Negative Correlation
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2021 ◽  
Vol 233 (5) ◽  
pp. e221
Niloufar Hafezi ◽  
Troy A. Markel ◽  
Natalie Mark ◽  
Cameron Colgate ◽  
Sarina Masso Maldonado ◽  

2021 ◽  
Vol 14 (11) ◽  
pp. 510
Per Bjarte Solibakke

This paper builds and implements multifactor stochastic volatility models for the international oil/energy markets (Brent oil and WTI oil) for the period 2011–2021. The main objective is to make step ahead volatility predictions for the front month contracts followed by an implication discussion for the market (differences) and observed data dependence important for market participants, implying predictability. The paper estimates multifactor stochastic volatility models for both contracts giving access to a long-simulated realization of the state vector with associated contract movements. The realization establishes a functional form of the conditional distributions, which are evaluated on observed data giving the conditional mean function for the volatility factors at the data points (nonlinear Kalman filter). For both Brent and WTI oil contracts, the first factor is a slow-moving persistent factor while the second factor is a fast-moving immediate mean reverting factor. The negative correlation between the mean and volatility suggests higher volatilities from negative price movements. The results indicate that holding volatility as an asset of its own is insurance against market crashes as well as being an excellent diversification instrument. Furthermore, the volatility data dependence is strong, indicating predictability. Hence, using the Kalman filter from a realization of an optimal multifactor SV model visualizes the latent step ahead volatility paths, and the data dependence gives access to accurate static forecasts. The results extend market transparency and make it easier to implement risk management including derivative trading (including swaps).

2021 ◽  
Vol 12 ◽  
Martin Merkt

In educational contexts, system-determined pauses are often used to interrupt the transient flow of information and thus avoid cognitive overload in dynamic learning materials. However, next to these didactically motivated interruptions, video-based learning materials may also be interrupted due to technical issues with regard to constrained bandwidth or outdated technology. Against this background, the current experiment investigated whether the interruption of dynamic representations due to technical issues negatively affects learning. For this purpose, 64 participants watched an Arabic language tutorial. They were either informed that the video included breaks in order to support learning or that there may be breaks due to technical issues. Contrary to our pre-registered hypotheses, the attribution of the pauses to technical issues did not hamper learning and did not affect participants' ratings regarding the usefulness and the disturbance caused by the pauses. However, exploratory analyses revealed a negative correlation between the perceived usefulness and the disturbance caused by the pauses. Limitations and implications of these findings are discussed.

Quaternary ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 33
Loïc Lebreton ◽  
Eugène Morin ◽  
Brad Gravina ◽  
Alexandre Michel ◽  
François Bachellerie ◽  

As micromammals are highly sensitive to changes in their habitat, variations in species representation are often used to reconstruct local environmental conditions. However, taphonomic aspects of micromammals are often overlooked, despite the fact that they can provide important information for our understanding of archaeological sites. La Roche-à-Pierrot, Saint-Césaire, is a major archaeological site for our understanding of the Middle-to-Upper Palaeolithic transition in Western Europe. Clearly documenting site formation processes, the post-depositional reworking of deposits and the sequence of human occupations is fundamental for providing a secure archaeostratigraphic context of the site. The exceptionally large accumulation of micromammals from recently excavated stratigraphic units at the site makes it possible to track variations in the density of micromammals across the stratigraphic sequence. The taphonomic analysis of micromammals demonstrates these variations are not related to a change in the main accumulation agent or post-depositional phenomena. A negative correlation between small mammal remains and archaeological material suggests that peaks in micromammal densities can potentially be correlated with periods when the site was abandoned or when human occupation was less intense, and therefore provide new data for interpreting the Saint-Césaire stratigraphic sequence.

