1,696 research outputs found
Resistance Breeding in Apple at Dresden-Pillnitz
Resistance breeding in apple has a long tradition at the Institute of Fruit Breeding now Julius Kuehn-institute in Dresden-Pillnitz. The breeding was aimed at the production of multiple resistance cultivars to allow a more sustainable and environmentally friendly production of apple. In the last decades a series of resistant cultivars (Re®-cultivars) bred in Dresden-Pillnitz has been released, ‘Recolor’ and ‘Rekarda’ in 2006. The main topic in the resistance breeding programme was scab resistance and the donor of scab resistance in most cultivars was Malus x floribunda 821. Due to the development of strains that are able to overcome resistance genes inherited by M. x floribunda 821 and due to the fact that single resistance genes can be broken easily, pyramiding of resistance genes is necessary. Besides scab, fire blight and powdery mildew are the main disease for which a pyramiding of genes is aspired in Pillnitz. Biotechnical approaches are necessary for the early detection of pyramided resistance genes in breeding clones. This paper will give an overview of the resistance breeding of apple in Pillnitz and the methods used
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The development of the Problematic Pornography Consumption Scale (PPCS)
Background: To date, no short scale exists with strong psychometric properties that can assess problematic pornography consumption based on an overarching theoretical background. Objectives: The goal of the present study was to develop a brief scale (Problematic Pornography Consumption Scale; PPCS) on the basis of Griffiths` (2005) six-component addiction model that can distinguish between non-problematic and problematic pornography use. Methods: The PPCS was developed using an online sample of 772 respondents (390 females, 382 males; Mage = 22.56, SD = 4.98 years). Items creation was based on previous problematic pornography use instruments and on the definitions of the factors of Griffiths’ model. Results: A confirmatory factor analysis was carried out—as the scale is based on a well-established theoretical model—leading to an 18-item second-order factor structure. The reliability of the PPCS was excellent and measurement invariance was established. In the current sample, 3.6% of the users belonged to the at-risk group. Based on the sensitivity and specificity analyses we identified an optimal cut-off to distinguish between problematic and non-problematic pornography users. Conclusion: The PPCS is a multidimensional scale of problematic pornography use with strong theoretical basis that also has strong psychometric properties in terms of factor structure and reliability
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Revisiting the role of impulsivity and compulsivity in problematic sexual behaviors
Impulsivity and compulsivity are transdiagnostic features associated with clinically relevant aspects of psychiatric disorders, including addictions. However, little research has investigated how impulsivity and compulsivity relate to hypersexuality and problematic pornography use. Thus, the aims of the present study were to investigate (a) self-reported impulsivity and compulsivity with respect to hypersexuality and problematic pornography use and (b) the similarities and possible differences between hypersexuality and problematic pornography use in these domains. Utilizing structural equation modeling (SEM) in a large community sample (N = 13,778 participants; female = 4,151, 30.1%), results indicated that impulsivity (β = .28, β = .26) and compulsivity (β = .23, β = .14) were weakly related to problematic pornography use among men and women, respectively. Impulsivity had a stronger relationship (β = .41, β = .42) with hypersexuality than did compulsivity (β = .21, β = .16) among men and women, respectively. Consequently, impulsivity and compulsivity may not contribute as substantially to problematic pornography use as some scholars have proposed. On the other hand, impulsivity might have a more prominent role in hypersexuality than in problematic pornography use. Future research should examine further social and situational factors associated with problematic pornography use
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Are sexual functioning problems associated with frequent pornography use and/or problematic pornography use? Results from a large community survey including males and females
There is much debate regarding whether pornography use has positive or negative associations with sexuality-related measures such as sexual functioning problems. The present study aimed to examine differential correlates between quantity (frequency of pornography use–FPU) and severity (problematic pornography use–PPU) of pornography use with respect to sexual functioning problems among both males and females. Multi-group structural equation modeling was conducted to investigate hypothesized associations between PPU, FPU, and sexual functioning problems among males and females (N=14,581 participants; females=4,352; 29.8%; Mage=33.6 years, SDage=11.0), controlling for age, sexual orientation, relationship status, and masturbation frequency. The hypothesized model had excellent fit to the data (CFI=.962, TLI=.961, RMSEA=.057 [95% CI=.056-.057]). Similar associations were identified in both genders, with all pathways being statistically significant (
Hypersexuality, gender, and sexual orientation: a large-scale psychometric survey study
