Life Cycle of the Oriental Compost Worm Perionyx Excavatus (Oligochaeta)

In order to exploit the concept of using vermiculture as biotechnology for waste control and protein production, the life cycle of the vermicomposting species, Perionyx excavatus, was studied. The development, growth and reproduction of P. excavatus  were investigated. Urine free cattle manure with a moisture content of 76-83% and a temperature of 25°C was used as substrate. Data were gathered over a period of 300 days. It was found that mating is not a prerequisite for cocoon production, which starts at the mean age of 24 days. Maturation was attained at the age of approximately 21 days. Cocoons were produced at a mean rate of 1,1 cocoons per worm per day. The mean incubation period of cocoons produced by batches of worms was 18,7 days with a mean hatching success of 63,4%. The mean incubation period of cocoons produced by single worms was 20,4 days with a mean hatching success of 40,4%. As a rule only one worm hatched per cocoon. The life cycle of this species is presented diagrammatically

The Winchcombe meteorite, a unique and pristine witness from the outer solar system.

Direct links between carbonaceous chondrites and their parent bodies in the solar system are rare. The Winchcombe meteorite is the most accurately recorded carbonaceous chondrite fall. Its pre-atmospheric orbit and cosmic-ray exposure age confirm that it arrived on Earth shortly after ejection from a primitive asteroid. Recovered only hours after falling, the composition of the Winchcombe meteorite is largely unmodified by the terrestrial environment. It contains abundant hydrated silicates formed during fluid-rock reactions, and carbon- and nitrogen-bearing organic matter including soluble protein amino acids. The near-pristine hydrogen isotopic composition of the Winchcombe meteorite is comparable to the terrestrial hydrosphere, providing further evidence that volatile-rich carbonaceous asteroids played an important role in the origin of Earth's water

The Winchcombe meteorite—A regolith breccia from a rubble pile CM chondrite asteroid

The Winchcombe meteorite is a CM chondrite breccia composed of eight distinct lithological units plus a cataclastic matrix. The degree of aqueous alteration varies between intensely altered CM2.0 and moderately altered CM2.6. Although no lithology dominates, three heavily altered rock types (CM2.1–2.3) represent >70 area%. Tochilinite–cronstedtite intergrowths (TCIs) are common in several lithologies. Their compositions can vary significantly, even within a single lithology, which can prevent a clear assessment of alteration extent if only TCI composition is considered. We suggest that this is due to early alteration under localized geochemical microenvironments creating a diversity of compositions and because later reprocessing was incomplete, leaving a record of the parent body's fluid history. In Winchcombe, the fragments of primary accretionary rock are held within a cataclastic matrix (~15 area%). This material is impact‐derived fallback debris. Its grain size and texture suggest that the disruption of the original parent asteroid responded by intergranular fracture at grain sizes <100 μm, while larger phases, such as whole chondrules, splintered apart. Re‐accretion formed a poorly lithified body. During atmospheric entry, the Winchcombe meteoroid broke apart with new fractures preferentially cutting through the weaker cataclastic matrix and separating the breccia into its component clasts. The strength of the cataclastic matrix imparts a control on the survival of CM chondrite meteoroids. Winchcombe's unweathered state and diversity of lithologies make it an ideal sample for exploring the geological history of the CM chondrite group

The Winchcombe meteorite—A regolith breccia from a rubble pile CM chondrite asteroid

The Winchcombe meteorite is a CM chondrite breccia composed of eight distinct lithological units plus a cataclastic matrix. The degree of aqueous alteration varies between intensely altered CM2.0 and moderately altered CM2.6. Although no lithology dominates, three heavily altered rock types (CM2.1–2.3) represent >70 area%. Tochilinite–cronstedtite intergrowths (TCIs) are common in several lithologies. Their compositions can vary significantly, even within a single lithology, which can prevent a clear assessment of alteration extent if only TCI composition is considered. We suggest that this is due to early alteration under localized geochemical microenvironments creating a diversity of compositions and because later reprocessing was incomplete, leaving a record of the parent body's fluid history. In Winchcombe, the fragments of primary accretionary rock are held within a cataclastic matrix (~15 area%). This material is impact‐derived fallback debris. Its grain size and texture suggest that the disruption of the original parent asteroid responded by intergranular fracture at grain sizes <100 μm, while larger phases, such as whole chondrules, splintered apart. Re‐accretion formed a poorly lithified body. During atmospheric entry, the Winchcombe meteoroid broke apart with new fractures preferentially cutting through the weaker cataclastic matrix and separating the breccia into its component clasts. The strength of the cataclastic matrix imparts a control on the survival of CM chondrite meteoroids. Winchcombe's unweathered state and diversity of lithologies make it an ideal sample for exploring the geological history of the CM chondrite group

