2,728 research outputs found
Time-delayed models of gene regulatory networks
We discuss different mathematical models of gene regulatory networks as relevant to the onset and development of cancer. After discussion of alternativemodelling approaches, we use a paradigmatic two-gene network to focus on the role played by time delays in the dynamics of gene regulatory networks. We contrast the dynamics of the reduced model arising in the limit of fast mRNA dynamics with that of the full model. The review concludes with the discussion of some open problems
High magnetic field pulsars and magnetars: a unified picture
We propose a unified picture of high magnetic field radio pulsars and
magnetars by arguing that they are all rotating high-field neutron stars, but
have different orientations of their magnetic axes with respective to their
rotation axes. In strong magnetic fields where photon splitting suppresses pair
creation near the surface, the high-field pulsars can have active inner
accelerators while the anomalous X-ray pulsars cannot. This can account for the
very different observed emission characteristics of the anomalous X-ray pulsar
1E 2259+586 and the high field radio pulsar PSR J1814-1744. A predicted
consequence of this picture is that radio pulsars having surface magnetic field
greater than about G should not exist.Comment: 5 pages, emulateapj style, accepted for publication in the ApJ
Letter
The role of debriefing in enhancing learning and development in professional boxing
The use of debriefing by 6 elite coaches (9–16 years’ experience coaching professional boxers) and 6 professional boxers (minimum 3 professional bouts) was explored via interviews (25–40 minutes). Boxers represented the featherweight, welterweight, and heavyweight divisions. Interview questions were framed around, 1) the use of video and data analysis, 2) coach-athlete interaction, and 3) learning and development. The importance of data, video, and the effective integration of performance analysis to facilitate comprehensive feedback to maximise learning opportunities was identified. The coach-athlete relationship, and engagement of the athlete within the debriefing process emerged as an aspect needing continual micro-management to ensure ongoing effectiveness. The development of an “open and honest” relationship and a “safe space” to air thoughts and opinions was greatly encouraged. The length of debriefing session did not appear to impact overall engagement. The use of video debriefing to facilitate a coach’s ability to develop the athletes mentally, in addition to their physical boxing capabilities, was a key and standout aspect that should be appropriately considered. The findings add to the limited investigation within boxing, providing insight into the debriefing processes within professional boxing by those on both sides, i.e. the coach and the athlete
Gender differences in work stressors and psychiatric morbidity at workplace in doctors and nurses
Background: Work environment is one of the key factors responsible for stress in human life. Different aspects of working conditions affect person’s work. Work stress in turn leads to psychiatric problems. Doctors and nurses are prone to be affected by work stressors as their work includes more human interactions.Methods: It is a cross sectional observational study conducted at a Medical College affiliated General Hospital. Total 400 subjects were surveyed for this study including 200 doctors and 200 nurses with equal gender distribution. Subjects were interviewed in groups and asked to fill up self-rated questionnaires during the interview. The demographic details were collected through a specially designed semi-structured proforma with workplace stressors checklist, presence of past or present psychiatric illness and presence of enduring stress other than workplace stress. Psychiatric morbidity was assessed by DASS and GHQ-28.Results: In males lack of staff or resources and in females disputes with staff or seniors are important stressors at workplace while long working hours and work responsibilities on holiday were considered as the least stressful. 9.45%, 20.2% and 29.2% having self-rated depression, stress and anxiety respectively in DASS. No significant difference found in gender as well as class as regards of psychiatric morbidity. Past or present psychiatric illness and stress other than work place are significantly associated with GHQ 28 Case-ness. 3.5% females were having suicidal ideas (GHQ item D7) as compared to 0.5% males.Conclusions: Measures for improving working conditions and environment, adequate resources, clarifying roles, constructive resolution of conflicts and stress management training are required to increase work productivity.
