Integrating generations with advanced reference counting garbage collectors

We propose the use of generations with modern reference counting. A reference counting collector is well suited to collect the old generation, containing a large fraction of live objects that are modified infrequently. Such a collector can be combined with a tracing collector to collect the young generation, typically containing a small fraction of live objects. We have designed such a collector appropriate for running on a multiprocessor. As our building blocks, we used the sliding‐views on‐the‐fly collectors. We have implemented the new collector on the Jikes Research Java Virtual Machine (Jikes RVM) and compared it with the concurrent reference counting collector supplied with the Jikes RVM package. Our measurements demonstrate short pause times, retaining those of the original on‐the‐fly collectors and a gain in application throughput time. It turns out that a modern reference counting collector may benefit from the use of generations. Copyright © 2006 John Wiley & Sons, Ltd.     

Deleting files in the Celeste peer-to-peer storage system

Celeste is a robust peer-to-peer object store built on top of a distributed hash table (DHT). Celeste is a working system, developed by Sun Microsystems Laboratories. During the development of Celeste, we faced the challenge of complete object deletion, and moreover, of deleting “files” composed of several different objects. This important problem is not solved by merely deleting meta-data, as there are scenarios in which all file contents must be deleted, e.g., due to a court order. Complete file deletion in a realistic peer-to-peer storage system has not been previously dealt with due to the intricacy of the problem — the system may experience high churn rates, nodes may crash or have intermittent connectivity, and the overlay network may become partitioned at times. We present an algorithm that eventually deletes all file contents, data and meta-data, in the aforementioned complex scenarios. The algorithm is fully functional and has been successfully integrated into Celeste.     

Comparative analysis of goal-setting strategies across cultures.

Only a few studies that have examined the effects of participation on an individual's goal acceptance and performance have been conducted within a cross-cultural context. In the present study, we tested for the contingency between the effectiveness of goal-setting strategies and cultural values. We examined three goal-setting strategies within three different cultural groups—assigned goals, goals participatively set by a group representative and the experimenter, and goals participatively set by a group. The three cultural groups studied were U.S. students (n?=?60), individualistic and having a high power distance; Israeli students from urban areas (n?=?60), collectivistic and having a low power distance; and Israeli students from kibbutzim (n?=?60), highly collectivistic and having a low power distance. Results indicated that participative strategies led to higher levels of goal acceptance and performance than the assigned strategy. Culture did not moderate the effect of goal-setting strategies on goal acceptance, but it appeared to moderate the strategy on performance for extremely difficult goals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Etheno adducts in spleen DNA of SJL mice stimulated to overproduce nitric oxide

In order to investigate specific DNA damage caused by nitric oxide (NO) induced lipid peroxidation, levels of promutagenic etheno adducts 1,N6-ethenodeoxyadenosine (epsilondA) and 3,N4-ethenodeoxycytidine (epsilondC) were measured in spleen DNA of SJL mice induced to produce high levels of NO by injection of RcsX (pre-B-cell lymphoma) cells. epsilondA and epsilondC levels were quantified by an ultrasensitive immunoaffinity-32P-post-labeling method. Spleen DNA of control mice (n = 5) had background levels of 9.2+/-5.4 epsilondA adducts per 10(9) dA and 13.1+/-5.7 epsilondC adducts per 10(9) dC. In RcsX cell-injected mice (n = 7), levels of these adducts were elevated approximately 6-fold, i.e. 53.9+/-39.4 epsilondA per 10(9) dA and 83.5+/-57.8 epsilondC per 10(9) dC (P < 0.05). Mice injected with RcsX cells and also treated with NG-methyl-L-arginine (NMA), an inhibitor of inducible nitric oxide synthase (n = 6), had significantly reduced levels (P < 0.05) of both epsilondA and epsilondC (13.5+/-5.7 epsilondA per 10(9) dA and 28.2+/-15.7 epsilondC per 10(9) dC). These findings constitute the first available evidence of formation of etheno adducts associated with NO overproduction in vivo. The adducts were presumably formed from lipid peroxidation products such as trans-4-hydroxy-2-nonenal (HNE), generated via oxidation of lipids by peroxynitrite. The results suggest that etheno-DNA adducts, among other types of damage, may contribute to the etiology of cancers associated with chronic infection/inflammation in which NO is overproduced.     

Al— Be alloys: Multipurpose metallic composite materials

The article is devoted to composite materials created on the basis of the technology of light alloys and developments of the All-Russia Institute of Aircraft Materials concerning beryllium alloys with a high modulus of elasticity. The competitiveness of such composite materials is determined by the high level of the specific strength properties, which exceed, in some cases, the characteristics of powder materials of a similar composition and approach the properties of titanium alloys and steels.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 9, pp. 23 – 26, September, 1996.     

