Fitoplancton en costas occidentales de Baja California en dos temporadas distintas de 1998

Phytoplankton was studied in two different seasons of 1998 (March-April and December), during two cruises along the western coasts of Baja California, in three zones. Two different protocols for obtaining and studying phytoplankton were followed. In the March-April season, phytoplankton had relatively low species richness and was dominated in cell density (up to 93%) by coccolithophorids (mainly Emiliania huxleyi), together with nanoplanktonic centric and pennate diatoms, with abundances ranging from 5.4 103 to 1.2 105 cells L-1. In December, phytoplankton had higher species richness and was represented by larger, chain-forming diatom species, such as Pseudonitzschia delicatissima and P. pungens, which were widespread and numerically significant. There was a relative scarcity of coccolithophorids and thecate dinoflagellates, and densities were between 7 102 and 1.4 106 cells L-1. Hydrographic and oceanographic conditions in March-April were influenced by the occurrence of El Niño and the phytoplankton structure was found to be modified accordingly, with nanoplanktonic coccolithophorids and diatoms being significant contributors to the total abundance. In contrast, post-upwelling conditions might have favoured relatively high densities of Pseudonitzschia and other diatoms in December, 1998. Coccolithophorids have not been previously regarded as important contributors to the phytoplankton abundances in Baja California.Se estudió el fitoplancton en dos temporadas diferentes de 1998 (marzo-abril y diciembre), durante dos cruceros en tres zonas de las costas de Baja California. Se siguieron dos protocolos distintos para obtener y estudiar el fitoplancton. En marzo-abril, el fitoplancton tuvo una riqueza de especies baja y estuvo dominado en densidades celulares (de hasta 93%) por cocolitofóridos (principalmente Emiliania huxleyi), junto con diatomeas centrales y pennales nanoplanctónicas, con abundancias desde 5.4 103 to 1.2 105 cells L-1. Para diciembre, el fitoplancton incrementó la riqueza de especies y estuvo representado por diatomeas más grandes, formadoras de cadenas, que se distribuyeron ampliamente y fueron numéricamente importantes, como: Pseudonitzschia delicatissima y P. pungens, con relativa escasez de cocolitofóridos y dinoflagelados tecados, con densidades entre 7 102 and 1.4 106 cells L-1. Las condiciones oceanográficas en marzo-abril indicaron la presencia de El Niño y los resultados mostraron una estructura de fitoplancton modificada por ello, con una contribución importante de cocolitofóridos y diatomeas nanoplanctónicas a la abundancia total. En cambio, en diciembre, las condiciones de post-surgencia pudieron haber favorecido las relativas altas densidades de especies de Pseudonitzschia y otras diatomeas. Los cocolitofóridos no habían sido documentados previamente como contribuyentes importantes a la abundancia fitoplanctónica en Baja California

Marea roja producida por el dinoflagelado Peridinium quinquecorne en Veracruz, México (oct-nov, 2002): morfología del agente causal.

In late October, 2002, a red tide was observed along the shore of the Port of Veracruz. Water samples were collected with bottle and fixed with lugols solution. Twelve days later a second set of samples was collected. In addition water temperature, dissolved oxygen and salinity measurements were taken from four stations. Species were identified with a Light microscope, and cells were counted using an inverted microscope, following the Utermöhl method. The species responsible, the armored dinoflagellate Peridinium quinquecorne Abé 1927, was studied in detail with scanning electron microscope, which showed a high morphological variation, mainly in both shape and size of the cell . The highest cell density reached to 2.5 x 106 cells l-1. The second samples set showed a notable decrease in the cell density of P. quinquecorne, which dropped to 4 975 cells l-1; other species occurring with lower densities were Dinophysis caudata and Pseudonitzschia spp., and surface temperature, salinity and dissolved oxygen were 26.3° C, 34 psu and 6.5 mg·l-1, respectively. Strong winds and cloudy sky were also recorded. No fish killings, odors or irritation were reported. This is the first report of a red tide caused by P. quinquecorne in Veracruz. As in other parts of the world no harmful effects were observed.A finales de octubre se observó una marea roja en la costa del Puerto de Veracruz. Se colectaron muestras superficiales de agua que se fijaron con acetato-lugol. Doce días después se efectuó un segundo muestreo en cuatro estaciones, además se midieron temperatura, oxígeno y salinidad. Las especies se identificaron con microscopio de luz, y se cuantificaron en microscopio invertido con el método Utermöhl, y en microscopio electrónico de barrido se confirmó la identidad del dinoflagelado tecado Peridinium quinquecorne Abé 1927, el cual mostró una alta variación morfológica, principalmente en forma y tamaño. La especie alcanzó una densidad de 2.5 x 106 cels l-1. En el segundo muestreo las concentraciones de P. quinquecorne descendieron hasta 4 975 cels l -1, otras especies ocurrieron en menores densidades, como fueron Dinophysis caudata y Pseudonitzschia spp; los valores de temperatura, salinidad y oxígeno disuelto fueron: 26.3°C, 34 ups y 6.5 mg l-1, respectivamente; se registraron vientos fuertes y cielo nublado. No hubo mortandad de peces, olores o irritación. Este es el primer registro de marea roja causada por P. quinquecorne en Veracruz donde, similar a otras partes del mundo, no fue nocivo

