56,726 research outputs found
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Problematic technology use during adolescence: why don’t teenagers seek treatment?
No full textIn recent issues of Education and Health, I have briefly reviewed the empirical evidence relating to problematic use of technology by adolescents including online video gaming (Griffiths, 2014), social networking (Griffiths, 2013a; Kuss & Griffiths, 2011), and mobile phone use (Griffiths, 2013b). Most of the research studies that have examined ‘technological addictions’ during adolescence have indicated that a small but significant minority experience severe problems resulting in detriments to education, physical fitness, psychological wellbeing, and family and personal relationships (Griffiths, 2010; Kuss, Griffiths, Karila & Billieux, 2014). Given these findings, why is it that so few teenagers seek treatment? This article briefly outlines a number of reasons why this might be the case by examining other literature on adolescent drug use and adolescent gambling (e.g., Chevalier & Griffiths, 2005; 2005; Griffiths, 2001). Three different types of explanation are discussed: (i) treatment-specific explanations, (ii) research-related explanations, and (iii) developmental and peer group explanations
Simulation data output used in Griffiths and Phelps lightning initiation model, revisited
No full textSimulation data output used in the paper titled "Griffiths and Phelps Lightning Initiation Model, Revisited" submitted for publication in JGR by A. Attanasio, P. R. Krehbiel, and C. L. da Silva.
The model simulates the collective dynamics of a system of positive streamers using the framework first proposed by Griffiths and Phelps [1976]. The README.txt file contains details about the data structure.
C. L. da Silva, Jan/29/2019</p
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Theoretical Loss and Gambling Intensity (Revisited): A Response to Braverman et al. (2013)
No full textIn this paper, we provide a brief response to Braverman and colleagues’ (2013) critique of our ‘Theoretical Loss’ metric as a measure of monetary gambling intensity (Auer & Griffiths, 2013; Auer, Schneeberger & Griffiths, 2012). We argue that ‘gambling intensity’ and ‘gambling involvement’ are essentially the same construct as descriptors of monetary gambling activity. Additionally, we acknowledge that playing duration (i.e., the amount of time – as opposed to money – actually spent gambling) is clearly another important indicator of gambling involvement – something that we have consistently noted in our previous studies including our empirical studies on gambling using behavioural tracking data. Braverman and colleagues claim that the concept of Theoretical Loss is nullified when statistical analysis focuses solely on one game type as the house edge is constant across all games. In fact, they state, the correlation between total amount wagered and Theoretical Loss is perfect. Unfortunately, this is incorrect. To disprove the claim made, we demonstrate that in sports betting (i.e., a single game type), the amount wagered does not reflect monetary gambling involvement using actual payout percentage data (based on 52,500 independent bets provided to us by an online European bookmaker). After reviewing the arguments presented by Braverman and colleagues, we are still of the view that when it comes to purely monetary measures of ‘gambling intensity’, the Theoretical Loss metric is a more robust and accurate measure than other financial proxy measures such as ‘amount wagered’ (i.e., bet size) as a measure of what players are prepared to financially risk while gambling
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Gaming addiction in adolescence (revisited)
No full textGaming addiction has become a topic of increasing research interest. Over the last 25 years, I have written many articles on adolescent video gaming for Education and Health as it is one of the research fields that is constantly evolving. In fact, over the last decade, there has been a significant increase in the number of scientific studies examining various aspects of online addiction particularly among adolescents and young adults (Kuss & Griffiths, 2012; Kuss, Griffiths, Karila & Billieux, 2014). Although the amount and the quality of research in the field has progressed much over this period, it is still in its infancy compared to other more established behavioural addictions (such as pathological gambling). This article briefly examines (i) how adolescent gaming addiction research has changed over the last three decades, (ii) how online gaming addiction has gained genuine psychiatric status, (iii) excessive gaming as an addiction, and (iv) where the gaming addiction field is going
Characterizations of Griffiths Positivity, Pluriharmonicity and Flatness
No full textDeng-Ning-Wang-Zhou showed that a Hermitian holomorphic vector bundle is Griffiths semi-positive if it satisfies the optimal -extension condition. As a generalization, we present a quantitative characterization of Griffiths positivity in terms of certain -extension conditions. We also show that a -valued measurable function is pluriharmonic if and only if it satisfies the equality part of the optimal -extension condition. This answers a conjecture of Inayama affirmatively. Moreover, the flatness of a possibly singular Hermitian metric is also equivalent to the equality part of the optimal -extension condition.Accepted by J. Funct. Anal. with minor revision
Conulinus randalanai Griffiths & Herbert 2013, sp. n.
