Natural convection in a triangular enclosure due to non-uniform cooling on top

Natural convection in a triangular enclosure subject to non-uniformly cooling at the inclined surfaces and uniformly heating at the base is investigated numerically. The numerical simulations of the unsteady flows over a range of Rayleigh numbers and aspect ratios are carried out using Finite Volume Method. Since the upper surface is cooled and the bottom surface is heated, the air flow in the enclosure is potentially unstable to Rayleigh Benard instability. It is revealed that the transient flow development in the enclosure can be classified into three distinct stages; an early stage, a transitional stage and a steady stage. It is also found that the flow inside the enclosure strongly depends on the governing parameters; Rayleigh number and aspect ratio. The asymmetric behaviour of the flow about the geometric centre line is discussed in detailed. The heat transfer through the roof and the ceiling as a form of Nusselt number is also reported in this study.

Prandtl number scaling of natural convection of the flow on an inclined at plate due to uniform surface heat flux

A new scaling analysis has been performed for the unsteady natural convection boundary layer under a downward facing inclined plate with uniform heat flux. The development of the thermal or viscous boundary layers may be classified into three distinct stages including an early stage, a transitional stage and a steady stage, which can be clearly identified in the analytical as well as numerical results. Earlier scaling shows that the existing scaling laws of the boundary layer thickness, velocity and steady state time scales for the natural convection flow on a heated plate of uniform heat flux provide a very poor prediction of the Prandtl number dependency. However, those scalings performed very well with Rayleigh number and aspect ratio dependency. In this study, a modifed Prandtl number scaling has been developed using a triple-layer integral approach for Pr > 1. It is seen that in comparison to the direct numerical simulations, the new scaling performs considerably better than the previous scaling.

Mortality and cost outcomes of elderly trauma patients admitted to intensive care and the general wards of an Australian tertiary referral hospital

Mortality and cost outcomes of elderly intensive care unit (ICU) trauma patients were characterised in a retrospective cohort study from an Australian tertiary ICU. Trauma patients admitted between January 2000 and December 2005 were grouped into three major age categories: aged ≥65 years admitted into ICU (n=272); aged ≥65 years admitted into general ward (n=610) and aged <65 years admitted into ICU (n=1617). Hospital mortality predictors were characterised as odds ratios (OR) using logistic regression. The impact of predictor variables on (log) total hospital-stay costs was determined using least squares regression. An alternate treatment-effects regression model estimated the mortality cost-effect as an endogenous variable. Mortality predictors (P ≤0.0001, comparator: ICU ≥65 years, ventilated) were: ICU <65 not-ventilated (OR 0.014); ICU <65 ventilated (OR 0.090); ICU age ≥65 not-ventilated (OR 0.061) and ward ≥65 (OR 0.086); increasing injury severity score and increased Charlson comorbidity index of 1 and 2, compared with zero (OR 2.21 [1.40 to 3.48] and OR 2.57 [1.45 to 4.55]). The raw mean daily ICU and hospital costs in A$ 2005 (US$) for age <65 and ≥65 to ICU, and ≥65 to the ward were; for year 2000: ICU, $2717 (1462) and $2777 (1494); hospital, $1837 (988) and $1590 (855); ward $933 (502); for year 2005: ICU, $3202 (2393) and $3086 (2307); hospital, $1938 (1449) and $1914 (1431); ward $1180 (882). Cost increments were predicted by age ≥65 and ICU admission, increasing injury severity score, mechanical ventilation, Charlson comorbidity index increments and hospital survival. Mortalitycost-effect was estimated at -63% by least squares regression and -82% by treatment-effects regression model. Patient demographic factors, injury severity and its consequences predict both cost and survival in trauma. The cost mortality effect was biased upwards by conventional least squares regression estimation.