The electrorheology of suspensions consisting of Na-Fluorohectorite synthetic clay particles in silicon oil
Under application of an electric field greater than a triggering electric
field kV/mm, suspensions obtained by dispersing particles of the
synthetic clay fluoro-hectorite in a silicon oil, aggregate into chain- and/or
column-like structures parallel to the applied electric field. This
micro-structuring results in a transition in the suspensions' rheological
behavior, from a Newtonian-like behavior to a shear-thinning rheology with a
significant yield stress. This behavior is studied as a function of particle
volume fraction and strength of the applied electric field, . The steady
shear flow curves are observed to scale onto a master curve with respect to
, in a manner similar to what was recently found for suspensions of laponite
clay [42]. In the case of Na-fluorohectorite, the corresponding dynamic yield
stress is demonstrated to scale with respect to as a power law with an
exponent , while the static yield stress inferred from
constant shear stress tests exhibits a similar behavior with . The suspensions are also studied in the framework of thixotropic fluids:
the bifurcation in the rheology behavior when letting the system flow and
evolve under a constant applied shear stress is characterized, and a
bifurcation yield stress, estimated as the applied shear stress at which
viscosity bifurcation occurs, is measured to scale as with to 0.6. All measured yield stresses increase with the particle
fraction of the suspension. For the static yield stress, a scaling law
, with , is found. The results are found to be
reasonably consistent with each other. Their similarities with-, and
discrepancies to- results obtained on laponite-oil suspensions are discussed
Effect of Indole 3-butyric acid (IBA), rooting media and their interaction on different rooting and growth characteristic of air-layers in guava (Psidium guajava L. cv. L-49)
The present investigation was undertaken to study the effect of different concentrations of Indole 3-butyric acid (0, 2000, 4000, 8000 and 10000 ppm), different types of rooting media (i.e. sphagnum moss, coco peat, vermicompost, sphagnum moss + coco peat and sphagnum moss + coco peat + vermicompost) and the interaction of these in different combinations on rooting and growth characteristic of guava, cv. L-49. The results revealed that the exogenous application of Indole 3-butyric acid (IBA) 8000 ppm with media combination of sphagnum moss + coco peat + vermicompost (I3M5) significantly increased the root characters i.e. success percent of air-layers (83.3 %), callus formation (23.7), number of primary roots (24.21) and secondary roots (32.57); and growth characters i.e. number of leaves (48.17), branches (7.92) and sprouts (8.48) and survival percentages (83.18) over the other treatments and control. Among the rooting media, the combination of sphagnum moss + coco peat + vermicompost (M5) produced the highest rooting percentage (71.27), root characters and growth characters during months of July and August
Absolute measurement of the unresolved cosmic X-ray background in the 0.5-8 keV band with Chandra
We present the absolute measurement of the unresolved 0.5-8 keV cosmic X-ray
background (CXB) in the Chandra Deep Fields (CDFs) North and South, the longest
observations with Chandra (2 Ms and 1 Ms, respectively). We measure the
unresolved CXB intensity by extracting spectra of the sky, removing all point
and extended sources detected in the CDF. To model and subtract the
instrumental background, we use observations obtained with ACIS in stowed
position, not exposed to the sky. The unresolved signal in the 0.5-1 keV band
is dominated by diffuse Galactic and local thermal-like emission. In the 1-8
keV band, the unresolved spectrum is adequately described by a power law with a
photon index 1.5. We find unresolved CXB intensities of (1.04+/-0.14)x10^-12
ergs cm^-2 s^-1 deg^-2 for the 1-2 keV band and (3.4+/-1.7)x10^-12 ergs cm^-2
s^-1 deg^-2 for the 2-8 keV band. Our detected unresolved intensities in these
bands significantly exceed the expected flux from sources below the CDF
detection limits, if one extrapolates the logN/logS curve to zero flux. Thus
these background intensities imply either a genuine diffuse component, or a
steepening of the logN/logS curve at low fluxes, most significantly for
energies <2 keV. Adding the unresolved intensity to the total contribution from
sources detected in these fields and wider-field surveys, we obtain a total
intensity of the extragalactic CXB of (4.6+/-0.3)x10^-12 ergs cm^-2 s^-1 deg^-2
for 1-2 keV and (1.7+/-0.2)x10^-11 ergs cm^-2 s^-1 deg^-2 for 2-8 keV. These
totals correspond to a CXB power law normalization (for photon index 1.4) of
10.9 photons cm^-2 s^-1 keV^-1 sr^-1 at 1 keV. This corresponds to resolved
fracations of 77+/-3% and 80+/-8% for 1-2 and 2-8 keV, respectively.Comment: 23 emulateapj pages, accepted for publication in ApJ. Minor
revisions, most notably a new summary of the error analysi
The DiPEP (Diagnosis of PE in Pregnancy) biomarker study: An observational cohort study augmented with additional cases to determine the diagnostic utility of biomarkers for suspected venous thromboembolism during pregnancy and puerperium
This study aimed to estimate the diagnostic utility of biomarkers for suspected venous thromboembolism (VTE) in pregnancy and the puerperium. Research nurses/midwives collected blood samples from 310 pregnant/postpartum women with suspected pulmonary emboli (PE) and 18 with diagnosed deep vein thrombosis (DVT). VTE was diagnosed using imaging, treatment and adverse outcome data. Primary analysis was limited to women with conclusive imaging (36 with VTE, 247 without). The area under the curve (AUC) for each biomarker was: activated partial thromboplastin time 0·669 (95% confidence interval 0·570-0·768), B-type natriuretic peptide 0·549 (0·453-0·645), C-reactive protein 0·542 (0·445-0·639), Clauss fibrinogen 0·589 (0·476-0·701), D-Dimer (by enzyme-linked immunosorbent assay) 0·668 (0·561-0·776), near-patient D-Dimer 0·651 (0·545-0·758), mid-regional pro-atrial natriuretic peptide 0·524 (0·418-0·630), prothrombin fragment 1 + 2 0·562 (0·462-0·661), plasmin-antiplasmin complexes 0·639 (0·536-0·742), prothombin time 0·613 (0·508-0·718), thrombin generation lag time 0·702 (0·598-0·806), thrombin generation endogenous potential 0·559 (0·437-0·681), thrombin generation peak 0·596 (0·478-0·715), thrombin generation time to peak 0·655 (0·541-0·769), soluble tissue factor 0·531 (0·424-0·638) and serum troponin 0·597 (0·499-0·695). No diagnostically useful threshold for diagnosing or ruling out VTE was identified. In pregnancy and the puerperium, conventional and candidate biomarkers have no utility either for their negative or positive predictive value in the diagnosis of VTE
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