Inaccessible Field Research Articles

Space–time characterization of ultrashort laser pulses: A perspective

The characterization of ultrashort laser pulses has significantly advanced beyond the standard spatial and temporal diagnostics to now include sophisticated spatio-temporal measurement techniques. In this perspective, we provide an overview of the current state of space–time characterization, discussing the theoretical foundations of ultrashort laser pulses, the various measurement techniques and their design trade-offs, and the challenges and opportunities for future development. We explore the extension of these techniques to different wavelength regimes and delve into the unique challenges posed by the characterization of polarization-structured beams. The potential for data-driven analysis to enhance the information extracted from the measurements is highlighted, along with the need for direct measurement of previously inaccessible field components, such as the longitudinal electric field in tightly focused beams. As these diagnostic tools continue to evolve, we anticipate a future where the intricate space–time structure of light can be analyzed on a routine basis, opening up new frontiers in ultrafast science and technology.

Coding to Connect: Centering Joy and Community in Elementary Computer Science Education

In this piece, we weave together personal reflections to explore the design and implementation of an unplugged, elementary computer science (CS) event, and examine the underlying pedagogical principles guiding this work. Critical CS scholars have increasingly called for centering joy and connection within CS, while simultaneously decentering the neoliberal focus on workforce development. We aimed to forefront these ideas with a CS event supported and led by a multi-stakeholder partnership between preservice teachers, staff, and faculty within California State University, Dominguez Hills’ College of Education, and the students, inservice teachers, and administration at 186th St. Elementary School. Historically, CS is an inequitable and inaccessible field that does not prioritize diversity or inclusion. By bringing together numerous stakeholders from across the community for a CS event centering joy, we hoped to shift perceptions and experiences of CS and find better ways of supporting and inspiring all our students and teachers.

A Study on Prediction of Diabetic Coronary Heart Disease Using Machine Learning Algorithms

One of the most prevalent illnesses in today's fast-paced culture is coronary heart disease in people with diabetes. It is challenging to foresee the onset of diabetic heart disease, a chronic ailment that affects people all over the world. One common misconception about machine learning is that it is an inaccessible field of study reserved for nerdy academics. However, concerning accuracy to predict disease based on symptoms, many studies have turned to machine learning methods, and this study provides a comparative analysis of these methods appeared in published research articles. This paper takes a close look at the research into predicting diabetic coronary artery disease using machine learning techniques, as well as the many different combinations of learning algorithms that have been employed to do so.

Decoding the cybaltern: cybercolonialism and postcolonial intellectuals in the digital age

ABSTRACT In this article, I look at how the modes of knowledge production in the digital age construct new colonial relations. I argue that these cybercolonial hierarchies are defined by a new elite: an artificial intelligentsia. In this regard, I discuss how the epistemic shifts in cybercolonialism redefine the role of postcolonial intellectuals in the digital age. In order to trace these shifts, I analyse the 2018 data scandal concerning Cambridge Analytica, a now defunct British political consulting firm allegedly involved in electioneering in 68 countries, to show that the power held by this artificial intelligentsia is encoded within a largely inaccessible field of computing, producing information that looks rhetorically neutral but is artificial in nature. My analysis demonstrates that this kind of knowledge production deepens the geopolitical hierarchies between the Global North and South as it bears new mechanisms of silencing. For the silenced subjects in cybercolonialism I coin the term cybaltern. The cybaltern refers to a group of people whose voices are muted and rendered unheard, paradoxically despite and because of the digital tools available to them. With this in mind, postcolonial intellectuals are given the task of decoding the discursive gaps and traps that (re)produce a condition of cybalternity.

Correlative infrared optical coherence tomography and hyperspectral chemical imaging.

Optical coherence tomography (OCT) is a high-resolution three-dimensional imaging technique that enables nondestructive measurements of surface and subsurface microstructures. Recent developments of OCT operating in the mid-infrared (MIR) range (around 4 µm) lifted fundamental scattering limitations and initiated applied material research in formerly inaccessible fields. The MIR spectral region, however, is also of great interest for spectroscopy and hyperspectral imaging, which allow highly selective and sensitive chemical studies of materials. In this contribution, we introduce an OCT system (dual-band, central wavelengths of 2 µm and 4 µm) combined with MIR spectroscopy that is implemented as a raster scanning chemical imaging modality. The fully integrated and cost-effective optical instrument is based on a single supercontinuum laser source (emission spectrum spanning from 1.1 µm to 4.4 µm). Capabilities of the in situ correlative measurements are experimentally demonstrated by obtaining complex multidimensional material data, comprising morphological and chemical information, from a multilayered composite ceramic-polymer specimen.

