Faunal mortality associated with massive beaching and decomposition of pelagic Sargassum.

In 2018, the Mexican Caribbean coast received a massive influx of pelagic Sargassum spp. that accumulated and decayed on beaches producing organic decomposition products that made the water turbid and brown. Between May and September of the same year there were several reports of mass mortality of marine biota in this area. From these reports we estimate that organisms belonging to 78 faunal species died as result of this event, with demersal neritic fish and Crustacea being the most affected groups. The cause of mortality appears to be the combined effect of high ammonium and hydrogen sulfide concentrations, together with hypoxic conditions. If massive arrival of pelagic Sargassum spp. continues and algae is left to decay on the beach in large volumes then deterioration in water quality could affect coral reefs close to shore. Furthermore, barriers placed in lagoons to intercept the Sargassum spp. before it reaches the beach could impact reef fauna if the algae is left to die and sink on site.

Extended gamma-ray sources around pulsars constrain the origin of the positron flux at Earth.

The unexpectedly high flux of cosmic-ray positrons detected at Earth may originate from nearby astrophysical sources, dark matter, or unknown processes of cosmic-ray secondary production. We report the detection, using the High-Altitude Water Cherenkov Observatory (HAWC), of extended tera-electron volt gamma-ray emission coincident with the locations of two nearby middle-aged pulsars (Geminga and PSR B0656+14). The HAWC observations demonstrate that these pulsars are indeed local sources of accelerated leptons, but the measured tera-electron volt emission profile constrains the diffusion of particles away from these sources to be much slower than previously assumed. We demonstrate that the leptons emitted by these objects are therefore unlikely to be the origin of the excess positrons, which may have a more exotic origin.

The Most Common HLA Antigens Found in Patients With Renal Transplants at the Specialties Hospital of "La Raza" Medical Center, Mexico.

BACKGROUND: The knowledge to understand transplant acceptance or rejection derives directly from knowing its genetic material and the major histocompatibility complex involved in immune response, so it is essential to identify the most common alleles in the Mexican population. METHODS: In the northern areas of the Federal District (DF), Hidalgo, and Mexico State, we performed an analysis of HLA class I (A and B) and HLA class II (DRß1 and DQß1) with the use of the PCR-SSP process (Invitrogen). We performed measures of central tendency and percentages of common alleles in the study population. RESULTS: We analyzed 718 results of patients before renal transplantation: 313 pairs of recipients and living donors and 92 patients receiving cadaveric donation. HLA allele A 02 536 (37.32%) was the most common allele found. In HLA B, the most common allele corresponded to 35, in 321 (22.35%), which was the most polymorphic. In HLA DRß1 the most common was 04, in 447 (31.12%), which was the least polymorphic; the most common was 03, in 777 (54.10%). CONCLUSIONS: We corroborated the frequency of alleles found in the considered population, which corresponds to the northern part of Mexico City as well as the states of Mexico and Hidalgo. It was determined that there is no risk allele for developing chronic kidney disease.

Time-of-flight mass measurements for nuclear processes in neutron star crusts.

We present results from time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory that are relevant for neutron star crust models. The masses of 16 neutron-rich nuclei in the scandium-nickel range were determined simultaneously, with the masses of (61)V, (63)Cr, (66)Mn, and (74)Ni measured for the first time with mass excesses of -30.510(890) MeV, -35.280(650) MeV, -36.900(790) MeV, and -49.210(990) MeV, respectively. With these results the locations of the dominant electron capture heat sources in the outer crust of accreting neutron stars that exhibit super bursts are now experimentally constrained. We find the experimental Q value for the (66)Fe→(66)Mn electron capture to be 2.1 MeV (2.6σ) smaller than predicted, resulting in the transition occurring significantly closer to the neutron star surface.

Production and beta decay of rp-process nuclei 96Cd, 98In, and 100Sn.

The beta-decay properties of the N=Z nuclei 96Cd, 98In, and 100Sn have been studied. These nuclei were produced at the National Superconducting Cyclotron Laboratory by fragmenting a 120 MeV/nucleon 112Sn primary beam on a Be target. The resulting radioactive beam was filtered in the A1900 and the newly commissioned Radio Frequency Fragment Separator to achieve a purity level suitable for decay studies. The observed production cross sections of these nuclei are lower than predicted by factors of 10-30. The half-life of 96Cd, which was the last experimentally unknown waiting point half-life of the astrophysical rp process, is 1.03_{-0.21};{+0.24} s. The implications of the experimental T_{1/2} value of 96Cd on the abundances predicted by rp process calculations and the origin of A=96 isobars such as 96Ru are explored.

Z = 50 shell gap near 100Sn from intermediate-energy Coulomb excitations in even-mass 106-112Sn isotopes.

