Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM.

Transmission spectroscopy1-3 of exoplanets has revealed signatures of water vapour, aerosols and alkali metals in a few dozen exoplanet atmospheres4,5. However, these previous inferences with the Hubble and Spitzer Space Telescopes were hindered by the observations' relatively narrow wavelength range and spectral resolving power, which precluded the unambiguous identification of other chemical species-in particular the primary carbon-bearing molecules6,7. Here we report a broad-wavelength 0.5-5.5 µm atmospheric transmission spectrum of WASP-39b8, a 1,200 K, roughly Saturn-mass, Jupiter-radius exoplanet, measured with the JWST NIRSpec's PRISM mode9 as part of the JWST Transiting Exoplanet Community Early Release Science Team Program10-12. We robustly detect several chemical species at high significance, including Na (19σ), H2O (33σ), CO2 (28σ) and CO (7σ). The non-detection of CH4, combined with a strong CO2 feature, favours atmospheric models with a super-solar atmospheric metallicity. An unanticipated absorption feature at 4 µm is best explained by SO2 (2.7σ), which could be a tracer of atmospheric photochemistry. These observations demonstrate JWST's sensitivity to a rich diversity of exoplanet compositions and chemical processes.

A radio-pulsing white dwarf binary star.

White dwarfs are compact stars, similar in size to Earth but approximately 200,000 times more massive. Isolated white dwarfs emit most of their power from ultraviolet to near-infrared wavelengths, but when in close orbits with less dense stars, white dwarfs can strip material from their companions and the resulting mass transfer can generate atomic line and X-ray emission, as well as near- and mid-infrared radiation if the white dwarf is magnetic. However, even in binaries, white dwarfs are rarely detected at far-infrared or radio frequencies. Here we report the discovery of a white dwarf/cool star binary that emits from X-ray to radio wavelengths. The star, AR Scorpii (henceforth AR Sco), was classified in the early 1970s as a δ-Scuti star, a common variety of periodic variable star. Our observations reveal instead a 3.56-hour period close binary, pulsing in brightness on a period of 1.97 minutes. The pulses are so intense that AR Sco's optical flux can increase by a factor of four within 30 seconds, and they are also detectable at radio frequencies. They reflect the spin of a magnetic white dwarf, which we find to be slowing down on a 107-year timescale. The spin-down power is an order of magnitude larger than that seen in electromagnetic radiation, which, together with an absence of obvious signs of accretion, suggests that AR Sco is primarily spin-powered. Although the pulsations are driven by the white dwarf's spin, they mainly originate from the cool star. AR Sco's broadband spectrum is characteristic of synchrotron radiation, requiring relativistic electrons. These must either originate from near the white dwarf or be generated in situ at the M star through direct interaction with the white dwarf's magnetosphere.

An orbital period of 0.94 days for the hot-Jupiter planet WASP-18b.

The 'hot Jupiters' that abound in lists of known extrasolar planets are thought to have formed far from their host stars, but migrate inwards through interactions with the proto-planetary disk from which they were born, or by an alternative mechanism such as planet-planet scattering. The hot Jupiters closest to their parent stars, at orbital distances of only approximately 0.02 astronomical units, have strong tidal interactions, and systems such as OGLE-TR-56 have been suggested as tests of tidal dissipation theory. Here we report the discovery of planet WASP-18b with an orbital period of 0.94 days and a mass of ten Jupiter masses (10 M(Jup)), resulting in a tidal interaction an order of magnitude stronger than that of planet OGLE-TR-56b. Under the assumption that the tidal-dissipation parameter Q of the host star is of the order of 10(6), as measured for Solar System bodies and binary stars and as often applied to extrasolar planets, WASP-18b will be spiralling inwards on a timescale less than a thousandth that of the lifetime of its host star. Therefore either WASP-18 is in a rare, exceptionally short-lived state, or the tidal dissipation in this system (and possibly other hot-Jupiter systems) must be much weaker than in the Solar System.

Adsorption properties of HKUST-1 toward hydrogen and other small molecules monitored by IR.