A Systematic Assessment of Paddy Losses at Various Stages from Harvest to Storage in the State of Goa

Paddy, the main field crop of Goa, is not profitable due to small and fragmented landholdings, inaccessible fields, lack of farm work force and mechanization. A study was conducted to assess the post-harvest practices and losses of paddy in Goa using the methodology developed by AICRP-PHT, ICAR to estimate losses by enquiry and actual observation methods. The study indicated that traditional methods of manual harvesting, threshing, winnowing, sun-drying on road side, parboiling in brass pots and storage in woven polybags with Vitex negundo (lingur leaves) or neem leaves for unprocessed paddy and boric powder for milled rice, were practiced in the state during 2011-13 with a slight shift towards mechanization during 2013-15. Most of the rice mills in Goa needed modernization and product diversification. Data indicated total losses of 19.26±14.63 % and 11.31±12.09 % by enquiry, and 5.92±2.62 % and 9.04±9.74 % (excluding parboiling by observation) in various unit operations of paddy production in the year 2011-13 and 2013-15, respectively. No on-farm value addition by farmers was practiced. Interventions in terms of infrastructure and mechanization, sensitization through trainings on modern methods of harvesting, processing, value addition, and improved storage methods are required to reduce the postharvest losses in Goa, and ensure better profit margin for farmers.

A Systematic Assessment of Paddy Losses at Various Stages from Harvest to Storage in the State of Goa

Paddy, the main field crop of Goa, is not profitable due to small and fragmented landholdings, inaccessible fields, lack of farm work force and mechanization. A study was conducted to assess the post-harvest practices and losses of paddy in Goa using the methodology developed by AICRP-PHT, ICAR to estimate losses by enquiry and actual observation methods. The study indicated that traditional methods of manual harvesting, threshing, winnowing, sun-drying on road side, parboiling in brass pots and storage in woven polybags with Vitex negundo (lingur leaves) or neem leaves for unprocessed paddy and boric powder for milled rice, were practiced in the state during 2011-13 with a slight shift towards mechanization during 2013-15. Most of the rice mills in Goa needed modernization and product diversification. Data indicated total losses of 19.26±14.63 % and 11.31±12.09 % by enquiry, and 5.92±2.62 % and 9.04±9.74 % (excluding parboiling by observation) in various unit operations of paddy production in the year 2011-13 and 2013-15, respectively. No on-farm value addition by farmers was practiced. Interventions in terms of infrastructure and mechanization, sensitization through trainings on modern methods of harvesting, processing, value addition, and improved storage methods are required to reduce the postharvest losses in Goa, and ensure better profit margin for farmers.

MULTI-LEVEL HETEROGENEITY-AWARE ENERGY-EFFICIENT CLUSTERING TECHNIQUE FOR WIRELESS SENSOR NETWORKS

Wireless sensor networks (WSNs) are gaining popularity owing to their applications in diverse fields due to availability of low-cost, low-powered miniature components and their enormous capabilities to reach inaccessible fields. In this paper, a multilevel framework for heterogeneous WSNs has been proposed that decides the value of heterogeneity parameters for allotment of number of nodes and initial node energy at each level in a realistic manner. It also provides a common platform for researchers to analyze their protocol. To validate the proposed framework, Heterogeneity-aware Energy-efficient Clustering (HEC) technique is modified to develop multi-level HEC (M-HEC) technique. This technique is evaluated and analyzed at seven different energy levels for different performance metrics. The stability period of the M-HEC technique improves with increasing number of heterogeneity levels in general. An improvement of about 215%, 332%, 444%, 355%, 363%, and 368% was observed with each successive addition of heterogeneity level from level-2 onwards.