2021 ◽  
Vol 10 (21) ◽  
pp. 4845
Chikako Hara ◽  
Miki Sawa ◽  
Fumi Gomi ◽  
Kohji Nishida

Purpose: This study aimed to assess driving capabilities in patients with exudative age-related macular degeneration (AMD) causing unilateral blindness or paracentral scotoma without vision deterioration. Methods: Of the 275 patients with AMD who responded to a questionnaire regarding car driving at Osaka University Hospital, we excluded 78 patients who answered that they had never driven. Finally, 197 patients were included (50 with bilateral and 142 with unilateral AMD). We investigated the relationship between the questionnaire findings and best-corrected visual acuity (BCVA). Results: The mean age was 74.8 ± 6.9 years, and the mean BCVA in the right and left eyes were 0.48 and 0.47, respectively. A negative correlation was observed between the proportion of patients who stopped driving due to AMD and the vision in the worse eye (p < 0.0001); however, 66% of participants were still driving. Regardless of the BCVA, 84% of them wished to continue driving. Concerning perceived dangerous situations, all patients reported an oversight of people or signals and night driving; further, patients with unilateral and bilateral vision deterioration reported vision narrowness and difficulty with discerning signal colours, respectively. Conclusion: Despite the associated danger, patients with AMD continued driving. Close attention should be paid to the driving activities among patients with AMD, even if they have passed the relevant driving tests.

2021 ◽  
Vol 12 ◽  
Peixin Fan ◽  
Miju Kim ◽  
Grace Liu ◽  
Yuting Zhai ◽  
Ting Liu ◽  

Calf diarrhea is one of the most concerning challenges facing both the dairy and beef cattle industry. Maintaining healthy gut microbiota is essential for preventing gastrointestinal disorders. Here, we observed significantly less bacterial richness in the abnormal feces with watery or hemorrhagic morphology compared to the normal solid feces. The normal solid feces showed high relative abundances of Osllospiraceae, Christensenellaceae, Barnesiella, and Lactobacillus, while the abnormal feces contained more bacterial taxa of Negativicutes, Tyzzerella, Parasutterella, Veillonella, Fusobacterium, and Campylobacter. Healthy calves had extensive bacterial-bacterial correlations, with negative correlation between Lactobacillus and potential diarrheagenic Escherichia coli-Shigella, but not in the abnormal feces. We isolated Lactobacillus species (L. reuteri, L. johnsonii, L. amylovorus, and L. animalis), with L. reuteri being the most abundant, from the healthy gut microbiota. Isolated Lactobacillus strains inhibited pathogenic strains including E. coli K88 and Salmonella Typhimurium. These findings indicate the importance of a diverse gut microbiota in newborn calf’s health and provide multiple potential probiotics that suppress pathogen colonization in the gastrointestinal tract to prevent calf diarrhea.

2021 ◽  
Vol 13 (1) ◽  
Rekha Gupta ◽  
B. Naveen Naik ◽  
Venkata Ganesh ◽  
Ajay Singh ◽  
Shiv Lal Soni ◽  

Abstract Background The COVID-19 pandemic and its consequent “social distancing” has fueled the use of social media platforms for educational purposes. Since the start of the pandemic, a plethora of experts and self-proclaimed experts have been keenly delivering webinars on COVID. This begs the question “Do webinars on COVID-19 really help in the improvement of knowledge base or management skills?”. The questionnaire was designed to assess information regarding COVID-webinars and their usefulness from the end-user standpoint. The response to the questions was measured using a 4- or 5-point Likert scale. The survey was open for a 4-week period with the extension of 1 week. Results The response rate was 54% as 270 out of 500 participants responded to the questionnaire. The majority of the respondents were anesthesiologists in-training, post-graduates, fellows, and seniors belonging to tertiary care settings with fewer percentages belonging to physicians and others. Most of the doctors had attended an average of 2 webinars per week. The tests of model effects showed a significant negative correlation of webinar quality ratings for district hospital healthcare setting of the attendees (of p value of 0.013) and for the number of COVID-related webinars attended per week (p value of 0.009). Conclusions Most respondents had favorable perceptions of webinars happening during the pandemic. However, there is a need for improvisation in the volume of webinars, target-audience-based delivery, and participant interaction to add value to this new dimension of teaching-learning.

