Cost‐Effectiveness of Early Childhood Interventions to Enhance Preschool: Evidence from a Randomized Experiment in Head Start Centers Enrolling Historically Underserved Populations

We evaluate the cost‐effectiveness of two early childhood interventions that use instructional coaching and parent coaching as levers for improvement. The study design allows us to compare the individual effects of each intervention as well as their combined effect on student outcomes. We find that teachers receiving instructional coaching improve their use of evidence‐based instructional practices, while families receiving parent coaching show increases in numerous responsive parenting behaviors associated with positive child outcomes. Both interventions demonstrate positive impacts on students, but only parent coaching shows statistically significant effects across a range of student outcomes. Instructional coaching alone is substantially less costly and may therefore be the most cost‐effective of the three treatment conditions; however, small sample sizes limit our ability to reach definitive conclusions. Policy simulations suggest that implementing these interventions could raise the overall cost‐effectiveness of Head Start by at least 16 percent.     

Technical note: Comparison of forensic swabs for intravaginal sampling

This study compared the currently used swab Prionics ForensiX Evidence Collection Kit with the alternatives Prionics ForensiX Evidence Collection Tube SafeDry and Sarstedt Forensic Swab XL. Volunteers provided intravaginal swabs collected with all swab types at specific time points after unprotected sexual intercourse. Quantifiable DNA, detectability of seminal fluid component (prostate specific antigen, PSA) and spermatozoa were evaluated to find the best-performing swab type.While Sarstedt XL showed significantly higher DNA quantities for sperm cell fractions than ForensiX Kit, the more concise PSA test results clearly favour ForensiX SafeDry. Reassuringly, mostly complete autosomal STR profiles of male components were obtained for sperm cell fractions at all time points and tested swabs. Switching to the higher performing ForensiX SafeDry with improved sampling and processing properties will also benefit victims, medical personnel, and investigators.     

Examination of pretreatment methods for DNA extraction from nails

In the conventional method of DNA extraction from nails, it takes approximately half a day to dissolve the nails. In this study, we examined whether using the HOrizontal Nail MAshing (HONMA) method, in which pressure is applied to the nail to crush it flat and increase its surface area, would improve DNA extraction efficiency. Fingernails (5 mg) provided by ten volunteers were used as samples. Nail pieces (1–3 pieces), shredded with nail clippers, were thinly stretched by applying 2 t of pressure to each piece using a hydraulic press. DNA was extracted by incubation at 56 °C for 10 min and 1 h during proteolysis. DNA yield from the nails pretreated using the HONMA method increased by 0.20–7.10 times compared with that from unprocessed nails. In particular, 10-min incubation using the HONMA method resulted in an average 2.05-fold increase in DNA yield compared with that under overnight incubation. However, the impact of using the HONMA method varied widely among individuals, and the amount of extracted DNA decreased in some cases, suggesting that the yield may differ depending on the nail quality.     

Automated DNA casework workflow: A retrospective study of the first implementation of FIDL at the Netherlands Forensic Institute

FIDL is a fast and automated DNA identification line which represents a series of software solutions automating the process from raw capillary electrophoresis data to reporting. This retrospective study provides insight in the numbers of cases, turnaround time, results compared to the standard workflow and the benefits automation has in a large volume workflow.     

"Biological identikit": Development of a SNPs-panel for the analysis of forensic DNA phenotyping and ancestry

Personal identification in mass disasters and in crimes is essential for humanitarian, ethical and legal reasons. In these contexts, when individuals cannot be identified by standard forensic DNA analysis, the Forensic DNA Phenotyping and the analysis of the biogeographical ancestry could help. The aim of this study was to evaluate the potential of a new panel of 891 SNPs in predicting phenotypic traits and biogeographical origin to create a “biological identikit”. In addition to fresh biological material, old evidence found at the crime scene or extracted and long-term stored DNA were tested with 41 SNPs for phenotyping and 850 SNPs for ancestry. All the SNPs were successfully incorporated into a single two-step multiplex PCR reaction using the IonAmpliSeq ™ Library Plus and applied for massive parallel sequencing with the Ion S5 platform using up to 0.05 ng/µL of DNA. The analysis of the results was carried out with an in-house predictive algorithm and consulting 20 population databases. By comparing the results obtained with identikit or video-photographic surveys, it was possible to predict phenotype and ancestry with an accuracy greater than 90%. While these new markers cannot identify a specific individual, they can be a valuable investigative tool.     

