The volcano rabbit—a shrinking distribution and a threatened habitat

The volcano rabbit (Romerolagus diazi) is a lagomorph endemic to the central mountains of the Trans-Mexican Volcanic Belt and is classified as threatened at extinction risk. It is a habitat specialist in bunchgrass communities. The annual wildfires that occur throughout its distribution range are a vulnerability factor for the species. However, the effects of wildfires on volcano rabbit populations are not fully understood. We evaluated the occupancy and change in the volcano rabbit relative abundance index in the burned bunchgrass communities of the Ajusco-Chichinautzin Mountain Range during an annual cycle of wildfire events. Additionally, we assessed the factors that favor and limit occupation and reoccupation by the volcano rabbit using the relative abundance index in burned plots as an indicator of these processes. The explanatory factors for the response of the volcano rabbit were its presence in the nearby unburned bunchgrasses, the height of three species of bunchgrass communities, the proportion of different types of vegetation cover within a 500 m radius around the burned plots, heterogeneity of the vegetation cover, and the extent of the wildfire. Statistical analyses indicated possible reoccupation in less than a year in burned bunchgrass communities adjacent to unburned bunchgrass communities with volcano rabbits. The relative abundance index of volcano rabbits was not favored when the maximum height of the Muhlenbergia macroura bunchgrass community was less than 0.77 m. When the vegetation around the burned plots was dominated by forest (cover >30% of the buffer) and the fire was extensive, the number of latrines decreased per month but increased when the bunchgrass and shrub cover was greater around the burned plots. While the statistical results are not conclusive, our findings indicate a direction for future projects, considering extensive monitoring to obtain a greater number of samples that contribute to consolidating the models presented.

On behalf of VRRSP Consultants, LLC, and Central Texas Regional Water Supply Corporation (CTRWSC), SWCA Environmental Consultants (SWCA), conducted further intensive cultural resources investigations of the Vista Ridge Regional Water Supply (Vista Ridge) Project in Burleson, Lee, Bastrop, Caldwell, Guadalupe, Comal, and Bexar Counties. The project will involve installation of a 140.2-mile-long, 60-inch-diameter water pipeline from Deanville, Burleson County, Texas, to north-central San Antonio, Bexar County, Texas. The area of potential effects (APE) will consist of the proposed centerline alignment and an 85-foot-wide corridor for temporary and permanent construction easements; however, SWCA surveyed a 100-foot-wide corridor to allow for minor shifts in the alignment. This addendum report details the findings of additional cultural resources investigations between 2016 and 2018, on the alignment. The Vista Ridge Project is subject to review under Section 106 of the National Historic Preservation Act (54 USC 306108) and its implementing regulations (36 CFR 800), in anticipation of a Nationwide Permit 12 from the U.S. Army Corps of Engineers in accordance with Section 404 of the Clean Water Act. In addition, the work is subject to compliance with the Antiquities Code of Texas (ACT) under Permit No. 7295, as the Vista Ridge Project ultimately will be owned by a political subdivision of the State of Texas. Furthermore, all human burials in the state of Texas are protected by law, as per the Texas Health and Safety Code Section 711 General Provisions Relating to Cemeteries and the Texas Administrative Code Title 13, THC, Chapter 22 Cemeteries, Sections 22.1 through 22.6. If human burials are encountered in the Project Area and the remains are determined to be Native American, they will be handled in accordance with procedures established through coordination with the THC; work in the affected area would only resume per THC authorization. Between 2016 and 2018, SWCA investigated approximately 29.5 miles of the current 140.2-mile-long project corridor and the proposed 6.9-mile-long wellfield pipeline that was not previously surveyed during the prior 2015 investigations (Acuña et al. 2016). Investigations consisted of intensive pedestrian survey augmented with shovel testing and hand-excavated auger probes and/or mechanical backhoe trenching in select areas. In addition, SWCA investigated the 25.82-acre terminus site slated for the construction of an integration system (Atwood and Ward 2017). SWCA also surveyed additional mileage, which included rerouted areas that are no longer part of the currently proposed alignment. SWCA excavated 967 shovel tests, 96 auger probes, and 85 backhoe trenches during these additional investigations. SWCA documented or further investigated 28 cultural resources within the Vista Ridge Project during the 2016 to 2018 investigations. Of the 28 resources, seven were isolated finds that did not warrant formal site recording or require additional investigations. The remaining 21 cultural resources include 15 prehistoric sites, three historic sites, and three multi-component sites with both prehistoric and historic cultural materials. Of the 21 sites, two (i.e., 41BP960 and 41BP961) are currently UNDETERMINED regarding eligibility for the National Register of Historic Places (NRHP) or as a State Antiquities Landmark (SAL), and one site (i.e., 41GU177) was determined to be ELIGIBLE for listing on the NRHP and for designation as a SAL. SWCA conducted testing and data recovery excavations at site 41GU177 and the results of testing investigations conducted under Permit No. 7295 are presented as an appendix to this report (Rodriguez et al. 2017); the data recovery investigations of site 41GU177 were completed under Permit No. 8231 and will be a separate report. Additionally, sites 41BP960 and 41BP961 have been avoided by design alignment changes and will not be impacted by the Vista Ridge Project. The remaining 18 cultural resources sites are considered NOT ELIGIBLE for nomination to the NRHP or for designation as SALs and no further cultural resources investigations or avoidance are recommended. In addition, SWCA documented two cemeteries (the Hill Cemetery and the Hoffman Cemetery) during the 2016 to 2018 investigations. Due to subsequent reroutes, the Hill Cemetery (located within the boundaries of site 41BP818) is now avoided and will not be impacted by the project. Mechanical scraping was conducted adjacent to the Hoffman Cemetery in compliance with the Texas Health and Safety Code; no evidence of interments was identified within the project area. In accordance with 36 CFR 800.4 and the ACT, SWCA has made a reasonable and good faith effort to identify cultural resources within the project area. Two sites (i.e., 41BP960 and 41BP961) are recommended as having UNDETERMINED eligibility for listing on the NRHP or for SAL designation and one site (41GU177) is recommended as ELIGIBLE. The remaining 18 are recommended as NOT ELIGIBLE for listing on the NRHP or for SAL designation. Site 41GU177 has been mitigated and the results will be presented in a stand-alone report (Nielsen et al. 2019). The two sites (41BP960 and 41BP961) of UNDETERMINED eligibility have been avoided by design alignment changes and will not be impacted by the project. No further work or avoidance strategy is recommended for the remaining 18 archaeological sites identified during the Vista Ridge Project.

Estudio de cohorte de base poblacional sobre la enfermedad pulmonar obstructiva crónica en Latinoamérica: métodos y resultados preliminares. Fase II del estudio PLATINO

We analyzed Mestizo (admixed) population samples from different geographic regions of Mexico (n= 1283) with 20 autosomal STRs (PowerPlex® 21, Promega Corp.). Allele frequencies and forensic parameters from the Northwest, Northeast, West, Center, and Southeast regions are reported, as well as from the pooled Mexican population sample. The combined PD and PE for this 20 STR system were > 0.9999999999 and > 0.99999996593% in all five population samples, respectively. Analysis of molecular variance (AMOVA) of these Mexican population samples, plus Monterrey (Northeast) and Mexico (Center) Cities, showed low but significant differences among Mexican-Mestizos from the seven populations (Fst = 0.20%; p = 0.0000). Structure analysis showed the highest proportion of Native American ancestry in Mexico City, Center, and Southeast regions, respectively, which was in agreement with the estimated genetic distances represented in a MDS plot and a NJ tree. The best fit of population clusters (K = 4) obtained with the Structure software indicates that Mexican-Mestizos are mainly composed by European, African, and two Native American ancestries. The European and Native American ancestries displayed a contrary gradient, increasing toward the North-West and South-Southeast, respectively. These 20 autosomal STR loci improved the admixture estimation regarding previous studies with the 13 CODIS-STRs, as supported by the higher similarity with previous estimates based on genome-wide SNP. In brief, this study validates the confident use of the PowerPlex® 21 system for human identification purposes in Mestizo populations throughout the Mexican territory.

Regional subsidence of Mexico City and its effects on seismic response

The Acambay earthquake of 1912 ( M ∼7.0), which occurred in the central Trans-Mexican Volcanic Belt (CTMVB) about 100 km west–northwest of Mexico City, has been thought to be a critical scenario event in the estimation of seismic hazard of the city. We use seismograms of two small earthquakes located near Actopan (15 December 2003; 18 May 2010) and recorded at station CUIG, a hill-zone site in Mexico City, as empirical Green’s functions (EGFs) for the Acambay region. Because Actopan, like Acambay, is situated in the CTMVB and both are located at about the same distance from CUIG, the use of the recordings of the Actopan earthquakes as EGFs is partly justified. We first analyze data of the two small earthquakes at a local station, DHIG, to estimate their seismic moment and stress drop. As there is considerable uncertainty in the estimated stress drops of the two events, we choose a reasonable range of values for them and apply a technique of random summation of EGFs to simulate ground motion at CUIG from a postulated M w 7 earthquake. The estimated geometric mean horizontal peak ground acceleration (PGA) and peak ground velocity (PGV) at CUIG range from 2.7 to 9.7 cm/s 2 and from 1.1 to 3.0 cm/s, respectively. Ground-motion maps for the entire city are presented using a simulated trace at CUIG and the known transfer functions of many sites within the city. The results are consistent with reported seismic intensities in Mexico City, and PGA and peak ground displacement (PGD) at a 2-s period at the seismic station of Tacubaya during the Acambay earthquake. Estimated ground motions suggest that a repeat of the event does not present significant hazard to Mexico City.

The Trans-Mexican volcanic belt is an active volcanic arc related to subduction along the Middle America trench and characterized by shallow seismicity and synvolcanic to postvolcanic extensional arc-parallel faulting. The Mezquital graben is a major intra-arc basin of the central Trans-Mexican volcanic belt. A doublet of moderate shallow shocks occurred in March and October 1976 in the region of this graben. These earthquakes were recorded by the Mexican National Seismological network, in particular, by the Bosch-Omori seismograph ( T = 18 sec) at the Tacubaya Observatory in Mexico City. We have carefully relocated the two main shocks and their major aftershocks by reading the original records and using a modified crustal velocity model for this region. A difference of ∼50 km is observed between the locations reported by the Mexican Seismological Service and those obtained in this study, which are additionally supported by the damage distribution of these earthquakes. A first-motion analysis, based on regional and teleseismic records, defines for the March and October shocks normal fault mechanisms, characterized by east–west-striking fault planes, which coincides with the orientation of the master faults of the Mezquital graben. After calculating the instrumental response, the source parameters were obtained from the Bosch-Omori seismograph records by body-wave modeling. For the March earthquake, we estimate a seismic moment of 4.5 × 1023 dyne cm (equivalent to M w 5.0) and a stress drop of 0.7 MPa, assuming a circular rupture model (radius, 3 km). Given the poor quality of the Bosch-Omori record for the October earthquake, we used comparison with the March event of long-period ( T = 20 sec) teleseismic records at two stations to obtain corresponding source parameters for the October event. By assuming a similar stress drop as for the March event, we obtain a M of 5.6 × 1023 dyne cm and M w 5.1 with a rupture length of 6.5 km. According to gravity data, the regional east–west faults are longer than reported. In particular, our detailed measurements indicate that the master fault of the Mezquital graben continue westward in the subsurface below the basin fill. In a more regional context, additional magnetic data suggest that the El Mezquital graben and Aljibes half-graben might be connected at their southern limits by part of the same fault system. This is the first earthquake doublet reported from central Mexico and the biggest seismic event in that zone during the past 50 years. From a physical point of view, it is possible that the seismic energy released by the March event was partially transferred toward the east, triggering the October shock further east on the same fault system. The presence of moderate seismicity in this zone should therefore be taken into account when assessing its seismic hazard.

The Indian Ocean Nodule Field: petrotectonic evolution and ferromanganese deposits

The Chalco sub-basin, the hydrogeological reserve of Mexico City, is located in the southern portion of Mexico City's basin, an intramontane valley located at 2200 m a.s.l. in the Trans-Mexican Volcanic Belt (Central Mexico). Several geophysical studies (dc resistivity, seismic refraction, gravity, well-logging) have been conducted in this area. The objectives of these independent surveys were different and of regional and local scopes. This study represents the first comprehensive effort to assimilate and interpret the data available to date from the area of the Chalco sub-basin and to infer its main basinal characteristics. According to the topography we obtained of the basement, a northeast-southwest structural high separates the sub-basin into two portions. The western portion is asymmetric and deeper than the eastern one. An east-west half graben-like structure is located in the western portion. This structure could make possible an east-west fluid flow at depth, and it also implies a differential subsidence. It was also possible to establish the stratigraphy of the volcano-sedimentary infill. The gravity models give the interface: (1) between lacustrine sediments (aquitard) and the granular aquifer and (2) between the granular aquifer and the basaltic container. The resistivity boundaries correspond to the contact zone between saline and fresh water in the aquitard and semiconfined aquifer respectively, and they correlate with the existence of a vertical flow of saline fluids from the aquitard to the aquifer. The estimate of the volume of fluids contained in the granular aquifer range between 2 and 5km3.

This study examined customers’ perception and patronage level of ABC Transport Shuttle Services in relation to the service failure(s) recorded in the recent past. A survey research was conducted using 386 respondents drawn from the past, present and potential customers of the company in Owerri, Uyo, Calabar, Onitsha, Warri, Port Harcourt, Enugu, Aba and Umuahia. Structured questionnaire were administered on these passengers while an oral interview was conducted with the ABC General Shuttle Manager. The study revealed that major areas of service failure in ABC Shuttle services include poor adherence to scheduled departure time(s), unfriendly system resulting from glaring service failures, delay in service delivery, aging buses and poor service failure management efforts. The study recommended among others, total overhauling of the shuttle system, strict adherence to scheduled departure(s) as well as periodic training of staff on effective customer relationship management and timely, efficient/effective service delivery.

Nigeria environment today is being confronted with myriads of ecological problems, which have resulted in serious degradation of many watersheds. These environmental problems are occurring at increasing and alarming rates and are being accelerated by man’s activities such as urbanization, increased agricultural activities, deforestation, bush burning, civil construction works, over-grazing and poor water resource management among others. These land-use transformation activities most times disrupt the natural processes of a basin thus triggering the occurrence of accelerated erosion, sedimentation, slope failure, flooding, drought, desert encroachment and pollution. Response to these problems in the recent past in the country has not been good, hence this paper. Effective and efficient basin management is a perquisite for reduction of natural disasters and achievement of sustainable development.

China had implemented the national strategies for Major Function-oriented Zones (MFOZs) to realize the goal of national sustainable development since 2010. This study analyzed and compared spatio-temporal characteristics and differences in built-up area for China’s MFOZs using a China’ s Land Use Database (CLUD) derived from high-resolution remotely sensed images in the periods of 2000–2010 and 2010–2013. To sum up: (1) The percentage of built-up area in each of the MFOZs was significantly different, revealing the gradient feature of national land development based on the distribution of the main functions. (2) Annual growth in built-up area in optimal development zones (ODZs) decreased significantly during 2010–2013 compared with the period 2000–2010, while annual growth in built-up area in key development zones (KDZs), agricultural production zones (APZs) and key ecological function zones (KEFZs) increased significantly. (3) In ODZs, the average annual increase in built-up area in the Yangtze River Delta region was significantly higher than in other regions; the average area increase and rate of increase of built-up area in KDZs was faster in the western region than in other regions; average annual area growth of built-up area in APZs in the northeast, central and western regions was twice as high as the previous decade on average; the annual rate of change and increase in the dynamic degree of built-up area were most notable in KEFZs in the central region. (4) The spatial pattern and characteristics of built-up area expansions in the period 2010–2013 reflected the gradient feature of the plan for MFOZs. But the rate of increase locally in built-up area in ODZs, APZs and KEFZs is fast, so the effective measures must be adopted in the implementation of national and regional policies. The conclusions indicated these methods and results were meaningful for future regulation strategies in optimizing national land development in China.

Objective: To analyze data prospectively collected from Mexican-mestizo patients who participated in randomized clinical trials between 2000-2016 in Mexico City. Results: Only data from 100 patients is presented. Idiopathic (iPAH, 60%), connective tissue disease PAH (CTD, 15%) and congenital heart disease-PAH. The latter was divided in corrected(12%) and non-corrected patients(n=13). 2% of iPAH were vasoresponders. Median age at RHC was 29 years, but iPAH and CTD tended to be older. BMI was 23.84 with no differnece between groups. Thyroid disorders were most frequent co-morbidity. In RHC, mPAP was signficantly higher in congenital-PAH group than other types. iPAH had lowest median cardiac output. 22% of patients were diagnosed before 2000, but only 6.1% treated with nifedipine before 1998. All patients received PAH pharmacotherapy, but time from diagnostic RHC to first use of drug was significantly different between and within groups. Endothelin receptor antagonists were most frequent drug used, followed by PDE-5 inhibitor. Except for CTD-PAH, significant improvement in functional class was found for all groups within 1-year after treatment. 30-53% received combination therapy. Corrected congenital-PAH had longest median time until addition of second drug, followed by iPAH and CTD. 10-40% had a drug class switch due to lack of supply, end of randomized or extended open-label trial phase. Cumulative survival from drug start to death (or censored at last oupatient visit) for 1,3,5 and 10 years were as follows: iPAH excluding vasoresponders (100%,95%,93%,87%), CTD (77%,66%,55%,0%) and corrected-congenital PAH (100%,92%,83%,75%). All Eisenmenger9s remain alive.

El objetivo del artículo es analizar la estructura productiva de la región centro de México, su desempeño económico y los cambios principales en el periodo 2003-2011. A partir de una matriz regional de insumo-producto, estimada para 2003, se identifican los clusters sectoriales mediante el método de componentes principales; de los seis encontrados destacan los de servicios avanzados y al consumidor, concentrados sobre todo en Ciudad de México. Aunque la metodología empleada sólo se basa en la fortaleza de las transacciones intersectoriales de compraventa, este análisis permite revelar las formas de organización económica y empresarial que tienen lugar en la región, para afrontar las presiones competitivas sobre su desarrollo y crecimiento económico.

Twin precast, pretensioned concrete bridges were recently built over Tlalpan Freeway - in one of Mexico City's most densely populated areas. Designed for a clear span of 170 (52 m) over a major freeway, they bring a new dimension to bridges for heavy traffic urban areas in seismic zones. Each of the twin gridgees consists of three longitudinal girders with a total length of 1539 ft (469 m). Each girder comprises 13 pretensioned elements of hollow box cross section with two upper flanges. The substructure consists of cast-in-place columns supported on a foundation of casst-in-place caissons and precast, reinforced concrete piles. Seismic forces are resisted by longitudinal frames integrating columns with main support elements, and by transverse reinforced concrete beams.