Unravelling the evolutionary history of kisspeptin

Experiments in sea cucumbers reveal how the physiological responses regulated by a neuropeptide called kisspeptin have evolved

The Effect of Early Adolescents’ Psychological Needs Satisfaction upon Their Perceived Competence in Information Skills and Intrinsic Motivation for Research

The American Association of School Librarians’ Standards for the 21st Century Learner make clear that information skills alone are not sufficient for student success; students must also value those skills, use them in a productive and responsible manner, and have the motivational “dispositions in action” to support successful research and independent lifelong learning. Self-determination theory highlights perceived competence and autonomy as two basic psychological needs that support intrinsically-motivated behavior. This study investigates the extent to which context factors inherent to the school library influence students’ perceived competence in the domain of information skills (PCIS), and their intrinsic motivation for research (IMR). The study explores this relationship among 1272 eighth grade 13-year old students in 20 states. Findings indicate that student perceptions of their school librarian’s autonomy supportiveness and their perceptions of the librarian’s technology competence contribute significantly to PCIS and IMR. These findings are important in that they highlight the important role that the school librarian may play in influencing student affect towards the activity of information uses and research, and likely their consequent learning outcomes

Supporting Inquiry by Identifying Gaps in Student Confidence: Development of a Measure of Perceived Competence

Critical to inquiry-based learning is information literacy. Educators can enhance students’ experiences during the inquiry process if they are aware of the skill areas in which students either have or lack confidence. This article describes the development and psychometric properties of the Perceived Competence in Information Skills (PCIS) measure. Educators can use the measure to support student inquiry by identifying and addressing gaps in student confidence. The measure is freely available through Syracuse University’s Center for Digital Literacy

Prognostic role of aldosterone in patients with acute coronary syndrome: short and medium term follow-up.

AIMS: Different studies have shown a correlation between aldosterone, atherosclerosis and ischemia in the past decade. Evidence exists for the relationship between high levels of aldosterone and augmented risk of cardiovascular diseases, such as hypertension, cardiac failure, coronary artery disease and stroke. The objective of this study was to determine the prognostic role of aldosterone in patients with myocardial infarction. METHODS:The study population included 96 consecutive patients admitted to our department for ST-elevated and non-ST-elevated myocardial infarction from June 2009 to March 2012. Plasma aldosterone levels were measured at admission to hospital in all patients. A 2-year prospective follow-up was performed, and fatal events and non-fatal events, such as reinfarction, congestive heart failure and arrhythmias, were recorded. RESULTS:Aldosterone levels at admission were associated with incidence of congestive heart failure (P\u200a=\u200a0.02), ventricular arrhythmias (P\u200a=\u200a0.01) and all complications (P\u200a=\u200a0.003) after 1-month follow-up. Moreover, high aldosterone levels gave important information in the medium term (24\u200a\ub1\u200a6 months). Specifically, aldosterone was a predictive variable of reinfarction (P\u200a<\u200a0.0001), congestive heart failure (P\u200a<\u200a0.0001) and adverse events (P\u200a=\u200a0.0002). The logistic regression analysis confirmed these results and showed that aldosterone may be predictive of adverse events at medium-term follow-up (odds ratio 1.1, 95% confidence interval 1.03-1.15, P\u200a=\u200a0.02). CONCLUSION:These data show a strong and significant correlation between plasma aldosterone levels at admission for myocardial infarction and fatal and nonfatal adverse events. Aldosterone appears to be a main marker of adverse clinical outcome, in accordance with the literature. These data suggest the need to identify whether antialdosteronic drug treatment, applied acutely in patients with aldosterone elevation, can influence favorably the prognosis of patients with myocardial infarction

Sensitivity of Nonrenormalizable Trajectories to the Bare Scale

Working in scalar field theory, we consider RG trajectories which correspond to nonrenormalizable theories, in the Wilsonian sense. An interesting question to ask of such trajectories is, given some fixed starting point in parameter space, how the effective action at the effective scale, Lambda, changes as the bare scale (and hence the duration of the flow down to Lambda) is changed. When the effective action satisfies Polchinski's version of the Exact Renormalization Group equation, we prove, directly from the path integral, that the dependence of the effective action on the bare scale, keeping the interaction part of the bare action fixed, is given by an equation of the same form as the Polchinski equation but with a kernel of the opposite sign. We then investigate whether similar equations exist for various generalizations of the Polchinski equation. Using nonperturbative, diagrammatic arguments we find that an action can always be constructed which satisfies the Polchinski-like equation under variation of the bare scale. For the family of flow equations in which the field is renormalized, but the blocking functional is the simplest allowed, this action is essentially identified with the effective action at Lambda = 0. This does not seem to hold for more elaborate generalizations.Comment: v1: 23 pages, 5 figures, v2: intro extended, refs added, published in jphy

Field programmable gate arrays implementations of low complexity soft-input soft-output low-density parity-check decoders

Low-density parity-check (LDPC) codes are very efficient error control codes that are being considered for use in many next-generation communication systems. In this study low complexity soft-input, soft-output (SISO) field programmable gate arrays (FPGA) implementations of a novel logarithmic sum-product (LogSP) iterative LDPC decoder and a recently proposed simplified soft Euclidean distance (SSD) iterative LDPC decoder are presented, and their complexities and performance are compared. These implementations operate over any choice of parity check matrix (including those randomly generated, structurally generated and either systematic or non-systematic) and can be parametrically adapted for any code rate. The proposed implementations are both of very low complexity, because they operate using only sums, subtractions, comparisons and look-up tables, which makes them particularly suitable for FPGA realisation. The SSD decoder has a lower implementation complexity than the LogSP LDPC decoder and it also offers the advantage of not requiring knowledge of the channel signal-to-noise ratio, unlike most other LDPC decoders.Fil: Arnone, Leonardo Jose. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Eléctrica; ArgentinaFil: Castiñeira Moreira, Jorge. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Eléctrica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Farrell, P. G.. Lancaster University; Reino Unid