Among microporous systems metal organic frameworks are considered promising materials for molecular adsorption. In this contribution infrared spectroscopy is successfully applied to highlight the positive role played by coordinatively unsaturated Cu2+ ions in HKUST-1, acting as specific interaction sites. A properly activated material, obtained after solvent removal, is characterized by a high fraction of coordinatively unsaturated Cu2+ ions acting as preferential adsorption sites that show specific activities towards some of the most common gaseous species (NO, CO2, CO, N2 and H2). From a temperature dependent IR study, it has been estimated that the H2 adsorption energy is as high as 10 kJ mol(-1). A very complex spectral evolution has been observed upon lowering the temperature. A further peculiarity of this material is the fact that it promotes ortho-para conversion of the adsorbed H2 species.

The location and ordering of fluoride ions in pure silica zeolites with framework types IFR and STF; implications for the mechanism of zeolite synthesis in fluoride media.

Single-crystal X-ray diffraction studies carried out at a synchrotron radiation source have allowed the structure solution and location of fluoride ions inside as-made pure silica zeolites with the IFR and STF framework structures. The local environment of the fluoride has been identified, and unusual ordering of the fluoride ions has been discovered in both cases. The details of the crystal structures are used to suggest structural features that are important in determining the ordering of fluoride ions in zeolites. A mechanism for how the fluoride ordering occurs is suggested for IFR and STF based on the local structure of small cages that make up these zeolites, and the implications for the mechanism of crystal growth are discussed.

Military surgery in Rwanda.

BACKGROUND: In April of 1994, a vicious civil was erupted in Rwanda, with more than 500,000 people massacred by extremist militias. The second United Nations Assistance Mission in Rwanda (UNAMIR II) deployed in August 1994 to monitor the ceasefire, with an Australian Defence Force Contingent of Health Service Support consisting of staff for the UNAMIR Head-quarters, and the Australian Medical Support Force (AS MSF). METHODS: A retrospective audit was conducted of all operative surgery performed during the year-long deployment, in the AS MSF operating theatres. RESULTS: Twenty surgeons rotated through in 6-week intervals. A total of 750 operations were performed on 547 patients, of which 636 (84.8%) involved civilians. A total of 558 (74.4%) cases were the result of trauma both accidental (38.4%) and war related (36%). The mean age of patients was 21.7 years. The age distribution was skewed, with 289 (38.5%) cases being performed on children. General surgeons performed a wide range of surgery, covering the majority of surgical specialties. These included cardiothoracic, neurosurgical, vascular and paediatric cases. Orthopaedic surgeons dealt with amputations, debridements and skin grafting in addition to bony injuries and infections. Children formed a substantial number of those treated, and required surgery for war-related injuries significantly more often than adults. CONCLUSIONS: Surgeons involved in future peacekeeping missions should be aware of the broad variety of clinical problems encountered, and undertake refresher training in the sub-specialties. Children are at great risk of violence in war, and if a civilization can be judged by the protection it affords its helpless, the Rwandan genocide and ensuing civil war represents a horrific example of the opposite extreme.

Pupils with special needs: a Scottish perspective.

The distinction between ordinary and special schooling in Scotland was effectively erased by the Education (Scotland) Act of 1981. This Act recognizes that any pupil who requires extra support to succeed in a regular classroom is a child who has special education needs. Presently, all pupils who, for whatever reason, do not cope successfully at school are collectively referred to as children with learning difficulties. The term "learning difficulties" reflects a broader spectrum of problems than those characteristically found in the category of learning disabilities used in the United States. In cases of dyslexia, the term "specific learning difficulties" (a subgroup of learning difficulties) is also used. All special education provision in based on individual needs. A child's needs are interpreted in relation to a continuum of special education needs and in the context of his or her unique environment. For pupils with learning difficulties, the needs-assessment process is typically informal and rarely results in an official record of need being opened for them. A description of Grampian Region, one of the largest administrative units in northern Scotland, reveals how special educational practice is organized to respond to pupils with learning difficulties in the current educational climate.

Recent military experience with malaria chemoprophylaxis.

