Miracle-dz/UniFAR-FTUs huggingface dataset:
Solving the Odd Perfect Number Problem: Some Old and New Approaches

A perfect number is a positive integer $N$ such that the sum of all the positive divisors of $N$ equals $2N$, denoted by $\sigma(N) = 2N$. The question of the existence of odd perfect numbers (OPNs) is one of the longest unsolved problems of number theory. This thesis presents some of the old as well as new approaches to solving the OPN Problem. In particular, a conjecture predicting an injective and surjective mapping $X = \sigma(p^k)/p^k, Y = \sigma(m^2)/m^2$ between OPNs $N = {p^k}{m^2}$ (with Euler factor $p^k$) and rational points on the hyperbolic arc $XY = 2$ with $1 < X < 1.25 < 1.6 < Y < 2$ and $2.85 < X + Y < 3$, is disproved. Various results on the abundancy index and solitary numbers are used in the disproof. Numerical evidence against the said conjecture will likewise be discussed. We will show that if an OPN $N$ has the form above, then $p^k < (2/3){m^2}$ follows from \cite{D10}. We will also attempt to prove a conjectured improvement of this last result to $p^k < m$ by observing that $\sigma(p^k)/m \neq 1$ and $\sigma(p^k)/m \neq \sigma(m)/p^k$ in all cases. Lastly, we also prove the following generalization: If $N = \displaystyle\prod_{i=1}^r {{p_i}^{{\alpha}_i}}$ is the canonical factorization of an OPN $N$, then $$\sigma({p_i}^{{\alpha}_i}) \leq (2/3){\frac{N}{{p_i}^{{\alpha}_i}}}$$ for all $i$. This gives rise to the inequality $$N^{2 - r} \leq (1/3)(2/3)^{r - 1}$$ which is true for all $r$, where $r = \omega(N)$ is the number of distinct prime factors of $N$.
Pretransplant BMI Significantly Affects Perioperative Course and Graft Survival after Kidney Transplantation: A Retrospective Analysis

Background. The number of kidney transplant recipients (KTRs) with overweight and obesity is increasing. It was shown that obesity is related to inferior patient and graft survival. We aimed to analyze intraoperative parameters and postoperative short and long-term course of kidney transplantation (KT) in body mass index (BMI)-stratified cohorts of KTRs. Methods. A retrospective analysis of a prospectively built database of 433 KTRs from 2014 to 2017 from a single transplant center was performed. The objective of the study was to analyze the association between BMI at the time of transplantation with intraoperative parameters, adverse events in early postoperative course, and the overall mortality and graft loss in BMI-stratified cohorts: normal (18.5 and 24.9 kg/m2), overweight (25–29.9 kg/m2) and obese (≥30 kg/m2). Results. Obesity was related to longer total procedure time (p = 0.0025) and longer warm ischemia time (p = 0.0003). The postoperative course in obese patients was complicated by higher incidence of DGF (delayed graft function), early surgical complications (defined as surgical complications <30 days from KT), reoperation rate, vascular complications, incidence of lymphocele and wound dehiscence. There was no difference between the normal weight and overweight KTRs. The one-month kidney function (p = 0.0001) and allograft survival (p = 0.029) were significantly inferior in obese patients with no difference between normal weight and overweight patients. One-year death-censored graft survival was better in patients with BMI < 30 (88.6 vs. 94.8% p = 0.05). BMI was a significant predictor of graft loss in univariate (p = 0.04) but not in multivariate analysis (p = 0.09). Conclusion. Pretransplant obesity significantly affects the intraoperative and postoperative course of kidney transplantation and graft function and survival. The course of transplantation of overweight is comparable to normal BMI KTRs, and presumably pretransplant weight reduction to the BMI < 30 kg/m2 may improve the short-term postoperative course of transplantation as well as may improve graft survival. Thus, pretransplant weight reduction in obese KTRs may significantly improve the results of kidney transplantation. Metabolic surgery may play a role in improving results of KT.
Laminar-Flow Forced Convection in Rectangular Tubes

