Groundwater lowering for construction of the Kilsby Tunnel – pumping and tunnelling

The Kilsby Tunnel, constructed in the 1830s under the direction of Robert Stephenson, faced severe problems when a section of the tunnel, almost 400 m long, was driven through water-bearing unstable ‘quicksand’ conditions. Contemporary methods were not well suited to tunnelling through such conditions, and in previous decades, several canal tunnels had been planned to specifically divert around expected ‘bad ground’, and others took years to complete at great expense. Stephenson’s team, drawing on their experience from the mining industry, did not take this approach and ultimately worked through the unstable ground, albeit with considerable delays and cost increases. This was achieved in part by establishing a large-scale groundwater pumping system, unique for the time, that lowered groundwater levels and stabilised the quicksand, which resulted from a buried channel of glaciofluvial sands, cut into bedrock, that had been missed by trial borings. Steam engines were used to pump from multiple shafts (including four dedicated pumping shafts, off set from the tunnel alignment), with a reported pumping rate of 136 l/s for several months. One unusual feature was the use of flatrod systems to transmit mechanical power horizontally; this allowed a single engine to drive pumps in several different shafts.

QTQTN motif upstream of the furin-cleavage site plays key role in SARS-CoV-2 infection and pathogenesis.

The furin cleavage site (FCS), an unusual feature in the SARS-CoV-2 spike protein, has been spotlighted as a factor key to facilitating infection and pathogenesis by increasing spike processing 1,2. Similarly, the QTQTN motif directly upstream of the FCS is also an unusual feature for group 2B coronaviruses (CoVs). The QTQTN deletion has consistently been observed in in vitro cultured virus stocks and some clinical isolates 3. To determine whether the QTQTN motif is critical to SARS-CoV-2 replication and pathogenesis, we generated a mutant deleting the QTQTN motif (ΔQTQTN). Here we report that the QTQTN deletion attenuates viral replication in respiratory cells in vitro and attenuates disease in vivo. The deletion results in a shortened, more rigid peptide loop that contains the FCS, and is less accessible to host proteases, such as TMPRSS2. Thus, the deletion reduced the efficiency of spike processing and attenuates SARS-CoV-2 infection. Importantly, the QTQTN motif also contains residues that are glycosylated4, and disruption its glycosylation also attenuates virus replication in a TMPRSS2-dependent manner. Together, our results reveal that three aspects of the S1/S2 cleavage site (the FCS, loop length, and glycosylation) are required for efficient SARS-CoV-2 replication and pathogenesis.

On the Role of Inhibition in Suppression-Induced Forgetting

Suppressing retrieval of unwanted memories can cause forgetting, an outcome often attributed to the recruitment of inhibitory control. This suppression-induced forgetting (SIF) generalizes to different cues used to test the suppressed content (cue-independence), a property taken as consistent with inhibition. But does cue-independent forgetting necessarily imply that a memory has been inhibited? Tomlinson et al. (2009) reported a surprising finding that pressing a button also led to cue-independent forgetting, which was taken as support for an alternative interference account. Here we investigated the role of inhibition in forgetting due to retrieval suppression and pressing buttons. We modified Tomlinson et al.’s procedure to examine an unusual feature they introduced that may have caused memory inhibition effects in their experiment: the omission of explicit task-cues. When tasks were uncued, we replicated the button-press forgetting effect; but when cued, pressing buttons caused no forgetting. Moreover, button-press forgetting partially reflects output-interference effects at test and not a lasting effect of interference. In contrast, SIF occurred regardless of these procedural changes. Collectively, these findings indicate that simply pressing a button does not induce forgetting, on its own, without confounding factors that introduce inhibition into the task and that inhibition likely underlies SIF.

Cystic Encapsulated Papillary Carcinoma in the Male Breast: An Unusual Feature With a Diagnostic Challenge

Papillary carcinoma in the male breast is uncommon. Here, we report a case of a large encapsulated papillary carcinoma (EPC) in a 62-year-old male. The patient presented with a left breast mass of 1-year duration and bloody nipple discharge for several days. Mammography and breast ultrasonography showed a large left breast mass. The initial biopsy demonstrated fat necrosis with acute and chronic inflammation only. Due to clinical suspicion, a repeat biopsy was performed and revealed scant fragments of papillary carcinoma in a background of inflammation. The patient underwent left total mastectomy. Grossly, the breast contained a 9.0 cm entirely cystic lesion lined by a hemorrhagic thick fibrotic wall. No solid area was identified in the cyst. The entire cyst wall was examined under microscopy; only a few sections with papillary carcinoma were identified. The lesion was confined to the cyst wall; so, a diagnosis of EPC was made. Compared to the previously reported EPC cases of male breast, the lesion of this case was unusually cystic, which making the diagnosis challenging. Therefore, awareness of this unusual feature, repeat biopsy when the pathology result is discordant, and extensive sampling of the lesion are essential for making the correct diagnosis and guiding patient management.

Two new species of Astrothelium (Trypetheliaceae) with amyloid ascospores inhabiting the canopy of Quercus humboldtii trees in Colombia

Subandine and high Andean forests are often dominated by oak trees and these are recognized as suitable phorophytes for diverse epiphyte communities. Among the latter, lichens in the upper strata appear to be understudied. Here, we report the discovery of two new species of Astrothelium (Trypetheliaceae), a diverse genus of tropical crustose lichens, both with the unusual feature of muriform, amyloid ascospores. Astrothelium mordonialensis is characterized by an olive-green thallus with solitary ascomata producing muriform and amyloid ascospores with tightened center and A. rogitamae by a light brownish to greenish grey thallus with yellow pigmented solitary ascomata, producing muriform and amyloid ascospores.

Supernova constraints on an axion-photon-dark photon interaction

We present the supernova constraints on an axion-photon-dark photon coupling, which can be the leading coupling to dark sector models and can also lead to dramatic changes to axion cosmology. We show that the supernova bound on this coupling has two unusual features. One occurs because the scattering that leads to the trapping regime converts axions and dark photons into each other. Thus, if one of the two new particles is sufficiently massive, both production and scattering become suppressed and the bounds from bulk emission and trapped (area) emission both weaken exponentially and do not intersection The other unusual feature occurs because for light dark photons, longitudinal modes couple more weakly than transverse modes do. Since the longitudinal mode is more weakly coupled, it can still cause excessive cooling even if the transverse mode is trapped. Thus, the supernova constraints for massive dark photons look like two independent supernova bounds super-imposed on top of each other.

Characteristics of sound production and associated pharyngeal jaws in the tomtate grunt Haemulon aurolineatum (Cuvier, 1830) in Caribbean reefs

The ability to produce sounds for acoustic communication is well known in different grunt species (Haemulidae). However, most of the sounds have not been described and the sound-producing mechanism of very few grunt species has been deeply studied. Additional data is needed to search for synapomorphy in the sonic mechanism. This study describes acoustic features and branchial anatomy in Haemulon aurolineatum. Correlations were found between some acoustic features and standard length, showing the largest specimens produced shorter, lower-pitched grunts of higher intensity. Examinations of acoustic features and branchial anatomy show that H. aurolineatum uses the same stridulatory mechanism described previously in H. flavolineatum. The unusual feature of Haemulon species concerns the fourth ceratobranchials. These appear to be part of the lower pharyngeal jaws since they possess firmly attached teeth that face the upper pharyngeal jaws. The stridulation results from the rubbing of both pharyngeal and fourth ceratobranchial teeth. This mechanism is probably common to the 23 Haemulon species, but additional information is needed regarding the mechanism of other Haemulinae species to produce stridulatory sounds. Fourth ceratobranchials could constitute a key element of Haemulinae ability to produce sounds providing an eventual synapomorphic aspect of the mechanism in the family.