General Point Research Articles

Seshadri constants on blow‐ups of Hirzebruch surfaces

AbstractLet be integers and let denote the Hirzebruch surface with invariant . We compute the Seshadri constants of an ample line bundle at an arbitrary point of the ‐point blow‐up of when and at a very general point when or . We also discuss several conjectures on linear systems of curves on the blow‐up of at very general points.

The Nazi Bomb Project: A Case Study of Value Neutrality in Science and Technology

Scientists in Nazi Germany attempted but failed to build an atomic bomb or working nuclear reactor during the years of the Second World War, 1939-1945. Can philosophical meaning be drawn from this history? The history of the Nazi scientists and nuclear fission raises important issues concerning the alleged value-neutrality of scientific research and technological development. We can also ask whether there is an ethical dimension to the failure of the Nazi bomb project. Did the scientists who worked in the Third Reich make a moral decision not to complete the development of a working nuclear reactor and/or a usable nuclear explosive device? In this essay, I argue that Werner Heisenberg and other Nazi scientists fell victim to a value-neutral conception of science that led them to make unethical choices in support of the Nazi regime. The story of the Nazi bomb project exemplifies a more general philosophical point: if scientists fail to understand the social, political, and cultural context of their research they will be vulnerable to ethically wrong decisions.

Extended formulations for binary optimal control problems

AbstractExtended formulations are an important tool in polyhedral combinatorics. Many combinatorial optimization problems require an exponential number of inequalities when modeled as a linear program in the natural space of variables. However, by adding artificial variables, one can often find a small linear formulation, i.e., one containing a polynomial number of variables and constraints, such that the projection to the original space of variables yields a perfect linear formulation. Motivated by binary optimal control problems with switching constraints, we show that a similar approach can be useful also for optimization problems in function space, in order to model the closed convex hull of feasible controls in a compact way. More specifically, we present small extended formulations for switches with bounded variation and for dwell-time constraints. For general linear switching point constraints, we devise an extended model linearizing the problem, but show that a small extended formulation that is compatible with discretization cannot exist unless P = NP.

Characteristic conic connections and torsion-free principal connections

We study the relation between torsion tensors of principal connections on G-structures and characteristic conic connections on associated cone structures. We formulate sufficient conditions under which the existence of a characteristic conic connection implies the existence of a torsion-free principal connection. We verify these conditions for adjoint varieties of simple Lie algebras, excluding those of type Aℓ≠2 or Cℓ. As an application, we give a complete classification of the germs of minimal rational curves whose VMRT at a general point is such an adjoint variety: nontrivial ones come from lines on hyperplane sections of certain Grassmannians or minimal rational curves on wonderful group compactifications.

Unchained Catenaries

Summary Catenaries are the curves formed by a uniform chain or cable suspended from two ends. They are seen in the natural world in structures such as spider webs, and they also occur in engineered structures, including bridges and overhead power lines. Catenaries and catenary arches are also employed in architecture for their beauty and strength. In this article, we look at catenaries where a chain is fixed at one endpoint but free to move over the other. Such catenaries will either be supported by the weight of the tail end of the chain and hence be “stable,” or else unwind off the free end and adopt the configuration of a vertically hanging chain. We develop two models, which are analyzed to determine the conditions under which a particular system will be either stable or unstable and determine the widest span for which a stable catenary exists. The predictions made here may be explored experimentally with relatively inexpensive apparatus. The models presented also invite extensions, such as more general free point locations and the addition of friction, which could dissipate the system energy.

ELEKTRON BİBLİOQRAFİYANIN İNFORMASİYA, TƏHSİL VƏ TƏDQİQAT MÜHİTİNDƏ ROLU

This research paper aims to highlight the current state of electronic bibliography and its role in spheres of information activity. In the article, electronic bibliographic activity was considered as an ele¬ment of scientific communication and interpreted as one of the important actors in meeting the information needs of users working in the field of information, education and scientific research. A brief explanation of electronic bibliographic products was given, and the advantages of the digital bibliographic service realized in the Internet environment were discussed. The article also classified users from a general point of view, and mentioned the necessity of bibliographic support for researchers and students when choosing literature.

