Karyotype depends on sperm head morphology in some amniote groups.

The karyotype of an organism is the set of gross features that characterize the way the genome is packaged into separate chromosomes. It has been known for decades that different taxonomic groups often have distinct karyotypic features, but whether selective forces act to maintain these differences over evolutionary timescales is an open question. In this paper we analyze a database of karyotype features and sperm head morphology in 103 mammal species with spatulate sperm heads and 90 sauropsid species (birds and non-avian reptiles) with vermiform heads.

Globally-distributed microbial eukaryotes exhibit endemism at deep-sea hydrothermal vents.

Single-celled microbial eukaryotes inhabit deep-sea hydrothermal vent environments and play critical ecological roles in the vent-associated microbial food web. 18S rRNA amplicon sequencing of diffuse venting fluids from four geographically- and geochemically-distinct hydrothermal vent fields was applied to investigate community diversity patterns among protistan assemblages. The four vent fields include Axial Seamount at the Juan de Fuca Ridge, Sea Cliff and Apollo at the Gorda Ridge, all in the NE Pacific Ocean, and Piccard and Von Damm at the Mid-Cayman Rise in the Caribbean Sea.

Accumulation of the gaseous hormone ethylene helps roots sense compact soil.

Soil compaction, in which soil grains are pressed together leaving less pore space for air and water, is a persistent problem in mechanized agriculture. Most plant roots fail to penetrate soil if it is too dense. One might assume that they are physically unable to penetrate the compact soil.

Oxygen uptake rates have contrasting responses to temperature in the root meristem and elongation zone.

Growing at either 15 or 25°C, roots of Arabidopsis thaliana, Columbia accession, produce cells at the same rate and have growth zones of the same length. To determine whether this constancy is related to energetics, we measured oxygen uptake by means of a vibrating oxygen-selective electrode. Concomitantly, the spatial distribution of elongation was measured kinematically, delineating meristem and elongation zone.

Dynamic Markers for Chaotic Motion in C. elegans.

We describe the locomotion of Caenorhabditis elegans (C. elegans) using nonlinear dynamics. C.

Ancient Metabolisms of a Thermophilic Subseafloor Bacterium.

The ancient origins of metabolism may be rooted deep in oceanic crust, and these early metabolisms may have persisted in the habitable thermal anoxic aquifer where conditions remain similar to those when they first appeared. The Wood-Ljungdahl pathway for acetogenesis is a key early biosynthetic pathway with the potential to influence ocean chemistry and productivity, but its contemporary role in oceanic crust is not well established. Here, we describe the genome of a novel acetogen from a thermal suboceanic aquifer olivine biofilm in the basaltic crust of the Juan de Fuca Ridge (JdFR) whose genome suggests it may utilize an ancient chemosynthetic lifestyle.

Osteology-focused redescription and description of the blood-feeding candirus Paracanthopoma parva and Paravandellia alleynei sp.n. (Trichomycteridae: Vandelliinae).

This study resolves a significant impediment to the taxonomy of the Neotropical endemic hematophagous candirus by providing the first high-resolution, CT-based osteological descriptions of type and nontype specimens of Paracanthopoma parva, type species of the genus. We also describe the distinctive new species Paravandellia alleynei based on specimens that were previously misidentified as Parac. parva in the only taxonomic study of that species since its 1935 description.

Pacemaker-Based Cardiac Neuromodulation Therapy in Patients With Hypertension: A Pilot Study.

Background In prior unblinded studies, cardiac neuromodulation therapy (CNT) employing a sequence of variably timed short and longer atrioventricular intervals yielded sustained reductions of systolic blood pressure (SBP) in patients with hypertension. The effects of CNT on SBP were investigated in this double-blind randomized pilot study. Methods and Results Eligible patients had daytime ambulatory SBP (aSBP) ≥130 mm Hg and office SBP ≥140 mm Hg despite taking ≥1 antihypertensive medication, and an indication for a dual-chamber pacemaker.

Scaling Laws for Mitotic Chromosomes.

During mitosis in higher eukaryotes, each chromosome condenses into a pair of rod-shaped chromatids. This process is co-regulated by the activity of several gene families, and the underlying biophysics remains poorly understood. To better understand the factors regulating chromosome condensation, we compiled a database of mitotic chromosome size and DNA content from the tables and figures of >200 published papers.

Corrigendum to "Emergency Medical Services resource capacity and competency amid COVID-19 in the United States: preliminary findings from a national survey" [Heliyon 6 (5) (May 2020) e03900].

[This corrects the article DOI: 10.1016/j.heliyon.

Erratum to "Emergency Medical Services resource capacity and competency amid COVID-19 in the United States: preliminary findings from a national survey" [Heliyon 6 (5) (May 2020) Article e03900].

[This corrects the article DOI: 10.1016/j.heliyon.

Emergency Medical Services resource capacity and competency amid COVID-19 in the United States: preliminary findings from a national survey.

Objective: This study aimed to investigate available resources, Personal Protective Equipment (PPE) availability, sanitation practices, institutional policies, and opinions among EMS professionals in the United States amid the COVID-19 pandemic using a self-report survey questionnaire.

Methods: An online 42-question multiple choice survey was randomly distributed between April 1, 2020, and April 16, 2020 to various active Emergency Medical Services (EMS) paid personnel in all 50 U.S.

New names and status for Pacific spiny species of (Solanaceae, subgenus Leptostemonum Bitter; the Leptostemonum Clade).