Infrared and Raman spectroscopic characterization of the carbonate mineral huanghoite - and in comparison with selected rare earth carbonates

Raman spectroscopy complimented with infrared spectroscopy has been used to study the rare earth based mineral huanghoite with possible formula given as BaCe(CO3)2F and compared with the Raman spectra of a series of selected natural halogenated carbonates from different origins including bastnasite, parisite and northupite. The Raman spectrum of huanghoite displays three bands are at 1072, 1084 and 1091 cm−1 attributed to the symmetric stretching vibration. The observation of three symmetric stretching vibrations is very unusual. The position of symmetric stretching vibration varies with mineral composition. Infrared spectroscopy of huanghoite show bands at 1319, 1382, 1422 and 1470 cm−1. No Raman bands of huanghoite were observed in these positions. Raman spectra of bastnasite, parisite and northupite show a single band at 1433, 1420 and 1554 cm−1 assigned to the ν3 (CO3)2− antisymmetric stretching mode. The observation of additional Raman bands for the ν3 modes for some halogenated carbonates is significant in that it shows distortion of the carbonate anion in the mineral structure. Four Raman bands for huanghoite are observed at 687, 704, 718 and 730 cm−1and assigned to the (CO3)2− ν2 bending modes. Raman bands are observed for huanghoite at around 627 cm−1 and are assigned to the (CO3)2− ν4 bending modes. Raman bands are observed for the carbonate ν4 in phase bending modes at 722 cm−1 for bastnasite, 736 and 684 cm−1 for parisite, 714 cm−1 for northupite. Raman bands for huanghoite observed at 3259, 3484 and 3589 cm−1 are attributed to water stretching bands. Multiple bands are observed in the OH stretching region for bastnasite and parisite indicating the presence of water and OH units in their mineral structure. Vibrational spectroscopy enables new information on the structure of huanghoite to be assessed.

Neurological consequences of diabetic ketoacidosis at initial presentation of type 1 diabetes in a prospective cohort study of children

OBJECTIVE To investigate the impact of new-onset diabetic ketoacidosis (DKA) during child- hood on brain morphology and function. RESEARCH DESIGN AND METHODS Patients aged 6–18 years with and without DKA at diagnosis were studied at four time points: <48 h, 5 days, 28 days, and 6 months postdiagnosis. Patients under- went magnetic resonance imaging (MRI) and spectroscopy with cognitive assess- ment at each time point. Relationships between clinical characteristics at presentation and MRI and neurologic outcomes were examined using multiple linear regression, repeated-measures, and ANCOVA analyses. RESULTS Thirty-six DKA and 59 non-DKA patients were recruited between 2004 and 2009. With DKA, cerebral white matter showed the greatest alterations with increased total white matter volume and higher mean diffusivity in the frontal, temporal, and parietal white matter. Total white matter volume decreased over the first 6 months. For gray matter in DKA patients, total volume was lower at baseline and increased over 6 months. Lower levels of N-acetylaspartate were noted at base- line in the frontal gray matter and basal ganglia. Mental state scores were lower at baseline and at 5 days. Of note, although changes in total and regional brain volumes over the first 5 days resolved, they were associated with poorer delayed memory recall and poorer sustained and divided attention at 6 months. Age at time of presentation and pH level were predictors of neuroimaging and functional outcomes. CONCLUSIONS DKA at type 1 diabetes diagnosis results in morphologic and functional brain changes. These changes are associated with adverse neurocognitive outcomes in the medium term.

The effect of multiplayer dynamic difficulty adjustment on the player experience of video games

Multiplayer Dynamic Difficulty Adjustment (mDDA) is a method of reducing the difference in player performance and subsequent challenge in competitive multiplayer video games. As a balance of between player skill and challenge experienced is necessary for optimal player experience, this experimental study investigates the effects of mDDA and awareness of its presence on player performance and experience using subjective and biometric measures. Early analysis indicates that mDDA normalizes performance and challenge as expected, but awareness of its presence can reduce its effectiveness.

Characteristics of high-performance ambipolar organic field-effect transistors based on a diketopyrrolopyrrole-benzothiadiazole copolymer

In this paper, we report the device characteristics of ambipolar thin-film transistors (TFTs) based on a diketopyrrolopyrrole-benzothiadiazole copolymer. This polymer semiconductor exhibits the largest comparable electron and hole mobility values in a single organic semiconductor. The key to realizing such high mobility values, which are $0.5&cm}{2}/\hbox{V}̇\hbox{s, is molecular design, i.e., the use of suitable surface treatments of the source/drain contact electrodes and device architectures, particularly top-gate configurations. The subthreshold characteristics of the TFT devices are greatly improved by the use of dual-gate device geometry. We also report the first measurement of the velocity distribution of electron and hole velocities in an ambipolar organic semiconductor.

