Periodicity and frequency coding in human auditory cortex

Understanding the neural coding of pitch and frequency is fundamental to the understanding of speech comprehension, music perception and the segregation of concurrent sound sources. Neuroimaging has made important contributions to defining the pattern of frequency sensitivity in humans. However, the precise way in which pitch sensitivity relates to these frequency-dependent regions remains unclear. Single-frequency tones also cannot be used to test this hypothesis as their pitch always equals their frequency. Here, temporal pitch (periodicity) and frequency coding were dissociated using stimuli that were bandpassed in different frequency spectra (centre frequencies 800 and 4500 Hz), yet were matched in their pitch characteristics. Cortical responses to both pitch-evoking stimuli typically occurred within a region that was also responsive to low frequencies. Its location extended across both primary and nonprimary auditory cortex. An additional control experiment demonstrated that this pitch-related effect was not simply caused by the generation of combination tones. Our findings support recent neurophysiological evidence for a cortical representation of pitch at the lateral border of the primary auditory cortex, while revealing new evidence that additional auditory fields are also likely to play a role in pitch coding

Heat and fluid flow in a scraped-surface heat exchanger containing a fluid with temperature-dependent viscosity

Scraped-surface heat exchangers (SSHEs) are extensively used in a wide variety of industrial settings where the continuous processing of fluids and fluid-like materials is involved. The steady non-isothermal flow of a Newtonian fluid with temperature-dependent viscosity in a narrow-gap SSHE when a constant temperature difference is imposed across the gap between the rotor and the stator is investigated. The mathematical model is formulated and the exact analytical solutions for the heat and fluid flow of a fluid with a general dependence of viscosity on temperature for a general blade shape are obtained. These solutions are then presented for the specific case of an exponential dependence of viscosity on temperature. Asymptotic methods are employed to investigate the behaviour of the solutions in several special limiting geometries and in the limits of weak and strong thermoviscosity. In particular, in the limit of strong thermoviscosity (i.e., strong heating or cooling and/or strong dependence of viscosity on temperature) the transverse and axial velocities become uniform in the bulk of the flow with boundary layers forming either just below the blade and just below the stationary upper wall or just above the blade and just above the moving lower wall. Results are presented for the most realistic case of a linear blade which illustrate the effect of varying the thermoviscosity of the fluid and the geometry of the SSHE on the flow

Scheduling MapReduce Jobs under Multi-Round Precedences

We consider non-preemptive scheduling of MapReduce jobs with multiple tasks in the practical scenario where each job requires several map-reduce rounds. We seek to minimize the average weighted completion time and consider scheduling on identical and unrelated parallel processors. For identical processors, we present LP-based O(1)-approximation algorithms. For unrelated processors, the approximation ratio naturally depends on the maximum number of rounds of any job. Since the number of rounds per job in typical MapReduce algorithms is a small constant, our scheduling algorithms achieve a small approximation ratio in practice. For the single-round case, we substantially improve on previously best known approximation guarantees for both identical and unrelated processors. Moreover, we conduct an experimental analysis and compare the performance of our algorithms against a fast heuristic and a lower bound on the optimal solution, thus demonstrating their promising practical performance

Natural parasitism of the Citrus Leafminer (Lepidoptera: Gracillariidae) over eight years in seven citrus regions of São Paulo, Brazil

