nils-herrmann/clean_scirepeval huggingface dataset:
Locally Linear Embedding and its Variants: Tutorial and Survey

This is a tutorial and survey paper for Locally Linear Embedding (LLE) and its variants. The idea of LLE is fitting the local structure of manifold in the embedding space. In this paper, we first cover LLE, kernel LLE, inverse LLE, and feature fusion with LLE. Then, we cover out-of-sample embedding using linear reconstruction, eigenfunctions, and kernel mapping. Incremental LLE is explained for embedding streaming data. Landmark LLE methods using the Nystrom approximation and locally linear landmarks are explained for big data embedding. We introduce the methods for parameter selection of number of neighbors using residual variance, Procrustes statistics, preservation neighborhood error, and local neighborhood selection. Afterwards, Supervised LLE (SLLE), enhanced SLLE, SLLE projection, probabilistic SLLE, supervised guided LLE (using Hilbert-Schmidt independence criterion), and semi-supervised LLE are explained for supervised and semi-supervised embedding. Robust LLE methods using least squares problem and penalty functions are also introduced for embedding in the presence of outliers and noise. Then, we introduce fusion of LLE with other manifold learning methods including Isomap (i.e., ISOLLE), principal component analysis, Fisher discriminant analysis, discriminant LLE, and Isotop. Finally, we explain weighted LLE in which the distances, reconstruction weights, or the embeddings are adjusted for better embedding; we cover weighted LLE for deformed distributed data, weighted LLE using probability of occurrence, SLLE by adjusting weights, modified LLE, and iterative LLE.

Field of study: Computer science
The Northwest Atlantic Mid-Ocean Canyon

The Northwest Atlantic Mid-Ocean Canyon is a depositional–erosional linear feature which extends southward from the northern Labrador Sea to the Sohm Abyssal Plain. Analysis of the data accumulated over the past 20 yr allows us to conclude: (1) The canyon does not have any major tributaries; (2) it is Quaternary in age; and (3) it is not a tectonic feature. However, neither the source nor the sedimentary process which constructed the canyon can as yet be established.

Field of study: Environmental science
Recognition and Significance of Pumice in Marine Pyroclastic Rocks

Pumice is abundant in many ancient sequences of marine pyroclastic rocks and is regarded as important evidence that contemporaneous, or nearly contemporaneous, volcanic activity was the source of at least some of the fragmental debris. The pumice in many such sequences of rocks, however, is easily overlooked, chiefly because most marine pyroclastic rocks have been altered or metamorphosed to varying degrees, masking or obliterating the delicate cellular structures of the original pumiceous material. With care, however, and with the knowledge that pumice-rich rocks commonly occur toward the top of thick, vertically graded beds of lapilli tuff and tuff breccia, the elusive pumiceous fraction of most sequences of rocks can generally be recognized. Hand-lens examination of wetted specimens in the field will usually reveal the wispy and ragged outlines of some of the pumice that is present. More detail can be seen in thick sections and in conventional thin sections of pumiceous rocks. In general, the pumice in more altered and metamorphosed rocks can be seen by careful examination of hand specimens or thick sections; the pumice in relatively unaltered rocks can best be seen in thin section. Examples of pumice-rich rocks from the Precambrian of Arizona, the Cretaceous of Puerto Rico, and the Tertiary of Japan are described and illustrated.

Field of study: Geology
SU-FF-T-99: Impact of Proper Bladder and Rectum Delineation in the Evaluation of the Effectiveness of IMRT in Prostate Cancer Radiotherapy