Green Fluorescent Protein in the sea urchin: new experimental approaches to transcriptional regulatory analysis in embryos and larvae

The use of Green Fluorescent Protein (GFP) as a reporter for expression transgenes opens the way to several new experimental strategies for the study of gene regulation in sea urchin development. A GFP coding sequence was associated with three different previously studied cis-regulatory systems, viz those of the SM50 gene, expressed in skeletogenic mesenchyme, the CyIIa gene, expressed in archenteron, skeletogenic and secondary mesenchyme, and the Endo16 gene, expressed in vegetal plate, archenteron and midgut. We demonstrate that the sensitivity with which expression can be detected is equal to or greater than that of whole-mount in situ hybridization applied to detection of CAT mRNA synthesized under the control of the same cis-regulatory systems. However, in addition to the important feature that it can be visualized nondestructively in living embryos, GFP has other advantages. First, it freely diffuses even within fine cytoplasmic cables, and thus reveals connections between cells, which in sea urchin embryos is particularly useful for observations on regulatory systems that operate in the syncytial skeletogenic mesenchyme. Second, GFP expression can be dramatically visualized in postembryonic larval tissues. This brings postembryonic larval developmental processes for the first time within the easy range of gene transfer analyses. Third, GFP permits identification and segregation of embryos in which the clonal incorporation of injected DNA has occurred in any particular desired region of the embryo. Thus, we show explicitly that, as expected, GFP transgenes are incorporated in the same nuclei together with other transgenes with which they are co-injected

Low temperature characterization of modulation doped SiGe grown on bonded silicon-on-insulator

Modulation doped pseudomorphic Si0.87Ge0.13 strained quantum wells were grown on bonded silicon-on-insulator (SOI) substrates. Comparison with similar structures grown on bulk Si(100) wafers shows that the SOI material has higher mobility at low temperatures with a maximum value of 16 810 cm 2/V s for 2.05 × 1011 cm – 2 carries at 298 mK. Effective masses obtained from the temperature dependence of Shubnikov–de Haas oscillations have a value of (0.27 ± 0.02) m0 compared to (0.23 ± 0.02) m0 for quantum wells on Si(100) while the cyclotron resonance effective masses obtained at higher magnetic fields without consideration for nonparabolicity effects have values between 0.25 and 0.29 m0. Ratios of the transport and quantum lifetimes, tau/tau q=2.13 ± 0.10, were obtained for the SOI material that are, we believe, the highest reported for any pseudomorphic SiGe modulation doped structure and demonstrates that there is less interface roughness or charge scattering in the SOI material than in metal–oxide–semiconductor field effect transistors or other pseudomorphic SiGe modulation doped quantum wells

Performance of a Simplified Soft-Distance decoding algorithm for LDPC codes over the Rayleigh fading channel

In this paper, we investigate the performance of a Soft-Input soft-Output decoding algorithm for LDPC codes that uses Euclidean distance as its metric, in the Rayleigh fading channel. It is found that its Bit Error Rate performance is close to that of traditional decoding algorithms like the SumProduct algorithm and its logarithmic version. Main characteristics of the proposed algorithm and its modification to perform over the Rayleigh channel are described. This algorithm uses squared Euclidean distance as the metric, does not require knowledge of the signal-to-noise ratio of the received signal, and is less complex to implement than other soft-input, soft-output algorithms.Fil: Arnone, Leonardo Jose. Universidad Nacional de Mar del Plata. Facultad de Ingeniería; ArgentinaFil: Liberatori, Mónica Cristina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Electrónica. Laboratorio de Comunicaciones; ArgentinaFil: Petruzzi, David Mario. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Electrónica. Laboratorio de Comunicaciones; ArgentinaFil: Farrell, P. G.. Lancaster University. Department of Communications Systems; Reino UnidoFil: Castiñeira Moreira, Jorge. Universidad Nacional de Mar del Plata. Facultad de Ingenieria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata; Argentin

Parameterisation of the chemical effects of sprites in the middle atmosphere

Transient luminous events, such as red sprites, occur in the middle atmosphere in the electric field above thunderstorms. We here address the question whether these processes may be a significant source of odd nitrogen and affect ozone or other important trace species. A well-established coupled ion-neutral chemical model has been extended for this purpose and applied together with estimated rates of ionisation, excitation and dissociation based on spectroscopic ratios from ISUAL on FORMOSAT-2. This approach is used to estimate the NO&lt;sub&gt;x&lt;/sub&gt; and ozone changes for two type cases. &lt;br&gt;&lt;br&gt; The NO&lt;sub&gt;x&lt;/sub&gt; enhancements are at most one order of magnitude in the streamers, which means a production of at most 10 mol per event, or (given a global rate of occurrence of three events per minute) some 150&amp;ndash;1500 kg per day. The present study therefore indicates that sprites are insignificant as a global source of NO&lt;sub&gt;x&lt;/sub&gt;. Local effects on ozone are also negligible, but the local enhancement of NO&lt;sub&gt;x&lt;/sub&gt; may be significant, up to 5 times the minimum background at 70 km in extraordinary cases