Measuring the impact of enterprise risk management on performance, value, and risk indicators of Borsa Istanbul XBANK companies with data mining prediction models

Risk management (RM) is viewed by organizations from a holistic perspective instead of a silo-based point of view and a change in basic assumptions has occurred in recent years. The comprehensive approach to RM that is developed based on a holistic perspective and is adopted by companies is called enterprise risk management (ERM). From the general point of view, it is expected that companies will have sustainable operations, improved performance and value, and controlled risks by using the ERM concept. In this article, the relations of ERM adaptation with firm performance, firm value, and risks were researched through ordinal variables such as the implementation level of ERM and the sophistication level of the organizational structure of ERM in regression models based on panel data (PD). Empirical evidence depending on a sample of ten banking companies listed on the Borsa Istanbul (BIST) Banks index (XBANK) for the period from 2019 to 2022 confirms the above basic argument for firm performance, firm value, and the insolvency risk of banks in general terms. In addition, the prediction accuracy of PD models is calculated for the performance, value, and risk indicators of banks, and the partial least squares regression model is proposed as the alternative prediction model of data mining.

A new discrepancy for sample generation in stochastic response analyses of aerospace problems with uncertain parameters

Good distribution of samples and weights can improve the computational accuracy and efficiency in the stochastic response analyses of aerospace problems with uncertain parameters. This work proposes a new generalized L2 discrepancy based on a general point (GL2D-GP) for generating samples and their corresponding weights. The proposed GL2D-GP is an extension of the existing discrepancy by introducing the non-same weights and a smaller box to measure probability errors. Minimizing the GL2D-GP can yield a weight optimization formula that generates a set of optimal non-identical weights for a given sample set. Through minimizing the GL2D-GP assigned to the set of optimal non-same weights, a new sample and weight generation method is developed. In the proposed method, the samples can be easily generated in terms of the generalized Halton formula with a series of optimal permutation vectors which are found by the intelligent evolutionary algorithm. Once the sample set is obtained, the optimal weights can be generated in terms of the weight optimization formula. Five numerical examples are presented to verify the high accuracy, efficiency, and strong robustness of the proposed sample generation method based on GL2D-GP.

Characteristics of non-randomised studies of drug treatments: cross sectional study

ObjectiveTo examine the characteristics of comparative non-randomised studies that assess the effectiveness or safety, or both, of drug treatments.DesignCross sectional study.Data sourcesMedline (Ovid), for reports published from 1 June 2022 to 31 August 2022.Eligibility criteria for selecting studiesReports of comparative non-randomised studies that assessed the effectiveness or safety, or both, of drug treatments were included. A randomly ordered sample was screened until 200 eligible reports were found.Data on general characteristics, reporting characteristics, and time point alignment were extracted, and possible related biases,witha piloted form inspired by reporting guidelines and the target trial emulation framework.ResultsOf 462 reports of non-randomised studies identified, 262 studies were excluded (32% had no comparator and 25% did not account for confounding factors). To assess time point alignment and possible related biases, three study time points were considered: eligibility, treatment assignment, and start of follow-up. Of the 200 included reports, 70% had one possible bias, related to: inclusion of prevalent users in 24%, post-treatment eligibility criteria in 32%, immortal time periods in 42%, and classification of treatment in 23%. Reporting was incomplete, and only 2% reported all six of the key elements considered: eligibility criteria (87%), description of treatment (46%), deviations in treatment (27%), causal contrast (11%), primary outcomes (90%), and confounding factors (88%). Most studies used routinely collected data (67%), but only 7% reported using validation studies of the codes or algorithms applied to select the population. Only 7% of reports mentioned registration on a trial registry and 3% had an available protocol.ConclusionsThe findings of the study suggest that although access to real world evidence could be valuable, the robustness and transparency of non-randomised studies need to be improved.