This study compares and evaluates different bladder and rectum delineation approaches using IMRT plans for prostate cases. A more comprehensive treatment plan evaluation can be performed using the biologically effective uniform dose (BEUD) together with the complication‐free tumorcontrol probability (P +).  A single physician outlined the prostate planning target volume (PTV), rectum, bladder and femoral heads of 10 consecutive prostate patients. IMRTtreatment plans were created with the Pinnacle treatment planning system (TPS). Two different bladder and rectum delineation approaches were examined. In the first approach the whole volume of bladder and rectum were delineated, whereas in the second approach, the delineation included only the volume of the organs lying in the range of 2 margins around the PTV. In the second case, the DVHs were normalized to their volume (2std normalized) and to the volume of the whole organ (2std relative to whole).  At the optimum dose levels of the dose distributions using the whole volume of bladder and rectum, 2 std relative to the whole volume and 2 std normalized, respectively, the P + is 67.7%, 51.2% and 32.7% for a BEUDPTV of 86.7 Gy, respectively. The respective total control probabilities, P B are 89.0%, 82.4% and 82.4% whereas the corresponding total complication probabilities, P I are 21.3%, 31.2% and 49.7%. More specifically, the response probabilities of the different tissues are 89.0%, 82.4% and 82.4% for the PTV, 0.0%, 0.0% and 0.01% for bladder and 21.3%, 31.2% and 49.7% for rectum. At the initially prescribed dose level (mean dose to the PTV = 79.4 Gy) the P I values become 6.7%, 12.4% and 27.8%.  The expected radiation induced bladder and rectum complications using different delineation approaches, should be estimated used appropriate dose‐response parameters, which should have been determined from studies of similar organ delineation methodology.

Field of study: Medicine, Physics
Post-monsoon air quality degradation across Northern India: assessing the impact of policy-related shifts in timing and amount of crop residue burnt

The past decade has seen the increasing severity of air pollution episodes across much of the highly populated Indo-Gangetic Plain (IGP), particularly during the post-monsoon season when crop residue burning (CRB) is most prevalent. Recent studies have suggested that a major, possibly dominant, contributor to this air quality decline is that northwest (NW) Indian rice residue burning has shifted later into the post-monsoon season, as an unintended consequence of a 2009 groundwater preservation policy that delayed the sowing of irrigated rice paddy. Here we combine air quality modelling of fine particulate matter (PM2.5) over IGP cities, with meteorology, fire and smoke emissions data to directly test this hypothesis. Our analysis of satellite-derived vegetation fires shows that an approximate 10-day shift in the timing of NW India post-monsoon residue burning occurred since the introduction of the 2009 groundwater preservation policy. For the air quality crisis of 2016, we found that NW Indian CRB timing shifts made a small contribution to worsening air quality (3% over Delhi) during the post-monsoon season. However, if the same agricultural fires were further delayed, air quality in the CRB source region (i.e. Ludhiana) and for Delhi could have deteriorated by 30% and 4.4%, respectively. Simulations for other years highlight strong inter-annual variabilities in the impact of these timing shifts, with the magnitude and even direction of PM2.5 concentration changes strongly dependent on specific meteorological conditions. Overall we find post-monsoon IGP air quality to be far more sensitive to meteorology and the amount of residue burned in the fields of NW India than to the timing shifts in residue burning we have identified. Our study calls for immediate actions to provide farmers affordable and sustainable alternatives to residue burning to hasten its effective prohibition, which is paramount to reducing the intensity of post-monsoon IGP air pollution episodes.

Field of study: Environmental science
Testing for Quaternion Propriety

We consider the problem of testing whether a quaternion-valued Gaussian random vector is proper. The quaternion covariance matrix fully describes the second-order properties of a quaternion random vector only if the distribution is proper. The exact distribution of the likelihood ratio test under the hypothesis of propriety is derived for general sample size N and vector dimensionality p. As this is in terms of Meijer's G-function, various approximations are considered, including Box-type and saddlepoint approximations. We find in particular that a new approach matching the first three cumulants is easy to implement and extremely accurate.

Field of study: Engineering
Image fusion method based on simultaneous sparse representation with non-subsampled contourlet transform

The image fusion method based on sparse representation in the single-scale image domain has produced better fusion results than the classic methods based on multi-scale analysis nowadays. However, due to the limited number of dictionary atoms, it is difficult to provide an accurate description for image details in the sparse-representation-based image fusion methods, and it requires a lot of time. A novel dictionary is constructed with non-subsampled contourlet transform and sparse representation by using the proposed simultaneous strategy. Then the novel dictionary could combine the sparsity attribute of the learning dictionary with a multi-scale feature of non-subsampled contourlet transform. Moreover, the simultaneous strategy is combined with this novel dictionary so that sparse coefficients can be represented with the same dictionary atoms and thus they can be compared in a reasonable and accurate way. Finally, the image fusion method along with this novel dictionary is proposed and named non-subsampled contourlet transform (NSCT)-simultaneous sparse representation (SSR). Experimental results show that the proposed fusion method NSCT-SSR, with its more excellent fusion effect and better anti-noise capability, outperforms the existing fusion methods, which are based on both multi-scale domain and sparse representation in the single-scale image domain.

