Persistence of Polydimethylsiloxane Condom Lubricants

Polydimethylsiloxane (PDMS) is commonly used to lubricate condoms. The detection of PDMS on swabs from complainants can be used to support an allegation of sexual assault. Previous research has focused on establishing analytical techniques for detecting PDMS. This research examined the persistence of PDMS on the penis, in the vagina, in the mouth, and on skin. The longest PDMS detection times were 20 h on the penis, 35 h in the vagina, and 52 h on skin. PDMS was detected up to 4 h in the mouth if the participant did not eat or drink and up to 9 h if the participant slept. PDMS was not detected in the mouth after eating or drinking. The presence of biological fluids had no detrimental effect on the analysis. Aqueous extraction of swabs for DNA did not remove any significant amount of PDMS; hence, swab remains could be subsequently analyzed for PDMS.     

Cold floor effects on homicide

The cold floor pattern (a lack of homicides on days with extremely cold temperatures that was found by Cheatwood in Baltimore) is to be expected by chance. Under a model in which the number of homicides and the maximum temperature are independent, the probability that a day will fall below the cold floor is small. The Baltimore data do not support a model in which extremely cold weather suppresses human aggression.     

Development of a harmonized method for the profiling of amphetamines. II. Stability of impurities in organic solvents

The present study focused on the stability of 22 amphetamine impurities dissolved in six organic solvents: isooctane, toluene, ethanol, dichloromethane, ethyl acetate, and diethyl ether. The aim was to find the most inert, and thereby most suitable, solvent for amphetamine profiling. Mixtures of the impurities were prepared in the different solvents, and changes in the concentrations of the individual compounds over-time were monitored by gas chromatographic analysis after 0, 4, 12, 24, 48, and 96 h. Isooctane and toluene provided the most inert conditions, although, a few of the impurities were insufficiently stable in these two solvents. The present experiments were performed as a part of the development of a harmonized method for profiling of amphetamine. The results can be used to support the choice of organic solvents for sample preparation. They also provide information about the stability of the impurities that are found in profiles of illicit amphetamine. This is essential due to the fact, that unstable compounds can have a negative influence on the comparison of profiles.     

Persistence of cellular material after exposure to water

Disposing of items of forensic relevance in bodies of water is one countermeasure offenders can use to avoid detection. The impact of immersion in water has been explored for blood, saliva, and semen; however, few studies have assessed touch DNA. Here we report on the effect of exposure to water on the persistence of touch DNA over prolonged periods of time. To evaluate the persistence of cells from touch DNA, after water exposure, three substrates and two water types were tested: plastic, metal, and ceramic, submerged into seawater or tap water. Diamond™ Nucleic Acid Dye was used to stain cells deposited by touch. Cell counts before and after water exposure were compared to investigate cell loss over time, ranging from 6 hours to 5 days. A logarithmic increase in the percent of cells lost was observed over time when the data for substrate and water type conditions were combined. Substrate type influenced the persistence of cells, with the metal substrate retaining cells longer than plastic or ceramic. The influence of water type appeared dependent on the substrate, with varied cell persistence on metal whereas plastic and ceramic recorded similar cell loss over time between water types. The ability to visualize cells after exposure to water could assist in triaging evidence within operational forensic laboratories and allow for targeted sampling. This proof-of-concept study demonstrated that greater than 50% of cells can persist on various items submerged in aqueous environments for at least 5 days, highlighting the possibility for downstream DNA testing.     

只有坚持劳动价值论才能发展劳动价值论

坚持和发展是正确对待马克思劳动价值论的不可分割的两个方面。本文一方面从坚持劳动价值论出发,对一些违背劳动价值论的观点试作一些评议;另一方面从劳动价值论也应与时俱进出发,联系当今实际提出深化对劳动价值论认识值得思考的若干问题。     

The Persistence of Textile Fibres Transferred During Simulated Contacts

The persistence of fibres transferred from acrylic, wool and polyester/viscose garments to a large range of recipients was examined. Transferred fibre persistence was lessened by (a) wearing the recipient garment, (b) wearing garments over the recipient, (c) transfer of fibres to a site on the recipient garment subject to contact with other surfaces such as in arm movement, (d) low pressure in the transferring contact, and (e) fibre size, fibres less than 2·5mm length being lost more slowly than longer fibres.     

