Phylogeography of Myrica nana: the Wumeng Mountains as a natural geographical isolation boundary on the Yunnan-Guizhou Plateau

The Yunnan-Guizhou Plateau (YGP) is characterized by the distinctive isolated habitat of limestone Karst Islands and features the Wumeng Mountains (Mts), which divide the YGP into the two Plateaus of Yunnan and Guizhou. This study aims to assess the effects of past geographic and environmental isolation and climate fluctuation on the flora distribution in the YGP. To this effect, we analyzed the phylogeographical pattern and genetic structure for Myrica nana, a vulnerable species endemic to the YGP, based on chloroplast and nuclear ribosomal DNA sequence. The results suggest that the genetic and haplotype network structures are divided into at least two groups—cpDNA haplotype H2 (or nrDNA haplotypes h1, h2, and the native haplotype) mainly distributed to the east of the Wumeng Mts, and cpDNA haplotype H1 and haplotypes H3–H10 (or nrDNA haplotype h3) distributed to the west of the Wumeng Mts. A deep genetic split was noted within the two groups to reach 25 steps, especially for the cpDNA fragment variation. The east–west divergence reveals the existence of a natural geographical isolation boundary in the form of the Wumeng Mts, which divides the YGP into the Yunnan and Guizhou Plateaus. Therefore, there existed at least two glacial refugia during the Quaternary glacial period, along with a genetic diversity center, and at least two large geographic protection units for the vulnerable species of M. nana, distributed throughout the eastern and western sides of the Wumeng Mts. This study not only clarifies that the phylogeographical pattern and genetic structure for M. nana can be attributed to geographic and environmental isolation and climate fluctuation, but it also proposes an effective strategy to protect vulnerable species and the important wild flora of the YGP.

Description of two fatal cases of melioidosis in Mexican children with acute pneumonia: case report

Background Melioidosis is an infectious disease caused by Burkholderia pseudomallei. In Mexico, the disease is rarely diagnosed in humans and there is no evidence of simultaneous environmental isolation of the pathogen. Here, we describe clinical profiles of fatal cases of melioidosis in two children, in a region without history of that disease. Case presentation About 48 h before onset of symptoms, patients swam in a natural body of water, and thereafter they rapidly developed fatal septicemic illness. Upon necropsy, samples from liver, spleen, lung, cerebrospinal fluid, and bronchial aspirate tissues contained Burkholderia pseudomallei. Environmental samples collected from the locations where the children swam also contained B. pseudomallei. All the clinical and environmental strains showed the same BOX-PCR pattern, suggesting that infection originated from the area where the patients were swimming. Conclusions The identification of B. pseudomallei confirmed that melioidosis disease exists in Sonora, Mexico. The presence of B. pseudomallei in the environment may suggest endemicity of the pathogen in the region. This study highlights the importance of strengthening laboratory capacity to prevent and control future melioidosis cases.

POPULATIONS OF THE MAJOR CARRIER RHOMBOMYS OPIMUS, VECTORS OF XENOPSYLLA FLEAS AND THE CAUSATIVE AGENT OF YERSINIA PESTIS IN THE CENTRAL ASIAN DESERT NATURAL FOCUS OF PLAGUE

In the Central Asia desert natural focus of plague, the major carrier of the Yersinia pestis agent is the great gerbil Rhombomys opimus, and its vectors include fleas of the Xenopsylla genus. Phenotypical and genotypical properties of the R. opimus populations, Xenopsylla fleas and Yersinia pestis strains have been studied in the Central Asia desert natural focus of plague. Phenotypic distinctions and population discreteness have been identified in R. opimus on the cytochrome b gene of the mitochondrial genome from three autonomous plague foci: Pre-Balkhash, Betpakdala and Pre-Ustyurt. Phenotypic distinctions have been found in Xenopsylla fleas in the Central Asia desert natural focus of plague, and the genotype of X. gerbilli minax fleas on the Cox2 gene of the mitochondrial DNA; these had been captured in the Betpakdala autonomous focus. The repertoire diversity in phenotypical properties of Y. pestis strains from different natural foci of plague has been demonstrated, and population discreteness of Y. pestis strains has been determined using the next-generation sequencing method for single nucleotide polymorphism genes. Results of the study suggest that geographical and environmental isolation and natural selection have led to heterogeneity in the three populations of the great gerbil, vector fleas and Y. pestis.

Isolation of Cryptococcus spp. from several environmental niches in São Luís, MA

Cryptococcosis is an invasive mycosis triggered by a complex of fungal pathogens present in various environmental niches. Cryptococcus neoformans, C. gattii, and emerging pathogens such as C. laurentii and C. albidus are found in aged excreta of Columba livia (pigeon), its natural disseminator. As the pigeon population has increased in São Luís, the objective of this research was to demonstrate the presence of Cryptococcus spp. in the excreta of C. livia in public environments. Twenty-three samples were collected at 14 sites, dispensed into conical tubes, homogenized with saline and chloramphenicol, and allowed to rest until processing. Twenty-four hours after collection, aliquots were distributed in a fungal culture medium and incubated. The macromorphological examination revealed levaduriform, mucoid, bright, isolated colonies compatible with Cryptococcus spp. In the micromorphological examination, 11 of the 23 samples (42.85%) showed the presence of cells with a thick, refringent capsule and mucopolysaccharide around the blastoconidia, typical of Cryptococcus spp. fungi. The other samples (57.14%) were negative for the fungus. The environmental isolation of this fungus in public areas is relevant to public health since the growing pigeon population in São Luís increases the risk of exposure and infection by dispersion of infectious propagules in the environment.

Cost Effective Permanent Well Plug & Abandon on Cluster-X With Complex Well Conditions

Regulation PTK-040 SKK MIGAS explained that the oil company must permanently close the wells post-production operations. Cluster-X has complex well conditions, so the observation needs to be cost-effective. The observation on this case refers to SNI 13-6910-2002 explaining the permanent abandonment of wells in the isolation of open-hole zones, perforation zones, blockage of casing stub (junk) as Primary well-barrier and the annular space blockage as a Secondary well-barrier. The next stage is the surface plug as an environmental isolation plug. API BUL E3-FIRST EDITION & NORSOK STANDARD D-010 are also needed for permanent abandonment on surface capping and slotted-liners in multiple reservoirs. Additional references such as API-Spec-10A are needed. The final stage is the testing of cement plugs, hole cleaning process, and budgeting. This paper discusses various conditions of wells on Cluster-X such as abnormally high pressure, cement plug with open-hole slotted-liners in multiple reservoirs, and junk left in-hole. The first step was to run with a balance plug method on ± 10,500-10,971 ft MD as Primary well-barrier. The next step was to run a cement squeeze method with bridge plug on ±7200-7500 ft MD as Secondary well-barrier. On the step of environmental isolation plug a cement plug retainer was run as a weight test with 15,000 pounds the same on previous steps. Type G class cement was selected to cement plug and ran off section milling tools above of the overpressure zone. The wells closure method compares between rigless method coiled tubing unit and portable rig (conventional) which can optimize plug & abandonment operating time and operational cost.

Electrical Detection of Degradation in Specimens of HVDC Cable Insulation

One of the challenges in laboratory investigation of degradation and ageing of HVDC cable insulation is related to securing, or in other words, imitating the real service environment of the material specimens. So far, the published data refer to experiments conducted in thermo-oxidative conditions, which is not the case during normal cable operation. In service, the cable insulation is protected by a metallic barrier that blocks the transfer of any substances in and out of the construction. By-products from the cross-linking reactions cannot diffuse out and any foreign substances are blocked from entering the insulation. Thus, in order to generate results that are valid, these conditions must be replicated in laboratory experiments. This contribution presents a methodology elaborated for performing ageing experiments in a hermetically sealed environment. Degradation of the material is evaluated through changes in the electrical tree inception voltage and test object capacitance over time. Securing the environmental isolation is accomplished with an isolation system consisting of a glass enclosure with attached metallic electrodes. Indium is used to create a glass-to-metal seal between the glass and the electrodes. The electrode geometry is of needle–plane type and the needle injection process is semi-automated to ensure specimen repeatability.

Experiences of Occupational Performance in Survivors of Stroke Attending Peer Support Groups

Background. Survivors of stroke often experience environmental isolation and decreased occupational performance after discharge from the hospital. Peer groups benefit psychological, social, and cognitive functioning, though few studies have examined their influence on occupational performance of survivors of stroke. Purpose. This study explores the experiences of occupational performance in survivors of stroke attending an outpatient peer support group. Method. An interpretive qualitative study using semi-structured interviews was conducted with seven survivors of stroke attending an outpatient peer support group. Data was thematically analyzed. Findings. Four themes related to the experience of peer support on occupational performance emerged: finding hope to return to meaningful occupation, a place for belonging, problem-solving occupational concerns, and finding purpose beyond oneself. Implications. This research adds to the existing literature that peer support groups help survivors of stroke reengage in meaningful occupations, manage their stroke experience, and move positively through recovery.