OBJECTIVE: To assess the value of various drug regimens for malaria prophylaxis under circumstances where dapsone and pyrimethamine (combined as Maloprim) and chloroquine, followed by the 14-day primaquine eradication course, were no longer effective in protecting military personnel against falciparum and vivax malaria. DESIGN, SETTING AND PARTICIPANTS: Various drug regimens given to four groups of healthy male members of the Australian Army during training exercises in malarious countries. INTERVENTIONS: Four groups of soldiers were given different regimens for 3-12 weeks: Group 1--mefloquine (250 mg weekly); Group 2--doxycycline (100 mg daily); Group 3--doxycycline (100 mg daily) and primaquine (7.5 mg daily); and Group 4--doxycycline (50 mg daily) and chloroquine (300 mg weekly). Except in Group 3, each of these regimens was followed by a 7.5 mg dose of primaquine three times a day for two weeks. MAIN OUTCOME MEASURES: The proportion of participants in the various prophylactic drug groups who developed falciparum or vivax malaria during or after the intervention. RESULTS: Group 1: 40 men receiving mefloquine were all protected against falciparum malaria but four (10%) developed vivax malaria. These results were not statistically different from those obtained for either falciparum (P = 0.28) or vivax (P = 0.36) malaria in the control group of 64 men receiving Maloprim and chloroquine. Group 2: 60 men receiving doxycycline (no control group) were all protected against falciparum malaria but two developed vivax malaria. Group 3: 124 men, of whom 55 received doxycycline and 69 primaquine in addition to doxycycline, were all protected against falciparum malaria. However, 13 men taking only doxycycline developed vivax malaria two to three weeks after prophylaxis, whereas no vivax infections were observed in the men taking the drug combination (P = 0.0001). Group 4: no malaria infections were observed in 125 men receiving doxycycline and chloroquine for 13 weeks, probably because of the low prevalence of malaria in the training area. CONCLUSIONS: These studies confirm that doxycycline is very effective in preventing falciparum malaria and, for the first time, also suggest that doxycycline used in combination with small doses of primaquine may prevent (not only suppress) vivax malaria. If further studies confirm these findings, the use of such a drug combination would reduce the incidence of both vivax and falciparum malaria in returning travellers. For individuals with a high risk of exposure to malaria, it would also forestall the need to take the bothersome primaquine eradication course.

HIV-1 seroprevalence in pregnant women testing positive on serologic screening for syphilis.

Epidemic increases in active syphilis have been reported in the geographic areas hit hard by acquired immunodeficiency syndrome. Although both epidemics have been associated with illicit substance abuse, the extent to which recent increases in syphilis are linked to the human immunodeficiency virus (HIV-1) epidemic is uncertain. In order to define the frequency of syphilis and HIV-1 coinfection in the pregnant patients seen at City Hospital Center at Elmhurst, we saved syphilis-positive serologic specimens from obstetrical patients for anonymous HIV-1 antibody testing. Of 120 women who tested positive for syphilis, 7/120 (5.8%) had antibodies to HIV-1; of the 44 women with VDRL titers greater than or equal to 1:16 (suggestive of a recent infection), 1/44 (2.3%) had antibodies to HIV-1.

Effects of lamotrigine on electrically induced afterdischarge duration in anaesthetised rat, dog, and marmoset.

The effects of lamotrigine (LTG), a novel potent anticonvulsant, following intravenous (i.v.) bolus injection were studied on the durations of electrically induced afterdischarges of the EEG in halothane-anaesthetised dogs and marmosets, species used in toxicity studies. For comparison, the effect of LTG on hippocampal afterdischarge duration was also studied in halothane anaesthetised rats, a species in which the anticonvulsant action of LTG has been widely investigated. The known anticonvulsants phenytoin (PHT) and phenobarbital (PB) were included for comparison. LTG reduced afterdischarge duration in a dose-dependent manner in rat and dog; it was approximately twofold more potent than PHT in the dog and three- to fourfold more potent than PB in both dog and rat (LTG ED50 values = 4.5 and 11.7 mg.kg-1 i.v. in dogs and rats, respectively). PHT was ineffective in the rat at sublethal doses (less than 40 mg.kg-1 i.v.). In limited studies in marmosets, i.v. administration of both LTG and PHT (both 5-15 mg.kg-1) reduced or abolished afterdischarge. Thus, LTG was a potent anticonvulsant in rat, dog, and marmoset in afterdischarge models of partial (focal) seizures and may be of utility in the treatment of partial seizures in humans.

Cardiovascular and neurological effects of laudanosine. Studies in mice and rats, and in conscious and anaesthetized dogs.

