Enhanced REC collaborative review through video-conferencing

As international collaborative health research activities increase, building research ethics committees (REC) infrastructure and capacity in lowand middle-income countries for efficient and thorough review of research protocols becomes more critical, especially in sub-Saharan Africa. International investigators may face multiple challenges when conducting research in these settings, an important one being the length of time involved in securing REC review and approval. We discuss an approach to the problem that involved organisation of ‘rapid review’ REC sub-committees who met via video-conference for collaborative review of research protocols

The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope: I. Overview of the instrument and its capabilities

We provide an overview of the design and capabilities of the near-infrared spectrograph (NIRSpec) onboard the James Webb Space Telescope. NIRSpec is designed to be capable of carrying out low-resolution ($R\!=30\!-330$) prism spectroscopy over the wavelength range $0.6-5.3\!~\mu$m and higher resolution ($R\!=500\!-1340$ or $R\!=1320\!-3600$) grating spectroscopy over $0.7-5.2\!~\mu$m, both in single-object mode employing any one of five fixed slits, or a 3.1$\times$3.2 arcsec$^2$ integral field unit, or in multiobject mode employing a novel programmable micro-shutter device covering a 3.6$\times$3.4~arcmin$^2$ field of view. The all-reflective optical chain of NIRSpec and the performance of its different components are described, and some of the trade-offs made in designing the instrument are touched upon. The faint-end spectrophotometric sensitivity expected of NIRSpec, as well as its dependency on the energetic particle environment that its two detector arrays are likely to be subjected to in orbit are also discussed

The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope: I. Overview of the instrument and its capabilities

We provide an overview of the design and capabilities of the near-infrared spectrograph (NIRSpec) onboard the James Webb Space Telescope. NIRSpec is designed to be capable of carrying out low-resolution ($R\!=30\!-330$) prism spectroscopy over the wavelength range $0.6-5.3\!~\mu$m and higher resolution ($R\!=500\!-1340$ or $R\!=1320\!-3600$) grating spectroscopy over $0.7-5.2\!~\mu$m, both in single-object mode employing any one of five fixed slits, or a 3.1$\times$3.2 arcsec$^2$ integral field unit, or in multiobject mode employing a novel programmable micro-shutter device covering a 3.6$\times$3.4~arcmin$^2$ field of view. The all-reflective optical chain of NIRSpec and the performance of its different components are described, and some of the trade-offs made in designing the instrument are touched upon. The faint-end spectrophotometric sensitivity expected of NIRSpec, as well as its dependency on the energetic particle environment that its two detector arrays are likely to be subjected to in orbit are also discussed

BREED AND HETEROSlS EFFECTS ON TESTICULAR DEVELOPMENT AND ENDOCRINE FUNCTION OF PUBERAL BOARS

Purebred and two-breed cross Duroc, Landrace, Spotted and Yorkshire boars were evaluated at 218 ± 6 d of age to determine the influence of breed on testicular development and on concentrations of luteinizing hormone (LH) and testosterone in blood serum after treatment with gonadotropin releasing hormone (GnRH). Concentrations of LH and testosterone were determined in serum samples obtained from the vena cava of 139 boars just before and 1, 2, 3 and 4 h after an im injection of 200/ μg of GnRH. The right testes of 136 boars were removed and sperm numbers were determined in homogenates of testicular parenchymae, capita-corpora epididymides and caudae epididymides. Crossbred boars weighed 7 kg more (P\u3c.05) than purebred boars. Testes, capitacorpora and caudae epididymides were heavier (P\u3c.01) for crossbred boars (46.4 ± 10.8, 3.8 ± 1.4 and 4.8 ± 1.4 g, respectively) than for purebred boars. Crossbred boars had more testicular sperm (33.7 ± 2.0 x 109 vs 25.4 ± 2.3 x 109, P\u3c.01), more capita-corpora epididymidal sperm (28.9 ± 1.7 x 109 vs 20.8 ± 2.1 x 109, P\u3c.01) and more caudae epididymidal sperm (53.6 ± 2.9 x 109 vs 43.8 ± 3.8 x 109, P\u3c.05) than purebred boars. Breed of boar influenced (P\u3c.05) testicular weight, capitacorpora weight and sperm numbers and caudal weight and sperm numbers. Concentrations of LH and testosterone in serum were similar (P\u3e.10) for crossbred and purebred boars at all but one sampling time. At 3 h after treatment with GnRH concentrations of LH were greater (P\u3c.05) in crossbred than purebred boars and concentrations of testosterone were greater (P\u3c.05) in crossbred than purebred boars at 4 h after GnRH. There was a significant breed x time interaction for concentrations of LH and testosterone. Breed of boar influenced (P\u3c.05) concentrations of LH at 1, 2 and 3 h after treatment with GnRH, and concentrations of testosterone were affected by breed at 2 and 4 h after treatment. However, breed of boar did not influence either LH or testosterone in serum before treatment with GnRH (0 h) and LH in serum at 4 h and testosterone in serum at 1 and 3 h after GnRH. These results indicate that breed of boars influences testicular characteristics and concentrations of testosterone and LH in serum after GnRH. Heterosis was detected for testicular and epididymidal weights and sperm numbers, but heterosis was not observed for concentrations of LH and testosterone in serum

