Physiological impacts of temperature variability and climate warming in hellbenders ().

Cold-adapted hellbender salamanders that inhabit cool mountain streams are expected to fare poorly under warmer projected climate scenarios. This study investigated the physiological consequences of long-term, naturalistic temperature variation on juvenile hellbenders under simulated current and warmer (+1.6 C) climates vs.

Influence of extracellular environment on the motility and structural properties of spermatozoa collected from hormonally stimulated Panamanian Golden Frog (Atelopus zeteki).

A better understanding of the factors influencing the biology of amphibian spermatozoa after release from the testis is a prerequisite to the development of sperm preservation methods. The objective of the study was to determine the effect of extracellular conditions (exposure to water and different temperatures) over time on the sperm motility and structural properties (including morphology and DNA integrity) collected from hormonally stimulated Atelopus zeteki. Following intraperitoneal injection of gonadotropin-releasing hormone agonist (des-Gly, D-Ala, Pro-NHEt GnRH; 4 μg/g of body weight), human chorionic gonadotropin (hCG, 10 IU/gbw), or Amphiplex™ (0.

Effects of hormonal stimulation on the concentration and quality of excreted spermatozoa in the critically endangered Panamanian golden frog (Atelopus zeteki).

Knowledge of basic gamete biology is critical to better protect and propagate endangered amphibian species and also to develop reproductive technologies combined with germplasm cryopreservation. The objectives of the study were to test different hormonal stimulations and then characterize the quantity and quality of Panamanian golden frog (Atelopus zeteki) spermatozoa. Following intraperitoneal injection of the gonadotropin-releasing hormone agonist (des-Gly, D-Ala, Pro-NHEt-GnRH 1, 2 or 4 μg/g of body weight), human chorionic gonadotropin (hCG; 5 or 10 IU/gbw), or Amphiplex™ (0.

A review of the biology and literature of the Gulf Coast Toad (Incilius nebulifer), native to Mexico and the United States.

The Gulf Coast Toad (Incilius nebulifer) is an abundant and widespread species within its range in the United States and Mexico, so it appears on many faunal checklists and is considered in diverse kinds of research. We review the basic biology, distribution, and published history of this species, identifying only those records and publications referable to I. nebulifer, to help researchers identify published works pertaining to I.

Cryptic impacts of temperature variability on amphibian immune function.

Ectothermic species living in temperate regions can experience rapid and potentially stressful changes in body temperature driven by abrupt weather changes. Yet, among amphibians, the physiological impacts of short-term temperature variation are largely unknown. Using an ex situ population of Cryptobranchus alleganiensis, an aquatic North American salamander, we tested the hypothesis that naturally occurring periods of temperature variation negatively impact amphibian health, either through direct effects on immune function or by increasing physiological stress.

Access to in vitro fertilization deserves increased regulation in the United States.

In the United States, it is generally accepted that people have the right to reproduce without government interference or regulation. The autonomy of the individual is held in high regard. Before the advent of assisted reproductive technology, heterosexual, monogamous relationships were the legally accepted standard means of human reproduction.

Tunable few-cycle and multicycle coherent terahertz radiation from relativistic electrons.

We report the generation of tunable, narrow-band, few-cycle and multicycle coherent terahertz (THz) pulses from a temporally modulated relativistic electron beam. We demonstrate that the frequency of the THz radiation and the number of the oscillation cycles of the THz electric field can be tuned by changing the modulation period of the electron beam through a temporally shaped photocathode drive laser. The central frequency of the THz spectrum is tunable from ∼0.

Exponential growth, superradiance, and tunability of a seeded free electron laser.

Exponential growth and superradiance regimes in a high-gain free electron laser (FEL) are studied in this paper for both a seeded FEL and a Self-Amplified Spontaneous Emission (SASE) FEL. The results are compared to the earlier superrdaince theory and the recent experimental observation. The influence of an initial energy chirp along the electron bunch on the superradiance mode is explored for the first time.

ABCD formalism and attosecond few-cycle pulse via chirp manipulation of a seeded free electron laser.

An ABCD formalism is identified to characterize a seeded Free Electron Laser (FEL) with three chirps: an initial frequency chirp in the seed Laser, an energy chirp in the electron bunch, and an intrinsic frequency chirp due to the FEL process. A scheme of generating attosecond few-cycle pulses is proposed by invoking an FEL seeded by high-order harmonic generation (HHG) from an infrared laser. The HHG seed has generic attosecond structure.