Field of study: Computer science
Noise correlations, entanglement, and Bell inequalities

In condensed matter physics, the interactions between the constituents of the system are typically known. The building blocks are mere electrons, protons and neutrons, their collective behavior has been shown to lead to a variety of astonishing phenomena. Classic examples of such quantum correlated systems are superconductivity , superfluidity  and the fractional quantum Hall effect (FQHE) . In these instances, the departure from usual behavior is often symptomatic of the presence of a non trivial ground state: a ground state which cannot be described by a systematic application of perturbation theory on the noninteracting system.

Field of study: Physics
Dynamics of 2D electron wave packets with different initial spin polarization in 2D structures with spin-orbit coupling

The effect of splitting and zitterbewegung of 2D-electrons wave packets in the presence of Rashba spin-orbit coupling has been investigated. It is shown that nonstandard dynamics of wave packets occurs in the systems where the complete system of eigenfunctions is formed by states with different chirality. The time evolution of wave packets depends on the initial electron spin orientation. It is established that the oscillations of packet centers decay with time. Similar effects were studied by us previously for packets with initial spin orientation perpendicular to the 2D electron gas plane.

Field of study: Physics
Reinforcing saccadic amplitude variability.

Saccadic endpoint variability is often viewed as the outcome of neural noise occurring during sensorimotor processing. However, part of this variability might result from operant learning. We tested this hypothesis by reinforcing dispersions of saccadic amplitude distributions, while maintaining constant their medians. In a first experiment we reinforced the least frequent saccadic amplitudes to increase variability, and then reinforced the central part of the amplitude distributions to reduce variability. The target was placed at a constant distance from the fovea after the saccade to maintain the postsaccadic visual signal constant and an auditory reinforcement was delivered depending on saccadic amplitude. The second experiment tested the effects of the contingency. We reinforced high levels of variability in 4 participants, whereas 4 other participants were assigned to a yoked control group. On average, saccadic amplitude standard deviations were doubled while the medians remained mostly unchanged in the experimental participants in both experiments, and variability returned to baseline level when low variability was reinforced. In the control group no consistent changes in amplitude distributions were observed. These results, showing that variability can be reinforced, challenge the idea of a stochastic neural noise. We instead propose that selection processes constrain saccadic amplitude distributions.

Field of study: Biology, Psychology
Preventing Electrical Shorts in Parallel-Plate Capacitors
with Single-Printed Dielectric Layer

Double-printing of dielectric layers is commonly used to prevent electrical shorts in parallel-plate capacitors, but this increases the thickness of the dielectric layer and diminishes the corresponding capacitance. Double-printing also complicates the production process and increases production costs. In this paper, it is demonstrated that capacitors with single-printed dielectric layers are without shorts if the layer is completely polymerized. Therefore, electrical shorts could also be related to the state of polymerization in a defect-free dielectric layer. To demonstrate this, the electrical functionality of capacitors with single-printed dielectric layers was studied in terms of intrinsic properties of the ultraviolet (UV) curable dielectric layer, which were varied according to the curing energy. The chemical structure of the cured layer was analyzed with infrared spectroscopy to obtain the appearance of polymerizable groups and crosslinks within the polymer structure. Differential scanning calorimetry was used to measure the glass transition temperature of the dielectric material. It increases rapidly with UV curing until the polymerization is completed, whereas a small increase with further curing confirms crosslinking of the polymer. The influence of structuring effects within a dielectric layer in the presence of electrical shorts between electrodes is discussed. This research confirms that a completely polymerized layer forms a barrier to leakage and helps to prevent the formation of conductive paths between electrodes. Therefore, a connection between the structure of polymerized layer and its electrical properties is highly reasonable.