‘An Overpowering “Itch for Writing”’: R.K. Philp, John Denman and the Culture of Self-Improvement

Abstract The abstract for your paper is included below. This will appear online only. After a briefly prominent career in Chartism, Robert Kemp Philp (1819–82) became one of the most widely published authors in Victorian Britain, promoting self-help and self-improvement through education. From a background in magazine journalism, he moved to producing serialised reference works which, when completed, were re-published in book form. This hybridisation of periodical journalism and the non-fiction book created a genre distinct from popular novels, non-fiction and magazines, yet one which was indebted to all three. The best known, Enquire Within Upon Everything (1856) sold almost 1.3 million copies by 1900 and remained in print until 1973. However, Philp has not enjoyed an enduring reputation: almost all his work was published anonymously, while the consumption of popular non-fiction has been largely overlooked in histories of the printed word. John Denman (fl. 1863–9) inhabited the shadier world of horse racing, where he was a high-stakes gambler and promoted off-course betting after it was criminalised. The article establishes a profound connection between the apostle of self-improvement and the mercurial man of the Turf: Denman was Philp’s alias. Their careers are reconstructed and analysed. Social ambition and a desire for fame impelled Philp to be a profligate author; but both he and his alter ego claimed to systematise hitherto opaque, confusing and inaccessible fields of knowledge. Philp took significant risks legally, financially and with his family’s reputation and well-being. This contrasts sharply with the picture of domestic contentment Philp assiduously promoted as a writer, but ideals of self-improvement underpinned them both.

Residual effect of pre and post emergence herbicides and fertility levels on succeeding crops after soybean

Herbicides proved important tool in modern farming systems. With the intense farming practice and multiple cropping, the paucity of agricultural labour is seen. Their peak demand for a short period, inaccessible field conditions during crop seasons also encourages using herbicides in modern farming. But continuous application of herbicides in intense cropping systems may leads to it’s residue accumulation in the soil. This persistence of a herbicide may limit the choice of succeeding crops. Therefore, residual studies are essential to determine the feasibility of any herbicide. Rabi sorghum, bajra, barley and ragi are the important succeeding crops grown after soybean in South Saurashtra region. Therefore, the present study about residual effect of pre and post emergence herbicides and fertility levels in succeeding crops after soybean was undertaken at Instructional Farm of Junagadh Agricultural University, Junagadh during Kharif season of 2006. Eighteen treatment combinations comprising six levels of weed management practices as main plot treatments viz., W 1 Pre-emergence pendimethalin @ 0.5 kg ha + HW and IC at 30 DAS, W 2 – Postemergence quizalofop-ethyl @ 40 g ha at 25 DAS + HW and IC at 45 DAS, W 3 Post-emergence imazethapyr @ 75 g ha at 25 DAS + HW and IC at 45 DAS , W 4 2 HW + 2 IC at 20 and 40 DAS, W 5 Weed free upto 60 DAS through hand weeding and W 6 Unweeded control and three levels of fertilizers as sub plot treatments viz., F 1 20:40:20 kg N:P 2 O 5 :K 2 O ha F 2 30:60:30 kg N:P 2 O 5 :K 2 O ha F 3 40:80:40 kg N:P 2 O 5 :K 2 O ha were tried in Split Plot Design with three replications. The soil of the experimental plot was low in available nitrogen, medium in available phosphorus and high in available potash. Pre-emergence application of pendimethalin herbicide was done after 24 hours of sowing of soybean and post pre-emergence application of herbicide quizalofop-ethyl and imazethapyr was done after 25 days after sowing. The succeeding crops Rabi sorghum, bajra, barley and ragi were sown after harvesting of soybean within a week. The biometric observation about germination percentage of succeeding crops was done after 10 days of sowing. Plant height

Novel ‘stratified‐meander’ technique improves survey effort of the rare Pagoda Rock Daisy growing remotely on rocky cliff edges

SummaryThis pilot study of the rare Pagoda Rock Daisy (Leucochrysum graminifolium) in the western Blue Mountains of New South Wales (Australia) proposes a simple survey method combining timed meander and grid‐cell survey design to improve the survey effort required for monitoring of species growing in remote and/or inaccessible field locations. Where Pagoda Rock Daisies were known to be present, detection time was both rapid and effective (mean of 4.9 min for each 1 ha grid). Notably, the total survey effort remained constant for all grids, even though Pagoda Rock Daisies were unevenly distributed in the landscape (approximately 17 min/ha). Ultimately, the time required to traverse the landscape was deemed to be the primary limiting factor affecting survey effort. The application of this method is not restricted to challenging locations such as cliff edges; this method could be scaled according to the landscape or organism under investigation, providing a rapid method for surveying and monitoring rare, introduced or other plants from a site‐based scale to a broader geographic area.