UAV or satellites? How to find the balance between efficiency and accuracy in above ground biomass estimation of artificial young coniferous forest?

The accurate estimation of Above Ground Biomass (AGB) is the basis for plantation forest carbon trading. This study focused on Picea crassifolia artificial plantations, extracting individual tree crown diameters and heights using Unmanned Aerial Vehicles (UAV) data and calculating the individual tree biomass using allometric growth equations. These results were then used to train a satellite image AGB prediction model. In additional, satellite images were resampled to different resolutions to assess the impact of satellite image resolution on model the accuracy. Finally, the model with the highest accuracy among the deep learning algorithms was selected to predicts the AGB within the P. crassifolia plantation forest. The results indicated that the accuracy of single tree crown diameters extracted from P. crassifolia point clouds significantly surpassed those extracted from general point clouds and Crown Height Model (CHM), while the accuracy of the heights extracted from all three sources was similar; RepLKNet outperformed GoogLeNet and ResNet in identifying plantation forest; random forest slightly outperformed XGBoost in the capability of AGB prediction, while the accuracy of the AGB prediction models initially increasd and then decreasd with satellite image resolution, reaching the highest accuracy at a resolution of 50 m. This indicates that the optimal satellite image resolution for estimating the AGB in the study area was affected by scale effects of 50 m. Compared with the combination of satellite data and manual field measurements, the concurrent use of UAVs and satellites offers significant advantages in terms of efficiency and accuracy. UAVs can replace manual sampling for carbon sequestration transactions for plantations.

On being a scholar/activist: Personal history and acquired wisdom

Requests to publicly think about what one has learned over time are always interesting to me. They require that authors reflect back on a trajectory that may not be totally clear even to the writers themselves. They ask writers to construct an historical narrative that is simultaneously both personal and intellectual/political. In this “acquired wisdom” essay, I want to engage with this combined task, to reflect on some of the political/intellectual/educational history of the development of my work over time, on some of the most important things I have learned, and on the situations and processes that made this more likely. At the same time, I want to situate this development in some of the more personal groundings that might explain how and why the work I’ve done came about. Let me begin with some general points that bear on my later comments about my grounding in politically engaged educational efforts. There are two fundamental motivations behind such critical work. The first is understanding the complex dynamics of exploitation, domination, and subordination that all too often structure our societies and their constitutive relations inside and outside of education. Yet, while understanding is absolutely crucial, it is not sufficient. Emerging out of such understandings is a commitment to interruption. Both understanding and interruption have their basis in a set of ethical and political commitments that are simultaneously collective and personal (Bourdieu, 2003). And both are crucial to me.

Autoequivalences of blow‐ups of minimal surfaces

AbstractLet be the blow‐up of in a finite set of very general points. We deduce from the work of Uehara [Trans. Amer. Math. Soc. 371 (2019), no. 5, 3529–3547] that has only standard autoequivalences, no non‐trivial Fourier–Mukai partners, and admits no spherical objects. If is the blow‐up of in 9 very general points, we provide an alternate and direct proof of the corresponding statement. Further, we show that the same result holds if is a blow‐up of finitely many points in a minimal surface of non‐negative Kodaira dimension which contains no ‐curves. Independently, we characterize spherical objects on blow‐ups of minimal surfaces of positive Kodaira dimension.

