7,371 research outputs found
BFKL versus HERA
The BFKL equation and the kT-factorization theorem are used to obtain
predictions for F2 in the small Bjorken-x region over a wide range of Q**2. The
dependence on the parameters, especially on those concerning the infrared
region, is discussed. After a background fit to recent experimental data
obtained at HERA and at Fermilab (E665 experiment), we find that the predicted,
almost Q**2 independent BFKL slope lambda >= 0.5 appears to be too steep at
lower Q**2 values. Thus there seems to be a chance that future HERA data can
distinguish between pure BFKL and conventional field theoretic renormalization
group approaches.Comment: 26 pages, 6 eps figures, LaTeX2e using epsfig.sty and amssymb.st
A unified BFKL and GLAP description of data
We argue that the use of the universal unintegrated gluon distribution and
the (or high energy) factorization theorem provides the natural framework
for describing observables at small x. We introduce a coupled pair of evolution
equations for the unintegrated gluon distribution and the sea quark
distribution which incorporate both the resummed leading BFKL
contributions and the resummed leading GLAP contributions. We solve
these unified equations in the perturbative QCD domain using simple parametic
forms of the nonperturbative part of the integrated distributions. With only
two (physically motivated) input parameters we find that this
factorization approach gives an excellent description of the measurements of
at HERA. In this way the unified evolution equations allow us to
determine the gluon and sea quark distributions and, moreover, to see the x
domain where the resummed effects become significant. We use
factorization to predict the longitudinal structure function and
the charm component of .Comment: 25 pages, LaTeX, 9 figure
The importance of tumor studies in the initial evaluation for Lynch syndrome: a comparison of MMR positive and negative patients
THE GLUON DISTRIBUTION AT SMALL x OBTAINED FROM A UNIFIED EVOLUTION EQUATION.
We solve a unified integral equation to obtain the and
dependence of the gluon distribution of a proton in the small regime; where
and are the longitudinal momentum fraction and the transverse
momentum of the gluon probed at a scale . The equation generates a gluon
with a steep behaviour, with , and a
distribution which broadens as decreases. We compare our solutions with, on
the one hand, those that we obtain using the double-leading-logarithm
approximation to Altarelli-Parisi evolution and, on the other hand, to those
that we determine from the BFKL equation.Comment: LaTeX file with 10 postscript figures (uuencoded
A Familial Adenomatous Polyposis (FAP) patient education conference and its impact on patients and families
The effect of a weight gain prevention intervention on moderate-vigorous physical activity among black women: the Shape Program
Background: Rates of physical inactivity are high among Black women living in the United States with overweight or obesity, especially those living in the rural South. This study was conducted to determine if an efficacious weight gain prevention intervention increased moderate-vigorous physical activity (MVPA).
Methods: The Shape Program, a weight gain prevention intervention implemented in community health centers in rural North Carolina, was designed for socioeconomically disadvantaged Black women with overweight or obesity. MVPA was measured using accelerometers, and summarized into 1- and 10-min bouts. We employed analyses of covariance (ANCOVA) to assess the relationship between changes in MVPA over 12 months, calculated as a change score, and intervention assignment (intervention versus usual care).
Results: Participants completing both baseline and 12-month accelerometer assessments (n = 121) had a mean age of 36.1 (SD = 5.43) years and a mean body mass index of 30.24 kg/m2 (SD = 2.60). At baseline, 38% met the physical activity recommendation (150 min of MVPA/week) when assessed using 10-min bouts, and 76% met the recommendation when assessed using 1-min bouts. There were no significant differences in change in MVPA participation among participants randomized to the intervention from baseline to 12-months using 1-min bouts (adjusted intervention mean [95% CI]: 20.50 [â109.09 to 150.10] vs. adjusted usual care mean [95% CI]: -80.04 [â209.21 to 49.13], P = .29), or 10-min bouts (adjusted intervention mean [95% CI]: 7.39 [â83.57 to 98.35] vs. adjusted usual care mean [95% CI]: -17.26 [â107.93 to 73.40], P = .70).
