Experimental and Theoretical Investigation of the Reaction of CH with Formaldehyde (CHO) at Very Low Temperatures and Application to Astrochemical Models.

Rate coefficients for the reaction of CH with CHO were measured for the first time over the temperature range of 37-603 K, with the CH radicals produced by pulsed laser photolysis and detected by CH radical chemiluminescence following their reaction with O. The low temperature measurements (≤93 K) relevant to the interstellar medium were made within a Laval nozzle gas expansion, while higher temperature measurements (≥308 K) were made within a temperature controlled reaction cell. The rate coefficients display a negative temperature dependence below 300 K, reaching (1.

Intrinsic and environmental drivers of pairwise cohesion in wild Canis social groups.

Animals within social groups respond to costs and benefits of sociality by adjusting the proportion of time they spend in close proximity to other individuals in the group (cohesion). Variation in cohesion between individuals, in turn, shapes important group-level processes such as subgroup formation and fission-fusion dynamics. Although critical to animal sociality, a comprehensive understanding of the factors influencing cohesion remains a gap in our knowledge of cooperative behavior in animals.

ERCAD: A Parametric Reactor Design Tool That Enables Rapid Prototyping and Optimization of Electrochemical Reactors through 3D Printing.

The reactors are an essential component of electrosynthetic reactions. As the electron transfer processes are heterogeneous, the reactors have a significant impact on reaction outcomes. This has resulted in reaction reproducibility being problematic, which commercial reactors alleviate somewhat but are expensive and cannot be optimized or iterated upon.

200 Years of The Haloform Reaction: Methods and Applications.

Discovered in 1822, the haloform reaction is one of the oldest synthetic organic reactions. The haloform reaction enables the synthesis of carboxylic acids, esters or amides from methyl ketones. The reaction proceeds via exhaustive α-halogenation and then substitution by a nucleophile to liberate a haloform.

Design and implementation of a new apparatus for astrochemistry: Kinetic measurements of the CH + OCS reaction and frequency comb spectroscopy in a cold uniform supersonic flow.

We present the development of a new astrochemical research tool, HILTRAC, the Highly Instrumented Low Temperature ReAction Chamber. The instrument is based on a pulsed form of the CRESU (Cinétique de Réaction en Écoulement Supersonique Uniforme, meaning reaction kinetics in a uniform supersonic flow) apparatus, with the aim of collecting kinetics and spectroscopic information on gas phase chemical reactions important in interstellar space or planetary atmospheres. We discuss the apparatus design and its flexibility, the implementation of pulsed laser photolysis followed by laser induced fluorescence, and the first implementation of direct infrared frequency comb spectroscopy (DFCS) coupled to the uniform supersonic flow.

A mystery revealed: an update on eosinophil and other blood cell morphology of the Argentine black and white tegu ().

Reptile white blood cell (WBC) morphological features are strikingly variable across species. In the Argentine black and white tegu (), red tegu (), and Savannah monitor (Var), previous reports described a WBC type with a single distinct, clear, linear- to ovoid- to crescent-shaped inclusion of presumptive monocytic origin. The objective of this study was to further investigate the origin of this unique WBC type with crescent-shaped inclusions.

Effectiveness of population-based recovery actions for threatened southern mountain caribou.

Habitat loss is affecting many species, including the southern mountain caribou (Rangifer tarandus caribou) population in western North America. Over the last half century, this threatened caribou population's range and abundance have dramatically contracted. An integrated population model was used to analyze 51 years (1973-2023) of demographic data from 40 southern mountain caribou subpopulations to assess the effectiveness of population-based recovery actions at increasing population growth.

Experimental and Theoretical Study of the OH-Initiated Degradation of Piperidine under Simulated Atmospheric Conditions.

The OH-initiated photo-oxidation of piperidine and the photolysis of 1-nitrosopiperidine were investigated in a large atmospheric simulation chamber and in theoretical calculations based on CCSD(T*)-F12a/aug-cc-pVTZ//M062X/aug-cc-pVTZ quantum chemistry results and master equation modeling of the pivotal reaction steps. The rate coefficient for the reaction of piperidine with OH radicals was determined by the relative rate method to be = (1.19 ± 0.

A Stoichiometric Haloform Coupling for Ester Synthesis with Secondary Alcohols.

