Measurement distortion of graphs in corporate reports: an experimental study

Graphs in corporate annual reports are a double-edged sword. While they offer the potential for improved communication of accounting information to users, the preparers of the annual reports can easily manipulate the graphs for their own interests. For over a decade, the empirical financial graphics literature has focused on examining company reporting practices. A particular concern has been measurement distortion, which violates a fundamental principle of graph construction. Unfortunately, it is not yet known whether observed levels of measurement distortion are likely to affect users' perceptions of financial performance. This study uses an experimental approach to address this issue. Pairs of graphs are shown to establish the level of difference that is just noticeable to graph readers. Six levels of "distortion" are investigated (5 per cent, 10 per cent, 20 per cent, 30 per cent, 40 per cent and 50 per cent). Results indicate that if financial graphs are to avoid distorting the perceptions of users, then no measurement distortions in excess of 10 per cent should be allowed. Users with lower levels of financial understanding appear to be most at risk of being misled by distorted graphs. Further research will be necessary to investigate whether this impact upon perceptions subsequently affects users' decisions in specific contexts

Efficient and automatic methods for flexible regression on spatiotemporal data, with applications to groundwater monitoring

Fitting statistical models to spatiotemporal data requires finding the right balance between imposing smoothness and following the data. In the context of P-splines, we propose a Bayesian framework for choosing the smoothing parameter which allows the construction of fully-automatic data-driven methods for fitting flexible models to spatiotemporal data. An implementation, which is highly computationally efficient and which exploits the sparsity of the design and penalty matrices, is proposed. The findings are illustrated using a simulation study and two examples, all concerned with the modelling of contaminants in groundwater. This suggests that the proposed strategy is more stable that competing methods based on the use of criteria such as GCV and AIC

A potential new method for determining the temperature of cool stars

‘The definitive version is available at www.blackwell-synergy.com.’ Copyright Blackwell Publishing DOI: 10.1111/j.1365-2966.2008.13489.xPeer reviewe

DETECTION OF PHYTOPLASMAS ASSOCIATED WITH KALIMANTAN WILT DISEASE OF COCONUT BY THE POLYMERASE CHAIN REACTION

ABSTRACTCoconut is the second Indonesia’s most important social commodityafter rice. There are more than 3.6 million hectares of coconut plantationsin Indonesia equivalent to one third of the total world coconut area.However, the production and productivity of the coconut are very low andunstable for various reasons, including pests and diseases. Kalimantan wilt(KW) disease causes extensive damage to coconut plantation. In previousinvestigations, bacteria, fungi, viruses, viroids and soil-borne pathogenssuch as nematodes were tested, but none of them were consistentlyassociated with the disease. The objective of this research was to detectand diagnose the phytoplasma associating with KW. Two DNA extractionmethods, namely a modification of CTAB method involving grindingcoconut trunk tissue in pre-warmed CTAB instead of liquid nitrogen, and asmall scale DNA extraction method, were used to prepare DNA fromcoconut trunk tissues. Research results showed that both methods werefound equally suitable for preparing DNA from coconut trunk tissues forPCR analysis. The phytoplasmas aetiology of KW has been proved by thenested PCR approach using P1/P7 and R16F2n/R16R2 primercombinations. The study has further demonstrated that the nested PCRapproach can be employed to effectively detect the presence ofphytoplasma both in infected and in symptomless coconut trunk tissues.Phytoplasma DNA was amplified from 95 out of 116 samples (81.9%).Based on source of samples, phytoplasma DNA was amplified from KWinfected and symptomless samples, 95.1% and 67.3% respectively. Thisstudy confirmed that KW is caused by phytoplasma.Key words : Coconut, Cocos nucifera L., plant disease, Kalimantan wiltdisease, phytoplasma, polymerase chain reaction, CentralKalimantanABSTRAKDeteksi phytoplasma yang berasosiasi dengan penyakitlayu Kalimantan pada kelapa dengan reaksi rantaipolymeraseKelapa merupakan komoditi sosial kedua setelah padi di Indonesiadengan luasan areal lebih dari 3.6 juta ha pertanaman, ekuivalen dengansepertiga luas kelapa dunia, hal ini menjadikan Indonesia sebagai negaraprodusen kelapa terluas di dunia. Sekarang ini produksi dan produktivitaskelapa sangat rendah dan tidak stabil yang disebabkan oleh berbagai alasantermasuk serangan hama dan penyakit. Penyakit layu Kalimantan telahmengakibatkan kerugian yang besar pada pertanaman kelapa. Penelitiansebelumnya untuk mengetahui penyebab penyakit dilakukan denganmenguji bakteri, cendawan, virus, viroid dan patogen tanah sepertinematoda tetapi tidak ada yang secara konsisten berasosiasi denganpenyakit layu Kalimantan. Penelitian ini bertujuan untuk mendeteksi danmendiagnosa phytoplasma sebagai penyebab penyakit yang berasosiasidengan layu Kalimantan. Penelitian ini menggunakan dua metode untukmengekstraksi DNA yaitu metode CTAB yang biasanya menggunakannitrogen cair dimodifikasi dengan menghancurkan sampel tanaman padaCTAB yang dipanaskan, dan metode skala kecil. Hasil penelitianmenunjukkan bahwa kedua metode yang digunakan menghasilkan DNAyang sama baiknya untuk analisis PCR. Teknik nested PCR menggunakankombinasi primer P1/P7 dan R16F2n/R16R2 dapat membuktikan bahwapenyebab penyakit layu Kalimantan adalah phytoplasma. Teknik ini jugasecara efektif dapat mendeteksi phytoplasma dalam jaringan tanamankelapa yang sudah terinfeksi maupun yang belum menunjukkan gejalapenyakit. DNA phytoplasma dapat dideteksi pada 95 sampel dari 116sampel (81.9%) yang dianalisis. Berdasarkan jenis sample yang diperiksaternyata phytoplasma dapat dideteksi pada sample yang terinfeksi maupunyang belum menunjukkan gejala penyakit masing-masing 95.1% dan67.3%. Hasil penelitian ini mengkonfirmasi bahwa penyakit layuKalimantan disebabkan oleh phytoplasma.Kata kunci: Kelapa, Cocos nucifera L., penyakit tanaman, penyakit layuKalimantan,  phytoplasma,  reaksi  rantai  polymerase,Kalimantan Tenga

Australian financial graphs: An empirical study

Extends understanding of graphical reporting practices in the Australian accounting environment. Nature of graph use in the annual reports of Australian companies; Cases where the principle of representational neutrality has been violated; Variation among graphical reporting practices

Link invariants from NN-state vertex models: an alternative construction independent of statistical models

We reproduce the hierarchy of link invariants associated to the series of $N$-state vertex models with a method different from the original construction due to Akutsu, Deguchi and Wadati. The alternative method substitutes the `crossing symmetry' property exhibited by the Boltzmann weights of the vertex models by a similar property which, for the purpose of constructing link invariants, encodes the same information but requires only the limit of the Boltzmann weights when the spectral parameter is sent to infinity.Comment: 20 pages, LaTeX, uses epsf.sty. To appear in Nucl. Phys.

Early-nineteenth-century southern African precipitation reconstructions from ships' logbooks

Atmospheric circulation in the oceans surrounding southern Africa plays an important role in determining its precipitation. This study uses wind information recorded in ships’ logbooks in order to statistically reconstruct summer and winter season precipitation at four southern African weather stations from 1796 to 1854. The reconstruction was obtained by first relating gridded 8° × 8° NCEP-DOE reanalysis seasonal mean wind vectors in the adjacent oceans to station precipitation. Over a 30-year calibration period (1979–2008), significant correlations between wind and precipitation at Cape Town, Mthatha and Royal National Park showed particular correspondence with those areas with the greatest concentration of logbook observations. Principal component regression was used to assess the potential of the dominant patterns of variability in the wind vectors as predictors to reconstruct precipitation. Cross-validation in the calibration period gave confidence that precipitation could be reconstructed at several stations across South Africa, meaning the regression relationships derived in the calibration period could be applied to the gridded seasonal mean logbook data to produce reconstructions of precipitation from 1796 to 1854. The reconstructions show a degree of correspondence with other regional data sets. For instance, the decade beginning in 1810 was the wettest of the period at Mthatha and Royal National Park, while the 1820s were the driest. At Cape Town, the 1820s were the wettest decade, with drier conditions observed in the 1830s. An index of west–east circulation in the summer season revealed correspondence with two documentary reconstructions of El Niño events and increased westerliness, although this did not always result in drier conditions. Attention is also drawn to the remaining 3000 yet to be digitised English East India Company logbooks which would provide a high-resolution picture of atmospheric circulation back to 1700 in the region under consideration

The fading of two transient ultraluminous x-ray sources to below the stellar mass Eddington limit

We report new detections of the two transient ultraluminous X-ray sources (ULXs) in NGC 5128 from an ongoing series of Chandra observations. Both sources have previously been observed L (2-3) × ∼10 erg s, at the lower end of the ULX luminosity range. The new observations allow us to study these sources in the luminosity regime frequented by the Galactic black hole X-ray binaries (BH XBs). We present the recent lightcurves of both ULXs. 1RXH J132519.8-430312 (ULX1) was observed at L 1 × 10 erg s, while CXOU J132518.2-430304 (ULX2) declined to L 2 × 10 erg s and then lingered at this luminosity for hundreds of days. We show that a reasonable upper limit for both duty cycles is 0.2, with a lower limit of 0.12 for ULX2. This duty cycle is larger than anticipated for transient ULXs in old stellar populations. By fitting simple spectral models in an observation with ∼50 counts we recover properties consistent with Galactic BH XBs, but inconclusive as to the spectral state. We utilize quantile analyses to demonstrate that the spectra are generally soft, and that in one observation the spectrum of ULX2 is inconsistent with a canonical hard state at >95% confidence. This is contrary to what would be expected of an accreting intermediate mass black hole primary, which we would expect to be in the hard state at these luminosities. We discuss the paucity of transient ULXs discovered in early-type galaxies and excogitate explanations. We suggest that the number of transient ULXs scales with the giant and sub-giant populations, rather than the total number of XBs.Peer reviewe

Failed attempts to improve the reliability of the alcohol Visual Probe Task following empirical recommendations

Introduction: The Visual Probe Task (VPT) is a computerised task used to measure attentional bias to substance-related stimuli. Little research has examined the psychometric properties of the VPT, despite concerns it demonstrates poor test-retest reliability and internal consistency. These issues can reduce confidence in inferences based on VPT performance. As such, we attempted to identify parameters under which the reliability of the alcohol VPT might be improved by applying recent empirical recommendations for outlier handling, bias calculation and task design from the anxiety literature. Methods: We reanalysed data from 3 previously published studies in our laboratory and 2 newly collected data-sets. We compared tasks which presented images on the left/right of the screen to above/below, whether participants responded to the location or content of the probe, and whether general alcohol-related images or images personalised to the individual were used. In each VPT we also applied a-priori outlier removal (2 and 3 standard deviations and median absolute difference) and data-driven outlier removal (Winsorising), in addition to calculating trial-level bias scores. Results: Across all studies and tasks internal consistency and test-retest reliability of attentional bias measures were inadequate. There was no consistent improvement in internal consistency or test-retest reliability as a function of outlier removal methods. Discussion: We were unable to demonstrate adequate reliability of the alcohol VPT, which further supports observations that these tasks may not yield reliable measures. Future research should focus on improving the reliability of these tasks or abandoning them in favour of more reliable alternatives