Factors associated with SARS-CoV-2 infection and outbreaks in long-term care facilities in England: a national cross-sectional survey

Background: Outbreaks of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have occurred in long-term care facilities (LTCFs) worldwide, but the reasons why some facilities are particularly vulnerable to outbreaks are poorly understood. We aimed to identify factors associated with SARS-CoV-2 infection and outbreaks among staff and residents in LTCFs. / Methods: We did a national cross-sectional survey of all LTCFs providing dementia care or care to adults aged 65 years or older in England between May 26 and June 19, 2020. The survey collected data from managers of eligible LTCFs on LTCF characteristics, staffing factors, the use of disease control measures, and the number of confirmed cases of infection among staff and residents in each LTCF. Survey responses were linked to individual-level SARS-CoV-2 RT-PCR test results obtained through the national testing programme in England between April 30 and June 13, 2020. The primary outcome was the weighted period prevalence of confirmed SARS-CoV-2 infections in residents and staff reported via the survey. Multivariable logistic regression models were fitted to identify factors associated with infection in staff and residents, an outbreak (defined as at least one case of SARS-CoV-2 infection in a resident or staff member), and a large outbreak (defined as LTCFs with more than a third of the total number of residents and staff combined testing positive, or with >20 residents and staff combined testing positive) using data from the survey and from the linked survey–test dataset. / Findings: 9081 eligible wLTCFs were identified, of which 5126 (56·4%) participated in the survey, providing data on 160 033 residents and 248 594 staff members. The weighted period prevalence of infection was 10·5% (95% CI 9·9–11·1) in residents and 3·8% (3·4–4·2) in staff members. 2724 (53·1%) LTCFs reported outbreaks, and 469 (9·1%) LTCFs reported large outbreaks. The odds of SARS-CoV-2 infection in residents (adjusted odds ratio [aOR] 0·80 [95% CI 0·75–0·86], p<0·0001) and staff (0·70 [0·65–0·77], p<0·0001), and of large outbreaks (0·59 [0·38–0·93], p=0·024) were significantly lower in LTCFs that paid staff statutory sick pay compared with those that did not. Each one unit increase in the staff-to-bed ratio was associated with a reduced odds of infection in residents (0·82 [0·78–0·87], p<0·0001) and staff (0·63 [0·59–0·68], p<0·0001. The odds of infection in residents (1·30 [1·23–1·37], p<0·0001) and staff (1·20 [1·13–1·29], p<0·0001), and of outbreaks (2·56 [1·94–3·49], p<0·0001) were significantly higher in LTCFs in which staff often or always cared for both infected or uninfected residents compared with those that cohorted staff with either infected or uninfected residents. Significantly increased odds of infection in residents (1·01 [1·01–1·01], p<0·0001) and staff (1·00 [1·00–1·01], p=0·0005), and of outbreaks (1·08 [1·05–1·10], p<0·0001) were associated with each one unit increase in the number of new admissions to the LTCF relative to baseline (March 1, 2020). The odds of infection in residents (1·19 [1·12–1·26], p<0·0001) and staff (1·19 [1·10–1·29], p<0·0001), and of large outbreaks (1·65 [1·07–2·54], p=0·024) were significantly higher in LTCFs that were for profit versus those that were not for profit. Frequent employment of agency nurses or carers was associated with a significantly increased odds of infection in residents (aOR 1·65 [1·56–1·74], p<0·0001) and staff (1·85 [1·72–1·98], p<0·0001), and of outbreaks (2·33 [1·72–3·16], p<0·0001) and large outbreaks (2·42 [1·67–3·51], p<0·0001) compared with no employment of agency nurses or carers. Compared with LTCFs that did not report difficulties in isolating residents, those that did had significantly higher odds of infection in residents (1·33 [1·28–1·38], p<0·0001) and staff (1·48 [1·41–1·56], p<0·0001), and of outbreaks (1·84 [1·48–2·30], p<0·0001) and large outbreaks (1·62 [1·24–2·11], p=0·0004). / Interpretation: Half of LTCFs had no cases of SARS-CoV-2 infection in the first wave of the pandemic. Reduced transmission from staff is associated with adequate sick pay, minimal use of agency staff, an increased staff-to-bed ratio, and staff cohorting with either infected or uninfected residents. Increased transmission from residents is associated with an increased number of new admissions to the facility and poor compliance with isolation procedures. / Funding: UK Government Department of Health and Social Care