Comparison of operational DNA recovery methods: Swabs versus tapelifts

It is routine among many jurisdictions to recover DNA using tapelifts on porous substrates (e.g. clothing) and swabs on non-porous substrates (e.g. tool handles). Here, we examine this by comparing the efficiency of the NSW jurisdiction’s specific swabbing and tapelift techniques on a range of porous and non-porous substrates. To test DNA recovery efficiency, 30 μl aliquots of 1:50 and 1:100 saliva dilutions were deposited onto the substrates, left to dry overnight, recovered, extracted, quantified and a subset profiled. Tapelifts recovered more DNA and DNA profiles with more detectable alleles than swabs for both saliva dilutions on porous substrates. For non-porous substrates, similar DNA quantities and profiles were generally recovered with both methods for both saliva dilutions. These data underpin current practices to recover DNA using tapelifts for porous substrates and swabs for non-porous substrates. These data also revealed severe degradation of DNA recovered from brass, supporting the on-going need to improve DNA recovery and analysis methods for brass substrates.     

Test of chlorine wipes for efficient removal of DNA from forensic genetics laboratories

Sodium hypochlorite is an efficient reagent for removal of unwanted DNA from laboratory surfaces. Here, we tested two different chlorine wipes and compared their performance to a 0.9–1.8% hypochlorite solution. WipeClean Chlorine Disinfection wipes contain > 0.1 g sodium hypochlorite/kg, whereas WetWipe Chlorine Desinfection wipes contain > 1000 ppm active chlorine. Clean surfaces were contaminated with 10 µL 0.5 ng/µL of massively parallel sequencing libraries. The DNA was dried and left for 45 min before any treatment. The surfaces were cleaned using either 1) a 0.9–1.8% hypochlorite solution and clean wipes, 2) a WipeClean wipe, 3) a WetWipe, or 4) the surface was not cleaned. All experiments were repeated three times. Subsequently, the surfaces were swabbed using cotton swabs. DNA was extracted from the swabs and the DNA concentrations were determined in quadruplicates by real-time PCR. This protocol was repeated after the soft plastic wrapping around the wipes were left open or closed for several weeks. The results showed that the WipeClean wipes efficiently removed DNA for up to four weeks after the box with the wipes were opened, whereas the WetWipe wipes dried faster and gradually lost their cleaning effect.     

鞋内底不同部位接触DNA提取初探

目的探讨鞋内底不同部位接触DNA提取检出率。方法取100名20-30岁的志愿者，将其穿用过的运动鞋和皮鞋鞋垫设置成不同穿用时间组、不同材料鞋垫组、穿用后不同放置时间组，根据脚的形态学及运动力学特点，将鞋垫分成8个区域进行脱落细胞提取，并进行DNA进行检验。结果鞋垫上8个不同区域提取到的脱落细胞DNA分型检验效果不同。足弓外侧区（足引折弓除外）的接触DNA检出率最高；足弓内侧、第1趾骨区、第1跖骨区及足跟区次之；第2～5趾骨区、第2～3跖骨区、第4～5跖骨区不容易成功提取到接触DNA。结论鞋内底接触DNA检出率与接触时间、放置时间、鞋垫材质均相关，分区提取检验DNA更有针对性。     

列宁晚年对国家机关改革的理论探索

列宁晚年对苏维埃国家机关存在的种种弊端以及改革国家机关的重要性和迫切性有着清醒的认识。他提出的一系列富有远见的国家机关改革思想，以及对改革过程中可能遇到的风险所作的分析，对推动当前我国国家机构改革仍有着重要的指导意义。     

旅俄华人共产党人未在中共建党过程中发挥主要作用问题探讨

数万名参与十月革命或捍卫十月革命成果并且有组织的旅俄华人共产党人或红军战士未能在中共建党过程中发挥主要作用；中共一大13名代表及其代表的57名党员无一人是旅俄华人共产党人中的“海归派”。这一问题的原因值得深思和研究。认真剖析当年旅俄华人共产党最高领导机构共产华员局在这一问题上的主观因素及其所处的客观社会条件，不难找到这一问题的答案。