Polymer-mediated synthesis of γ-Fe2O3 nano-particles

Nano-particles of γ-Fe2O3 were synthesized by reacting polyethylene oxide–FeCl3 complex with NH4OH. These were characterized by X-ray diffraction (XRD), scanning electron miscroscopy (SEM), selected area electron diffraction (SAED) and transmision electron microscopy (TEM). The average particle size was found to be 10 nm, as determined from the line broadening of the main XRD peak. The crystalline phase was a spinel-type tetragonal structure, which was confirmed from the electron diffraction pattern. The zero field cooled magnetization of samples with varying γ-Fe2O3 content as a function of temperature was measured using a vibrating sample magnetometer. The magnetization curves show a peak at low temperature (15 K) corresponding to the blocking temperature TB. The value of TB was found to decrease with decreasing particle size. The magnetization measurements with respect to field at 5 and 170 K confirmed the transition from superparamagnetic to spin-glass state at TB, as evidenced from the remanence and hysteresis. These results can be explained on the basis of Néel's theory of superparamagnetism as applied to nano-particles.

Search-phase echolocation calls of the New Zealand lesser short-tailed bat (Mystacina tuberculata) and long-tailed bat (Chalinolobus tuberculatus).

This paper describes the search-phase echolocation calls of lesser short-tailed bats (Mystacina tuberculata) and long-tailed bats (Chalinolobus tuberculatus). Calls were recorded from all three subspecies of short-tailed bat and seven populations of long-tailed bat, three in Northland, two in the central North Island, and two in the lower South Island. The calls were recorded in the field and digitised, then three spectral components and one temporal component of the calls were measured. Calls of the lesser short-tailed bat could be loosely classified into subspecies by means of multivariate discriminant function analysis. Similarly, long-tailed bat calls showed regional variation, and discriminant function analysis was able to fit calls to regional groups with a high rate of success. The significance of the results presented is discussed in terms of the conservation of New Zealand bats and the unique ecology of the lesser short-tailed bat.

The structure and connectivity of semantic memory in the healthy older adult brain

The anterior temporal lobes (ATLs) have been proposed to serve as a "hub" linking amodal or domain general information about the meaning of words, objects, facts and people distributed throughout the brain in semantic memory. The two primary sources of evidence supporting this proposal, viz. structural imaging studies in semantic dementia (SD) patients and functional imaging investigations, are not without problems. Similarly, knowledge about the anatomo-functional connectivity of semantic memory is limited to a handful of intra-operative electrocortical stimulation (IES) investigations in patients. Here, using principal components analyses (PCA) of a battery of conceptual and non-conceptual tests coupled with voxel based morphometry (VBM) and diffusion tensor imaging (DTI) in a sample of healthy older adults aged 55-85. years, we show that amodal semantic memory relies on a predominantly left lateralised network of grey matter regions involving the ATL, posterior temporal and posterior inferior parietal lobes, with prominent involvement of the left inferior fronto-occipital fasciculus (IFOF) and uncinate fasciculus fibre pathways. These results demonstrate relationships between semantic memory, brain structure and connectivity essential for human communication and cognition.