The citrus leafminer (CLM) Phyllocnists citrella Stainton (Lepidoptera: Gracillariidae) was frst recorded in Brazil in 1996. In 1998, the parasitoid Ageniaspis citricola Logvinovskaya (Hymenoptera: Encyrtdae) was introduced and established in many regions of the country. In this study, 130 onehour-samplings of sweet orange leaves (Citrus sinensis [L.] Osbeck) hostng CLM pupal chambers were carried out to estmate the CLM parasitsm rate (%) by its parasitoids in 7 regions of São Paulo State between 2000 and 2008. The sample sizes varied from 10 to 275 leaves (mean = 65). The most abundant parasitoid was the encyrtd A. citricola (found in 91.8% of the samplings). The highest level of CLM parasitsm by A. citricola was recorded in the southern region (Botucatu), 70.2 ± 6.6 (mean ± SEM), and the lowest level was recorded in the northern region (Barretos), 12.8 ± 5.7%. CLM parasitsm by A. citricola and by natve parasitoids (Galeopsomyia fausta LaSalle, Cirrospilus spp. and Elasmus sp.) did not differ between seasons. The 6-fold increase in the use of insectcides in citrus groves, afer 2004 when the Huanglongbing (HLB) disease was found in São Paulo State, did not reduce the level of CLM parasitsm. The level of parasitsm was 50.8 ± 4.2% before the advent of HLB (2000–2004) and 56.0 ± 4.4% thereafer (2005–2008), indicatng adaptaton of A. citricola in a disturbed agroecosystem.A minadora das folhas dos citros (MFC), Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), foi encontrada pela primeira vez no Brasil em 1996. Em 1998, o parasitoide Ageniaspis citricola Logvinovskaya (Hymenoptera: Encyrtidae) foi introduzido e se estabeleceu em várias regiões do país. Nesse estudo, foram feitas130 amostragens, de uma hora, de folhas de laranjeiras doces [Citrus sinensis (L.) Osbeck] com câmaras pupais da MFC, para se estimar o parasitismo da MFC em 7 regiões do estado de São Paulo, entre 2000 e 2008. O tamanho das amostras variou de 10 a 275 folhas (média = 65). O parasitoide mais abundante foi o encirtídeo A. citricola (encontrado em 91.8% das amostragens). O maior parasitismo da MFC por A. citricola foi observado na região sul do estado (Botucatu), 70,2 ± 6,6 (média ± EPM), e o menor parasitismo na região norte (Barretos), 12,8 ± 5,7%. O parasitismo da MFC por A. citricola e seus parasitoides nativos (Galeopsomyia fausta LaSalle, Cirrospilus spp. and Elasmus sp.) não diferiram entre as estações do ano. O aumento de seis vezes no uso de inseticidas nos pomares de citros, após 2004, quando o Huanglongbing (HLB) foi encontrado no estado de São Paulo, não reduziu o nível de parasitismo da MFC. O nível médio de parasitismo foi de 50,8 ± 4,2%, antes do HLB (2000-2004), e 56,0 ± 4,4%, após o HLB (2005-2008), indicando a adaptação de A. citricola a um agroecossistema perturbado.info:eu-repo/semantics/publishedVersio

Sensory Qualities of Oysters Unaltered by a Short Exposure to Combined Elevated pCO2 and Temperature

Reliance on the marine environment for the provision of food is ever-increasing, but future climate change threatens production. Despite this concern, the impact on seafood quality and success of the seafood industry is unknown. Using a short-term study, we test these concerns using a major aquaculture species-Crassostrea gigas-exposing them to three acidification and warming scenarios: (1) ambient pCO2 (~400 ppm) & control temperature (15°C), (2) ambient pCO2 (~400 ppm) & elevated temperature (20°C), (3) elevated pCO2 (~1,000 ppm) & elevated temperature (20°C). Oyster quality was assessed by scoring appearance, aroma, taste, and overall acceptability. A panel of five experts was asked to score nine oysters-three from each treatment-according to agreed criteria. Results indicate that these levels of acidification and warming did not significantly alter the sensory properties of C. gigas, and notably the overall acceptability remained unchanged. Non-statistically supported trends suggest that several sensory attributes-opacity, mouthfeel, aspect of meat, shininess, meat resistance, meat texture, and creaminess-may improve under acidification and warming scenarios. These findings can be considered positive for the future of the aquaculture and food sectors. Crassostrea gigas therefore is expected to remain a key species for food security that is resilient to climate change, whilst retaining its valuable attributes

The key role of nitric oxide in hypoxia: hypoxic vasodilation and energy supply-demand matching

Significance: a mismatch between energy supply and demand induces tissue hypoxia with the potential to cause cell death and organ failure. Whenever arterial oxygen concentration is reduced, increases in blood flow - 'hypoxic vasodilation' - occur in an attempt to restore oxygen supply. Nitric oxide is a major signalling and effector molecule mediating the body's response to hypoxia, given its unique characteristics of vasodilation (improving blood flow and oxygen supply) and modulation of energetic metabolism (reducing oxygen consumption and promoting utilization of alternative pathways). Recent advances: this review covers the role of oxygen in metabolism and responses to hypoxia, the hemodynamic and metabolic effects of nitric oxide, and mechanisms underlying the involvement of nitric oxide in hypoxic vasodilation. Recent insights into nitric oxide metabolism will be discussed, including the role for dietary intake of nitrate, endogenous nitrite reductases, and release of nitric oxide from storage pools. The processes through which nitric oxide levels are elevated during hypoxia are presented, namely (i) increased synthesis from nitric oxide synthases, increased reduction of nitrite to nitric oxide by heme- or pterin-based enzymes and increased release from nitric oxide stores, and (ii) reduced deactivation by mitochondrial cytochrome c oxidase. Critical issues: several reviews covered modulation of energetic metabolism by nitric oxide, while here we highlight the crucial role NO plays in achieving cardiocirculatory homeostasis during acute hypoxia through both vasodilation and metabolic suppression Future directions: we identify a key position for nitric oxide in the body's adaptation to an acute energy supply-demand mismatc

HIV prevalence and undiagnosed infection among a community sample of gay and bisexual men in Scotland, 2005-2011: implications for HIV testing policy and prevention