Back to the Roots: Polynomial System Solving, Linear Algebra, Systems Theory

Multivariate polynomial system solving and polynomial optimization problems arise as central problems in many systems theory, identification and control settings. Traditionally, methods for solving polynomial equations have been developed in the area of algebraic geometry. Although a large body of literature is available, it is known as one of the most inaccessible fields of mathematics. In this paper we present a method for solving systems of polynomial equations employing numerical linear algebra and systems theory tools only, such as realization theory, SVD/QR, and eigenvalue computations. The task at hand is translated into the realm of linear algebra by separating coefficients and monomials into a coefficient matrix multiplied with a basis of monomials. Applying realization theory to the structure in the monomial basis allows to find all solutions of the system from eigenvalue computations. Solving a polynomial optimization problem is shown to be equivalent to an extremal eigenvalue problem. Relevant applications are found in identification and control, such as the global optimization of structured total least squares problems.

Analysis of bar morphology using multi-temporal and multi-sensor satellite images: Example from the Han Estuary, Korea

In the present paper, we report a new powerful technique of studying bar morphology using multi-sensor and multi-temporal satellite images with examples from the inaccessible field sites of the Han Estuary in Korea. The technique utilizes the ability of multi-spectral optical sensors for classifying the types of land cover, and the ability of synthetic aperture radar (SAR) for acquiring radar imagery during day and night, irrespective of cloud cover. Combining the data acquired by both types of sensors at different times, the bar morphology of the Han Estuary is analyzed in this study. The Han Estuary is situated on the North Limit Line (NNL) dividing North and South Korea, and considered to have retained its rich ecological value. However, because of the limited access to the estuary, little information is available on the morphology of the Han Estuary, and the technique based on satellite remote sensing described in this paper is the most suitable and only approach to obtaining information on such inaccessible areas. In the present paper, the bar morphology of the Han Estuary from the years 2000 to 2009 is investigated using multi-temporal spaceborne optical sensors including those on board of SPOT-5, LANDSAT-7, QuickBird, KOMPSAT-2, and OrbView-3, and also C-band synthetic aperture radar (SAR) on board of RADARSAT-1 and ENVISAT with limited field survey data. Sixteen sets of optical data and twelve sets of SAR data were used to study the spatial and temporal variations of bar morphology and the effects of tide and precipitation. The results show that there was some variation in shape and size of bars depending on the location. The tidal effect is large on the bars closer to the open Yellow Sea, and the effect of precipitation was observed on the bars located in the mouths of rivers. Based on the changes of the bar–water boundary, a topographical map was produced, showing the relative height of bars. Using the technique of satellite remote sensing, this paper has shown, for the first time, the long-term bar morphological characteristics of the restricted Han Estuary on the NLL, and the authors anticipate that the results together with the relative height map of bars will constitute the basis of future morphological and ecological studies in this important estuary.