Assessment of panel performance in CATA and RATA experiment

AbstractCATATIS is a recently developed method for the analysis of multiple binary datasets such as Check‐All‐That‐Apply (CATA) data. CATATIS yields a homogeneity index reflecting the overall agreement among the panelists and weights associated with the panelists that highlight the extent to which they agree with the general point of view. These weights are used to compute an average group configuration, which is submitted to Correspondence Analysis to derive a perceptual product map. Here, CATATIS is extended to situations where the data are not binary. In particular, we focus on the case of data from a CATA experiment with repetitions and data from a Rate‐All‐That‐Apply (RATA) experiment. Furthermore, a hypothesis‐testing framework based on permutations is set up to assess the significance of the weights associated with the panelists. Finally, the general strategy of analysis is illustrated using data from real case studies pertaining to CATA and RATA experiments.Practical ApplicationsEvaluating panel performance is often important in sensory studies, especially in industrial contexts. While many professionals are familiar with evaluating the outputs of conventional descriptive analysis, the increasing adoption of rapid sensory methods calls for methods and tools tailored to different sensory tasks. Our paper introduces an approach (CATATIS) to enhance the interpretation of the outputs of CATA and RATA tasks, focusing on attribute consistency, overall panel agreement, and individual weights associated with panelists. The approach is demonstrated through concrete case studies. CATATIS, together with its extensions, are available in XLSTAT software and in the R package ClustBlock.

Lifetime Induced Abortions and Live Births: A 40-Year Historical Cohort Study

ObjectivesLittle is known about whether induced abortions are associated with the final lifetime number of live births (life births). The objective of this study was to examine the association between the number of life births with the number of abortions a female has had in her lifetime. MethodsIn a national cohort design, we followed all Danish females from ages 15 to 44 years through the period 1977–2017 for induced abortions and live births. For each lifetime number of induced abortions, the average number of life births was assessed, and rates with 95% CI were calculated. ResultsThe study included 409 497 females who completed 222 482 induced abortions and 831 742 live births. Of 265 573 (64.9%) females who did not have any induced abortion, the average number of life births was 2.09 (95% CI 2.08–2.10). For females with 1 (23.4%), 2 (7.4%), 3 (2.6%), 4 (1.0%), and ≥5 (0.7%) induced abortions during their reproductive lifespan, the average number of life births was 1.88 (1.87–1.89), 1.99 (1.98–2.00), 2.09 (2.06–2.11), 2.13 (2.09–2.15), and 2.25 (2.21–2.29), respectively. The increase in number of life births in females with 1 to females with 5+ induced abortions was 4.7% for each additional induced abortion. ConclusionWe found the number of induced abortions during a woman’s reproductive lifespan to be positively correlated to the number of live births. This association is likely explained by a high fecundity in females with multiple pregnancies including induced abortions and suggests that even several induced abortions do not compromise a woman’s general reproductive end points.

How to Conduct a Freedom-to-Operate Analysis for a Drug Repurposing Project

This document provides the general methodology and specific resource access points for performing a Freedom-to-Operate (FtO) analysis tailored to the needs of a drug repurposing project. It has been deliberately written to be performed with minimal technical resources: Only web access is required, and no use is made of artificial intelligence tools. It can be performed by the inventors, up to the point where potentially critical findings (if any) are discussed with a patent attorney. When done properly, this method actually improves the relevance of the analysis, since no patent specialist can be expected to be fully familiar with all the scientific aspects of a repurposing project. While patent searches are the dominant motive, there is also discussion of how to recruit suitable suppliers, an issue that is particularly important when the compound is reformulated (as will be the case in most cases).

Identify the Most Common Challenges and Coping Strategies that Teachers Encounter in Managing Large Class Teaching

Background: It is very difficult to talk about all the problems regarding large size classes. However, there are certain problems which may look small from general point of view but can affect teaching - learning process strictly. Definitely, there are certain problems which are related to all large English classes and cannot be ignored at any time. Dealing with large number of students constitutes a real challenge to every teacher. variety of students with multi - level IQ and learning style, class environment organization, difficulty of setting and crowd control, less attention to students, limited students’ learning monitoring and difficulty in engaging all students in activities. It is a very important issue for every instructor to be involved in teaching large number of students especially, in EFL contexts. Objectives: To find out the most common challenges teachers may encounter in managing of teaching large classes and to help instructors to be aware of those problems they may face with large number of students in order to take action to overcome at least of the challenges. Method and Material: This is qualitative research; the research design is descriptive and the data was analyzed descriptively. In this research, first we searched for the keywords which related to the research topic through the online academic and up to date sources such as (ADRI, Research Gate, and Google Scholars). Out of 32 articles, we reviewed twenty - one of them that mostly explained the challenges of large classes. The articles were published between (1970 - 2010) years. Results: Dealing with large classes constitutes a real challenge to every teacher: The major hypothesis is that effective teaching and producing learning is critically constrained by the large size of classes and the students’ perception about large classes being negative. The findings indicated that small - group learning are more effective in promoting greater academic achievement, and enhances favorable attitudes toward learning. Conclusion: Most researches showed that benefit usually occur when class size is reduced to less than 20 students otherwise problem of acquisition and classroom management arise and learning process will be not occur effectively. There are other variables such as the quality of teachers, students’ degree of motivation, and role of the parents may interface and come into play in leaning process.