Études à la nano-échelle des échantillons de l’astéroïde Ryugu : Caractérisation des effets d’altération spatiale par microscopie électronique

International audienc

Spectroscopie vibrationnelle à la nano-échelle en STEM : étude des effets d’altération spatiale sur la signature IR de l’astéroïde Ryugu

International audienceLe récent développement de microscopes électroniques monochromatés dédiés à la spectroscopie EELS à haute résolution met sur le devant de la scène la possibilité d’atteindre la gamme spectrale de l’infrarouge moyen avec, au mieux, une résolution spectrale de 40 cm-1 [1]. Cette technique ouvre une porte vers des comparaisons avec des études IR à plus large échelle.En parallèle, la mission spatiale Hayabusa2 de la JAXA a ramené, fin 2020, 5,4 g de la surface de l’astéroïde carboné Ryugu. Une partie de ces grains présentent une surface modifiée par des effets d’altération spatiale [2]. Ce phénomène est principalement dû à l’irradiation par vent solaire et aux bombardements micro-météoritiques sur la surface d’objets dépourvus d’atmosphère. L’étude de ces échantillons permet donc de mieux comprendre comment un astéroïde de type-C évolue lorsqu’il est exposé à ces sollicitations externes. Les surfaces modifiées par ces phénomènes d’altération spatiale ont été identifiées au MEB et des lames minces y ont été prélevées (FIB). La minéralogie de Ryugu est principalement constituée de phyllosilicates (silicates hydratés). Les phénomènes d’altération spatiale entraînent leur amorphisation ainsi que la formation de couches vésiculées (jusqu’à ~3 μm d’épaisseur). Nos résultats montrent qu’il est possible d’isoler les signatures spectrales IR de ces couches fondues de celles de la matrice hydratée. En particulier, nous mettons en évidence la perte des modes vibrationnels d’H2O et d’-OH dans ces couches fondues. Cela pourrait expliquer pourquoi la bande à 2.7 μm, correspondant aux groupements hydroxyles, est deux fois moins intense dans les données de NIRS3 que dans celles des échantillons collectés [3]. Nous observons également la perte des modes liés à la matière organique dans les couches fondues, en adéquation avec les donées EDS. Nous démontrons donc que l’altération spatiale peut significativement modifier les signatures IR d’astéroïdes de type-C hydratés, pouvant entraîner une sous-estimation de leur teneur en eau et en carbone lors de leur analyse à distance (ie. James Webb Space Telescope)

Space weathering influence on Ryugu’s IR signature: insights from nanoscale vibrational spectroscopy in the STEM

International audienceJAXA’s Hayabusa2 mission brought back 5.4 g of material from the surface of the carbonaceous asteroid Ryugu. Some grains show evidence of a modified surface attributed to space-weathering effects [1], which result from solar-wind irradiation and/or micrometeoroid bombardment. In collaboration with the Hayabusa2-Initial-Analysis Min-Pet Fine Team and the Hayabusa2-Initial-Analysis core, their study should allow to investigate, for the first time, how a C-type, hydrated asteroid surface evolves when subjected to space weathering. Alongside, the recent development of monochromated electron microscopes dedicated to high resolution EELS makes it possible to reach the Mid-IR spectral range (~40 cm-1 spectral resolution at best) [2]. It thus opens the possibility for comparison with bulk IR studies with the advantage of the TEM spatial resolution. Here, we study the modified surfaces and underlying matrix of several small Ryugu grains, originating from both touchdown A and C [3]. Surfaces modified by space weathering were first identified by SEM and FIB sections were prepared.The main product of space weathering is glassy and vesiculated layer likely resulting from the melting of Ryugu materials due to micrometeorite impacts. Our results show that it is possible to distinguish the spectral signature of both space weathered melt layers and underlying preserved matrix. In particular, we evidence the loss of the H2O and -OH vibrational modes in the melt layers. It could explain why the 2.7 µm band, corresponding to hydroxyl groups in phyllosilicates, is twice less intense in NIRS3 spectra than in the returned samples ones [4]. We also observe that the organic modes are absent in the melt layers, in agreement with the EDS data. We thus demonstrate that space weathering strongly modifies the IR signature of hydrated and C-rich airless bodies, and may lead to the underestimation of their water and carbon content when analyzed by remote sensing