Criteria for Hypersexual Disorder (HD) were proposed for consideration in the DSM-5 but ultimately excluded for a variety of reasons. Regardless, research continues to investigate hypersexual behavior (HB). The Hypersexual Behavior Inventory (HBI) is one of the most robust scales assessing HB, but further examination is needed to explore its psychometric properties among different groups. Therefore, the aim of the present study was to examine the generalizability of the HBI in a large, diverse, nonclinical sample (N = 18,034 participants; females = 6132; 34.0%; Mage = 33.6 years, SDage = 11.1) across both gender and sexual orientation. Measurement invariance testing was carried out to ensure gender- and sexual-orintation based comparisons were meaningful. Results demonstrated when both gender and sexual-orientation were considered (i.e., heterosexual males vs. LGBTQ males vs. heterosexual females vs. LGBTQ females), LGBTQ males had significantly higher latent means on the HBI factors. Results also demonstrated LGBTQ males had the highest scores on other possible indicators of hypersexuality (e.g., frequency of masturbation, number of sexual partners, or frequency of pornography viewing). These findings suggest LGBTQ males may be a group most at risk of engaging in hypersexual behavior and LGBTQ females are at a higher risk of engaging in hypersexual activities due to coping problems. Given the largescale nature of the study, the findings significantly contribute to the currently growing body of literature on hypersexuality
On packing spanning arborescences with matroid constraint
Let D = (V + s, A) be a digraph with a designated root vertex S. Edmonds’ seminal result (see J. Edmonds [4]) implies that D has a packing of k spanning s-arborescences if and only if D has a packing of k (s, t)-paths for all t ∈ V, where a packing means arc-disjoint subgraphs. Let M be a matroid on the set of arcs leaving S. A packing of (s,t) -paths is called M-based if their arcs leaving S form a base of M while a packing of s-arborescences is called M -based if, for all t ∈ V, the packing of (s, t) -paths provided by the arborescences is M -based. Durand de Gevigney, Nguyen, and Szigeti proved in [3] that D has an M-based packing of s -arborescences if and only if D has an M-based packing of (s,t) -paths for all t ∈ V. Bérczi and Frank conjectured that this statement can be strengthened in the sense of Edmonds’ theorem such that each S -arborescence is required to be spanning. Specifically, they conjectured that D has an M -based packing of spanning S -arborescences if and only if D has an M -based packing of (s,t) -paths for all t ∈ V. In this paper we disprove this conjecture in its general form and we prove that the corresponding decision problem is NP-complete. We also prove that the conjecture holds for several fundamental classes of matroids, such as graphic matroids and transversal matroids. For all the results presented in this paper, the undirected counterpart also holds
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The psychometric properties of the Hypersexual Behavior Inventory using a large-scale nonclinical sample
The conceptualization of hypersexuality has begun to converge as a result of proposed diagnostic criteria. However, its measurement is still diverse. The Hypersexual Behavior Inventory (HBI) is one of the most appropriate scales used to assess hypersexuality, but further examination is needed to test its psychometric properties among different clinical and nonclinical groups, including samples outside of the United States. The aim of the present study was to investigate the reliability and the generalizability of HBI and to determine a cutoff score on a large, diverse, online, nonclinical sample (N = 18,034 participants; females = 6132; 34.0%; Mage = 33.6 years, SDage = 11.1). Confirmatory factor analysis (CFA) and reliability indices provided support for the structure of the HBI and demonstrated excellent reliability. Employing latent profile analysis (LPA), seven classes emerged, but they could not be reliably distinguished by objective sexuality-related characteristics. Moreover, it was not possible to determine an adequate cutoff score, most likely due to the low prevalence rate of hypersexuality in the population. HBI can be reliably used to measure the extent of hypersexual urges, fantasies, and behavior; however, objective indicators and a clinical interview are essential to claim that a given individual may exhibit features of problematic sexual behavior
An empirical study on the motivations underlying augmented reality games: the case of Pokémon Go during and after Pokémon fever
In 2016, Pokémon Go became the most popular game in the history of smartphone games and was among the first games to feature geo-located augmented reality (AR) elements. The goal of the present research was to obtain a deeper understanding concerning the motivations underlying Pokémon Go use and to create a measure that assesses these motivations. By extending the framework of the Motives for Online Gaming Questionnaire, three new factors – Outdoor Activity, Nostalgia, and Boredom – were added based on the findings of qualitative analysis, and which led to the creation of the Motives for Online Gaming Questionnaire - Pokémon Go extension (MOGQ-PG). Confirmatory factor analysis was carried out on a sample of Pokémon Go players (N = 621). Results demonstrated that the final 37-item, first-order, 10-factor model had appropriate factor structure and internal consistency. A second follow-up study on Pokémon Go players (N = 510) examined associations between gaming motivations, problematic use, and impulsivity. Results demonstrated that impulsivity was not related to the MOGQ-PG motives. Results also showed that competition and fantasy motivations predicted problematic gaming behavior. The present research is the first empirical contribution to the assessment and understanding of the motivational background of playing AR games such as Pokémon Go
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