Filtrations on the knot contact homology of transverse knots

We construct a new invariant of transverse links in the standard contact structure on R^3. This invariant is a doubly filtered version of the knot contact homology differential graded algebra (DGA) of the link. Here the knot contact homology of a link in R^3 is the Legendrian contact homology DGA of its conormal lift into the unit cotangent bundle S^*R^3 of R^3, and the filtrations are constructed by counting intersections of the holomorphic disks of the DGA differential with two conormal lifts of the contact structure. We also present a combinatorial formula for the filtered DGA in terms of braid representatives of transverse links and apply it to show that the new invariant is independent of previously known invariants of transverse links.Comment: 23 pages, v2: minor corrections suggested by refere

Critique of proposed limit to space--time measurement, based on Wigner's clocks and mirrors

Based on a relation between inertial time intervals and the Riemannian curvature, we show that space--time uncertainty derived by Ng and van Dam implies absurd uncertainties of the Riemannian curvature.Comment: 5 pages, LaTex, field "Author:" correcte

Burst-by-Burst Adaptive Decision Feedback Equalised TCM, TTCM and BICM for H.263-Assisted Wireless Video Telephony

Decision Feedback Equaliser (DFE) aided wideband Burst-by-Burst (BbB) Adaptive Trellis Coded Modulation (TCM), Turbo Trellis Coded Modulation (TTCM) and Bit-Interleaved Coded Modulation (BICM) assisted H.263-based video transceivers are proposed and characterised in performance terms when communicating over the COST 207 Typical Urban wideband fading channel. Specifically, four different modulation modes, namely 4QAM, 8PSK, 16QAM and 64QAM are invoked and protected by the above-mentioned coded modulation schemes. The TTCM assisted scheme was found to provide the best video performance, although at the cost of the highest complexity. A range of lower-complexity arrangements will also be characterised. Finally, in order to confirm these findings in an important practical environment, we have also investigated the adaptive TTCM scheme in the CDMA-based Universal Mobile Telecommunications System's (UMTS) Terrestrial Radio Access (UTRA) scenario and the good performance of adaptive TTCM scheme recorded when communicating over the COST 207 channels was retained in the UTRA environment

Multiwavelength pyrometer for gray and non-gray surfaces in the presence of interfering radiation

A method and apparatus for detecting the temperature of gray and non-gray bodies in the presence of interfering radiation are presented. A gray body has a constant emissivity less than 1 and a non-gray body has an emissivity which varies with wavelength. The emissivity and reflectivity of the surface is determined over a range of wavelengths. Spectra are also measured of the extraneous interference radiation source and the surface of the object to be measured in the presence of the extraneous interference radiation source. An auxiliary radiation source is used to determine the reflectivity of the surface and also the emissivity. The measured spectrum of the surfaces in the presence of the extraneous interference radiation source is set equal to the emissivity of the surface multiplied by a Planck function containing a temperature term T plus the surface reflectivity multiplied by the spectrum of the extraneous interference radiation source. The equation is then solved for T to determine the temperature of the surface

Changes in organic aerosol composition with aging inferred from aerosol mass spectra

Organic aerosols (OA) can be separated with factor analysis of aerosol mass spectrometer (AMS) data into hydrocarbon-like OA (HOA) and oxygenated OA (OOA). We develop a new method to parameterize H:C of OOA in terms of f_(43)(ratio of m/z 43, mostly C_2H_3O^+, to total signal in the component mass spectrum). Such parameterization allows for the transformation of large database of ambient OOA components from the f_(44) (mostly CO^+_2, likely from acid groups) vs. f_(43) space ("triangle plot") (Ng et al., 2010) into the Van Krevelen diagram (H:C vs. O:C) (Van Krevelen, 1950). Heald et al. (2010) examined the evolution of total OA in the Van Krevelen diagram. In this work total OA is deconvolved into components that correspond to primary (HOA and others) and secondary (OOA) organic aerosols. By deconvolving total OA into different components, we remove physical mixing effects between secondary and primary aerosols which allows for examination of the evolution of OOA components alone in the Van Krevelen space. This provides a unique means of following ambient secondary OA evolution that is analogous to and can be compared with trends observed in chamber studies of secondary organic aerosol formation. The triangle plot in Ng et al. (2010) indicates that f_(44) of OOA components increases with photochemical age, suggesting the importance of acid formation in OOA evolution. Once they are transformed with the new parameterization, the triangle plot of the OOA components from all sites occupy an area in Van Krevelen space which follows a ΔH:C/ΔO:C slope of ~ −0.5. This slope suggests that ambient OOA aging results in net changes in chemical composition that are equivalent to the addition of both acid and alcohol/peroxide functional groups without fragmentation (i.e. C-C bond breakage), and/or the addition of acid groups with fragmentation. These results provide a framework for linking the bulk aerosol chemical composition evolution to molecular-level studies