Field of study: Materials science
Elementary study of PIN diode as device delayed breakdown

This paper summarizes an experimental study of the delayed breakdown performance of silicon PIN diode. Single PIN diode, double series PIN diodes and stacked PIN diodes in parallel and series were tested,the results shown that the pulsefronts of input voltage became steep obviously.Single PIN diode operates at a hold-off voltage exceeding 2.2 kV, and the time rate of voltage(dV/dt) is promoted from 0.95 kV/ns to 1.37 kV/ns. Double series PIN diodes operates at a hold-off voltage of 4.2 kV, and the dV/dt is promoted from 1.7 kV/ns to 2.3 kV/ns. Stacked PIN diodes in parallel and series operate at a hold-off voltage of 8.0 kV,and the dV/dt is promoted from 2.4 kV/ns to 3.2 kV/ns.

Field of study: Physics
Boron clusters: Do they receive the deserved interest?

New applications in which the carborane and metallacarborane species play a crucial role have been recently developed. In these applications, clusters display many particular characteristics that do not find parallel in their organic counterparts. The o-carborane can modulate the C···C distances depending on the substituents bonded to the cluster carbon atom and can lead to the formation of uncommon halogenophosphane charge-transfer “spoke ” complexes with iodine due to their electron-withdrawing capacity. Besides, metallacarboranes have been used as doping agents in organic conducting polymers and as catalysts in Kharasch reactions.

Field of study: Chemistry
Study on Reactive Power Optimization of Wind Farm Based on Voltage Stability Sensitivity

A method on reactive power optimization of wind farm based on voltage stability sensitivity is proposed.Equation on voltage stability sensitivity of SNB is presented.By aid of scheme of connecting Taipingli wind farm to Hunan power grid,reasonable reactive power allocation is suggested to improve voltage stability of power system which includes wind farm by means of reactive power optimization compensation calculation.

Field of study: Engineering, Physics
Masters of All They Surveyed: Exploration, Geography, and a British El Dorado (review)

Histories of British empire in the Americas tend to emphasize British activities in North America and the Caribbean. D. Graham Burnett reminds us that Britain's imperial project began with the sixteenth-century exploration of what is now Guyana by Sir Walter Ralegh, whose quest for El Dorado produced not only dreams of wealth and glory but an early map of Guyana's interior. As Burnett shows, later authorities would both appropriate and amend this map as part of the process of staking nineteenth-century territorial claims. In a book that draws from methods of literary analysis, imperial history, and the histories of science and cartography, Burnett uses the case study of a human agent (surveyor Robert H. Schomburgk) active in a mid-nineteenth century colonial territory (British Guyana) to further two distinct scholarly projects. First, Burnett analyzes traverse survey techniques for insight into cartographic and navigational science. Second, he looks at how imperial governments used science to justify territorial claims. Burnett's work, which draws heavily on Schomburgk's diaries, reports and maps, introduces the explorer as a key agent of empire as well as important to histories of discovery and science.

Field of study: History
A free boundary value problem related to the combustion of a solid: flux boundary conditions

We demonstrate the existence, uniqueness, and continuous dependence upon the data for the solution (u, v, s) of the free boundary value problem: ut = auxx, vt = (3vxx, 0 < x < s(t), 0 < t < T, u(x, 0) = (x), v(x, 0) = 0 < x < s(0) = b. -aux(0, t) = f(t), -0vx(O, t) g(t), 0 < t < T, aux(s(t),t) = -(7 + u(s(t),t))s(t), (3vx(s(t),t) = (n v(s(t),t))s(t), 0 < t < T, s(t) = u(v(s(t),t)) exp(—8/v(s(t),t))F(u(s(t), t)), 0 < t < T, where a,/3,7,6, and /x are positive constants related to the physical constants.