The effects of laudanosine, a metabolite of atracurium, on the behaviour of conscious mice, rats and dogs, and on cardiovascular function in conscious and anaesthetized dogs have been evaluated: EEG studies were performed in anaesthetized dogs. In mice and rats, i.v. bolus doses of laudanosine 10-20 mg kg-1, caused convulsions and hind limb extensions; these effects were prevented by pretreatment with diazepam. After the continuous infusion of laudanosine to conscious dogs, plasma concentrations in the order of 1.2 micrograms ml-1 did not cause behavioural disturbances. In anaesthetized dogs, laudanosine plasma concentrations of more than 6 micrograms ml-1 caused hypotension and bradycardia, laudanosine concentrations greater than 10 micrograms ml-1 induced epileptic EEG spiking and plasma concentrations greater than 17 micrograms ml-1 produced prolonged seizures. There is a wide difference between laudanosine plasma concentrations in patients given atracurium by bolus injection or by short-term infusion for surgical use and those required to induce epileptic activity in dogs. However, during the prolonged infusion of atracurium to patients this difference will be decreased. It is unlikely that the use of atracurium, in patients, would result in plasma concentrations of laudanosine capable of producing neurological or cardiovascular disturbances.

Three-terminal noninverting optoelectronic logic device.

A novel noninverting optoelectronic logic device using a GaAs/AlGaAs multiple-quantum-well modulator is demonstrated that combines electronic nonlinearity with optical input and output and is bistable. The device is bistable but displays hard limiting and an optical gain of 12.

Pharmacological studies on lamotrigine, a novel potential antiepileptic drug: I. Anticonvulsant profile in mice and rats.

Lamotrigine (LTG), 3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine, is a structurally novel anticonvulsant. The anticonvulsant profile of LTG following oral administration in two standard anticonvulsant tests, the maximal electroshock (MES) test in mice and rats and the pentylenetetrazol (PTZ) infusion test in mice, was studied in comparison with the known anticonvulsant drugs phenytoin (PHT), phenobarbitone, diazepam, carbamazepine (CBZ), sodium valproate, ethosuximide (ETH), and troxidone (TROX). ED50 values for the abolition of hindlimb extension (HLE) in the MES test and PTZ infusion tests and doses increasing the latency of PTZ-evoked clonus were determined. The duration of action of LTG was examined in rats and mice in the MES test by determining ED50 values for the abolition of HLE at various drug intervals to shock administration. In the MES test, LTG was well absorbed in both species, with peak activity at 1 h and persistence at this level of potency for at least 8 h. Of the drugs examined, LTG was ranked the most potent and persistent in both species. LTG also abolished PTZ-evoked HLE, while ETH and TROX were inactive. Clonus latency was not increased by LTG, PHT, or CBZ, but was significantly increased (p less than 0.05) by the remaining anticonvulsants. Thus, LTG resembled PHT and CBZ in its ability to block HLE but not to increase PTZ-induced clonus latency. Acute behavioural studies in mice and rats have suggested a wide separation between anticonvulsant doses and those producing behavioural impairment. These results suggest that LTG may be of value in the treatment of generalised tonic-clonic and partial seizures.

Quantitative studies of N-methyl-D-aspartate, 2-amino-5-phosphonovalerate and cis-2,3-piperidine dicarboxylate interactions on the neonatal rat spinal cord in vitro.

The interactions between N-methyl-D-aspartate (NMDA), (+/-)2-amino-5-phosphonovalerate (2AP5) and (+/-)cis-2.3-piperidine dicarboxylate (cis-PDA) were examined quantitatively in the neonatal rat spinal cord in vitro. NMDA and cis-PDA evoked concentration-dependent motoneuronal depolarizations. The maximal cis-PDA-evoked response was approximately 60% of that evoked by NMDA. When applied in combination with fixed concentrations of cis-PDA, NMDA evoked concentration-dependent depolarizations superimposed upon the basal cis-PDA-evoked depolarizations, the dose-response curve for which intercepted the control dose-response curve and was subsequently moved to the right compared with the control curve. 2AP5 shifted the NMDA dose-response curves to the right and Schild regression analysis gave a pKB of 5.0 with a slope of 1.00. 2AP5 also moved the cis-PDA dose-response-curve (apparent KB 3.1 X 10(-5) M) to the right and abolished the cis-PDA component of the NMDA + cis-DPA dose-response curve. These results are consistent with the predictions of drug-receptor theory for the interactions of a full agonist (NMDA), competitive antagonist (2AP5) and partial agonist (cis-PDA) and represent further evidence for a population of excitatory amino acid receptors for which NMDA is a selective agonist.