Rare isotope beams of neutron-deficient 106,108,110Sn from the fragmentation of 124Xe were employed in an intermediate-energy Coulomb excitation experiment. The measured B(E2,0(1)(+)-->2(1)(+)) values for 108Sn and 110Sn and the results obtained for the 106Sn show that the transition strengths for these nuclei are larger than predicted by current state-of-the-art shell-model calculations. This discrepancy might be explained by contributions of the protons from within the Z = 50 shell to the structure of low-energy excited states in this region.

Probing shell structure and shape changes in neutron-rich sulfur isotopes through transient-field g-factor measurements on fast radioactive beams of 38S and 40S.

The shell structure underlying shape changes in neutron-rich nuclei near N = 28 has been investigated by a novel application of the transient-field technique to measure the first-excited-state g factors in 38S and 40S produced as fast radioactive beams. There is a fine balance between proton and neutron contributions to the magnetic moments in both nuclei. The g factor of deformed 40S does not resemble that of a conventional collective nucleus because spin contributions are more important than usual.

Quadrupole deformation of the self-conjugate nucleus 72Kr.

We report on the first determination of the absolute B(E2;0+(1)-->2+(1)) excitation strength in the N=Z nucleus 72Kr. 72Kr is the heaviest N=Z nucleus for which this quantity has been measured and provides a benchmark in a region of the nuclear chart dominated by rapidly changing deformations and shapes mediated by the interplay of strongly oblate and prolate-driving orbitals. The deduced quadrupole deformation strength is in agreement with a variety of self-consistent models that predict an oblate shape for the ground state of 72Kr. Large-scale shell-model Monte Carlo calculations reproduce the experimental B(E2) value and link the result to the occupation of the deformation-driving g9/2 orbit.

Especies de dinoflagelados del género Gambierdiscus (Dinophyceae) del Mar Caribe mexicano / Species of dinoflagellates of the genus Gambierdiscus (Dinophyceae) in the Mexican Caribbean Sea

Algunos dinoflagelados de hábitos bénticos están relacionados con la ciguatera, por consumo de pescado, en áreas tropicales. En el Caribe mexicano la ciguatera es un padecimiento relativamente común, sin embargo solo existe un trabajo sobre este tema y muy pocos antecedentes publicados sobre fitoplancton y microalgas bénticas. En este estudio se analizó material recolectado en varios puntos a lo largo de las costas del Estado de Quintana Roo, tanto con red de fitoplancton (54 mm), como de sedimento y epífitas de plantas macroscópicas, para estudiar los dinoflagelados tóxicos y asociados. Se registra la presencia de tres especies del género Gambierdiscus, asociadas con la producción de toxinas causantes de la ciguatera: G. belizeanus, G. toxicus y G. yasumotoi, todas distribuídas en áreas costeras poco profundas, incluyendo lagunas costeras. Las especies han sido estudiadas con microscopía de luz y electrónica de barrido. Para el reconocimiento de las especies se emplearon los caracteres morfológicos usuales, pero eventualmente se pueden usar caracteres fisiológicos, ecológicos y moleculares. La llamada "comunidad ciguatoxigénica" también está formada por especies de los géneros Prorocentrum, Ostreopsis y Coolia, cuyo estudio florístico y taxonómico se recomienda ampliamente, así como investigaciones complementarias de aspectos biológicos, ecológicos, fisiológicos y epidemiológicos de esta comunidad

Some dinoflagellates with benthic habits are related to ciguatera intoxication by fish consumption, especially in tropical areas. In the Mexican Caribbean, ciguatera is relatively common, but only one paper seems to have been published on the subject, and there are very few publicactions on phytoplankton and benthic microalgae. Material collected along the coast of the State of Quintana Roo with phytoplankton net (54 mm) and directly from sediment and epiphytes of macroscopic plants, was searched for toxic and other associated dinoflagellates. Samples were studied by light and scanning electron microscopy. Morphological characters were useful for species identification, but eventually physiological, ecological and molecular characters could also be used. Three species of Gambierdiscus, related to the production of ciguatera toxins, were identified: G. belizeanus, G. toxicus and G. yasumotoi. They are distributed in shallow coastal areas, including coastal lagoons

[Species of dinoflagellates of the genus Gambierdiscus (Dinophyceae) in the Mexican Caribbean Sea]. / Especies de dinoflagelados del género Gambierdiscus (Dinophyceae) del Mar Caribe Mexicano.

Some dinoflagellates with benthic habits are related to ciguatera intoxication by fish consumption, especially in tropical areas. In the Mexican Caribbean, ciguatera is relatively common, but only one paper seems to have been published on the subject, and there are very few publicactions on phytoplankton and benthic microalgae. Material collected along the coast of the State of Quintana Roo with phytoplankton net (54 mm) and directly from sediment and epiphytes of macroscopic plants, was searched for toxic and other associated dinoflagellates. Samples were studied by light and scanning electron microscopy. Morphological characters were useful for species identification, but eventually physiological, ecological and molecular characters could also be used. Three species of Gambierdiscus, related to the production of ciguatera toxins, were identified: G. belizeanus, G. toxicus and G. yasumotoi. They are distributed in shallow coastal areas, including coastal lagoons.