Aptly named Aharonov-Bohm effect has classical analogue, long history

Writing about what is usually termed the Aharonov-Bohm (AB) effect, Peter Sturrock and Timothy Groves argue (Physics Today, April 2010, page 8) that the same physics was discovered a decade earlier 1 1. W. Ehrenberg, R. E. Siday, Proc. Phys. Soc. B 62, 8 (1949). and should rightly be called the Ehrenberg-Siday effect. I agree that Werner Ehrenberg and Raymond Siday deserve recognition for their anticipation of AB. Indeed, in recent talks celebrating the 50th anniversary of AB, I began by describing the unfairly neglected paper by Ehrenberg and Siday. Nevertheless, I have come to a different conclusion from Sturrock and Groves: The expression “Aharonov-Bohm effect” is justified, for two reasons.First, although there is no doubt that the work by Ehrenberg and Siday anticipated how inaccessible magnetic flux can influence electron interference, that was as a curiosity, at the end of a paper whose main emphasis was the Hamiltonian analysis of electron optics. By contrast, Yakir Aharonov and David Bohm emphasized from the start, as an essential and general aspect of quantum mechanics, the physical influence of inaccessible fields that act nonlocally through the vector potential.Second, Ehrenberg and Siday’s semi-classical approximation—essentially applying the Dirac magnetic phase factor to electrons traveling on either side of the flux—implies a wavefunction that is multivalued and therefore not the correct solution of Schrödinger’s equation. The lack of a single-valued wavefunction leaves their prediction open to doubt. By contrast, Aharonov and Bohm derived the exact single-valued solution for waves scattered by a flux line. Recently, it was shown that the Ehrenberg-Siday approximation corresponds to the first terms in a “many-whirls” representation that treats the exact AB wavefunction as a topological sum over paths circling the flux. 2 2. M. V. Berry, J. Phys. A (in press). Attribution of credit is a delicate matter. It tends to excite strong feelings, and I write about it reluctantly. But the Ehrenberg-Siday paper does seem to exemplify the unfortunate phenomenon identified by Alfred North White-head in a 1916 address to the British Association for the Advancement of Science: “Everything of importance has been said before, by someone who did not discover it.”In a companion letter in the April 2010 issue, Alexander Ershkovich correctly points out that the AB effect is present in classical Hamiltonian mechanics, even though remote magnetic fields cannot influence Newtonian trajectories. He advocates a “search for experiments that might prove … a classical analogue of the Aharonov-Bohm effect.” Such an experiment exists already. In the classical physics of waves on a moving medium, the flow velocity acts like the vector potential in quantum mechanics, so the flow vorticity acts like the magnetic field; the analogy is precise. Fine details of the AB wavefunction were observed in ripples on the surface of water swirling irrotationally into a bathtub vortex, 3 3. M. V. Berry, R. G. Chambers, M. D. Large, C. Upstill, J. C. Walmsley, Eur. J. Phys. 1, 154 (1980). whose core is the analogue of inaccessible magnetic flux. REFERENCESSection:ChooseTop of pageREFERENCES <<CITING ARTICLES1. W. Ehrenberg, R. E. Siday, Proc. Phys. Soc. B 62, 8 (1949). Google ScholarCrossref2. M. V. Berry, J. Phys. A (in press). Google Scholar3. M. V. Berry, R. G. Chambers, M. D. Large, C. Upstill, J. C. Walmsley, Eur. J. Phys. 1, 154 (1980). Google ScholarCrossref© 2010 American Institute of Physics.

Ultrafast differential ion mobility spectrometry at extreme electric fields in multichannel microchips.

The maximum electric field intensity (E) in field asymmetric waveform ion mobility spectrometry (FAIMS) analyses was doubled to E > 60 kV/cm. In earlier devices with >0.5 mm gaps, such strong fields cause electrical breakdown for nearly all gases at ambient pressure. As the Paschen curves are sublinear, thinner gaps permit higher E: here, we established 61 kV/cm in N(2) using microchips with 35 microm gaps. As FAIMS efficiency is exceptionally sensitive to E, such values can in theory accelerate analyses at equal resolution by over an order of magnitude. Here we demonstrate FAIMS filtering in approximately 20 micros or approximately 1% of the previously needed time, with a resolving power of about half that for "macroscopic" units but sufficing for many applications. Microscopic gaps enable concurrent ion processing in multiple (here, 47) channels, which greatly relaxes the charge capacity constraints of planar FAIMS designs. These chips were integrated with a beta-radiation ion source and charge detector. The separation performance is in line with first-principles modeling that accounts for high-field and anisotropic ion diffusion. By extending FAIMS operation into the previously inaccessible field range, the present instrument advances the capabilities for research into ion transport and expands options for separation of hard-to-resolve species.

