Properties of highly clustered networks

We propose and solve exactly a model of a network that has both a tunable degree distribution and a tunable clustering coefficient. Among other things, our results indicate that increased clustering leads to a decrease in the size of the giant component of the network. We also study SIR-type epidemic processes within the model and find that clustering decreases the size of epidemics, but also decreases the epidemic threshold, making it easier for diseases to spread. In addition, clustering causes epidemics to saturate sooner, meaning that they infect a near-maximal fraction of the network for quite low transmission rates.Comment: 7 pages, 2 figures, 1 tabl

A framework for the analysis of the potential performance of Chief Information Officers

Information Systems Function is an organisational area of major importance in the context of the competitive development of organisations. At the centre of the Information Systems Function we find the Chief Information Officer (CIO), who is the main responsible for the organisation and leadership of this function. Given the nature of the duties assigned to the CIO, her/his work directly influences the development of an organisation, so it has become important to assess her/his potential performance before s/he finds herself/him in charge of the information systems function. This article proposes the CIO Performance Square - a framework for analysing the potential performance of CIOs based on their education and experience.- (undefined

MutSα expression predicts a lower disease-free survival in malignant salivary gland tumors: an immunohistochemical study

Background: Appropriate DNA replication is vital to maintain cell integrity at the genomic level. Malfunction on DNA repair mechanisms can have implications related to tumor behavior. Our aim was to evaluate the expression of key complexes of the DNA mismatch-repair system MutSα (hMSH2-hMSH6) and MutSβ (hMSH2-hMSH3) in a panel comprising the most common benign and malignant salivary gland tumors (SGT), and to determine their association with disease-free survival. Material and Methods: Ten cases of normal salivary gland (NSG) and 92 of SGT (54 benign and 38 malignant) were retrieved. Immunohistochemistry was performed for hMSH2, hMSH3, hMSH6. Scanned slides were digitally analyzed based on the percentage of positive cells with nuclear staining. Cases were further classified in MutSαhigh and MutSβhigh based on hMSH2-hMSH6 and hMSH3-hMSH6 expression, respectively. Results: hMSH3 expression was lower in malignant SGT compared to NSG and benign cases. Adenoid cystic carcinoma (ACC) cases with perineural invasion presented a lower percentage of hMSH3 positive cells. hMSH6 was downregulated in both benign and malignant SGT compared to NSG. Malignant SGT cases with MutSαhigh expression had lower disease-free survival compared to MutSαlow cases. A 10.26-fold increased risk of presenting local recurrence was observed. Conclusions: Our findings suggest that a lack of hMSH3 protein function is associated with a more aggressive phenotype (malignancy and perineural invasion) and that MutSα overexpression predicts a poor clinical outcome in malignant SGT

Placental CD4(+) T cells from preeclamptic patients cause autoantibodies to the angiotensin II type I receptor and hypertension in a pregnant rat model of preeclampsia

AIM: Preeclampsia (PE) is a hypertensive disorder of pregnancy associated with activated CD4(+) T cells and autoantibodies to angiotensin II type 1 receptor (AT1-AA). We have previously shown that CD4(+) T cells isolated from women with PE cause hypertension, increased tumor necrosis factor alpha (TNF-α), endothelin-1, and soluble fms-like tyrosine kinase-1 (sFlt-1) when injected into pregnant nude-athymic rats compared to CD4(+) T cells from normal pregnant (NP) women. However, the role of PE CD4(+) T cells to cause AT1-AA as a mechanism of hypertension is not known. Our goal was to determine if PE CD4(+) T cells stimulate AT1-AA in pregnant nude-athymic rats. METHODS: CD4(+) T cells were isolated from human NP and PE placentasand injected into nude-athymic rats on gestational day (GD) 12. In order to examine the role of the PE CD4(+) T cells to stimulate B cell secretion of AT1-AA, a subset of the rats receiving PE CD4(+) T cells were treated with rituximab on GD 14 or anti-CD40 ligand (anti-CD40L) on GD 12. On GD 19, mean arterial pressure (MAP) and tissues were obtained. RESULTS: MAP [114 ± 1 mmHg (n = 9)] and AT1-AA [19.8 ± 0.9 beats per minute (bpm, n = 4)] were increased in NP nude + PE CD4(+) T cells compared to NP nude + NP CD4(+) T cells [98 ± 2 mmHg (n = 7, P < 0.05) and 1.3 ± 0.9 bpm (n = 5, P < 0.05)]. Rituximab (103 ± 2 mmHg, n = 3, P < 0.05) and anti-CD40L (102 ± 1 mmHg, n = 3, P < 0.05) lowered MAP compared to NP nude + PE CD4(+) T cells. Circulating a proliferation-inducing ligand (APRIL) and placental angiotensin-converting enzyme 2 (ACE-2) activity was increased in response to PE CD4(+) T cells. CONCLUSIONS: These results show that placental CD4(+) T cells play an important role in the pathophysiology of PE, by activating B cells secreting AT1-AA to cause hypertension during pregnancy