The problem of laminar-flow heat transfer in tubes of rectangular and triangular cross section is considered. A numerical relaxation method is used to obtain minimum limiting Nusselt-number magnitudes to supplement the presently available data. Boundary conditions of both constant heat input per unit of length, and constant wall temperature are included. For the case of rectangular tubes sufficient points have been calculated so that interpolation of the limiting Nusselt numbers for any aspect ratio can be accomplished. Experimental data are presented for a square tube for both constant wall temperature and constant heat input, and for a rectangular tube, aspect ratio 2.62, for constant wall temperature. These data, together with the limiting Nusselt-number theory, provide a rational basis for estimation of entrance-length effects for rectangular tubes, and result in a correlation in the form, NNu = ϕ[NRNPr/(l/4rh)], applicable to the design of gas-flow heat exchangers.
Flexible Multibody Dynamics: A Finite Element Approach

Preface. Introduction. Generalized Coordinates for Mechanism Analysis. Kinematics of Finite Motion. Parameterization of Spherical Motion. Rigid Body Dynamics. The Elastic Beam. System Constraints: Modelling of Joints. Substructuring Techniques. Static and Kinematic Analyses of Multibody Systems. Time Integration of Constrained Systems. Automatic Step Size Control. Energy Conserving Time Integration. References. Index.
Out-of-equilibrium generalized fluctuation-dissipation relations

We discuss fluctuation-dissipation relations valid under general conditions even out of equilibrium. The response function is expressed in terms of unperperturbed correlation functions, where contributions peculiar to non-equilibrium can appear. Such extra terms take into account the interaction among the relevant degrees of freedom in the system. We illustrate the general formalism with two examples: driven granular systems and anomalous diffusion on comb structures.
H/sub /spl infin// preview control and fixed-lag smoothing I: matrix ARE solutions in continuous-time systems

Preview control and fixed-lag smoothing allow an anti-causal component in the controller/estimator. Time domain variational analysis is used in a reduction to an open loop differential game, leading to a complete, necessary and sufficient characterization of suboptimal values and an explicit state space design, in terms of a parameterized (non-standard) algebraic matrix Riccati equation in a general continuous time linear system setting. The solution offers insight into the appropriate structure of the associated Hamiltonian, where the state and co-state are not the usual state of the original dynamic system and that of its adjoint. Rather, the state and co-state are selected to capture the respective lumped effects of initial data and future input selection in the allied game.
Aktivitas Imunomodulator Ekstrak Petroleum Eter Umbi Bengkoang (Pachyrhizus erosus) pada Mencit Balb/c yang Diinduksi Vaksin Hepatitis B

Ekstrak non polar umbi bengkoang (Pachyrhizus erosus) mengandung senyawa fitosterol berupa β-sitosterol yang diduga mempunyai efek imunomodulator in vivo. Tujuan penelitian ini untuk mengetahui pengaruh pemberian ekstrak petroleum eter (EPE) bengkoang terhadap parameter respon imun non spesifik dan spesifik pada mencit Balb/c yang diinduksi vaksin hepatitis B. Hewan uji mencit secara acak dibagi menjadi 4 kelompok. Kelompok I sebagai kontrol negatif, kelompok II diberi perlakuan obat standard levamisol 2,5 mg/kgBB, kelompok III dan IV berturut-turut diberi EPE bengkoang dosis 100 dan 200 mg/kgBB. Perlakuan diberikan secara peroral selama 18 hari. Efek imunomodulator EPE bengkoang dievaluasi berdasarkan aktivitas fagositosis makrofag, proliferasi limfosit, produksi antibodi atau imunoglobulin G (IgG), serta produksi sitokin tumor necrosis factor-α (TNF-α) dan interleukin-10 (IL-10). Hasil penelitian menunjukkan bahwa pemberian EPE bengkoang mampu meningkatkan kapasitas dan indeks fagositosis makrofag serta proliferasi limfosit secara signifikan (p<0,05). Semakin tinggi dosis EPE bengkoang, produksi IgG semakin turun (p<0,05), sementara produksi TNF-α meningkat dan IL-10 turun namun perubahannya tidak signifikan (p>0,05). EPE bengkoang mempunyai efek imunomodulator dengan meningkatkan respon imun non spesifik sedangkan respon imun spesifik (humoral) turun tergantung dosis.
Exact C$^{\ast}$-algebras and $C_0(X)$-structure

