Radio AGN in 13,240 galaxy clusters from the Sloan Digital Sky Survey

We correlate the positions of 13,240 Brightest Cluster Galaxies (BCGs) with 0.1 <= z <= 0.3 from the maxBCG catalog with radio sources from the FIRST survey to study the sizes and distributions of radio AGN in galaxy clusters. We find that 19.7% of our BCGs are associated with FIRST sources, and this fraction depends on the stellar mass of the BCG, and to a lesser extent on the richness of the parent cluster (in the sense of increasing radio loudness with increasing mass). The intrinsic size of the radio emission associated with the BCGs peaks at 55 kpc, with a tail extending to 200 kpc. The radio power of the extended sources places them on the divide between FR I and FR II type sources, while sources compact in the radio tend to be somewhat less radio-luminous. We also detect an excess of radio sources associated with the cluster, instead of with the BCG itself, extending out to ~1.4 Mpc.Comment: 14 pages, 6 figures, accepted for publication in ApJ

Flexible contracts and human capital investments

As suggested by human capital theory, workers with flexible contracts participate lessoften in training than those with permanent contracts. We find that this is merely dueto the fact that flexworkers receive less employer–funded training, a gap they can onlypartly compensate for by their own training investments. Flexworkers particularlyparticipate less in firm–specific training that is meant to keep up with new skilldemands than workers with permanent contracts. However, for those who participatein employer–funded firm–specific training, a temporary contract appears to facilitatethe transition to a permanent contract with the same employer. However, this doesnot hold for participation in self–paid training. This training, which is usually generaltraining, does not help in finding a better job.education, training and the labour market;

Flexible contracts and human capital investments

As suggested by human capital theory, workers with flexible contracts participate less often intraining than those with permanent contracts. We find that this is merely due to the fact thatflexworkers receive less employer–funded training, a gap they can only partly compensate for bytheir own training investments. Flexworkers particularly participate less in firm–specifictraining that is meant to keep up with new skill demands than workers with permanent contracts.However, for those who participate in employer–funded firm–specific training, a temporary contractappears to facilitate the transition to a permanent contract with the same employer. However, thisdoes not hold for participation in self–paid training. This training, which is usually generaltraining, does not help in finding a better job.labour economics ;

The role of geographic mobility in reducing education-job mismatches in the Netherlands.

In this paper we investigate the relationship between geographic mobility and education-job mismatch in the Netherlands. We focus on the role of geographic mobility in reducing the probability of graduates working (i) jobs below their education level; (ii) jobs outside their study field; (iii) part-time jobs; (iv) flexible jobs; or (v) jobs paid below the wage expected at the beginning of the career. For this purpose we use data on secondary and higher vocational education graduates in the period 1996–2001. We show that graduates who are mobile have higher probability of finding jobs at the acquired education level than those who are not. Moreover, mobile graduates have higher probability of finding full-time or permanent jobs. This suggests that mobility is sought to prevent not only having to take a job below the acquired education level, but also other education-job mismatches; graduates are spatially flexible particularly to ensure full-time jobs.Geographic labour mobility;job mismatch;occupational choice;

Can social science still be used as a foundation for public policy? On improving the reliability of evidence.

John Jerrim and Robert de Vries argue a radical overhaul is needed of how social science is published and produced for it to provide a helpful basis for public policy. More progress is needed in particular over the lack of transparency of the research process, publication bias for positive findings and improved quality assurance mechanisms for peer review

The electroclinic effect and modulated phases in smectic liquid crystals

We explore the possibility that the large electroclinic effect observed in ferroelectric liquid crystals arises from the presence of an ordered array of disclination lines and walls. If the spacing of these defects is in the subvisible range, this modulated phase would be similar macroscopically to a smectic A phase. The application of an electric field distorts the array, producing a large polarization, and hence a large electroclinic effect. We show that with suitable elastic parameters and sufficiently large chirality, the modulated phase is favored over the smectic A and helically twisted smectic C* phases. We propose various experimental tests of this scenario.Comment: 9 pages, 7 figures; new version includes dipolar interactions and bend-twist couplin

The relationship between geographical mobility and education-job mismatches

In this paper we investigate the relationship between geographical mobility and education-job mismatches. School-leavers might adjust to local labour market frictions by accepting some education-job mismatch combined with a mobility decision. We focus on the relationship between the mobility decision and the following education-job mismatches: a job below the educational level, outside the educational field, part-time or flexible jobs at the beginning of the career. For this purpose we use data about school-leavers from secondary education and higher vocational education in the period 1996-2001. The analysis is conducted at a disaggregated spatial level to incorporate differences in behaviour of school-leavers at the regional level. We find that school-leavers who are more mobile have a lower probability to have a job below the acquired educational level compared with school-leavers who are less mobile. Moreover, school-leavers who are more mobile experience especially a lower probability of a part-time or a flexible job. This result suggests that school-leavers not only try to prevent a job below the acquired educational level, but also other education-job mismatches in their mobility decision.

Laparoscopic Versus Open Cholecystectomy: A Prospective Matched-Cohort Study

To compare the results of laparoscopic cholecystectomy (LC) and open cholecystectomy (OC) for symptomatic cholelithiasis in elective surgery we performed a prospective matched-cohort study. Hundred consecutive patients who underwent LC in the period Sept. 1990-June 1992, and 100 patients who were age and sex matched and underwent an elective OC in the foregoing two years (1989-1990) were studied. The median operation time for LC (75, 40-180 min) was significantly longer than for OC (55, 20-155 min; p < 0.001). Postoperative hospitalization was significantly shorter after LC (3, 1-16 days), compared with OC (7, 4-22 days; p<0.001). Conversion of LC to OC occurred in 12 (12%) patients initially scheduled to undergo LC. Complications occurred in 5 patients (5%) after LC and in 5 patients (5%) after OC. The calculated expenses (operation and postoperative hospitalization, 3rd class) were approximately fl. 3740,- for LC (excl. investments for pieces of apparatus) and fl. 6725,- for OC. This study demonstrates that LC can be performed safely with the number of complications comparable to those for OC. Bile duct injury is a serious potential threat. The main advantages ofLC are the minimal trauma, with more rapid recovery. Insurers seem to benefit from reduced postoperative disability and earlier discharge