Field of study: Mathematics
Lees tussen die reëls... alle invoertariewe is nie gelyk nie

Invoertariewe of invoerregte word lankal nie meer gebruik as ’n maatreel om binnelandse bedrywe teen ingevoerde produkte te beskerm nie. Invoertariewe word deur die regering gebruik as handels- en -nywerheidsbeleidsinstrumente om plaaslike produksie, die behoud en skepping van werksgeleenthede, en internasionale mededingendheid te bevorder.

Field of study: Agricultural and Food sciences
The effects of UV‐B radiation on epidermal anatomy in loblolly pine (Pinus taeda L.) and Scots pine (Pinus sylvestris L.)

The effects of enhanced UV-B radiation on the needle anatomy of loblolly pine (Pinus taeda L.) and Scots pine (Pinus sylvestris L.) were studied in the field under supplemental UV-B radiation supplied by a modulated irradiation system. The supplemental UV-B levels were designed to simulate either a 16 or 25% loss of stratospheric ozone over College Park, Maryland. Enhanced UV-B radiation caused different responses in these two species. The needles of loblolly pine had larger amounts of tannin in the lumen of epidermal cells and more wall-bound phenolics in the outer epidermal walls of UV-B-treated needles, whereas the most pronounced effect on Scots pine needles was increased cutinization. In both species, the outer epidermal cell walls thickened and the needle cross-sectional and mesophyll areas decreased (statistically significantly only in Scots pine). This suggests that more carbon may have been allocated to the protection mechanisms at the expense of photosynthetic area. The difference in response between these species suggests that the response to UV-B radiation is not mediated by a single mechanism and that no generalization with regard to the effects of UV-B on conifers can be made.

Field of study: Environmental science
DRAINAGE EVOLUTION IN NORTHEASTERN MONTANA AND NORTHWESTERN NORTH DAKOTA

Topography and the distribution of gravels support suggestions by earlier investigators that the master streams of northeastern Montana and northwestern North Dakota flowed northward across the present trench of the Missouri until diverted in the Pleistocene. The age of the pre-diversion drainage is not precisely known. The ancestral streams cross early Tertiary structures. It has been suggested that the streams are antecedent and are pre-Tertiary. However, middle or later Tertiary superposition from a high-level erosion surface seems equally possible.

Miocene-Pliocene (?) gravels along the ancestral valleys indicate that the streams date back at least to the latter part of the Tertiary. A high-level gravel of possibly Oligocene or Miocene age parallels Yellowstone Valley for long distances, suggesting that the Yellowstone may have followed approximately its present path across the area in mid-Tertiary time.

The ancestral Missouri, Yellowstone, and Little Missouri rivers were diverted to form the present Missouri probably in Kansan time. This is earlier than the date proposed for the glacial Missouri in South Dakota, but the dates are not necessarily contradictory. Little Missouri River was diverted again by early Wisconsin ice and joins the Missouri 80 miles farther downstream than it did formerly.

Both the Yellowstone and Missouri hug the right sides of their valleys and apparently did so in pre-Pleistocene time. Uptilting to the northwest or the effects of terrestrial rotation are possible explanations. Further work is required to test these possibilities.

Field of study: Geology
Quantum confinement and phase transition in PbS nanowire: A first principles study

We report first principles density functional calculations of the electronic structures and energy bandgaps ( Δ E g ) in PbS nanowires (NW). The Δ E g is tuned by varying the diameter of the NW – revealing the role of quantum confinement . Compressive radial strain (CS) on the NW is shown to be responsible for a semiconducting to metallic phase transition. When compared with the valence band, the conduction band (CB) of the NW, which has a significant contribution from the excited 3 d -orbital of S, is found to be more sensitive to the CS with the CB minimum shifting towards and eventually crossing the Fermi energy as CS increases. The origin of the observed phase transition in a recent experiment is attributed to the CS on the PbS nanowire.

Field of study: Physics
Bromination of 2, 3-dimethylindole

In bromination of indoles, the bromine atom will most probably enter at position 2 or 3. For example, indole and 2-methylindole  brominate at position 3, while some 3-substituted indoles  brominate at position 2. In the case of 2, 3-dimethylindole it was shown [3], that bromine does not enter the benzene ring, as would have been expected, but adds to the active 2, 3 (double) bond of the indole.

Field of study: Chemistry