We study tensor products of a $C_0 (X)$-algebra $A$ and a $C_0 (Y)$-algebra $B$, and analyse the structure of their minimal tensor product $A \otimes B$ as a $C_0 (X \times Y)$-algebra. We show that when $A$ and $B$ define continuous C$^{\ast}$-bundles, that continuity of the bundle arising from the $C_0 (X \times Y)$-algebra $A \otimes B$ is a strictly weaker property than continuity of the `fibrewise tensor products' studied by Kirchberg and Wassermann. For a fixed quasi-standard C$^{\ast}$-algebra $A$, we show that $A \otimes B$ is quasi-standard for all quasi-standard $B$ precisely when $A$ is exact, and exhibit some related equivalences.
Consequences of the impact of COVID-19 pandemic on breast cancer at a single Italian institution

Aim: To evaluate the local impact of the coronavirus disease 2019 (COVID-19) pandemic on breast cancer (BC) care, with particular attention to the economical and psychological consequences of the possible delay of new diagnoses and treatments. Methods: Three years’ activity (from 2019 to 2021) has been compared. The number of BCs diagnosed from the total amount of mammographic and ultrasound (US) examinations performed in women aged more than 40 years old has been considered. A Pearson’s chi-squared test was performed to verify differences between results. Statistical significance was set at P ≤ 0.01. Results: A statistically significant difference was found in the number of BC diagnosed between screening and ambulatory care patients in both the 2019–2020 (χ2 = 24.93, P < 0.01) and 2019–2021 (χ2 = 29.93, P < 0.01) comparisons. No statistically significant difference was found in the data recorded between 2020 and 2021 (χ2 = 2.35, P > 0.01). By evaluating the specific age groups for each year, a statistically significant difference (P < 0.01) was found in the number of BC diagnosed in screening patients aged 50–69 years old in both 2019–2020 and 2019–2021 comparisons. The percentages of early BC diagnosed in 2019, 2020, and 2021 were 80.9%, 91.7%, and 89.8%, respectively. The adherence rates to screening in 2019, 2020, and 2021 were 67.5%, 45.2%, and 56.9%, respectively. Conclusions: Results showed a reduction of new diagnoses in the screening range during the pandemic in comparison with the previous period. The high percentage of early BC would seem to have prevented worsening outcomes. Nevertheless, women who have not undergone screening could present a more advanced stage disease in the following years. Consequently, the evaluation of possible solutions to guarantee an essential level of care with the purpose to avoid worsening patients’ outcomes and the increase in healthcare costs is mandatory.
Assessment of Different Infectious Bovine Rhinotracheitis Marker Vaccines in Calves

Three commercially available infectious bovine rhinotracheitis (IBR) live marker vaccines were evaluated for their ability to provide clinical protection to vaccinated calves against wild-type (wt) Bovine alphaherpesvirus-1 (BoHV-1) challenge and their possible effect on wt BoHV-1 latency reactivation following the challenge. On 35 post-vaccination days (PVDs), all animals were challenged with wt BoHV-1. Only the calves in the control group developed severe forms of IBR. The reactivation of latent BoHV-1 was induced by dexamethasone (DMS) treatment on 28 post-challenge days (PCDs). All animals showed IBR clinical signs on three post-DMS treatment days (PDTDs). On PVD 14, all vaccinated animals developed neutralizing antibodies (NAs), whereas in control animals, the NAs appeared post-challenge. The positivity for glycoprotein-B (gB) was detected using real-time polymerase chain reactions in all animals from PCDs 1 to 7. In contrast, the gB-positivity was observed in the immunized calves from PDTDs 3 to 10. Positive expression of gD and gE was observed in nasal swabs of all calves on PDTD 7. These findings suggested that the IBR marker vaccines evaluated in this study protected against wt BoHV-1-induced disease but not against wt BoHV-1-induced latency reactivation, indicating the necessity of developing new products to protect animals from wt BoHV-1-induced latency.
Intergenerational transmission of historical memory of volcanic risk in Mexico

