rates, complications, return to sports activity, and sports preference. Methods: Between 2010 and 2022, prospectively collected data were obtained from an institutional database. Patients aged 50 years or older who underwent primary arthroscopic ACL reconstruction with either HT or QT autograft and had a minimum 2-year follow-up were included. Patients with concomitant meniscal, cartilage, and medial collateral ligament injuries were also included. Patients undergoing revision ACL reconstruction, those undergoing primary ACL reconstruction with a graft other than HT or QT autograft, and those with contralateral knee injuries or ipsilateral osteoarthritis (Ahlbäck stage ≥2) were excluded. Patients were evaluated in terms of the Lysholm knee score, Tegner activity level, and visual analog scale (VAS) score for pain before injury and at 2-year follow-up, as well as graft failure, QT rupture, and return to sport. The Mann-Whitney test was used to analyze unpaired samples, whereas the Friedman test was used to analyze variables over time. The χ2 statistic test was used to determine differences in categorical data between groups. Results: The number of patients in the QT and HT groups was 85 and 143, respectively. In the QT and HT groups, the mean age was 54.4 years (range, 50-65 years) and 56.4 years (range, 50-65 years), respectively, and 49% and 51% of patients were men, respectively. The 2 groups did not differ significantly in terms of age, sex, time from injury to surgery, and concomitant injuries. No significant differences in preinjury patient-reported outcome measures, consisting of the Lysholm score, Tegner activity level, and VAS pain score, were found between the 2 groups (P > .05). At the 2-year follow-up, the Lysholm knee score, Tegner activity level, and VAS pain score improved to preinjury levels and no significant differences in preinjury and 2-year follow-up functional scores were noted between the 2 groups (P > .05). Furthermore, at the 2-year follow-up, the Lysholm score and VAS pain score did not show significant differences (P = .390 and P = .131, respectively) between the QT and HT groups. Similarly, no differences in Tegner activity level were observed between the HT and QT groups at the 2-year follow-up. No significant differences in terms of the minimal clinically important difference were detected between the 2 groups for the Lysholm knee score (P = .410) and Tegner activity level (P = .420). The 2 groups did not differ in terms of patients’ percentage of sports participation at baseline and at the 2-year follow-up (P > .05). A significant decrease (P = .01) in participation in skiing/snowboarding was reported in the HT group at the 2-year follow-up compared with baseline (116 patients [81%] vs 98 patients [69%]). No case of graft failure or QT rupture was reported in either group. Conclusions: Arthroscopic ACL reconstruction using HT or QT autografts in athletically active patients aged 50 years or older provides satisfactory patient-reported functional outcomes and allows recovery of the preinjury level of activity. Level of Evidence: Level III, retrospective cohort study
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No full textResearch PaperReproductive problems among dairy animals are one of the major causes of loss in dairy sector. These problems can be tackled by imparting appropriate knowledge to the livestock owners. An attempt was made to measure the knowledge of livestock owners by developing a knowledge test on reproductive problems of dairy animals. The study was undertaken in Karnal district of Haryana state, India. Data were solicited from 300 livestock farmers who had at least one milch animal at the time of investigation. In addition to developing schedules for socio-economic variables, a knowledge test was also developed for measuring knowledge construct. Data were solicited on scientific treatment of affected dairy animals and 59.54% knowledge was observed on reproductive traits. Study indicates that majority of livestock farmers adopted scientific methods for treating their animals. Respondents’ age, extension contact and milk production were positively and significantly correlated with knowledge. Therefore, imparting quality practical training and periodical assessment of performance of lay inseminators for improving their skills and knowledge regarding estrus detection and insemination needs to be emphasized. Extension machinery has to be an ideal bridge between research/development institutions and dairy farmers for their catalytic effect (Meena & Malik, 2009). Extensive awareness programs are needed for inculcating scientific outlook among livestock farmers on these complex problems. Easy accessibility of veterinary hospital at village level can reduce the adoption of indigenous technical knowledge in treatment of these complex problems.Not Availabl