Fernando Pessoan ortonyymi ja heteronyymit modernistis-romanttisena myyttinä

Tutkimuksessani selvitän portugalilaisrunoilija Fernando Pessoan (1888-1935) heteronyymejä ja ortonyymiä modernistis-romanttisena myyttinä. Myytin piirteet paljastuivat Pessoan omia kirjoituksia ja runoja tutkimalla ja käyttämällä apuna Pessoa-tutkimusta. Tutkimusaineistonani ovat Pessoa-ortonyymin Mensagem-runoelma ja ”Autopsykografia”-runo, Álvaro de Campoksen vuonna 1917 Portugal Futurista –lehdessä julkaistu ”Ultimatum”-runomanifesti, Alberto Caeiron ”Guardador de Rebanhos”-runosikermä sekä Ricardo Reisin ”Oodit”-kokonaisuuteen kuuluvat runot: n:ro 59 ”Acima da verdade estão os deuses” (”Totuuden yläpuolella ovat jumalat”, 1914), n:ro 66 ”Olho os campos, Neera” (”Katson peltoja, Neera”, 1917), n:ro 181 ”Amo o que vejo” (”Rakastan sitä mitä näen”, 1934), n:ro 175 ”Estas só. Ninguem o sabe.” (”Olet yksin. Kukaan ei tiedä sitä”, 1933). Tutkimuksessani romanttisen runouden keskeisinä piirteinä pidetään uskoa taiteilijaneroon (geniukseen), mimeettiseen illuusioon (taide tavoittelee ulkoisen todellisuuden toisintamista mahdollisimman autenttisena) ja tekijän ja kokijan eli subjektin ja objektin erottamiseen toisistaan. Käsitänkin modernin runon tutkimuksessani hylänneen monia entisiä käsityksiä ja vastakkainasetteluja muun muassa tekijän ja ulkopuolisen maailman, mielen ja kielen välillä. Näitä moderneja ”rikkomuksia” identifioin ja määrittelen Pessoan heteronyymien runoudessa. Tutkimukseni apukäsitteitä ovat vilpittömyys ja autenttisuus, jotka kuvaavat runoilijan suhdetta itseensä ja muihin ja joita on pohtinut mm. Lionel Trilling teoksessaan Sincerity and authencity. Romanttisessa runoudessa suhde yhteisöön muodostui ensisijaisesti suhteessa omaan itseen, yhtenäiseen minuuteen nojaavan vilpittömyyden kautta, modernissa runoudessa hajanaisuutta ja yksilön suhdetta myös yhteisöön korostavan autenttisuuden avulla. Tutkimuksessani havaitsin, että Pessoa on jo tuotantonsa alusta lähtien kehittänyt tietoisesti modernistis-romanttista myyttiä – päätelmää tukivat niin Pessoan omat kirjoitukset kuin runoanalyysini. Pessoa ennusti ensimmäisen kerran romanttiseen nerotaiteilijaan vertautuvaa ”supra-Camõesia” ”A nova poesia Portuguesa Sociologicamente considerada” –esseessään vuonna 1912. Campoksen ”Ultimatum”-manifestissa puhuja uskoi muutaman useita kymmeniä persoonallisuuksia hallitsevan ”Synteesi-Ihmisen” tai ”supra-Camõesin” ilmestymiseen. ”Synteesi-Ihmisen” oli määrä palauttaa kukoistukseensa lamaantuneessa tilassa ollut Portugalin kirjallisuus uuteen kukoistukseensa. Eräänlaisen perustan koko myytille loi vuotta ennen Pessoan kuolemaa julkaistu Mensagem (suom. Viesti), jossa runoilija esittää saudosistisen ja sebastianistisen perustan. Teixeira de Pascoaesin kehittämä saudosismi näkyy Mensagemissa uskona Portugalin valtion perustajien ja laajentajien – löytöretkeilijöiden – edustamaan voittoisaan lusofoniseen mentaliteettiin, jonka Pessoa asettaa niin kansakunnan, runoilijan kuin ihmisen ihanteeksi. Toinen Mensagemissa esiintyvä myytin rakennusaine on sebastianismi eli usko kuningas Sebastianin (1554-1578) paluuseen. ”Synteesi-Ihminen”/”supra-Camões” oli reinkarnoitunut Sebastian, jonka piti palauttaa kansa ja kulttuuri kukoistukseensa lusofonisen valloittajamentaliteetin avulla. ”Autopsykografia”-runossaan Pessoa esittää puolestaan runoilijaa koskevan modernin poetiikan ongelmineen: esittävyyteen perustuva taide etäännyttää kokijan – taiteilijan – aina väistämättä ensimmäisestä, spontaanista ja luonnollisesta kokemuksesta ja tekee hänestä teeskentelijän ja simulakrumien (Baudrillard), toisen tason merkityksen tuottajan. ”Autopsykografian” moderni poetiikka koskee myös lukijaa, joka ei tavoita runoilijan välittämää merkitystä vaan kolmannen tason merkityksen. ”Autopsykografian” runous- ja ihmiskäsitys on moderni: runoilija on ammattimainen teeskentelijä, lähtökohtaisesti vilpillinen ja epäautenttinen. Pessoa ja Campos edustavat Pessoan objektiivisia heteronyymejä ja myytin modernia puolta. Pessoan subjektiiviset heteronyymit Reis ja Caeiro täydentävät objektiviisia, modernin ihmisen ahdistusta ja levottomuutta ilmaisseita Pessoaa ja Camposta ollen luonteeltaan romanttisia vilpittömyyden kannattajia. Caeiro arvosti näköaistia yli muiden aistien. Hänen tavoitteenaan oli katsoa aina kuin ensimmäistä kertaa, spontaanisti ja välittömästi kuin lapsi. Reis puolestaan korosti harmoniaa jumalten, ihmisten ja luonnon välillä ja uskoi kohtuullisiin aistinautintoihin. Molemmat muodostivat Pessoan myytin romanttisen puolen yhteisessä halussaan hylätä sosiaaliset roolit ja opetukset ja palata kohti yksilöllistä minää. Vilpittömyys ja autenttisuus ovat Caeiron ja Reisin ohjeita runoilijalle ja ihmiselle. Objektiiviset ja subjektiiviset heteronyymit yhdessä muodostavat modernistis-romanttisen myytin, joka kokonaisuudessaan on looginen: objektiiviset heteronyymit esittivät teeskentelyn, vilpillisyyden ja moderniuden ongelmat; subjektiiviset tarjosivat ratkaisua niihin, poisopettelua sosiaalisista rooleista ja rohkeutta mennä kohti omaa yksilöllistä minuutta.

