Vegetation Changes Ten Years after Catclaw Mimosa ( \u3cem\u3e Mimosa laxiflora \u3c/em\u3e ) Control with Tebuthiuron in a Short Grass Prairie at Northern Sonora, Mexico

Catclaw mimosa (Mimosa laxiflora) is a native, perennial half-size brush, which invades short grass prairie and competes with desirable species for water, nutrients and light interferes with cattle grazing and reduces range productivity. Tebuthiuron [1-(5-tert-Butyl-1,3,4-thiadiazol-2-yl)-1,3-dimethylurea; chemical formula C9H16N4OS] is a granular herbicide used to control invasive shrubby species on rangelands with sustainable forage responses (McGinty et al., 2009). Research trials conducted in the Chihuahuan and Sonoran deserts show that tebuthiuron at rates of 0.5 to 1.5 kg a.i./ha effectively controlled most shrubby species and significant increase forage in the Matorral area in Mexico and USA. Local information regarding catclaw mimosa control and forage production increases sustain after bush control in the short grass prairies does not exist. This study was conducted to evaluate vegetation changes after the application of tebuthiuron at rates of 0 and 1.5 kg a.i./ha to control high infestations of catclaw mimosa in the short grass prairies

Effectiveness of Tronador to Control Brittlebush in Buffelgrass Pastures at Central Sonora, México

Buffelgrass (Cenchrus ciliaris L.) is an introduced species which is planted in low productive semi-arid rangelands in northern Mexico to increase productivity and ranchers profit. Brittlebush (Encelia farinosa) is a native half size shrub of low forage value that invades buffelgrass stands. Buffelgrass pastures lose productivity as brittlebush densities increase. Once brittlebush infestations occur plant densities do not decline unless brush control practices are applied. Mechanical treatments are mainly used when grass seeding is needed. Prescribed burning and manual control as well as granular herbicides have resulted on good plant control. Most liquid herbicides are either not as effective for plant control or not economically feasibles. Tronador is a new released herbicide but no data is available for its use. This study was conducted to evaluate several doses of Tronador to control brittlebush infestations and measure buffelgrass forage responses

Vegetation Changes Following Biosolids Applications at an Old Boer Lovegrass Pasture in Northern Sonora, México

Short grass prairies (Bouteloua-Aristida) are the main vegetation type in northern Sonora, México, however, factors such as land fragmentation, overgrazing, severe droughts and lack of infrastructure in most ranches poor grazing management has caused land degradation. Boer lovegrass (Eragrostis curvula var. conferta) is an introduced species planted to increase productivity on deteriorated rangelands. Forage production with Boer lovegrass increases two to three fold as compared to native grasses after range seeding but productivity declines as stands become old. Biosolids have been recognized as a useful soil amendment and source of nitrogen, phosphorus, organic matter and other nutrients, which can enhance soil physical properties as well as plant yield (US Environmental Protection Agency 1999, Kinney et al. 2006). These organic compounds of human origins may play an important role in rangelands increasing soil fertility, however data do not exist to justify its use in México. This study was conducted to evaluate forage responses of old Boer lovegrass stands to biosolids applications

\u3cem\u3eAcacia cochliacantha\u3c/em\u3e Control in Buffel Grass Pastures at Alamos, Sonora, Mexico

Chirahui (Acacia cochliacantha) is an aggressive tall-shrub which invades buffelgrass (Cenchrus ciliaris L.) in the short jungle area of Southern Sonora, Mexico. As brush invasion takes over the pastures buffelgrass forage production declines and spiny brush species interferes with cattle grazing (Martin et al., 1995). Manual brush control practices are common in the area but are normally ineffective because plants re-sprout back and reinvade pastures. Tordon 101 herbicide (64.0 g a.i./l Picloram + 240.0 g a.i/l 2,4-D) has been widely used for brush control in northern Mexico but it is expensive and is planned to go out of the market soon. Prado herbicide (621.3 g a.i./kg. Amynopyralid + 94.5 g a.i./kg. Metsulfuron metil) is a new and economic product released from Dow Agrosciences in Mexico but no local data is available for its use. This study was conducted in summer of 2011 to evaluate the efficiency of Prado herbicide and manual control by machete to reduce chirahui populations

Leaf Blast \u3cem\u3e Pyricularia grisea \u3c/em\u3e Effects on Buffelgrass Forage and Seed Production in Northwestern Mexico