<b>Objective</b><p></p> To examine HIV prevalence, HIV testing behaviour, undiagnosed infection and risk factors for HIV positivity among a community sample of gay men in Scotland.<p></p> <b>Methods</b><p></p> Cross-sectional survey of gay and bisexual men attending commercial gay venues in Glasgow and Edinburgh, Scotland with voluntary anonymous HIV testing of oral fluid samples in 2011. A response rate of 65.2% was achieved (1515 participants).<p></p> <b>Results</b><p></p> HIV prevalence (4.8%, 95% confidence interval, CI 3.8% to 6.2%) remained stable compared to previous survey years (2005 and 2008) and the proportion of undiagnosed infection among HIV-positive men (25.4%) remained similar to that recorded in 2008. Half of the participants who provided an oral fluid sample stated that they had had an HIV test in the previous 12 months; this proportion is significantly higher when compared to previous study years (50.7% versus 33.8% in 2005, p<0.001). Older age (>25 years) was associated with HIV positivity (1.8% in those <25 versus 6.4% in older ages group) as was a sexually transmitted infection (STI) diagnosis within the previous 12 months (adjusted odds ratio 2.13, 95% CI 1.09–4.14). There was no significant association between age and having an STI or age and any of the sexual behaviours recorded.<p></p> <b>Conclusion</b><p></p> HIV transmission continues to occur among gay and bisexual men in Scotland. Despite evidence of recent testing within the previous six months, suggesting a willingness to test, the current opt-out policy may have reached its limit with regards to maximising HIV test uptake. Novel strategies are required to improve regular testing opportunities and more frequent testing as there are implications for the use of other biomedical HIV interventions.<p></p&gt

The Plasmodium falciparum, Nima-related kinase Pfnek-4: a marker for asexual parasites committed to sexual differentiation

<b>Background</b> Malaria parasites undergo, in the vertebrate host, a developmental switch from asexual replication to sexual differentiation leading to the formation of gametocytes, the only form able to survive in the mosquito vector. Regulation of the onset of the sexual phase remains largely unknown and represents an important gap in the understanding of the parasite's complex biology. <b>Methods:</b> The expression and function of the Nima-related kinase Pfnek-4 during the early sexual development of the human malaria parasite Plasmodium falciparum were investigated, using three types of transgenic Plasmodium falciparum 3D7 lines: (i) episomally expressing a Pfnek-4-GFP fusion protein under the control of its cognate pfnek-4 promoter; (ii) episomally expressing negative or positive selectable markers, yeast cytosine deaminase-uridyl phosphoribosyl transferase, or human dihydrofolate reductase, under the control of the pfnek-4 promoter; and (iii) lacking a functional pfnek-4 gene. Parasite transfectants were analysed by fluorescence microscopy and flow cytometry. In vitro growth rate and gametocyte formation were determined by Giemsa-stained blood smears. <b>Results:</b> The Pfnek-4-GFP protein was found to be expressed in stage II to V gametocytes and, unexpectedly, in a subset of asexual-stage parasites undergoing schizogony. Culture conditions stimulating gametocyte formation resulted in significant increase of this schizont subpopulation. Moreover, sorted asexual parasites expressing the Pfnek-4-GFP protein displayed elevated gametocyte formation when returned to in vitro culture in presence of fresh red blood cells, when compared to GFP- parasites from the same initial population. Negative selection of asexual parasites expressing pfnek-4 showed a marginal reduction in growth rate, whereas positive selection caused a marked reduction in parasitaemia, but was not sufficient to completely abolish proliferation. Pfnek-4- clones are not affected in their asexual growth and produced normal numbers of stage V gametocytes. <b>Conclusions:</b> The results indicate that Pfnek-4 is not strictly gametocyte-specific, and is expressed in a small subset of asexual parasites displaying high rate conversion to sexual development. Pfnek-4 is not required for erythrocytic schizogony and gametocytogenesis. This is the first study to report the use of a molecular marker for the sorting of sexually-committed schizont stage P. falciparum parasites, which opens the way to molecular characterization of this pre-differentiated subpopulation

Psychological type and attitude towards Celtic Christianity among committed Churchgoers in the United Kingdom: an empirical study

This article takes the burgeoning interest in Celtic Christianity as a key example of the way in which churches may be responding to the changing spiritual and religious landscape in the United Kingdom today and examines the power of psychological type theory to account for variation in the attitude of committed churchgoers to this innovation. Data provided by a sample of 248 Anglican clergy and lay church officers (who completed the Francis Psychological Type Scales together with the Attitude toward Celtic Christianity Scale) demonstrated that intuitive types, feeling types, and perceiving types reported a more positive attitude towards Celtic Christianity than sensing types, thinking types, and judging types. These findings are interpreted to analyse the appeal of Celtic Christianity and to suggest why some committed churchgoers may find this innovation less attractive