No full textConulinus randalanai sp. n. Fig. 10 Etymology: Named for Roger Randalana, on-site manager of the Tsingy Beanka reserve and participant in many malacological expeditions throughout Madagascar. Diagnosis: Shell bulimiform, whorls relatively elongate, body whorl comprising approx. 66% of total shell height; spire profile cyrtoconoid; columella reflected, umbilicus narrow; sculptured by microscopic axial riblets and even finer spiral threads; lustreless, mauve-brown, paler apically. Description: Shell: Elongate-bulimiform, thin; body whorl comprising approx. 66 % of total shell height; spire profile cyrtoconoid, suture not strongly indented; whorls weakly convex, base a little more strongly so, periphery rounded; umbilicus reduced to a narrow tube-like channel by reflected upper portion of columella lip. Protoconch of approx. 1¼ whorls, smooth. Teleoconch of a further 4¾–5 whorls; appearing smooth, but microsculptured by numerous, very fine, close-set axial riblets, and even finer microscopic spiral threads; axial riblets becoming less regular with growth and resembling fine, uneven growthlines on last adult whorl, spiral sculpture persisting throughout and extending on to base. Aperture elongate-ovate; somewhat oblique to vertical axis of shell; peristome incomplete, simple and thin; no subterminal thickening evident inside outer lip; upper part of columella reflected and compressed against preceding whorl such that its edge is narrow (pleat-like in some specimens) and the umbilicus restricted to a very narrow, tube-like channel. Shell somewhat lustreless rather than glossy; predominantly mauve-brown in the freshest specimens, with some axial variations in intensity particularly on middle spire whorls; paler pinkish brown to fawn apically. Dimensions: Holotype, height 16.9 mm, max. diameter 8.5 mm; largest specimen, height 17.5 mm. Holotype: MADAGASCAR: Central W Madagascar, ca 60 km E of Maintirano, E of Belitsaka, E part of Tsingy Beanka, 18.06145°S 44.52595°E, ca 450 m, in leaf-litter and tsingy slots in comparatively lush tall dry deciduous/evergreen forest on south-facing hill, 2.x.2006, O. Griffiths, R. Randalana, D. Herbert & L. Davis, st’n 12/06 (AMS C.469591). Paratypes: St’n R 02/10 (NMSA L8469 /T2897, 1 specimen; AMS C.469584, 4 specimens; MNHN IM-2010-20069, 1 specimen). Additional locality data: Tsingy Beanka: st’ns 03/10, 11/10. Distribution: Evidently a narrow-range endemic; known only from the Tsingy Beanka. Habitat: Fresh dead shells have been found in tall, relatively lush dry deciduous and evergreen forest. No living specimens known. Remarks:The only comparable species known from Madagascar is C. rufoniger (Reeve, 1849), but that species differs in having more rounded whorls, a less elongate shape and a darker, chestnut brown colour (Fig. 7D, E). It also lacks spiral sculpture, and has a wider umbilicus and a thickened white varix inside the outer lip at maturity. C. rufoniger has been mostly recorded from north-eastern Madagascar (Fischer-Piette et al. 1994), but we can also confirm its presence at Antsingimavo (st’ns 04/06, 06/06), Tsingy Beanka (st’ns 01/09, 02/09, 09/09) and in the Tsingy de Bemaraha (Manombolo River). In the absence of anatomical data, our referral of this species to Conulinus is tentative. In its shape and spiral microsculpture, C. randalanai also resembles some species of Rachis Albers, 1850, but it lacks the colour pattern of dark spots and/or spiral bands commonly seen in species of that genus. Indeed, the referral of C. rufoniger to Conulinus also requires confirmation.Published as part of Griffiths, O. L. & Herbert, D. G., 2013, New species of land snails (Mollusca: Gastropoda) from two isolated karst formations in central western Madagascar: Tsingy Beanka and Antsingimavo, with additional notes on other regional endemics, pp. 1-48 in African Invertebrates 54 (1) on pages 15-16, DOI: 10.5733/afin.054.0101, http://zenodo.org/record/767010
Schooling and education.
No full textSchooling and education by Giles R. Wright with Howard L. Green and Lee R. Parks. Number 4 in the New Jersey Ethnic Life Series. Published by New Jersey Historical Commission
Ampelita lindae Griffiths & Herbert 2013, sp. n.
No full textAmpelita lindae sp. n. Fig. 14 Etymology: Named for Linda Davis, manager of the Mollusca collection at the KwaZuluNatal Museum and one of the members of the team that discovered this species. Diagnosis: Shell discoidal, spire flat or nearly so, periphery rounded; aperture strongly descendant with reflected rim; umbilicus wide; surface rough, sculptured by raised collabral vermiform granules; lustreless, mid-brown with whitish, flake-like markings and a pale peri-umbilical band. Description: Shell: Medium sized, relatively thin, discoidal with very low spire (H:D= 0.357 –0.485); periphery at or just above mid-whorl, rounded or weakly angled; a very weak supraperipheral gutter evident in occasional individuals, particularly near start of last whorl; suture indented, final part of last adult whorl descending steeply prior to aperture; umbilicus wide, funnel-shaped. Protoconch of ca 1¼–1½ whorls, the first smooth, thereafter with numerous, irregular, axially elongate granules; junction with teleoconch ill-defined. Teleoconch of a further 2½ whorls; with irregular growth-lines and an uneven sculpture of raised vermiform granules, in a primarily collabral alignment (Fig. 14D); surface thus rendered rough to the touch; granules not simply periostracal, but present on underlying shell; this sculpture continues onto base and into umbilicus. Aperture elongate-ovate, strongly oblique to vertical axis of shell; peristome incomplete, interrupted in parietal region; rim of peristome reflected forming a flaring lip. Shell lustreless, covered with a predominantly mid-brown periostracum when fresh, with irregular, pale, flake-like markings; underlying shell mostly pale with darker brownish spiral bands either side of a pale, peri-umbilical band; sometimes also darker behind flared aperture lip. Aperture lip white, interior greyish brown in fresh material. Dimensions: Holotype, max. diameter 30.5 mm, height 12.6 mm; largest specimen, max. diameter 31.4 mm, height 12.7 mm. Holotype: MADAGASCAR: Central W Madagascar, ca 10 km NE of Belitsaka and ca 60 km E of Maintirano, E side of Tsingy Beanka, in leaf-litter and amongst limestone boulders in tall moist east-facing forest growing on limestone, above Bokarano River Cave, 17.90568°S 44.48822°E, ca 230 m, 29.x.2009, O. Griffiths, D. Herbert, L. Davis & R. Randalana, st’n 07/09 (AMS C.474167). Paratypes: Same data as holotype (NMSA L8468 /T2903, 1 adult specimen); st’n 07/10 (AMS C.469580, 3 adult specimens); st’n 09/10 (AMS C.469579, 1 adult specimen); st’n 07/10 (TMAM T163, 1 adult specimen). Distribution: Evidently a narrow-range endemic, currently known only from Tsingy Beanka; not yet known from either Tsingy de Bemaraha or Antsingimavo. Habitat: Known only from fresh dead shells collected in leaf-litter in tall, east-facing, evergreen forest in the central part of Tsingy Beanka. Remarks: With its relatively small, very depressed shell and rough, vermiform microsculpture, A. lindae is a distinctive species. A. granulosa (Deshayes, 1840) (from the north-eastern tip of Madagascar), another species with coarse microsculpture, is much larger and has distinct periostracal bristles arising from the granules, a feature not evident in the present species. Additional material resembling A. lindae has been found as subfossils in the Kasijy Forest (Kelifely Plateau). These are larger (max. diameter 32.9–35.0 mm, height 15.3– 17.9 mm) than the present material but are clearly morphologically close to it. The material available, however, is inadequate to permit thorough study and meaningful comparison.Published as part of Griffiths, O. L. & Herbert, D. G., 2013, New species of land snails (Mollusca: Gastropoda) from two isolated karst formations in central western Madagascar: Tsingy Beanka and Antsingimavo, with additional notes on other regional endemics, pp. 1-48 in African Invertebrates 54 (1) on pages 21-22, DOI: 10.5733/afin.054.0101, http://zenodo.org/record/767010
Studies on the meiofauna of rocky shores
No full textBibliography: leaves 88-97.Annual macrofaunal and meiofaunal standing stocks were estimated on an exposed rocky shore along the west coast of False Bay, South Africa, using comparable area based sampling techniques. While meiofaunal densities exceeded those of macrofauna in all zones, by an overall ratio of approximately 400:1, macrofaunal biomass exceeded that of meiofauna by an overall ratio of 10:1. The numbers of meiofauna were not evenly distributed across the shore but varied with the algal standing stocks in each zone and their sediment load. By incorporating turnover ratios from the literature, mean annual productivity ratios were calculated which suggested that meiofauna were responsible for 25 of total (excluding bacterial) secondary production. To follow this up, the impact of wave exposure on the meiofauna of one species of alga (viz. Gelidium pristoides) was examined on five shores around False Bay. Meiofaunal densities (dominated by animals between 63um-280um) were significantly greater on sheltered than exposed shores. As the minimum width of Gelidium fronds exceeds that of these permanent meiofauna, and tufts offer little resistance to wave action, only those individuals living in the dense, holdfast region of plants could escape the impact of waves on exposed shores. Total meiofaunal biomass per plant remained constant irrespective of shore type, due to the greater numbers of juvenile bivalves and amphipods on exposed shores. Algal and herbivore biomass were not significantly different between shore types around False Bay and therefore, the proportional contribution by meiofauna to total secondary production on sheltered shores was predicted to be greater than on exposed shores, where the biomass of macrofaunal filter feeders was very high. It has previously been argued that differences in meiofaunal communities between plant species are a result of differential surface area, number of habitats and refugia from predation. The possible fate of meiofaunal productivity as food for higher trophic levels (fish) and the mediating role played by algal complexity was investigated in a series of carefully designed laboratory and field experiments
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A latent profile approach for the study of internet gaming disorder, social media addiction, and psychopathology in a normative sample of adolescents
No full textBackground: For a small minority of individuals, the overuse of digital technologies has been associated with negative factors, including psychological distress and psychopathological symptoms. Two technology-based addictions – internet gaming disorder (IGD) and social media addiction (SMA) – have been found to be related to comorbid disorders and impulsivity especially in adolescents and emerging adults’ populations, but results in this field are inconclusive
Purpose: Using the latent profile analysis (LPA), this study identified different profiles of adolescents characterized by unique patterns of psychopathological risks, and similar levels of impulsivity, IGD, and SMA. Participants and methods: A total of 643 participants (312 males; Mage =16.02 years) were divided into three age groups (early, mid-, and late adolescence). They completed a battery of scales comprising: Internet Gaming Disorder Scale–Short Form, Bergen Social Media Addiction Scale, Barratt Impulsiveness Scale for Adolescents, and Symptom Checklist-90-R. Results: LPAs revealed distinct profiles across early, mid- and late adolescence with regards to the psychopathological variables taken into account. Specifically, only two profiles were identified in the 14–15 year age group, whereas three profiles emerged in the 16–17 year age group. Conclusion: This study highlighted that the profiles identified in each age group differed in terms of psychopathological risk (low, medium and high), showing instead similar (and non-clinical) scores in technology-based addictions and impulsivity. Results could be useful in designing prevention and intervention programs in youth showing similar patterns for technology-based addictions, but different levels of psychopathological symptom
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