Five new species of spiny solanums (Solanum subgenus Leptostemonum Bitter; the Leptostemonum Clade) are described from the islands of the Pacific. Two of the new species are from Fiji ( D.McClelland, .

Flowering plant immune repertoires expand under mycorrhizal symbiosis.

Immune perception in flowering plants is mediated by a repertoire of cytoplasmic and cell-surface receptors that detect invading microbes and their effects on cells. Here, we show that several large families of immune receptors exhibit size variations related to a plant's competence to host symbiotic root fungi (mycorrhiza). Plants that do not participate in mycorrhizal associations have significantly smaller immune repertoires, while the most promiscuous symbiotic hosts (ectomycorrhizal plant species) have significantly larger immune repertoires.

Applying multivariate analysis to characterize spirits from Acoli, Uganda, by their metal contents.

Quality control during spirits production and means of authenticating or verifying sources of spirits in the sub-Saharan region of Africa are limited due to lack of resources and the scientific acumen required to develop methodologies for characterizing spirits. However, the increasing needs to protect consumers from negligence, or willful contamination of spirits in this region underscores the urgency with which growth in this area must happen. In this paper, we describe a multivariate statistical framework upon which characterization, identification and authentication of spirits could be developed.

Speeding the Detection of Vessel Cannulation: An In-Vitro Stimulation Study.

Background: Some practitioners "prime" small IV angiocatheter needles with 0.9% sodium chloride-claiming this modification speeds visual detection of blood in the angiocatheter flash chamber on vessel cannulation.

Methods: We compared the time required for human blood to travel the length of saline-primed and saline-unprimed 24- and 22-gauge angiocatheter needles (Introcan Safety IV Catheter; B.

Occurrence of the large ostracod, (Baird, 1862), in temporary waters of Montserrat, Lesser Antilles.

Four populations of the large freshwater ostracod, (Baird, 1862), were discovered on the Caribbean island of Montserrat. These are the first records of the species on Montserrat and extend its known distribution approximately 113 km northwest and 63 km southeast of the closest known populations on Îles des Saintes (Guadeloupe) and Nevis, respectively. We provide the first DNA barcode for , a 686 bp fragment of the COI gene which may be used for future comparative studies of this widely distributed species.

Co-infection does not predict disease signs in tortoises.

In disease ecology, the host immune system interacts with environmental conditions and pathogen properties to affect the impact of disease on the host. Within the host, pathogens may interact to facilitate or inhibit each other's growth, and pathogens interact with different hosts differently. We investigated co-infection of two and the association of infection with clinical signs of upper respiratory tract disease in four congeneric tortoise host species () in the United States to detect differences in infection risk and disease dynamics in these hosts.

Fourier-Based Diffraction Analysis of Live Caenorhabditis elegans.

This manuscript describes how to classify nematodes using temporal far-field diffraction signatures. A single C. elegans is suspended in a water column inside an optical cuvette.

Neuroelectric Tuning of Cortical Oscillations by Apical Dendrites in Loop Circuits.

Bundles of relatively long apical dendrites dominate the neurons that make up the thickness of the cerebral cortex. It is proposed that a major function of the apical dendrite is to produce sustained oscillations at a specific frequency that can serve as a common timing unit for the processing of information in circuits connected to that apical dendrite. Many layer 5 and 6 pyramidal neurons are connected to thalamic neurons in loop circuits.

A Transcriptomics and Comparative Genomics Analysis Reveals Gene Families with a Role in Body Plan Complexity.

We analyzed tissue-specific transcriptomes of and identified 66 gene families with a high frequency of "gradient genes" - genes showing a significant expression gradient between tissues. Gradient gene families include many with roles in hormone and peptide signaling, cell wall synthesis and remodeling, secondary metabolism, transcriptional regulation, and transport between cells. We compared the size of the gradient gene families among the genomes of four plant species with radically different body plans - a single-celled algae, a moss, a eudicot, and a monocot - and found that most of the gradient gene families (58/66) expanded in parallel with the evolution of morphological complexity.

Fishing Quotas, Induced Allee Effect, and Fluctuation-Driven Extinction.

We explore the potential of modifications to standard fishery models (for example Gordon-Schafer-Munro) to help understand events such as the collapse of the North Atlantic cod fishery. In particular we find that quota-driven and similar harvesting strategies induce an effective strong Allee effect (collapse if the population falls below a critical level). In the presence of environmental noise, fish population dynamics is similar to a random walk with (non-linear) drift.

Oregonator Scaling Motivated by the Showalter-Noyes Limit.

The Belousov-Zhabotinsky (BZ) reaction is the prototype oscillatory chemical system. We investigate here a new scaling of the Oregonator model of BZ chemical kinetics and use this scaling to elucidate fundamental properties of BZ dynamics. In particular, the Showalter-Noyes criterion for oscillation, that the product [BrO][H] exceeds a critical value, arises naturally as a subcritical Hopf bifurcation in this setting, as does the reduction to a two-variable model.

A new record of the freshwater polychaete Namanereis hummelincki (Polychaeta: Nereididae) from epigean waters of Montserrat.

The presence of the freshwater polychaete, Namanereis hummelincki (Augener), on Montserrat is documented for the first time. Although collected in the sediment of a freshwater stream, this subterranean species most likely lives in groundwater aquifers. A mitochondrial cytochrome c oxidase subunit I (COI) sequence obtained from this material supports assignment to the genus Namanereis Chamberlin, and morphological analysis supports identification as N.