Integrated use of SRM, Landsat ETM+ data and 3D perspective views to identify the tectonic geomorphology of Dehradun valley, India

The present study aims to develop an integrated shaded relief model (SRM), remote sensing image and three‐dimensional (3D) perspective view based approach for delineating tectonic geomorphology of the Dehradun Intermontane valley, India. SRM created from digital elevation model (DEM) actually represents the information of the bare ground surface without any surface cover such as vegetation and landuse. Under user‐specified positions of the sun, this was useful in enhancing the lineaments. This, coupled with Landsat ETM+ data and 3D perspective views has proven to be a very good tool for the identification of geological features. In a hilly terrain, like the present area, having dense forest cover, many places are inaccessible and geological field mapping is quite difficult. This approach successfully identified tectonic geomorphological features like faults, alluvial fans and terraces in the present area. Comparison of the identified faults and geomorphic features with published work and field checks reveals that this method of mapping can reduce the time and effort required in fieldwork to a large extent.

Community participation as an interactive learning process: experiences from a schistosomiasis control project in Zimbabwe

A schistosomiasis control project was undertaken from 1994 to 1998 in Guruve District, Zimbabwe, based on the active involvement of local communities in the growing and application of the molluscicidal plant Phytolacca dodecandra as a supplement to other control measures such as chemotherapy and health education. The berries of P. dodecandra are highly molluscicidal to the intermediate host snails of schistosomiasis and is rapidly degradable in water. It was observed that plant care fluctuated during the study period. Only a few households participated in snail control activities, although 97% of respondents in a baseline survey had stated a willingness to take part. This invoked an investigation to explore the reality from a user perspective. Focus group discussions, semi-structured interviews and observations were used to solicit information. In spite of a cultural inclination for collective work, many reasons for low-level involvement emerged, inter alia the low perceived value of the project, demands for tangible benefits, inaccessible fields and weak leadership. This study shows that community participation is a complex process upon which a multiplicity of social and cultural determinants have an impact. If community participation is to become successful in development programmes it ought to be viewed as a mutual learning process where obstacles are identified and discussed and solutions shared among community members and project staff.

Archaeomagnetism: An Error Assessment of Fired Material Observations in the British Directional Database.

The direction of the geomagnetic field in Britain is now moderately well established for the last 2, 000 year based on analyses of the directions of magnetic remanence isolated at some 466 archaeological sites in Britain and parts of N.E. France. The vast majority of these observations are of fired, in situ archaeological materials, with only 21 site observations being based on sediments. Most of these findings are only available in virtually inaccessible field reports and theses, or similar such publications, so the summary mean site British values have been placed into a database; this has then been extended to include may directional observations on a global basis. These data are now available as Dbase and Access databases, as well as in ASCII form. It is hoped that such data will enable more detailed secular variation studies to be undertaken and encourage other workers to add their observations to this database, particularly those that may otherwise be observed scatter with that expected from archaeomagnetic, geomagnetic and archaeological site sources suggest that the precision of the mean direction is only a partial estimate of the total error, evaluated as being of the order of ±5° for any given site that may have taken place after the last heating. There is also clear evidence for invalid age assignments in some of the published data but increasing archaeomagnetic data are now enabling such errors to be re-evaluated and the technique is thus improving as more data accumulate.

A bound state model of the electric Aharonov-Bohm effect

It is shown how the electric form of the Aharonov-Bohm effect can be demonstrated using a very simple one dimensional bound state model system. The measurable effects of an inaccessible field in such a model are examined and the results of some explicit calculations are given. Their bearing on the question of the localization of electromagnetic causation in quantum mechanics is discussed.

The scattering of charged particles on the toroidal solenoid

The charged particle scattering amplitude on the magnetic field of a toroidal solenoid is obtained in the first Born and high-energy approximations. It is shown that multiconnectedness of the accessible space, non-triviality vector potentials in it and the single-valuedness of the wavefunctions used are not enough for the existence of the Aharonov-Bohm effect. Criteria are given for this. Surrounding the toroidal solenoid with barriers of different geometrical forms, the author observes that the magnetic field contribution to the scattering amplitude depends crucially both on the barrier height and its form. The latter could hardly be explained by particle penetration into the H not=0 region. The author proposes an addendum to Tonomura's experiments which probably could clear up any doubts about the existence of the AB effect. The gedanken experiment is discussed which shows that the effect of inaccessible fields could be observed even in a simply connected space.