A Study of the Predictors of Persistence in Stalking Situations

Stalkers engaging in persistent campaigns of harassment have the potential to cause immense harm to their victims and themselves. Being able to estimate which stalkers are likely to persist longest is important to clinicians dealing with both perpetrators and victims. This study of 200 stalkers investigated characteristics of the stalkers and their behaviour that were associated with increased persistence. Logistic regression models were developed to predict low, moderate, and highly persistent stalking. The results supported previous research indicating that the type of prior relationship between stalker and victim is strongly associated with persistence, with prior acquaintances the most persistent, and strangers least. Being aged over 30, sending the victim unsolicited materials, and having an intimacy seeking or resentful motivation was also associated with greater persistence, as was the presence of psychosis.

Persistence of innovation: stylised facts and panel data evidence

This paper investigates whether firms innovate persistently or discontinuously over time using an innovation panel data set on German manufacturing and service firms for the period 1994–2002. It turns out that innovation behaviour is permanent at the firm level to a very large extent. Using a dynamic random effects discrete choice model and a new estimator recently proposed by Wooldridge (2005), I further shed some light on the driving forces for this phenomenon. The econometric results show that past innovation experience is an important determinant for manufacturing as well as for service sector firms, and hence confirm the hypothesis of true state dependence. In addition, the results highlight the important role of knowledge provided by skilled employees and unobserved individual heterogeneity in explaining the persistence of innovation.

The Recovery and Persistence of Salivary DNA on Human Skin

Abstract: Salivary DNA is encountered in many crimes, such as sexual assaults and murders. In this study, saliva from three male donors was deposited on the skin of three female recipients. The amount of male salivary DNA remaining on the female skin was measured over a 96‐h period using the Quantifiler? Y Human Male DNA Quantification Kit. In eight of the nine experiments, a full male DNA profile matching the donor was obtained even after 96 h. In addition, the study showed that the concentration of salivary DNA varied from donor to donor and from day to day. The efficiency of two recovery methods, wet and dry swabbing and minitaping, was compared. The results indicate the tapelift method gave higher DNA recovery. This study also examined the secondary transfer of salivary DNA from skin to fabrics. Cotton and polyester give higher DNA transfer than leather.     

Persistence of transferred fragrance on fabrics for forensic reconstruction applications

It has recently been established that volatile organic compounds (VOCs) successfully transfer between clothing even with a short contact of 10 s, highlighting the potential to use VOCs in forensic reconstruction scenarios, such as sexual assault cases. The mid and low volatility compounds transferred in greater amounts than high volatility compounds. This study presents empirical data addressing the persistence of transferred VOCs on clothing for the first time. A series of experiments were carried out to determine the persistence of VOCs on clothing for time periods of up 4 weeks, on natural and synthetic fibres, and at three different environmental temperatures. The data indicate that the highest VOC amounts are generally obtained for shorter persistence times of up to 1 d. Whilst high volatility compounds were not recovered in sufficient amounts to allow quantification, the four other transferred VOCs were successfully quantified for persistence times of up to 4 weeks. The persistence for mid-volatility compounds follows decay curve trends in line with those previously obtained for fibres, glass and pollen. When comparing the persistence of VOCs on a natural and a synthetic fibre, for a persistence time of 1 h, the transferred VOCs were retained on a natural fibre in higher amounts than on a synthetic fibre. However, for longer persistence times the concentration of VOCs was similar between the two fabrics. Lastly, lower environmental temperatures resulted in higher recoveries for most VOCs, especially for short persistence times. These findings demonstrate that optimal recovery of VOCs from clothing occurs when the fabric is kept at cooler temperatures and analysed soon after the fragrance transfer occurred, although VOC recovery was possible at higher temperatures and after longer persistence times. Given the transfer and persistence characteristics of VOCs from fragrance, there is potential for fragrance to be used as a form of trace in forensic reconstruction approaches.     