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Search for invisible decays of the Higgs boson produced via vector boson fusion in proton-proton collisions at s\sqrt{s} = 13 TeV

A search for invisible decays of the Higgs boson produced via vector boson fusion (VBF) has been performed with 101  fb$^{-1}$ of proton-proton collisions delivered by the LHC at $\sqrt{s}$ =13  TeV and collected by the CMS detector in 2017 and 2018. The sensitivity to the VBF production mechanism is enhanced by constructing two analysis categories, one based on missing transverse momentum and a second based on the properties of jets. In addition to control regions with Z and W boson candidate events, a highly populated control region, based on the production of a photon in association with jets, is used to constrain the dominant irreducible background from the invisible decay of a Z boson produced in association with jets. The results of this search are combined with all previous measurements in the VBF topology, based on data collected in 2012 (at $\sqrt{s}$ =8  TeV), 2015, and 2016, corresponding to integrated luminosities of 19.7, 2.3, and 36.3  fb$^{-1}$, respectively. The observed (expected) upper limit on the invisible branching fraction of the Higgs boson is found to be 0.18 (0.10) at the 95% confidence level, assuming the standard model production cross section. The results are also interpreted in the context of Higgs-portal models

Observation of the Bc+_\mathrm{c}^+ Meson in Pb-Pb and pp Collisions at sNN\sqrt{s_{\mathrm{NN}}} = 5.02 TeV and Measurement of its Nuclear Modification Factor

The B$_\mathrm{c}^+$ meson is observed for the first time in heavy ion collisions. Data from the CMS detector are used to study the production of the B$_\mathrm{c}^+$ meson in lead-lead (Pb-Pb) and proton-proton (pp) collisions at a center-of-mass energy per nucleon pair of $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV , via the B$_\mathrm{c}^+$ → (J/ψ → μ$^+$μ$^−$)μ$^+$ν$_μ$ decay. The B$_\mathrm{c}^+$ nuclear modification factor, derived from the PbPb-to-pp ratio of production cross sections, is measured in two bins of the trimuon transverse momentum and of the PbPb collision centrality. The B$_\mathrm{c}^+$meson is shown to be less suppressed than quarkonia and most of the open heavy-flavor mesons, suggesting that effects of the hot and dense nuclear matter created in heavy ion collisions contribute to its production. This measurement sets forth a promising new probe of the interplay of suppression and enhancement mechanisms in the production of heavy-flavor mesons in the quark-gluon plasma

Inclusive nonresonant multilepton probes of new phenomena at s\sqrt{s}= 13 TeV

An inclusive search for nonresonant signatures of beyond the standard model (SM) phenomena in events with three or more charged leptons, including hadronically decaying τ leptons, is presented. The analysis is based on a data sample corresponding to an integrated luminosity of 138 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$= 13 TeV collected by the CMS experiment at the LHC in 2016–2018. Events are categorized based on the lepton and b-tagged jet multiplicities and various kinematic variables. Three scenarios of physics beyond the SM are probed, and signal-specific boosted decision trees are used for enhancing sensitivity. No significant deviations from the background expectations are observed. Lower limits are set at 95% confidence level on the mass of type-III seesaw heavy fermions in the range 845–1065 GeV for various decay branching fraction combinations to SM leptons. Doublet and singlet vectorlike τ lepton extensions of the SM are excluded for masses below 1045 GeV and in the mass range 125–150 GeV, respectively. Scalar leptoquarks decaying exclusively to a top quark and a lepton are excluded below 1.12–1.42 TeV, depending on the lepton flavor. For the type-III seesaw as well as the vectorlike doublet model, these constraints are the most stringent to date. For the vectorlike singlet model, these are the first constraints from the LHC experiments. Detailed results are also presented to facilitate alternative theoretical interpretations

Search for high-mass resonances decaying to a jet and a Lorentz-boosted resonance in proton-proton collisions at √s = 13 TeV

A search is reported for high-mass hadronic resonances that decay to a parton and a Lorentz-boosted resonance, which in turn decays into a pair of partons. The search is based on data collected with the CMS detector at the LHC in proton-proton collisions at , corresponding to an integrated luminosity of 138. The boosted resonance is reconstructed as a single wide jet with substructure consistent with a two-body decay. The high-mass resonance is thus considered as a dijet system. The jet substructure information and the kinematic properties of cascade resonance decays are exploited to disentangle the signal from the large quantum chromodynamics multijet background. The dijet mass spectrum is analyzed for the presence of new high-mass resonances, and is found to be consistent with the standard model background predictions. Results are interpreted in a warped extra dimension model where the high-mass resonance is a Kaluza–Klein gluon, the boosted resonance is a radion, and the final state partons are all gluons. Limits on the production cross section are set as a function of the Kaluza–Klein gluon and radion masses. These limits exclude at 95% confidence level models with Kaluza–Klein gluon masses in the range 2.0 to 4.3 TeV and radion masses in the range 0.20 to 0.74 TeV. By exploring a novel experimental signature, the observed limits on the Kaluza–Klein gluon mass are extended by up to about 1 TeV compared to previous searches