[Volume and function of the right ventricle before and after intraluminal pulmonary valvuloplasty]. / Volúmenes y función del ventrículo derecho pre y postvalvuloplastia intraluminal pulmonar.

With the purpose of studying the right ventricular infundibulum response to the obstruction of the pulmonary blood flow, the authors inform the results of the right ventricular volumes, and function changes before and after pulmonary intraluminal valvuloplasty performed in six adult patients with congenital stenosis of the pulmonary valve. After the valvuloplasty, all right ventricular volumes increased but only slightly, except for the end systolic volume at the right infundibulum, which decreased after valvuloplasty (for alpha = 0.10, p less than 0.10). The ejection fraction of this infundibulum increased after valvuloplasty (for alpha = 0.05 p less than 0.03), while the ejection fraction of the inflow chamber remained unaltered. In the same way decreased the work and power of the inflow tract of the right ventricle, regardless the decreased in the ventricular overload post-valvuloplasty; however, the ratio work vs. end diastolic volume of the right ventricle decreased (for alpha = 0.05, p less than 0.03). The authors discuss these results in relation with the changes produced by the obstruction, acute or chronic, of the pulmonary blood flow on the infundibular wall tension and contractility, whose structure and behavior allow to propose that the function of the infundibulum by means of contraction protects the pulmonary vasculature, against right ventricle hypertension.

Transient expression of 5-HT1A receptor binding sites in some areas of the rat CNS during postnatal development.

The developmental evolution of 5-HT1A receptor binding sites was examined in the rat CNS during the early postnatal period using quantitative autoradiography and binding assays with 3H-8-OH-DPAT as the selective ligand. A progressive increase in the density of 5-HT1A sites was observed in the hippocampus, septum and cerebral cortex, up to adult levels which were reached around the third postnatal week. In contrast, complex biphasic (increase then decrease) changes were noted in other structures (for instance the nucleus of the lateral lemniscus), and even a progressive decrease in the density of 5-HT1A sites took place in the cerebellum during the first two postnatal weeks. The transient expression of 5-HT1A receptor binding sites in a structure such as the cerebellum which develops exclusively for the postnatal period further supports that 5-HT might play a trophic role during maturation of the CNS.

[Cardiac index, oxygen and serum lactate consumption in infants with hypovolemic and septic shock]. / Indice cardíaco, consumo de oxígeno y lactato sérico en lactantes con choque hipovolémico y séptico.

Determination was made of cardiac output (using the stain dilution technique), gases in blood and serum lactate levels in eight infants with hypovolemic shock and sixteen with septic shock. The data were carried to indexes (values per square meter of body surface). In children with hypovolemic shock the cardiac index was 1.88 +/- 0.031/min/m,2 while in septic patients it was 4.02 +/- 1.011/min/m2. The peripheral resistances were 3,079 din/min/cm.5 in hypovolemic cases and 907 din/min in the septic. In both groups serum lactante levels rised close to 4 mM 61. Oxigen consumption was found low in hypovolemic patients and slightly high in the septic. It is concluded that our data are similar to those reported in similar studies in adults and hypodynamic shock is shown in hypovolemic patients, while hyperdynamic shock appears in septic cases.

[Salicylate poisoning. Determination of the free fraction using the ultrafiltration method]. / Intoxicación por salicilatos. Determinación de la fracción libre por método de ultrafiltrado.

Seventeen infants under one year of age admitted to the Emergency Service of the General Hospital of the Medical Center La Raza during the year 1976 were included in this study with the diagnosis of salicylate poisoning. Determination of plasma salicylate by the ultrafiltrate method was practiced to all patients. A direct relationship between total plasmatic salicylate and its free fraction was found together with an inverse proportion between percentage of total free--salicylate and plasma pH and a lineal correlation between plasma free--salicylate and salicylate obtained in spinal fluid. It is concluded that determination of the free fraction of plasma salicylate is an easy diagnostic method for the better evaluation of salicylate acid poisoning in the infant.

[Blood coagulation disorders in infants with infectious gastroenteritis]. / Alteraciones de la coagulación en lactantes con gastroenteritis infecciosa.

The study included 28 infants with infectious gastroenteritis who evolved with disturbances of coagulation and in whom laboratory tests were practiced by micromethods through capillary puncture. The most frequently seen abnormality was a combination of vitamin K dependent factors deficiency with thrombocytopenia. Another observation in our study is that hypofibrinogenemia in infants with infectious gastroenteritis is not always secondary to disseminated intravascular coagulation. A decrease in fibrinogen in these cases is explained by a lack in synthesis of this factor in infants with malnutrition since out of 16 malnourished infants, 75% evolved with hypofibrinogenemia, while eutrophic infants evolved with normal fibrinogen. The disseminated intravascular coagulation syndrome was seen more frequently in patients with infectious gastroenteritis complicated with septicemia and shock, 57% of the patients did not show manifestations of bleeding nor of thrombosis which justifies in these cases a systematic investigation of the coagulation mechanism.