The Role of Social Security in Household Decisions: Var Estimates of Saving and Fertility Behaviour in Germany

Estimating saving and fertility simultaneously by the VAR method, we find that social security cover has a positive effect on household saving, and a negative effect on fertility. In Germany, as in other countries where the hypothesis was tested, social security is thus good for growth. A possible explanation for this unconventional finding is that compulsory saving in the form of pension contributions tends to displace intra-family transfers, rather than asset formation. However, the negative effect of social security on fertility tends to erode the system’s own contributory base, because it reduces the number of future contributors. That is one of the reasons why, in Germany as elsewhere, pay-as-you-go pension systems tend to be financially unstable. To some extent, this is counteracted by child-related benefits, which tend to encourage fertility, but the effect appears to be weak.

Child labor handbook

This paper surveys many aspects and issues of child labor, including its causes and effects as well as policies associated with it. Child labor has come to be considered an expression of poverty, both a cause and an effect of underdevelopment. Child labor cannot be viewed in isolation from educational, health, fertility, and technological issues; and is not necessarily an aberration but a rational household response to an adverse economic environment. With this in mind, the following proposition was supported - that forbidding children to work or making school attendance compulsory without changing the economic environment may, if effectively enforced, leave children worse off. There is a tendency to believe that income redistribution from the rich to the poor is more powerful for reducing child labor than a universal income rise. It is also indicated that child labor cuts across policy boundaries: health, education, labor market, capital security, criminal law, international peace keeping, income growth, and distribution all have a bearing on child labor. Therefore, reducing child labor cannot be regarded as just another policy issue.Child Labor,Street Children,Youth and Governance,Children and Youth,Health Monitoring&Evaluation

A FIRST DETERMINATION OF THE SURFACE DENSITY OF GALAXY CLUSTERS AT VERY LOW X--RAY FLUXES

We present the first results of a serendipitous search for clusters of galaxies in deep ROSAT-PSPC pointed observations at high galactic latitude. The survey is being carried out using a Wavelet based Detection Algorithm which is not biased against extended, low surface brightness sources. A new flux--diameter limited sample of 10 cluster candidates has been created from $\rm\sim 3 \, deg^2$ surveyed area. Preliminary CCD observations have revealed that a large fraction of these candidates correspond to a visible enhancement in the galaxy surface density, and several others have been identified from other surveys. We believe these sources to be either low--moderate redshift groups or intermediate to high redshift clusters. We show X-ray and optical images of some of the clusters identified to date. We present, for the first time, the derived number density of the galaxy clusters to a flux limit of $\rm 1\cdot 10^{-14} erg cm^{-2} s^{-1}$ (0.5--2.0 keV). This extends the $\log N$--$\log S$ of previous cluster surveys by more than one decade in flux. Results are compared to theoretical predictions for cluster number counts.Comment: uuencoded compressed Postscript, 7 pages including 4 figures. Accepted for publication in Ap. J. Letters

The ROSAT Deep Cluster Survey: the X-ray Luminosity Function out to z=0.8

We present the X-ray Luminosity Function (XLF) of the ROSAT Deep Cluster Survey (RDCS) sample over the redshift range 0.05-0.8. Our results are derived from a complete flux-limited subsample of 70 galaxy clusters, representing the brightest half of the total sample, which have been spectroscopically identified down to the flux limit of 4*10^{-14} erg/cm^2/s (0.5-2.0 keV) and have been selected via a serendipitous search in ROSAT-PSPC pointed observations. The redshift baseline is large enough that evolutionary effects can be studied within the sample. The local XLF (z < 0.25) is found to be in excellent agreement with previous determinations using the ROSAT All-Sky Survey data. The XLF at higher redshifts, when combined with the deepest number counts constructed to date (f>2*10^{-14} arg/cm^2/s), reveal no significant evolution at least out to z=0.8, over a luminosity range 2*10^{42}-3*10^{44} erg/s in the [0.5-2 keV] band. These findings extend the study of cluster evolution to the highest redshifts and the faintest fluxes probed so far in X-ray surveys. They complement and do not necessarily conflict with those of the Einstein Extended Medium Sensitivity Survey, leaving the possibility of negative evolution of the brightest end of the XLF at high redshifts.Comment: 12 pages, 4 figures, LaTeX (aasms4.sty). To appear in ApJ Letter

Evolution in the iron abundance of the ICM

We present a Chandra analysis of the X-ray spectra of 56 clusters of galaxies at $z>0.3$, which cover a temperature range of $3> kT > 15$ keV. Our analysis is aimed at measuring the iron abundance in the ICM out to the highest redshift probed to date. We find that the emission-weighted iron abundance measured within $(0.15-0.3) R_{vir}$ in clusters below 5 keV is, on average, a factor of $\sim2$ higher than in hotter clusters, following $Z(T)\simeq 0.88 T^{-0.47} Z_\odot$, which confirms the trend seen in local samples. We made use of combined spectral analysis performed over five redshift bins at $0.3> z > 1.3$ to estimate the average emission weighted iron abundance. We find a constant average iron abundance $Z_{Fe}\simeq 0.25 Z_\odot$ as a function of redshift, but only for clusters at $z>0.5$. The emission-weighted iron abundance is significantly higher ($Z_{Fe}\simeq0.4 Z_\odot$) in the redshift range $z\simeq0.3-0.5$, approaching the value measured locally in the inner $0.15 R_{vir}$ radii for a mix of cool-core and non cool-core clusters in the redshift range $0.1<z<0.3$. The decrease in $Z_{Fe}$ with $z$ can be parametrized by a power law of the form $\sim(1+z)^{-1.25}$. The observed evolution implies that the average iron content of the ICM at the present epoch is a factor of $\sim2$ larger than at $z\simeq 1.2$. We confirm that the ICM is already significantly enriched ($Z_{Fe}\simeq0.25 Z_\odot$) at a look-back time of 9 Gyr. Our data provide significant constraints on the time scales and physical processes that drive the chemical enrichment of the ICM.Comment: 4 pages, 4 figures, to appear in the Proceedings of "The Extreme Universe in the Suzaku Era", Dicember 2006, Kyoto (Japan