Collective memory is built on concepts and meanings that a population shares and builds over time. These contents are perpetuated through oral transmission from generation to generation. In the case of populations exposed to volcanic risk, coexistence with the volcano is part of their history and daily life. The present study focuses on understanding the meanings, perceptions, and responses facing (before and after) volcanic crises. All these are taken from the collective memory that has been transmitted intergenerationally after the new stage of activity of the Popocatepetl volcano in 1994. It was carried out with qualitative methodology, based on symbolic interactionism, integrating elements of ethnography and grounded theory. People of different age groups from a Mexican community near the Popocatepetl volcano participated. The techniques used were in-depth interviews, focus groups, and participant observation. The historical memory of the volcano’s activity before and after the last reactivation was reconstructed, thus evidencing the generational processes.
The Urgency of Education in Islamic Boarding Schools in Improving The Quality of Islamic-Based Character Education

This research aims to determine the importance of education at the Miftahul Mubtadiin Ar-Ridlo Islamic Boarding School, Nganjuk, in increasing the quality of Islamic character education. A qualitative approach is used in this study. Researchers employed observation techniques, interviews, and documentation to obtain data. According to the findings of this study, character education at the Miftahul Mubtadiin Ar-Ridlo Islamic Boarding School, Nganjuk, is well maintained and operational. It is demonstrated by alumni who have good personalities, noble character, and the ability to live independently. Supporting variables include students, caregivers and caregivers who persevere, and families that consistently provide good direction and habituation to students during vacations (in particular). The problems found are personal factors, environmental factors and the rapid development of science and technology. So it can be concluded the character education in pesantren can be effective with the coaching, mentoring, and unique approaches by ustadz and administrators, parents and banning electronic devices. According to the existing description, education at the Miftahul Mubtadiin Ar-Ridlo Islamic Boarding School, Nganjuk, substantially boosts the quality of Islamic character education.
Prospective evaluation of socket shield technique for immediate implant placement in anterior maxilla

Purpose: The purpose of the study was to report the four year implant survival rate for immediate implant placement using socket shield technique. Objectives included evaluation of the esthetic outcomes and to report any complications associated with this technique. Material and methods: This study is a prospective cohort of 10 consecutive patients with Implant placement between the maxillary first premolars using socket shield technique. Data were collected (PPD, BOP, PES, buccal width of keratinized mucosa, peri-apical radiographs and photographs) to assess and compare the changes in peri-implant tissues in pre-operative and follow up visits. Results: All the implants osseointegrated successfully without any adverse events. Peri-implant probing revealed healthy conditions in terms of pocket depth and bleeding on probing. Mean buccal width of keratinized mucosa of 4.1 was achieved. A mean pink aesthetic score of 12.3 was recorded. Conclusion: Within the limitations of this study, the results were suggesting that socket shield technique is effective in maintaining the hard and soft tissue architecture of anterior maxillary region and delivers high esthetic outcomes with shorter duration of treatment period. However, a prospective randomized study to compare socket shield with other techniques is needed to draw any definitive conclusion.
Reduction in Noise Correlation is Associated with Improved Behavioural Performance

Background: Visual perception constitutes the dominant method by which we process our environment, yet the neuronal substrates that underlie visual perception in the brain are not well understood. Noise correla- tion, defined as the correlation in non-stimulus evoked activity between neurons, has been shown to impact both encoding and decoding processes of visual stimuli. We wanted to determine whether changes in noise correlation can predict behavioural performance in a coherent motion-detection task. Methods: Two macaque monkeys (Macaca mulatta) were trained in a coherent motion-detection task, where they learned to fixate on a screen and anticipate the onset of a motion coherence stimulus. During this task, spike activity from pairs of neurons of the middle temporal area (area MT) were recorded and data was analyzed using MATLAB. Specifically, we examined noise correlation as a function of time and success rate in the task. Results: We found a decrease in the correlation in activity between neurons in area MT prior to the onset of the motion coherence stimulus. This decrease was accompanied by improved behavioural performance in the motion coherence-detection task. Limitations: The activity in pairs of neurons may not accurately represent overall activity in a population of neurons. In addition, control experiments to better assess the nature of the common input that leads to a reduction in noise correlation were not conducted. Conclusions: Despite these limitations, we have shown that a reduction in noise correlation prior to stimulus onset is accompanied by improved behavioural performance, suggesting that noise correlation may be a critical parameter that can aid in our understanding of how visual perception occurs in the brain.
Decoherence: the obstacle to quantum computation