Prevalence of Down's syndrome in Asturias, 1987-1993. Members of the Work Group of the RCDA

OBJECTIVE: To determine the frequency of Down Syndrome (DS) in Asturias and the prenatal diagnosis impact on the birth prevalence of this chromosomal anomaly. METHODS: The analysed data came from the Registry of Congenital Defects of Asturias (1990-1993) and from a retrospective study conducted by the same working group (1987-1989). The total prevalence rates and the prevalence at birth were calculated. RESULTS: Out of 55,601 births, DS was recorded in 83 cases: 69 livebirths, two fetal deaths and 12 induced abortions following prenatal diagnosis, giving a total prevalence rate of 14.9 per 10,000 and a birth prevalence of 12.8. The proportion of induced abortions was 15 per cent in this period; the proportion of cases in the high risk maternal age group (35 years and over) was around 50% of the total. The proportion of induced abortions was 15 per cent in this period. CONCLUSIONS: The frequency of DS in Asturias is comparable to the other populations. Prenatal diagnosis had little impact on the birth prevalence figures. These results may help us draw up prevention and prenatal diagnosis policies for these defects in Asturias when giving the frequency of this health problem.     

Enantiospecific drug analysis via the ortho-phthalaldehyde/homochiral thiol derivatization method

Pre-column derivatization with o-phthaldialdehyde and an optically active thiol has hitherto been used mainly for liquid-chromatographic chiral separation of amino acids. Chiral separation of non-amino-acid primary amines, especially of pharmaceuticals, via this approach has been largely ignored. We have therefore examined the applicability of the method to the chiral resolution of several pharmaceutical amines. o-Phthaldialdehyde and four commercially available homochiral thiols were used to study the separation of the enantiomers of amphetamine, p-hydroxyamphetamine, p-chloroamphetamine, 3-amino- 1-phenylbutane, 3-amino-1-(4-hydroxyphenyl)-butane, mexiletine, tocainide, tranylcypromine and rimantadine. The resulting highly fluorescent isoindole derivatives were resolved on a Waters Nova-Pak C18 column using mobile phases consisting of mixtures of methanol, a sodium acetate buffer and acetonitrile, and the column effluent was monitored using fluorescence or UV detection. In some cases the fluorescence and/or the UV absorbance of the two diastereomers were unequal. It was found that the resolution of most of the amines could be optimized by varying the homochiral thiol in the derivatization step. This method of chiral separation may have wide applicability in enantiospecific drug analysis of non-amino-acid primary amines due to its simplicity and the high sensitivity it provides.     

Ultrastructural morphometric study of the prostate of the rat after microsurgical denervation

In an epidemiological study, markers of bone formation (serum osteocalcin and C-terminal propeptide of type I collagen) and bone resorption [urinary type I collagen peptides (Crosslaps), urinary total pyridinoline (TPYRI), urinary deoxypyridinoline (DPYRI) as well as female sex hormones (serum estradiol)], follicle-stimulating hormone (FSH) and luteinizing hormone were measured in 237 women. This cohort aged 44-66 years, came for their first medical examination since menopause to the outpatient menopause clinic at the Kaiser-Franz-Josef-Hospital, Vienna. The women were all 0.5-5.0 years since cessation of menses and were not taking medications other than hormone replacement therapy [52 cases, 21.9%)] and had no diseases known to affect bone and mineral metabolism. The best correlation was found between urinary DPYRI and urinary TPYRI (r = 0. 63, P = 0.0001), followed by urinary Crosslaps and urinary DPYRI (r = 0.47, p = 0.0001). Only weak but significant correlations between E2 and urinary Crosslaps (r = -0.21, P < 0.0001) as well as serum E2 and serum osteocalcin (r = -0.16, P = 0.0007), were observed. Of the 237 women 53% suffered from a severe E2 deficiency (E2 < 10.0 ng/liter). In these patients, urinary Crosslaps (+48%) and serum osteocalcin (+22%) were significantly higher (P < 0.0001) compared with those patients with E2 levels > 10 ng/liter. Women with E2 levels >10 ng/liter were further subdivided into those with and without sex hormone replacement therapy, whereby no statistical differences in any of the biochemical markers could be observed between these groups. We could clearly demonstrate that in postmenopausal women suffering from severe E2 deficiency (E2 < 10 ng/liter), urinary Crosslaps and serum osteocalcin are significantly increased, indicating in principle a clear correlation between E2 deficiency and these markers of bone turnover.     

Norrie-Warburg syndrome: two novel mutations in patients with classical clinical phenotype

Norrie-Warburg syndrome (NWS) is a rare X-linked disorder characterized by blindness, which is invariable, deafness and mental disturbances, which are present occasionally. We describe here two novel mutations, a missense mutation (C126S) and a 1-base pair insertion (insT466/T467), together with a recurrent mutation (M1V), found in patients presenting with the classical clinical phenotype of NWS. All three mutations are likely to result in prominent structural changes of the norrin protein.