Use of balloon catheter dilation vs. traditional endoscopic sinus surgery in management of light and severe chronic rhinosinusitis of the frontal sinus: a multicenter prospective randomized study

OBJECTIVE: Chronic rhinosinusitis (CRS) of the frontal sinus is a complex pathological condition and many surgical techniques were described to treat this area endoscopically, like traditional endoscopic sinus surgery (ESS) and balloon catheter dilation (BCD). PATIENTS AND METHODS: We designed a multicenter prospective randomized study to assess the validity and safety of BCD vs. ESS in symptomatological chronic rhinosinusitis of the frontal sinus enrolling a population of 102 adult patients (64 men and 38 women; overall 148 frontal sinuses studied) with non-polypoid CRS. For a better evaluation of the disease, in our study we decided to analyze both radiological (Lund-McKay CT scoring modified by Zinreich) and symptomatological results (SNOT-20 questionnaire). We divided the population affected in two groups, one with light/mild frontal CRS and the other with moderate/severe frontal CRS, basing on radiological findings at Lund-MacKay modified by Zinreich score. Every group was divided in two subgroups, in one we used BCD and in the other we used traditional ESS. RESULTS: The current literature does not support the suggestion that indications for BCD and ESS are identical, and additional research is needed to determine the role for BCD in specific patient populations. The results showed a not statistically significative difference between BCD and conventional ESS of the frontal sinus in patients with light/mild CRS and in patients with moderate/severe CRS at Lund-Mackay modified by Zinreich score. The same not statistically significative difference was observed comparing the results of SNOT-20 questionnaire in the group of light/mild frontal chronic rhinosinusitis. However, we noticed a statistically significant better outcome of SNOT-20 score in patients with moderate/severe chronic rhinosinusitis that underwent BCD of frontal sinus compared to ESS. CONCLUSIONS: BCD and ESS are two alternative weapons in the baggage of every endoscopic surgeon, even because they present similar outcomes, safeness and effectiveness both in light/mild and moderate/severe chronic rhinosinusitis of the frontal sinus. An interesting result of our study was the statistically significant better outcome of SNOT-20 score in patients that underwent BCD of frontal sinus for a moderate/severe CRS, compared to those that underwent a traditional ESS

Why do Indian Children Work, and is it Bad for Them?

The causes and consequences of child labour are examined theoretically and empirically within a household decision framework, with endogenous fertility and mortality. The data come from a nationally representative survey of Indian rural households. The complex interactions uncovered by the analysis suggest that mere prohibition of child labour, or the imposition of school attendance, could make things worse, and would be difficult to enforce. Beneficially reducing child labour requires changing the economic environment to which the work of the children constitutes, in the great majority of the cases, the rational response. Suitable policies include reductions in the cost of attending school, and public health improvements. The effects of these policies go far beyond direct impacts. Health policies have favourable indirect repercussions on the school attendance, demand for educational material, and labour participation of children. Educational policies have favourable indirect repercussions on the nutritional status of children. Both types of policies discourage fertility. Income re-distribution may be helpful, but land re-distribution could be counterproductive

Experimental Realization of Optimal Noise Estimation for a General Pauli Channel

We present the experimental realization of the optimal estimation protocol for a Pauli noisy channel. The method is based on the generation of 2-qubit Bell states and the introduction of quantum noise in a controlled way on one of the state subsystems. The efficiency of the optimal estimation, achieved by a Bell measurement, is shown to outperform quantum process tomography

Tracing the evolution in the iron content of the ICM

We present a Chandra analysis of the X-ray spectra of 56 clusters of galaxies at z>0.3, which cover a temperature range of 3>kT>15 keV. Our analysis is aimed at measuring the iron abundance in the ICM out to the highest redshift probed to date. We find that the emission-weighted iron abundance measured within (0.15-0.3)R_vir in clusters below 5 keV is, on average, a factor of ~2 higher than in hotter clusters, following Z(T)~0.88T^-(0.47)Z_o, which confirms the trend seen in local samples. We made use of combined spectral analysis performed over five redshift bins at 0.3>z>1.3 to estimate the average emission weighted iron abundance. We find a constant average iron abundance Z_Fe~0.25Z_o as a function of redshift, but only for clusters at z>0.5. The emission-weighted iron abundance is significantly higher (Z_Fe~0.4Z_o) in the redshift range z~0.3-0.5, approaching the value measured locally in the inner 0.15R_vir radii for a mix of cool-core and non cool-core clusters in the redshift range 0.1<z<0.3. The decrease in Z_Fe with redshift can be parametrized by a power law of the form ~(1+z)^(-1.25). The observed evolution implies that the average iron content of the ICM at the present epoch is a factor of ~2 larger than at z=1.2. We confirm that the ICM is already significantly enriched (Z_Fe~0.25Z_o) at a look-back time of 9 Gyr. Our data provide significant constraints on the time scales and physical processes that drive the chemical enrichment of the ICM.Comment: 6 pages, 6 figures, to appear in the Proceedings of "Heating vs. Cooling in Galaxies and Clusters of Galaxies", August 2006, Garching (Germany