Alan Turing laid the foundation for the modern computer in 1936 when he introduced the concept of a universal computer; now known as a Turing machine. But it took another 10 years of research before the first electronic computer, the ENIAC, was actually built by scientists at the University of Pennsylvania. The ENIAC was capable of performing arithmetic on numbers Up to 10 digits long.
Molecular and Morphological Analyses Support Different Taxonomic Units for Asian and Australo-Pacific Forms of Ischnura aurora (Odonata, Coenagrionidae)

Despite the great technological progress that has aided taxonomical identification, taxonomical issues remain for certain species found in remote and/or understudied geographical areas. The damselfly species Ischnura aurora has been the subject of a long-standing taxonomical debate, focused mainly on the existence of morphological and behavioural differences between Asian and Australo-Pacific forms of this species that could justify their placement into two different species. Here, we carried out a comparative morphological analysis of specimens currently identified as I. rubilio from India and I. aurora from Asia and Oceania, combined with the analysis of mitochondrial and nuclear sequence data, both developed by us and available in public repositories. Our results split the Asian and Australo-Pacific forms of I. aurora into two well-differentiated taxonomic units and, hence, different (albeit closely related) species, and support the specific status of I. rubilio. The results of our genetic analyses suggest the existence of a third (and even fourth) taxonomic unit, stressing the need to revise all available material belonging to the different I. aurora subspecies that have been described. Finally, we have identified several questionable DNA sequences currently available in public repositories, upon which previous conclusions about the phylogenetic position of I. rubilio are based. Our study stresses the importance of being able to link available DNA sequence data with voucher specimens as well as to carry out a careful examination of DNA sequence data prior to their inclusion in taxonomical studies.
Comparison of Early and Late Onset Psoriasis (EOP and LOP) Regarding Systemic Inflammatory Comorbidities: LOP is a More Rapid Subtype of Psoriasis

Introduction Early onset psoriasis (EOP) and late onset psoriasis (LOP) differ regarding genetic background, clinical presentation and course of disease. Objectives In this study, comparison of EOP and LOP regarding systemic inflammatory comorbidities which are frequently seen in psoriasis and determination of possible differences is aimed. Methods A total of 160 plaque psoriasis patients (121 with EOP and 39 with LOP) were enrolled for the study. Data was collected with face-to-face questionnaire and patients medical chart evaluation. Collected data included medical and family history, clinical features and parameters indicating severity of psoriasis, results of laboratory work-up, physical and dermatological examination findings, presence of joint and nail involvement and associated inflammatory systemic comorbidities such as cardiovascular diseases (CVD), diabetes mellitus (DM), hypertension (HT), metabolic syndrome (MS), obesity. Results Nail involvement and PsA occurred more rapidly in LOP compared to EOP (P < 0.01, P < 0.01). Compared frequencies in LOP and EOP were 7.7% versus 0.8% for CVD, 38.5% versus 14% for HT, 33.3% versus 9.9% for DM and 44.7% versus 24.8% for MS, respectively. CVD, HT, DM and MS were significantly more frequent in LOP compared to EOP (P = 0.045, P = 0.001, P < 0.01, P = 0.022). Results of multivariate analysis performed taking into account the age, gender, severity parameters of disease, alcohol consumption, smoking habits and other concurrent systemic comorbidities revealed LOP to be an independent risk factor for CVD and DM (P < 0.01, R2: 0.036, P < 0.01, R2: 0.077). Conclusions LOP seems to interact with systemic comorbidities hence generates more severe inflammatory burden and shows a more rapid course.
APPLICABILITY OF DIRECT EVAPORATIVE COOLING FOR LOW-RISE RESIDENTIAL BUILDING IN SURABAYA

Direct evaporative cooling has been widely known as the passive design strategy for ameliorating the thermal conditions of building in hot-dry climates. In the recent past, the strategy has been extended to warm-humid climates. The scope varies from exploring the system to applying the method to buildings. Few studies have been conducted regarding its application on a multi-story residential building. In response to this gap, the present study will explore the strategy's applicability on the typical low-rise housing in Surabaya and analyze its environmental consequences. Simulation is used as the primary method for the analyses. Results of the study show that direct evaporative cooling is applicable in warm-humid tropics, but with some notes regarding the increase of air humidity. Dimensional properties of the cooling pad can be arranged to minimize the increased humidity.