REPRODUCTIVE AND TESTICULAR CHARACTERISTICS OF PUREBRED AND CROSSBRED BOARS

One-hundred-ninety-five Duroc (D), Hampshire (H), Duroc x Hampshire (D x H) and Hampshire x Duroc (H x D) boars were evaluated for reproductive performance. One-hundred- sixteen boars were castrated at approximately 225 days of age to evaluate testicular and epididymidal weights and sperm numbers. Testes from crossbred boars were 95.33 ± 22.81 g heavier (P\u3c.01) and contained 14.41 ± 3.92 billion more sperm (P\u3c.01) than those from purebred boars. Testes from Hampshire boars were 50.40 ± 31.75 g heavier with 6.27 ± 5.45 billion more sperm than those from Durocs. There were no significant differences between breeds for caput-corpus epididymidal measurements. Durocs had 24.55 ± 12.16 billion more sperm (P\u3c.05) in the cauda epididymis than Hampshire boars. Testes weight and testes sperm numbers were significantly correlated with caput-corpus epididymidal and cauda epididymidal sperm numbers. Correlations of testicular and epididymidal characteristics with growth rate and backfat to 100 kg were small and nonsignificant. Twenty 7.5-month to 9-month-old D1 D x H and H x D boars and 19 H boars were each mated to two Yorkshire gilts to evaluate reproductive efficiency. Conception rates were: D, 63.2%; D x H, 67.5%; H x D, 60.0%; and H, 48.6%. Number of embryos 30-days postbreeding was 10.66 ± .49 and 11.25 ± .43 (P\u3e.10) for gilts mated to purebred and crossbred sires, respectively. Twenty-eight of 36 crossbred boars mated each time they were exposed to an estrus gilt but only 11 of 36 of the purebred boars mated each time. None of the crossbred boars failed to mate more than once, while 15 of 36 purebred boars failed to mate two or more times. In general, differences among breed groups for time required to mount after exposure to estrus gilt and length of ejaculation time were small and nonsignificant

REPRODUCTIVE CHARACTERISTICS OF BOARS DURING AND AFTER EXPOSURE TO INCREASED AMBIENT TEMPERATURE

Reproductive performance of 12 11-month-old Yorkshire boars was determined during and after exposure to control or increased ambient temperatures. After 3 weeks adjustment at 23 C in temperature controlled chambers, six boars were heat stressed by exposure to 34.5 ± 1.0 C for 8 hr and 31.0 ± 1.0 C for 16 hr during each 24-hr period and six control boars were maintained at 23.0 ± 1.0 C for 11 weeks. All boars were subsequently exposed to 23 C for 6 weeks. Semen was collected twice weekly before, during and after heat stress and boars were naturally mated with gilts during weeks 7 to 11 of treatment. Daily rectal temperatures and respiratory rates were increased during heat stress, but the ability to ejaculate and semen volume were not altered. Percentage motile sperm was decreased during heat stress (P\u3c.005) and did not return to normal values until 5 weeks after the end of exposure to increased ambient temperatures. Daily sperm output from heat stressed boars was decreased (P\u3c.025) during daily ejaculation on days 33 to 38 of treatment and averaged 54% of the total sperm ejaculated by control boars. At 30 days after natural breeding only 59% (P\u3c.05) of the gilts bred by heat stressed boars were pregnant compared to 82% for gilts mated to control boars