Preliminary Analysis of the Environmental Effects on RNA Degradation: Modeling a Realistic Crime Scene

In forensic science, polymerase chain reaction (PCR) became an indispensable tool given the limited amount of biological samples usually encountered at crime scenes. DNA analysis is used to identify the source of biological samples typically obtained from a single hair, or droplet of blood. Determining the source of the biological evidence can provide a spatial link, thereby including or excluding a suspect at a crime scene or other locations related to a crime investigation. In spite of the great efficiency in human identification, DNA analysis cannot provide any information regarding time of deposition of the sample. The ability to establish a temporal connection reveals key information for crime scene reconstruction and evidence interpretation; this is especially true when determining if the DNA sample found at the crime scene was left at the moment of the crime or originated from an unrelated event. Estimating the age of the biological sample would be particularly important in cases where the victim and suspect are known to have a personal relationship. The development of quantitative reverse-transcription real-time polymerase chain reaction, has stimulated scientist to explore the potential use of RNA as a forensic tool. Multiple studies have reported the use of RNA analysis on body fluid identification, age determination of injuries and wounds and for post-mortem interval (PMI). Previously, our laboratory has shown that the estimation of age of a biological sample can be determined by measuring the degradation rates of two different RNA segments using real-time RT PCR method. In addition, it has also been demonstrated that, under controlled conditions, RNA decay proceeds in a predictable fashion. However, it is unrealistic to expect that in real crime scenes the biological sample will be exposed to an invariable environment. We investigated the environmental effects on beta-actin and 18S RNAs decay, more specifically; the effects of fluctuating temperatures and humidity by exposing bloodstain samples in two different rooms at WVU\u27s Crime House One during a 90 day period. Daily temperature and relative humidity were recorded in each room. We also investigated the potential use of outdoor temperature to predict indoor temperature. In addition, we investigated the incorporation of accumulated degree days (ADD) into RNA degradation analysis in order to take into account the temperature changes in a non-controlled environment. We believe this will allow for a more accurate and reliable method for estimating time of deposition of blood samples. Our results indicate that the environmental conditions had an effect on the degradation rate of both beta-actin and 18S RNAs. The basement environment presented high but generally constant temperature and RNA decay occurred in a linear, predictable fashion. However, the accuracy of our estimation method was extremely decreased in a highly variable environment (attic). This suggests that our assay would only be accurate if there is no extreme fluctuation in temperature. Finally, our results show the importance of knowing the environmental conditions for an accurate estimation of time of deposition and how the data interpretation could be affected, if this information is unknown. After the 90 day exposure period, the basement had an ADD value of 1,496.047 while the attic had an ADD of 508.967 and the airport ADD was 143.111. Thus, using the ADD from one of these environments to estimate time of deposition on the other could lead to estimating the age of the sample as older or younger then it\u27s true value

Estrutura genética e demográfica do caranguejo-uçá (Ucides cordatus) na costa do Brasil

O caranguejo Ucides cordatus, popularmente conhecido no Brasil como caranguejo-uçá, é encontrado em manguezais desde o estado de Santa Catarina até a Flórida, nos Estados Unidos. No Brasil, a grande demanda por esta espécie na indústria alimentícia é a causa da cata de várias toneladas de indivíduos todos os anos. Somados a este fator, a destruição dos manguezais e o surgimento de uma doença letal vêm sendo apontados como agentes causadores de severas reduções nos estoques naturais de U. cordatus. Uma vez que reduções populacionais severas tendem a provocar eventos de efeito gargalo e, consequentemente, redução da aptidão dos indivíduos ao longo do tempo, estudos de genética de populações que se dediquem a entender o padrão da distribuição genética, quantificar o fluxo gênico e avaliar as tendências demográficas das populações, são essenciais na elaboração de estratégias de manejo e de conservação. Portanto, neste trabalho, utilizamos sequências de 568 pb da subunidade 1 do gene mitocondrial citocromo c oxidase de 181 espécimes de U. cordatus coletados em 15 localidades ao longo da costa brasileira, entre os estados de Santa Catarina e Maranhão, que compreendem praticamente toda a região de ocorrência da espécie no Brasil. Do total de sequências, 80 haplótipos foram revelados, caracterizando uma elevada diversidade haplotípica (h=0,925). Por outro lado, a diversidade nucleotídica foi baixa (π =0,00462), dada a diferença de poucos pares de bases entre os haplótipos. A relação hierárquica entre os haplótipos não demonstrou nenhuma estruturação geográfica da diversidade genética. Além disso, a análise de variância molecular e os valores da estatística-Φ (Φst=0,00231) revelaram que a maior parte da variação genética em U. cordatus está contida no nível intrapopulacional (98,8%), e apenas uma fração sutil entre os grupos de populações (2,5%). Os valores de Fs de Fu e D de Tajima revelaram-se negativos, indicando que as populações de U. cordatus sofreram eventos de expansão populacional recente. Este cenário também foi confirmado através da análise de mismatch distribution, na qual distribuições unimodais foram encontradas para todas as populações. Nossos dados são concordantes com trabalhos prévios que indicam que o fluxo gênico em U. cordatus é suficientemente amplo a fim de produzir homogeneidade genética entre as populações. Este perfil é condizente com a estratégia de exportação das larvas desta espécie para alto mar, no qual fatores oceanográficos, como correntes marinhas, podem agir de forma a ampliar a dispersão destas formas imaturas

Study of the Distillability of Werner States Using Entanglement Witnesses and Robust Semidefinite Programs

We use Robust Semidefinite Programs and Entanglement Witnesses to study the distillability of Werner states. We perform exact numerical calculations which show 2-undistillability in a region of the state space which was previously conjectured to be undistillable. We also introduce bases which yield interesting expressions for the {\em distillability witnesses} and for a tensor product of Werner states with arbitrary number of copies.Comment: 16 pages, 2 figure

Quantum Correlations and Coherence in Spin-1 Heisenberg Chains

We explore quantum and classical correlations along with coherence in the ground states of spin-1 Heisenberg chains, namely the one-dimensional XXZ model and the one-dimensional bilinear biquadratic model, with the techniques of density matrix renormalization group theory. Exploiting the tools of quantum information theory, that is, by studying quantum discord, quantum mutual information and three recently introduced coherence measures in the reduced density matrix of two nearest neighbor spins in the bulk, we investigate the quantum phase transitions and special symmetry points in these models. We point out the relative strengths and weaknesses of correlation and coherence measures as figures of merit to witness the quantum phase transitions and symmetry points in the considered spin-1 Heisenberg chains. In particular, we demonstrate that as none of the studied measures can detect the infinite order Kosterlitz-Thouless transition in the XXZ model, they appear to be able to signal the existence of the same type of transition in the biliear biquadratic model. However, we argue that what is actually detected by the measures here is the SU(3) symmetry point of the model rather than the infinite order quantum phase transition. Moreover, we show in the XXZ model that examining even single site coherence can be sufficient to spotlight the second-order phase transition and the SU(2) symmetry point.Comment: 8 pages. 5 figure

Viable entanglement detection of unknown mixed states in low dimensions

We explore procedures to detect entanglement of unknown mixed states, which can be experimentally viable. The heart of the method is a hierarchy of simple feasibility problems, which provides sufficient conditions to entanglement. Our numerical investigations indicate that the entanglement is detected with a cost which is much lower than full state tomography. The procedure is applicable to both free and bound entanglement, and involves only single copy measurements.Comment: 8 pages, 9 figures, 4 table