Blockade of CD40 ligand for intercellular communication reduces hypertension, placental oxidative stress, and AT1-AA in response to adoptive transfer of CD4(+) T lymphocytes from RUPP rats

Preeclampsia (PE) is associated with altered immune activation during pregnancy. We have previously shown that adoptive transfer of CD4+ T cells from the reduced uterine perfusion pressure (RUPP) rat model of PE increases blood pressure, oxidative stress (ROS), and inflammation in normal pregnant recipient rats. The objective of this study was to determine if blockade of communication via the CD40-CD40 ligand (CD40L) interaction between placental ischemia-induced CD4+ T cells with endogenous normal pregnant (NP) cells would improve pathophysiology that was previously observed in NP recipient rats of RUPP CD4+ T cells. Splenic CD4+ T lymphocytes were magnetically separated, incubated with 2.5 {mu}g/ml anti-CD40 ligand ({alpha}CD40L) overnight, and transferred into NP rats on day 12 of gestation (NP+RUPP CD4+ T+anti-CD40L). On day 19 of gestation, blood pressure (MAP), blood, and tissues were collected. MAP was 99 +/- 2 in NP (n = 13), 116 +/- 4 in NP+RUPP CD4+ T cells (n = 7; P < 0.01); MAP only increased to 104 +/- 2 in NP+RUPP CD4+ T cells+CD40L (n = 24) (P < 0.05 vs. NP+RUPP CD4+ T cells). Mechanisms of hypertension in response to RUPP CD4+ T cells include endothelin-1 (ET-1), ROS, and angiotensin II type I receptor (AT1-AA) were analyzed. Inhibition of CD40L binding reduced placental ET-1 to 2.3-fold above NP rats and normalized placental ROS from 318.6 +/- 89 in NP+RUPP CD4+ T cells (P < 0.05) to 118.7 +/- 24 in NP+RUPP CD4+ T+anti-CD40L (P < 0.05). AT1-AA was also normalized with inhibition of CD40L. These data suggest that placental ischemia-induced T-cell communication via the CD40L is one important mechanism leading to much of the pathophysiology of PE

Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter

Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuz'min energy threshold, \nobreak{$6\times 10^{19}$eV}. The anisotropy was measured by the fraction of arrival directions that are less than $3.1^\circ$ from the position of an active galactic nucleus within 75 Mpc (using the V\'eron-Cetty and V\'eron $12^{\rm th}$ catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is $(38^{+7}_{-6})$, compared with $21$ expected for isotropic cosmic rays. This is down from the early estimate of $(69^{+11}_{-13})$. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function is shown for the enlarged set of arrival directions and compared to the isotropic expectation.Comment: Accepted for publication in Astroparticle Physics on 31 August 201

Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory

Atmospheric parameters, such as pressure (P), temperature (T) and density, affect the development of extensive air showers initiated by energetic cosmic rays. We have studied the impact of atmospheric variations on extensive air showers by means of the surface detector of the Pierre Auger Observatory. The rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find that the observed behaviour is explained by a model including the effects associated with the variations of pressure and density. The former affects the longitudinal development of air showers while the latter influences the Moliere radius and hence the lateral distribution of the shower particles. The model is validated with full simulations of extensive air showers using atmospheric profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle Physic