Daphniid zooplankton assemblage shifts in response to eutrophication and metal contamination during the Anthropocene

Additional results from the principal component analyses conducted on eutrophication and metals data, as well as daphniid assemblages, and species richness rarefaction

The influence of facemasks on communication in healthcare settings: a systematic review

PurposeAlthough a well-established aspect of healthcare practice, the impact of facemasks on verbal communication is surprisingly ambiguous.Materials and MethodsA systematic search was conducted in APA PSYCHinfo, CINAHL, NHS Knowledge Network, Medline and SPORTDiscus databases from inception to November 2022 according to the PRISMA guidelines. Studies reporting an objective measure of speech understanding in adults, where information was transmitted or received whilst wearing a facemask were included. Risk of bias of included studies was assessed with the Newcastle-Ottawa score.ResultsFour hundred and thirty-three studies were identified, of which fifteen were suitable for inclusion, incorporating 350 participants with a median age of 49 (range 19 to 74) years. Wide heterogeneity of test parameters and outcome measurement prohibited pooling of data. 93% (14 of 15) studies reported a deleterious effect of facemasks on speech understanding, and 100% (5 of 5) of the included studies reported attenuation of sound with facemask usage. Background noise added further deleterious effects on speech understanding which was particularly problematic within hearing-impaired populations. Risk of bias in included studies varied but overall was modest.ConclusionsDespite considerable complexity and heterogeneity in outcome measure, 93% (14 of 15) articles suggest respiratory protective equipment negatively affects speech understanding in normal hearing and hearing-impaired adults.Implications for Rehabilitation As a result of the covid-19 pandemic, facemask use is now commonplace across all healthcare and rehabilitation settings and has material implications for interpersonal communication. This systematic review of human communicative studies highlights that the use of facemasks does indeed inhibit communication through effects on speech intelligibility and through sound attenuation. These effects are evident in both normal hearing and hearing-impaired adults due to the visual cues required with lipreading and facial expressions during communication. The presence of background noise also produces deleterious effects on speech understanding and is more problematic for hearing-impaired populations. Simple recommendations to reduce background noise (where possible), to step closer (where social-distancing rules permit), to speak louder or to use speech to text applications (if practical) could all mitigate these communicative barriers. Further an awareness of persons with hearing impairments, the function (or otherwise) of hearing aids in those patients that require these, and an ability to use transparent facemasks can be specifically helpful

Diagnosis and management of testicular compartment syndrome caused by tension hydrocele

A hydrocele is an abnormal collection of fluid within the tunica vaginalis which may either be congenital or acquired. Hydroceles are usually painless and don\u27t require immediate intervention unless they impact activities of daily living. This case demonstrates a rare complication of hydroceles termed tension hydrocele which presented with scrotal swelling and acute pain. Unlike the classic presentation of hydroceles with minimal pain or discomfort, it is important to recognize tension hydroceles as an extremely rare but possible cause of acute scrotum, which needs to be emergently diagnosed and treated

Internal performance of a nonaxisymmetric nozzle with a rotating upper flap and a center-pivoted lower flap

An investigation was conducted at wind-off conditions in the static-test facility of the Langley 16-Foot Transonic Tunnel to determine the internal performance characteristics of a single expansion-ramp nozzle with thrust-vectoring capability to 105 degrees. Thrust vectoring was accomplished by the downward rotation of an upper flap with adaptive capability for internal contouring and a corresponding rotation of a center-pivoted lower flap. The static internal performance of configurations with pitch thrust-vector angles of 0 degrees, 60 degrees, and 105 degrees each with two throat areas, was investigated. The nozzle pressure ratio was varied from 1.5 to approximately 8.0 (5.0 for the maximum throat area configurations). Results of this study indicated that the nozzle configuration of the present investigation, when vectored, provided excellent flow-turning capability with relatively high levels of internal performance. In all cases, the thrust vector angle was a function of the nozzle pressure ratio. This result is expected because the flow is bounded by a single expansion surface on both vectored- and unvectored-nozzle geometries

Multiple sulfur isotope signatures of sulfite and thiosulfate reduction by the model dissimilatory sulfate-reducer, Desulfovibrio alaskensis str. G20