Common buffelgrass Cenchrus ciliaris (T-4464) is an introduced species intensively planted in Mexico to increase productivity on rangelands. Studies have shown that the species produces 5 to 10 times more forage as compared to native species on rangelands (Martin et al., 1995). Previous studies in the Gulf of Mexico have shown that the fungus Pyricularia grisea causes a disease in buffelgrass known as leaf blight and induce serious damage to the plant affecting forage production and nutritive quality (Ocumpaugh and Rodríguez, 1998; González, 2002). Injuries begin in the inferior leafs as small dark stains that later are converted in injuries bronze color of round and elliptic form, necrotic, with dark red margins and with a chlorotic yellow halo (Rodriguez et al., 1999). A high humidity and temperature condition in the Pacific Northwest during the last years is believed to be creating ideal conditions for Pyricularia which is suspected to affect buffelgrass. Currently, no data are available in this region to confirm fungus presence and its impact on forage and seed productivity on buffelgrass pastures. The study was conducted at north central Sonora, Mexico to: a) evaluate the incidence and damage intensity of Pyricularia grisea in buffelgrass pastures and b) to determine its impact on forage and seed production

Morphology and magnetic properties of W-capped Co nanoparticles

3 páginas, 3 figuras, 2 tablas.-- et al.Co–W nanoparticles formed by sequential sputtering of Co on amorphous alumina substrate and subsequent W capping are studied by high resolution and by scanning transmission electron microscopies, and by superconducting quantum interference device magnetometry. The analysis is focused on W nominal thickness dependence. Results suggest the formation of amorphous Co–W alloy nanoparticles, whose magnetic moment per Co atom is systematically reduced as the nominal thickness of W capping layer increases. The Co–W nanoparticles show superparamagnetic behavior. The activation energy for moment reversal and the effective anisotropy are obtained.The financial support of MAT08/1077 is acknowledged. A. I. Figueroa acknowledges a JAE-Predoc grant.Peer reviewe

Las hormonas sexuales modulan el crecimiento renal compensador (CRC) y la función renal en la uninefrectomía (uNx)

The role played by sexual hormones and vasoactive substances in the compensatory renal growth (CRG) that follows uninephrectomy (uNx) is still controversial. Intact and gonadectomized adult Wistar rats of both sexes, with and without uNx, performed at 90 days age, were studied at age 150 days. Daily urine volume, electrolyte excretion and kallikrein activity (UKa) were determined. Afterwards, glomerular filtration rate and blood pressure were measured, the kidneys weighed and DNA, protein and RNA studied to determine nuclei content and cell size. When the remnant kidney weight at age 150 days was compared with the weight of the kidney removed at the time of uNx, male uNx rats showed the greatest CRG (50%) while growth in the other uNx groups was 25%, 15% and 19% in orchidectomized, female and ovariectomized rats, respectively. The small CRG observed in the uNx female rats was accompanied by the lowest glomerular filtration value, 0.56 ± 0.02 ml/min/g kwt compared, with the other uNx groups, p < 0.05. Cell size (protein or RNA/DNA) was similar for all the groups except for uNx orchidectomized rats. In this group the cytoplasmatic protein or RNA content was lower than in the other groups while DNA (nuclei content) was similar. Some degree of hyperplasia was determined by DNA content in the uNx groups. Male sexual hormones positively influenced CRG and its absence modulated cell size. Female sexual hormones, instead, did not appear to stimulate CRG. The kallikrein kinin system may not be involved in CRG.La importancia que pueden tener las hormonas sexuales y sustancias vasoactivas sobre el crecimiento renal compensador (CRC) que sigue a la uninefrectomía es aún materia de debate. Se estudiaron ratas Wistar de ambos sexos, a los 150 días de vida, intactas y gonadectomizadas con y sin uNx, realizada a los 90 días de vida. Se midió volumen urinario diario y excreción de electrolitos y actividad de kalikreína urinaria. Se midió filtrado glomerular y presión arterial media extrayéndose luego los riñones que fueron pesados y preparados para estudios histológicos y determinación de ADN, ARN y proteínas para estimar contenido nuclear y tamaño celular. El CRC fue calculado comparando el peso del riñón al momento de las uNx (90 dias de vida) con aquel obtenido a los 150 días de vida. En las ratas macho uNx se observó el mayor CRC (50%) mientras que, en los otros grupos uNx solo alcanzó un 25%, 15% y 19%. El filtrado glomerular acompañó los cambios morfológicos observándose el menor filtrado en las ratas hembras uNx respecto al resto de los grupos 0.56 ± 0.02, p < 0.05. El tamaño celular (proteína o ARN/ ADN) fue similar para todos los grupos excepto para los orquidectomizados uNx, cuyo contenido citoplasmático fue menor. El contenido nuclear (ADN) fue semejante en todos los grupos. Se observó que el CRC está influenciado positivamente por las hormonas sexuales masculinas y su ausencia modula el tamaño celular. La falta de hormonas sexuales femeninas, en cambio, afecta negativamente el CRC. El sistema kalikreína kinina no parecería estar involucrado en el CRC.Fil: Azurmendi, Pablo Javier. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Investigaciones Medicas; ArgentinaFil: Oddo, Elisabet M.. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Investigaciones Medicas; ArgentinaFil: Toledo, Jorge E.. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Investigaciones Medicas; ArgentinaFil: Martin, Rodolfo Santiago. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Investigaciones Medicas; ArgentinaFil: Ibarra, Fernando R.. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Investigaciones Medicas; ArgentinaFil: Arrizurieta, Elvira. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Investigaciones Medicas; Argentin