Reconstruction of the anterior cruciate ligament: a historical view
No full textManagement of anterior cruciate ligament (ACL) tears has continuously evolved since its first description in approximately 170 A.D. by Claudius Galenus of Pergamum and Rome. The initial immobilization using casts was replaced by a variety of surgical and conservative approaches over the past centuries. The first successful case of ACL repair was conducted by Mayo Robson in 1885, suturing cruciate at the femoral site. In the nineteenth century, surgical techniques were focused on restoring knee kinematics and published the first ACL repair. The use of grafts for ACL reconstruction was introduced in 1917 but gained popularity in the late 1900s. The introduction of arthroscopy in the 1980s represented the greatest milestones in the development of ACL surgery, along with the refinements of indications, development of modern strategies, and improvement in rehabilitation methods. Despite the rapid development and multitude of new treatment approaches for ACL injuries in the last 20 years, autografting has remained the treatment of choice. Compared to the initial methods, arthroscopic procedures are mainly performed, and more resistant and safer fixation devices are available. This results in significantly less trauma from the surgery and more satisfactory long-term results. The most commonly used procedures are still patellar tendon or hamstring autograft. Additionally, popular, but less common, is the use of quadriceps tendon (QT) grafts and allografts. In parallel with surgical developments, biological reconstruction focusing on the preservation of ACL remnants through the use of cell culture techniques, partial reconstruction, tissue engineering, and gene therapy has gained popularity. In 2013, Claes reported the discovery of a new ligament [anterolateral ligament (ALL)] in the knee that could completely change the treatment of knee injuries. The intent of these modifications is to significantly improve the primary restriction of rotational laxity of the knee after ACL injury. Kinematic studies have demonstrated that anatomic ACL reconstruction and anterolateral reconstruction are synergistic in controlling pivot displacement. Recently, there has been an increased focus on the application of artificial intelligence and machine learning to improve predictive capability within numerous sectors of medicine, including orthopedic surgery
The relationship between spatial pooling and attention in saccadic and perceptual tasks
No full textAbstractSaccades aimed at spatially extended targets land reliably at central locations determined by pooling information across the target shape [Melcher, D., & Kowler, E. (1999). Shape, surfaces and saccades. Vision Research, 39, 2929–2946; Vishwanath, D., & Kowler, E. (2003). Localization of shapes: Eye movements and perception compared. Vision Research, 43, 1637–1653]. Previous findings of saccadic errors when attempting to look at a target in the midst of distractors encouraged suggestions that pooling occurs indiscriminately, with little or no influence of a selective filter to eliminate the influence of nearby distractors. To determine the effectiveness of filtering, saccadic localization was studied for saccades made to a set of target elements (discs) interleaved with an equivalent set of distractors of a different color. With such interleaved elements, selection and spatial pooling are constrained to occur over the same spatial region. The results showed that filtering was effective and saccadic landing position was determined mainly by the target elements. Concurrent perceptual judgments made about the same stimuli (estimating the mean size of either target or distractor discs) showed better performance for the target discs than distractors, confirming that perceptual attention was allocated to the set of target elements. These results: (1) support the role of attention in setting the input to the spatial pooling process that guides saccades to spatially extended targets, and (2) show that perceptual judgments of mean value, often thought to impose modest attentional demands, are not immune to the constraints of this pre-saccadic filter
Adaptive particle encapsulation using digital opto-fluidic lithography