Studies of phosphazenes. Part 14. The tautomerism of oxocyclotriphosphazadienes

The tautomeric behaviour of monohydroxycyclotriphosphazatrienes has been investigated by 31P n.m.r. spectroscopy. These derivatives exist as oxocyclotriphosphazadiene tautomers in which the hydrogen atom is attached to a ring nitrogen atom to the phosphoryl group. Three types of prototropic behaviour are observed : (a) no exchange is detected and only one tautomer is present [e.g. N3HP3(NHBut)2R3O (R = OMe or OEt)]; (b) exchange takes place between two equivalent sites and only one tautomer is observed [e.g. N3HP3R5O (R = OMe or OPh); N3HP3Ph4RO (R = OMe or OEt)]; and (c) exchange occurs between two non-equivalent sites and two tautomers are present [e.g. N3HP3Ph2R3O (R = OMe, OEt, or OPrn)]. It is shown that basicity calculations using substituent constants have predictive value since they are in good agreement with the spectroscopic observations.

What lies beneath? The pattern and abundance of the subterranean tuber bank of the invasive liana cat's claw creeper, Macfadyena unguis-cati (Bignoniaceae)

Cat’s claw creeper, Macfadyena unguis-cati (L.) Gentry (Bignoniaceae) is a major environmental weed of riparian areas, rainforest communities and remnant natural vegetation in coastal Queensland and New South Wales, Australia. In densely infested areas, it smothers standing vegetation, including large trees, and causes canopy collapse. Quantitative data on the ecology of this invasive vine are generally lacking. The present study examines the underground tuber traits of M. unguis-cati and explores their links with aboveground parameters at five infested sites spanning both riparian and inland vegetation. Tubers were abundant in terms of density (~1000 per m2), although small in size and low in level of interconnectivity. M. unguis-cati also exhibits multiple stems per plant. Of all traits screened, the link between stand (stem density) and tuber density was the most significant and yielded a promising bivariate relationship for the purposes of estimation, prediction and management of what lies beneath the soil surface of a given M. unguis-cati infestation site. The study also suggests that new recruitment is primarily from seeds, not from vegetative propagation as previously thought. The results highlight the need for future biological-control efforts to focus on introducing specialist seed- and pod-feeding insects to reduce seed-output.

Pressure-induced first-order transition in layered crystalline semiconductor GeSe to a metallic phase

The electrical resistivity of layerd crystalline GeSe has been investigated up to a pressure of 100 kbar and down to liquid-nitrogen temperature by use of a Bridgman anvil device. A pressure-induced first-order phase transition has been observed in single-crystal GeSe near 6 GPa. The high-pressure phase is found to be quenchable and an x-ray diffraction study of the quenched material reveals that it has the face-centered-cubic structure. Resistivity measurements as a function of pressure and temperature suggest that the high-pressure phase is metallic.