Nutritive Value and Cattle Preferences in an Old Boer Lovegrass Stand Treated with Biosolids in Cananea, Sonora, México

Boer lovegrass (Eragrostis curvula var. conferta) is an introduced species planted to increase productivity on deteriorated rangelands in northern Mexico. Forage production with Boer lovegrass achieves an increase of two to three fold when compared to native grasses, however, as stands became old, pasture productivity and forage quality declines due to a reduction in available nutrients causing a reduction in grazing capacity and beef production. Previous studies have shown that biosolids enhance seedling establishment, plant growth and increases forage production in the species, but no data is available to measure changes in forage quality and animal performance. This study was conducted to evaluate pasture nutritive value and cattle preferences on a 15 year old Boer lovegrass stand three summers following biosolids application

Profitability of Early Weaning of Beef Cows at Northern Sonora, Mexico: A Rancher Experience

Amount and distribution of precipitation is normally inadequate and uncertain in arid and semiarid Sonoran Desert rangelands. Low precipitation reduces forage quality and quantity and it can negatively influence livestock yield reducing milk production and calf gains. Early removal of the calf from its dam reduces forage needs of the cow-calf enterprise and has been found to improve body weight gain and pregnancy rates in the cow herd (Mulliniks et al., 2013). Additionally, weaning calves early can result in improved animal performance by increasing pregnancy rates, cow body condition scores and increased steer carcass quality while reducing forage needs of the cow-calf enterprise. Under normal conditions, a cow must yield a calf every year to be economically profitable so care should be taken in animal and range management to accomplish these goals. Blanco et al., (2009), reported that income received for early weaned calves may be greater than traditionally weaned calves. Previous studies in Mexico have shown that early weaning is a practical tool for calf production; however, local information regarding performance of cows following early weaning does not exist. The objectives of this study were to evaluate the effect of early and normal weaning of calves on cows performance, percent pregnancy, calving interval and total profitability

Influence of Polymorphisms Involved in Platelet Activation and Inflammatory Response on Aspirin-Related Upper Gastrointestinal Bleeding: A Case-Control Study

Background: Despite the wide benefits of aspirin and its cost-effectiveness, aspirin prescriptions have been reduced due to idiosyncratic responses in susceptible individuals. Low-dose aspirin and single-nucleotide polymorphisms (SNPs) are independently associated with increased risk of gastrointestinal hemorrhage; however, to-date, no studies investigated the SNP-aspirin interaction effect on upper gastrointestinal hemorrhage (UGIH). Therefore, we aimed to evaluate the role of 25 SNPs in multiple genes involved in platelet activation, angiogenesis and inflammatory response in aspirin-related UGIH. Methods: A multicenter, full case-control study was conducted in patients exposed and unexposed to aspirin. Three hundred twenty-six cases diagnosed with UGIH were matched with 748 controls (1:3) by age, gender, health center, and recruitment date. Only adults of European origin were included. Participants were stratified by aspirin exposure and genotype [(Aspirin(-), wild-type), (Aspirin(+), wild-type), (Aspirin(+), genetic variation), (Aspirin(-), genetic variation)]. For each SNP, the Odds Ratio of UGIH and their 95% confidence intervals were estimated in each subgroup by using the generalized linear mixed models for dependent binomial variables. SNP-aspirin interaction effect was estimated through Relative Excess Risk due to Interaction (RERI) measures. Results: We observed two categories of SNPs that might modify the risk magnitude of UGIH in aspirin consumers. Seven SNPs (rs1387180 A > G, rs2238631 T > C, rs1799964 T > C, rs5050 T > C/T > G, rs689466 T > C, rs1799983 T > A/T > G, and rs7756935 C > A) were "positive modifiers" associated with an excess of risk from aspirin exposure and carrying that genetic variation (1.75 T, rs1131882 G > A, rs4311994 C > T, rs10120688 G > A, rs4251961 T > C, rs3778355 G > C, rs1330344 C > T, rs5275 A > G/A > T, and rs3779647 C > T) were "negative modifiers" and associated with a reduced risk in aspirin users (-2.74 </= RERI </= -0.95). Conclusion: This preliminary study suggests that polymorphisms in genes involved in platelets activity, angiogenesis and inflammatory response might modify the risk of aspirin-related UGIH. Further studies with larger sample size and in different populations are needed to confirm our findings. If confirmed, this might have great impact on public health, thanks to aspirin's prophylactic properties in diseases of high incidence and severity