No full textEncapsulation of living cells using microgels has a wide range of applications in pharmaceutical research, tissue engineering, regenerative medicine, and personalized drug screening. Various cell encapsulation techniques have been proposed thus far focusing on creating cell-laden microgel particles. However, current techniques have limited control over the shape and size of the encapsulating particles and lack ability to address individual cells. This research aims to develop a method for adaptive encapsulation of particles with geometrically and biochemically complex micro-particles. To this end, we demonstrate image-based particle detection in a microfluidic channel and real-time in-flow lithography to encapsulate suspended particle employing a digital micro display as a dynamically reconfigurable virtual photomask. Digital dynamic mask is economical and offers the flexibility of rapidly changing the mask on demand. Microfluidic environment allows for mass production of micro-particles having various chemical composition in a continuous manner. Combining these unique capabilities, we present encapsulation of individual particles with graphically encoded information. Visual information (shape, size, and location) of polystyrene micro-beads suspended in a photo-curable liquid resin is acquired through digital imaging and subsequent image analysis, based on which desired digital patterns, possibly with graphical information, are created and optically projected on the target beads for lithographical in-flow encapsulation. The work presented in this thesis provides a new method for particle encapsulation, which has the potential to lead to a breakthrough solution in pharmaceutical engineering, cancer research, and tissue engineering.M.S.Includes bibliographical referencesby Manish Boorug
Biomolecular transport at and through two-dimensional materials
No full textTwo-dimensional (2D) materials have transformed single molecule nanoscale manipulation and molecular detection. Graphene is one such 2D material whose single-atom thickness and high in-plane electrical conductivity enables potential nanopore sensing applications for controllable nanofluidics and nanopore sensing applications conducive towards biomolecule sequencing. A nanopore sequencer operates by recording the ionic current as a single-stranded DNA molecule is electrophoretically driven through a nanopore; ionic current blockades unique to each nucleotide provide a key to the sequence readout. 2D materials provide the ultimate resolution by isolating one or two nucleotides in the nanopore at a given instance. A major challenge limiting the applications of nanopores for sequencing is the stochastic transport of DNA through the nanopore contributing to noise in the readout.
Experiments have tested DNA transport though graphene nanopores however the strong hydrophobic interactions between DNA and graphene limit DNA capture and transport. To increase throughput, exper- iments tested geometric modifications and chemical functionalization of the nanopore as well as altering the solvent conditions to control the passage of DNA through the nanopore with varying degrees of success. To optimize and test the design of nanopores in 2D materials, an atomistic description of these processes is extremely valuable.
Here, several modalities of controlling DNA and ion transport through graphene nanopores are compre- hensively investigated using all-atom molecular dynamics simulations. The first modality is an application of local electric potentials on the surface of free-standing graphene membranes to limit the transport speed of DNA. Charge on the graphene membrane was discovered to limit DNA transport as well as effect the conformation of adsorbed DNA on the surface of graphene. Similar potentials applied on the surface of graphene-silica-graphene hetrostructures were found to modulate the ion selectivity and induce ionic current rectification useful to serve as elements of a nanofluidic circuit. The second modality focuses on a con- trolled method of DNA delivery to the nanopore by harnessing the strong physioadsorption of DNA onto graphene and defects naturally present on the surface of graphene to guide the lateral transport of DNA to the nanopore opening. The defect guided delivery method may be potentially be used for precise delivery, concentration and storage of scarce biomolecular species and on-demand chemical reactions. Transport of DNA through the 2D material MoS2 in a specialized viscosity gradient was also investigated to determine the nature of molecular transport in unique solvent conditions. Lipid transport diffusion on graphene and the osmotic permeability and selectivity of the biological nanopore OmpF were characterized in conjunction with experiments. Results presented in this dissertation provide key insights into the design of solid-state nanopore based DNA sequencing devices.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2021-12-01The student, Manish Shankla, accepted the attached license on 2019-11-20 at 09:29.The student, Manish Shankla, submitted this Dissertation for approval on 2019-11-20 at 09:38.This Dissertation was approved for publication on 2019-11-21 at 11:09.DSpace SAF Submission Ingestion Package generated from Vireo submission #14572 on 2020-02-28 at 17:36:27Made available in DSpace on 2020-03-02T22:38:45Z (GMT). No. of bitstreams: 2
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