Hegemonic conceptualizations of empowerment in entrepreneurship and their suitability for collective contexts

The relationship between empowerment and entrepreneurship in collective societies is, in our view, insufficiently examined. Accepted definitions of empowerment and the assumptions underlying programs and research designs based on them result in outcomes that self-fulfil and, as a result, disappoint. Several issues are prevalent: the empowerment potential of programs is overestimated and the dominant view of what constitutes an ‘empowered self’ does not go deep enough to explore, and reframe, the self and its relationship to agency—two issues at the core of empowerment definitions and formulations. In this conceptual article, we examine the entrepreneurship and empowerment literature to suggest ways forward for the future health and relevance of the subject area. We highlight a serious methodological and perceptual issue within the literature, which offers many opportunities for theory development in the field

A new species of micro-mangrove crab of the genus Haberma Ng & Schubart, 2002 (Crustacea, Brachyura, Sesarmidae) from Hong Kong

The sesarmid genus Haberma Ng & Schubart, 2002, currently contains two species of small mangrove crabs with the first two pairs of the male ambulatory legs possessing characteristic subchelate dactyli and propodi. A new species, H. tingkok, is here described from Hong Kong. It can be separated from H. nanum Ng & Schubart, 2002 (from Singapore), and H. kamora Rahayu & Ng, 2005 (from Indonesian Papua) by its carapace shape, proportions of the ambulatory legs, and structures of the male pleon and male first gonopod.published_or_final_versio

SPINO-PELVIC KINEMATICS AND TRUNK MUSCLE ACTIVATION IN PROLONGED ERGOMETER ROWING: MECHANICAL ETIOLOGY OF NON-SPECIFIC LOW BACK PAIN IN ADOLESCENT ROWERS

The aim of this study was to determine whether adolescent rowers with and without low back pain (LBP) displayed differences in spino-pelvic kinematics and trunk muscle activation during prolonged ergometer rowing. Ten rowers with LBP and twelve rowers without LBP performed a 20 minute ergometer trial with kinematics, muscle activation and self reported perception of pain data (VAS) collected during the trial. Results of this study show that rowers with LBP postured their lumbar spine in flexion for a greater proportion of the drive phase and nearer to their end range of flexion when compared to those without LBP. This study highlights potential mechanisms for the ramping of back pain in adolescent rowers

SPINO-PELVIC KINEMATICS AND TRUNK MUSCLE ACTIVATION IN PROLONGED ERGOMETER ROWING: MECHANICAL ETIOLOGY OF NON-SPECIFIC LOW BACK PAIN IN ADOLESCENT ROWERS

The aim of this study was to determine whether adolescent rowers with and without low back pain (LBP) displayed differences in spino-pelvic kinematics and trunk muscle activation during prolonged ergometer rowing. Ten rowers with LBP and twelve rowers without LBP performed a 20 minute ergometer trial with kinematics, muscle activation and self reported perception of pain data (VAS) collected during the trial. Results of this study show that rowers with LBP postured their lumbar spine in flexion for a greater proportion of the drive phase and nearer to their end range of flexion when compared to those without LBP. This study highlights potential mechanisms for the ramping of back pain in adolescent rowers

Integrative model of behavioural intention: the influence of environmental concern and condition factors on food waste separation

Purpose This paper positions environmental concern as the antecedent of attitude, subjective norm and perceived behavioural control. It also sets to expand the theory of planned behaviour by including two condition factors: favourable situation and facility availability on the intention to separate food waste at source. Design/methodology/approach The study collects data by using self-administered questionnaires on 682 respondents in Malaysia. Structural equation modelling is employed to test the conceptual model and the proposed hypotheses. Findings The results show that environmental concern positively influences attitude and subjective norms, which, in turn, influences food waste separation intention. Favourable situation and facility availability are found to influence the separation intention. Originality/value This study is one of the earliest studies to investigate residents’ intention to participate in food waste separation at a source that employs the expanded theory of planned behaviour with environmental concern and condition factors