Dissimilatory sulfate reduction serves as a key metabolic carbon remineralization process in anoxic marine environments. Sulfate reducing microorganisms can impart a wide range in mass-dependent sulfur isotopic fractionation. As such, the presence and relative activity of these organisms is identifiable from geological materials. By extension, sulfur isotope records are used to infer the redox balance of marine sedimentary environments, and the oxidation state of Earth's oceans and atmosphere. However, recent work suggests that our understanding of microbial sulfate reduction (MSRs) may be missing complexity associated with the presence and role of key chemical intermediates in the reductive process. This study provides a test of proposed metabolic models of sulfate reduction by growing an axenic culture of the well-studied MSRs, Desulfovibrio alaskensis strain G20, under electron donor limited conditions on the terminal electron acceptors sulfate, sulfite or thiosulfate, and tracking the multiple S isotopic consequences of each condition set. The dissimilatory reduction of thiosulfate and sulfite produce unique minor isotope effects, as compared to the reduction of sulfate. Further, these experiments reveal a complex biochemistry associated with sulfite reduction. That is, under high sulfite concentrations, sulfur is shuttled to an intermediate pool of thiosulfate. Site-specific isotope fractionation (within thiosulfate) is very large (34ε ~ 30‰) while terminal product sulfide carries only a small fractionation from the initial sulfite (34ε < 10‰): a signature similar in magnitude to sulfate and thiosulfate reduction. Together these findings show that microbial sulfate reduction (MSR) is highly sensitive to the concentration of environmentally important sulfur-cycle intermediates (sulfite and thiosulfate), especially when thiosulfate and the large site-specific isotope effects are involved

The Proportion of Fixed-Point-Free Elements of a Transitive Permutation Group

In 1990 Hendrik W. Lenstra, Jr. asked the following question: if G is a transitive permutation group of degree n and A is the set of elements of G that move every letter, then can one find a lower bound (in terms of n) for f(G) = |A|/|G|? Shortly thereafter, Arjeh Cohen showed that 1/n is such a bound. Lenstra’s problem arose from his work on the number field sieve. A simple example of how f(G) arises in number theory is the following: if h is an irreducible polynomial over the integers, consider the proportion: |{primes ≤ x | h has no zeroes mod p}| / |{primes ≤ x}| As x → ∞, this ratio approaches f(G), where G is the Galois group of h considered as a permutation group on its roots. Our results in this paper include explicit calculations of f(G) for groups G in several families. We also obtain results useful for computing f(G) when G is a wreath product or a direct product of permutation groups. Using this we show that {f(G) | G is transitive} is dense in [0, 1]. The corresponding conclusion is true if we restrict G to primitive groups

Adjuvant Radiotherapy for Synchronous Bilateral Testicular Seminoma: A Case Report and a Review of the Pertinent Literature

Few cases of synchronous bilateral stage I seminomas have been reported in the world literature. We present a case of bilateral synchronous testicular seminoma, the current literature on the management of stage I seminoma, and the implications for radiotherapy. A forty-year-old man presented with synchronous bilateral classical seminomas, both stage IA. After undergoing bilateral inguinal orchiectomy, he received adjuvant external beam radiotherapy, with a standard paraaortic field. After 18 months of followup, he remains well, without evidence of recurrence. Bilateral germ cell tumors (BGCTs) are reported consistently at a low rate. Bilateral radical inguinal orchiectomy is standard of care, yet some groups have proposed an organ preservation approach. Of the reported cases of bilateral stage I synchronous GCT, with concordant seminoma histology, most of them were treated with bilateral orchiectomy and adjuvant radiotherapy. Although morbidity associated with radiotherapy directed at the abdomen is not negligible, adjuvant paraaortic radiotherapy remains safe and well-tolerated treatment regime. Bilateral synchronous stage I seminoma of the testes is rare. Organ preservation remains investigational. Chemotherapy is probably a reasonable option. We propose that patients with bilateral stage I synchronous GCT, with concordant seminoma histology, should be managed with bilateral orchiectomy, followed by paraaortic radiotherapy