Dipping and coating operations. Occupational Safety and Health Administration (OSHA), Labor. Final rule

OSHA's standards for dipping and coating operations, codified at sections 1910.108 and 1910.94(d), are designed to protect employees from fire, explosion, and other hazards associated with these operations. On April 7, 1998 (63 FR 16918), OSHA published proposed revisions to these standards in the Federal Register. The Federal Register announcement requested comments on the proposed rule, as well as on three major issues identified by OSHA. Based on these comments and other considerations, the Agency has developed the final standard to accomplish several goals: To rewrite the former standards in plain language; to consolidate the former requirements in sequential sections (sections 1910.122 through 1910.126 in subpart H of part 1910); and to update the former standards to increase the compliance options available to employers. In addition to achieving these goals, OSHA concludes that the final rule being published today will enhance employee protection by making it more understandable and useful to employers and employees and more flexible and performance-oriented than the former rules. The final rule accomplishes these goals without increasing the regulatory burden of employers or reducing employee protection.     

“平等主体关系说”的弃与留——未来《民法典》调整对象条款之抉择

《民法通则》采纳"平等主体关系说"厘定民法的调整对象,混淆了事实与规范,将本是规范状态的平等视为调整对象事实层面的规定性,不仅存在因果倒置的逻辑错误,淡化民法对平等的追求,而且不能完成对民法调整对象的界定,并蜕变为法院逃避裁判责任的规范基础。"平等主体关系说"之所以成为《民法通则》的现实选择,渊源于彰显民法独立性的历史需要。事易时移,我国未来《民法典》关于调整对象条款的抉择应向区分公、私法的逻辑回归,采取确立其他法部门调整对象之负面清单的立法模式,《民法典》不再设置调整对象条款,或对调整对象作空洞化处理,从中抽离平等主体等实质内涵,落实民法的本位法地位。     

自制海洛因标准品在常用有机溶剂中稳定性研究

目的 研发海洛因标准品及优化分析方法,以对云南缴获海洛因样本提纯制备成的自制海洛因对照品在常用有机溶剂中的稳定性进一步研究.方法 采用内标及GC、GC/MS方法,通过对提纯制备的海洛因在5种有机溶剂中冷藏保存后含量的变化,观察海洛因在常用有机溶剂中的稳定性.结果 乙醇、三氯甲烷及乙腈为溶剂的自制海洛因对照品储备液,保存30天时间范围内海洛因含量未发生明显变化;以丙酮作为溶剂的自制海洛因对照品储备液,在7至30天时间范围内,海洛因含量明显升高;以甲醇作为溶剂的自制海洛因对照品储备液,在0小时至30天时间范围内,海洛因含量一直呈明显的下降趋势.结论 乙醇、三氯甲烷及乙腈可以作为海洛因样品储备液溶剂使用,丙酮、甲醇不适合作为海洛因样品储备液溶剂使用.     

Persistence of intimate partner violence among families referred to child welfare

The purpose of this study is to examine the longitudinal course of intimate partner violence (IPV) among female caregivers of children receiving child welfare services. Data are derived from the National Survey of Child and Adolescent Well-Being, a national probability study of children investigated for child abuse and neglect in the United States. Caregivers (n = 861) are interviewed about demographic characteristics, mental health, substance use, and physical violence by a partner at the close of the investigation and at an 18-month follow-up. Polychotomous logistic regression examines the associations of severe and minor IPV controlling for caregiver and environmental characteristics. The results suggest that factors related to initial risk for IPV do not affect the continuation of IPV and that patterns of IPV differ for racial and ethnic groups.     

Competing Risks, Persistence, and Desistance in Analyzing Recidivism

A statistical procedure is developed to analyze recidivism in samples whichare subject to the presence of desisters and to multiple modes ofreconviction. This allows for a more accurate study of individuals'transition and hazard in the type and timing of offenses following aspecific type of conviction. The use of a nonparametric approach forinvestigating failure in the presence of other acting causes is shown;initial estimators of the probabilities of reconviction for different typesof offenses are obtained, and the method can be used both to display thedata and to choose an appropriate parametric family for the survivaltimes. An exponential mixture model for competing risks is presented insuch a way that it allows us to adjust for concomitant variables and toassess their effects on the probabilities both of reconviction forpredetermined types of offenses and desistance and of the hazards ofreconviction; a method for assessing calibration of predicted survivalprobabilities is suggested. A 21-year follow-up of persons convicted ofindecent assault on a female in 1973 illustrates the methods; we find ahigh probability of sexual reconviction for individuals with previoussexual convictions and evidence of diversity and a raised hazard ofreconviction for young chronic offenders.