Conclusions: Although prior research determined that the Shape intervention promoted weight gain prevention, MVPA did not increase significantly among intervention participants from baseline to 12 months. The classification of bouts had a marked effect on the prevalence estimates of those meeting physical activity recommendations. More research is needed to understand how to promote increased MVPA in weight gain prevention interventions
Development of exchange lists for M editerranean and H ealthy E ating D iets: implementation in an intervention trial
Background There has been little research published on the adaptation of diabetic exchange list diet approaches for the design of intervention diets in health research despite their clinical utility. The exchange list approach can provide clear and precise guidance on multiple dietary changes simultaneously. The present study aimed to develop exchange list diets for M editerranean and H ealthy E ating, and to evaluate adherence, dietary intakes and markers of health risks with each counselling approach in 120 subjects at increased risk for developing colon cancer. Methods A randomised clinical trial was implemented in the USA involving telephone counselling. The M editerranean diet had 10 dietary goals targeting increases in monoâunsaturated fats, n â3 fats, whole grains and the amount and variety of fruits and vegetables. The Healthy Eating diet had five dietary goals that were based on the US H ealthy P eople 2010 recommendations. Results Dietary compliance was similar in both diet arms, with 82â88% of goals being met at 6Â months, although subjects took more time to achieve the M editerranean goals than the H ealthy E ating goals. The relatively modest fruit and vegetable goals in the Healthy Eating arm were exceeded, resulting in fruit and vegetable intakes of approximately eight servings per day in each arm after 6Â months. A significant ( P Â <Â 0.05) weight loss and a decrease in serum C âreactive protein concentrations were observed in the overweight/obese subgroup of subjects in the M editerranean arm in the absence of weight loss goals. Conclusions Counselling for the M editerranean diet may be useful for both improving diet quality and for achieving a modest weight loss in overweight or obese individuals.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108685/1/jhn12158.pd
Deep inelastic events containing a forward photon as a probe of small dynamics
We calculate the rate of producing deep inelastic events containing an
energetic isolated forward photon at HERA. We quantify the enhancement arising
from the leading gluon emissions with a view to using such events to
identify the underlying dynamics.Comment: 11 pages, Latex, 7 ps figure
MAGE-A cancer/testis antigens inhibit MDM2 ubiquitylation function and promote increased levels of MDM4
Melanoma antigen A (MAGE-A) proteins comprise a structurally and biochemically similar sub-family of Cancer/Testis antigens that are expressed in many cancer types and are thought to contribute actively to malignancy. MAGE-A proteins are established regulators of certain cancer-associated transcription factors, including p53, and are activators of several RING finger-dependent ubiquitin E3 ligases. Here, we show that MAGE-A2 associates with MDM2, a ubiquitin E3 ligase that mediates ubiquitylation of more than 20 substrates including mainly p53, MDM2 itself, and MDM4, a potent p53 inhibitor and MDM2 partner that is structurally related to MDM2. We find that MAGE-A2 interacts with MDM2 via the N-terminal p53-binding pocket and the RING finger domain of MDM2 that is required for homo/hetero-dimerization and for E2 ligase interaction. Consistent with these data, we show that MAGE-A2 is a potent inhibitor of the E3 ubiquitin ligase activity of MDM2, yet it does not have any significant effect on p53 turnover mediated by MDM2. Strikingly, however, increased MAGE-A2 expression leads to reduced ubiquitylation and increased levels of MDM4. Similarly, silencing of endogenous MAGE-A expression diminishes MDM4 levels in a manner that can be rescued by the proteasomal inhibitor, bortezomid, and permits increased MDM2/MDM4 association. These data suggest that MAGE-A proteins can: (i) uncouple the ubiquitin ligase and degradation functions of MDM2; (ii) act as potent inhibitors of E3 ligase function; and (iii) regulate the turnover of MDM4. We also find an association between the presence of MAGE-A and increased MDM4 levels in primary breast cancer, suggesting that MAGE-A-dependent control of MDM4 levels has relevance to cancer clinically
Managing affect in learners' questions in undergraduate science
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2012 Society for Research into Higher Education.This article aims to position students' classroom questioning within the literature surrounding affect and its impact on learning. The article consists of two main sections. First, the act of questioning is discussed in order to highlight how affect shapes the process of questioning, and a four-part genesis to question-asking that we call CARE is described: the construction, asking, reception and evaluation of a learner's question. This work is contextualised through studies in science education and through our work with university students in undergraduate chemistry, although conducted in the firm belief that it has more general application. The second section focuses on teaching strategies to encourage and manage learners' questions, based here upon the conviction that university students in this case learn through questioning, and that an inquiry-based environment promotes better learning than a simple âtransmissionâ setting. Seven teaching strategies developed from the authors' work are described, where university teachers âscaffoldâ learning through supporting learners' questions, and working with these to structure and organise the content and the shape of their teaching. The article concludes with a summary of the main issues, highlighting the impact of the affective dimension of learning through questioning, and a discussion of the implications for future research
- âŠ