2021 ◽  
Vol 17 (5) ◽  
pp. 443-447
N.V. Pasyechko ◽  
V.M. Kulchinska ◽  
S.V. Kadubets

Background. In recent years, thyroid diseases occupy the top places in the structure of the endocrine pathology. There exists a tight functional relationship between the thyroid and reproductive systems, which leads to a high probability of the development of combined disorders in one of these links of homeostasis. The problem of reproductive health disorders is of particular concern around the world and is relevant to the study of the impact of thyroid diseases on both fertility and pregnancy, especially in conditions of comorbidity. The purpose of the study was to investigate the effect of myo-inositol on the reproductive function of women with subclinical hypothyroidism on the background of autoimmune thyroiditis and obesity. Materials and methods. The study included 98 patients aged 18–40 years with subclinical hypothyroidism, overweight, or obesity on the background of autoimmune thyroiditis. They were randomly subdivided into two groups. Patients of the first group (n = 49) before the basic treatment received myo-inositol at a dose of 2000 mg/day and cholecalciferol at a dose of 2000 IU/day. Patients of the second group (n = 49) before the basic treatment received only cholecalciferol at a dose of 2000 IU/day. Results. Vitamin D deficiency was observed in 90.81 % of women with subclinical hypothyroidism, and vitamin D insufficiency in 9.19 %. A negative correlation was found between the level of 25(OH)D and the level of TPO-Ab (r = –0.189; p < 0.05). There was a weak negative correlation between the level of 25(OH)D and the level of the HOMA-IR (r = –0.168; p < 0.05). The administration of myo-inositol together with vitamin D led to a significant increase in the content of 25(OH)D, as well as to a decrease in the titer of TPO-Ab. Conclusions. The positive effect of myo-inositol drugs together with vitamin D on the functional state of the thyroid gland, on the level of TPO-Ab and HOMA-IR in women of reproductive age with subclinical hypothyroidism and obesity has been established.

2021 ◽  
Vol 13 (1) ◽  
Mahboobeh Yeganeh-Hajahmadi ◽  
Hamid Najafipour ◽  
Farzaneh Rostamzadeh ◽  
Ahmad Naghibzadeh-Tahami

Abstract Background Hypertension and diabetes are among the most important risk factors of cardiovascular diseases. Klotho and SIRT1 are known as anti-aging factors with beneficial effects on cardiovascular system. In this study we investigated the serum Klotho and SIRT1 levels in pre-diabetic and pre-hypertensive individuals and then in diabetic and hypertensive patients to see their relationship with these diseases. Method 229 individuals divided into six groups with similar gender and age distribution 1—Control (normal BP and FBS) 2—pre-diabetic (FBS between 100 and 125 mg/dl) 3—diabetic (FBS ≥ 126 mg/dl), 4—pre-hypertensive (SBP 120–139 or DBP 80–89 mm Hg) 5—hypertensive (SBP ≥ 140 or DBP ≥ 90 mm Hg), and 6—patients with combined hypertension/diabetes. Serum levels of Klotho and SIRT1 were measured by ELISA method. Results Serum Klotho and STRT1 levels decreased in pre-diabetes and returned to normal in diabetic patients. Their concentration increased in pre-hypertension and recovered to normal in hypertension. In the physiologic range of FBS there is a negative correlation between Klotho and SIRT1 with FBS. When pathologic ranges of FBS added to analysis, the negative correlation abolished/U shaped. Also an inverse U shape correlation observed between Klotho and SIRT1 with MAP in the range of normal to hypertensive BP levels. There was an overall positive relationship between the serum levels of Klotho and SIRT1 themselves. Conclusion The serum levels of the anti-aging proteins Klotho and SIRT1 increases or reduces at the onset of the disease, as a compensatory mechanism, but as the disease progresses their level recovers.

Atmosphere ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1368
Alireza Karimi ◽  
Pir Mohammad ◽  
Sadaf Gachkar ◽  
Darya Gachkar ◽  
Antonio García-Martínez ◽  

This study investigates the diurnal, seasonal, monthly and temporal variation of land surface temperature (LST) and surface urban heat island intensity (SUHII) over the Isfahan metropolitan area, Iran, during 2003–2019 using MODIS data. It also examines the driving factors of SUHII like cropland, built-up areas (BI), the urban–rural difference in enhanced vegetation index (ΔEVI), evapotranspiration (ΔET), and white sky albedo (ΔWSA). The results reveal the presence of urban cool islands during the daytime and urban heat islands at night. The maximum SUHII was observed at 22:30 pm, while the minimum was at 10:30 am. The summer months (June to September) show higher SUHII compared to the winter months (February to May). The daytime SUHII demonstrates a robust positive correlation with cropland and ΔWSA, and a negative correlation with ΔET, ΔEVI, and BI. The nighttime SUHII displays a negative correlation with ΔET and ΔEVI.

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