Effective cone of the blowup of the symmetric product of a curve

Let C C be a smooth curve of genus g ≥ 1 g \geq 1 and let C ( 2 ) C^{(2)} be its second symmetric product. In this note we prove that if C C is very general, then the blowup of C ( 2 ) C^{(2)} at a very general point has nonpolyhedral pseudo-effective cone. The strategy is to consider first the case of hyperelliptic curves and then to show that having polyhedral pseudo-effective cone is a closed property for families of surfaces.

Diagnosis Ability Evaluation of TMJ Condylar Disorders of Panoramic Radiographs in Senior Dental Students

Introduction: The temporomandibular joint is a unique and complex joint in the human body due to anatomical and functional reasons. The present study was conducted with the aim of investigating the knowledge of the senior dentistry students of Yazd Dental School about temporomandibular joint radiographic changes in panoramic images in 2022-2023. Methods: A cross-sectional descriptive analytical study was conducted with the participation of 59 senior dentistry students. After obtaining the consent of the students and collecting their background information, a questionnaire containing 14 questions was presented to the students with the aim of examining the students' ability to distinguish between normal, dislocation, hypoplasia, hyperplasia, osteophyte and condylar erosion appearance. Finally, the descriptive data were presented in the form of numbers and percentages in the form of a table. Data analysis was done with SPSS version16 and T-test. The significance level of the tests was considered less than 0.05. Results: The results showed that there was no significant difference in students' ability score according to their gender and type of entry (national-international) (P>0.05). The grade of students according to general point average (GPA) showed a significant difference (P<0.05). Conclusion: Based on the results of the study, and considering the importance and high prevalence of TMJ disorders, senior dentistry students in Yazd City did not have acceptable knowledge about radiographic changes in the TMJ joint.

Exploring applications of Computational Design techniques and design for manufacturability for costs reduction of prefabricated timber-based façades: The ‘LegnAttivo’ design prototype

Several research initiatives across the European Union investigated the application of off-site prefabrication strategies for energy refurbishment of buildings. Although the results obtained, none of these projects offer a solution for reducing the overall cost.This paper presents the results of the ‘LegnAttivo’ project, an applied research initiative that investigates applications of Mass Customization and Design for Manufacturability to reduce the cost of prefabricated timber-based façades for energy refurbishment. Applying a Design Science Research approach, the research develops a design prototype of timber-based façade elements for the energy refurbishment of the Italian building stock. Relying on a single case study which is a starting point for future generalizations and extensions of the method, results highlight that applications of Design for Manufacturability combined with Computational Design techniques provide effective and efficient solutions, even under extremely customized requirements, and bring to considerable saves, aligned with the ones measured by the scientific community.

Interpolation of fat points on K3 and abelian surfaces

AbstractWe prove that any number of general fat points of any multiplicities impose the expected number of conditions on a linear system on a smooth projective surface, in several cases including primitive linear systems on very general K3 and abelian surfaces, “Du Val” linear systems on blowups of at nine very general points, and certain linear systems on some ruled surfaces over elliptic curves. This is done by answering a question of the author about the case of only one fat point on a certain ruled surface, which follows from a circle of results due to Treibich–Verdier, Segal–Wilson, and others.