The haloform reaction from methyl ketones to carboxylic acids is one of the oldest known synthetic organic reactions, which has been used in myriad applications over the decades. The corresponding reaction to produce esters is, however, less developed, as the reaction is generally limited to simple, primary alcohols that are used in solvent-level quantities, thereby restricting the complexity of esters that can be directly formed. Herein, we detail the development of a general ester-forming haloform coupling reaction using one equivalent of alcohol.

Experimental and Theoretical Investigation of the Reaction of NH with NO at Very Low Temperatures.

The first experimental study of the low-temperature kinetics of the gas-phase reaction between NH and NO has been performed. A pulsed laser photolysis-laser-induced fluorescence technique was used to create and monitor the temporal decay of NH in the presence of NO. Measurements were carried out over the temperature range of 24-106 K, with the low temperatures achieved using a pulsed Laval nozzle expansion.

and Statistical Rate Theory Exploration of the CH (XΠ) + OCS Gas-Phase Reaction.

The first theoretical results regarding the gas-phase reaction mechanism and kinetics of the CH (XΠ) + OCS reaction are presented here. This reaction has a proposed importance in the removal of OCS in regions of the interstellar medium (ISM) and has the potential to form the recently observed HCS/HSC isomers, with both constitutional isomers having recently been observed in the L483 molecular cloud in a 40:1 ratio. Statistical rate theory simulations were performed on stationary points along the reaction potential energy surface (PES) obtained from calculations at the RO-CCSD(T)/aug-cc-pV(Q+d)Z//M06-2X-D3/aug-cc-pV(Q+d)Z level of theory over the temperature and total density range of 150-3000 K and 10-10 cm, respectively, using a Master Equation analysis.

DETERMINATION OF ECHOCARDIOGRAPHIC TECHNIQUES FOR CLINICAL ASSESSMENT OF GALAPAGOS ( COMPLEX) AND ALDABRA () TORTOISES.

The first objective of this study was to establish clinically relevant techniques for cardiac echocardiography in nonanesthetized Galapagos ( complex) and Aldabra () tortoises. A second objective was to establish guidelines for determining normal echocardiographic anatomy and function in both species. Select echocardiographic reference values were defined for 17 healthy Galapagos tortoises and 27 healthy Aldabra tortoises.

Experimental, theoretical, and astrochemical modelling investigation of the gas-phase reaction between the amidogen radical (NH) and acetaldehyde (CHCHO) at low temperatures.

The first experimental study of the low-temperature kinetics of the gas-phase reaction of NH with acetaldehyde (CHCHO) has been performed. Experiments were carried out using laser-flash photolysis and laser-induced fluorescence spectroscopy to create and monitor the temporal decay of NH in the presence of CHCHO. Low temperatures relevant to the interstellar medium were achieved using a pulsed Laval nozzle expansion.

Extreme Concentrations of Nitric Oxide Control Daytime Oxidation and Quench Nocturnal Oxidation Chemistry in Delhi during Highly Polluted Episodes.

Delhi, India, suffers from periods of very poor air quality, but little is known about the chemical production of secondary pollutants in this highly polluted environment. During the postmonsoon period in 2018, extremely high nighttime concentrations of NO (NO and NO) and volatile organic compounds (VOCs) were observed, with median NO mixing ratios of ∼200 ppbV (maximum of ∼700 ppbV). A detailed chemical box model constrained to a comprehensive suite of speciated VOC and NO measurements revealed very low nighttime concentrations of oxidants, NO, O, and OH, driven by high nighttime NO concentrations.

Validating HONO as an Intermediate Tracer of the External Cycling of Reactive Nitrogen in the Background Atmosphere.

In the urban atmosphere, nitrogen oxide (NO═NO + NO)-related reactions dominate the formation of nitrous acid (HONO). Here, we validated an external cycling route of HONO and NO, i.e.

Experimental and theoretical study of the low-temperature kinetics of the reaction of CN with CHO and implications for interstellar environments.

Rate coefficients for the reaction of CN with CHO were measured for the first time below room temperature in the range 32-103 K using a pulsed Laval nozzle apparatus together with the Pulsed Laser Photolysis-Laser-Induced Fluorescence technique. The rate coefficients exhibited a strong negative temperature dependence, reaching (4.62 ± 0.

Heart Disease and Stroke Statistics-2023 Update: A Report From the American Heart Association.

Background: The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

Methods: The American Heart Association, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing.