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During the Mid-Pleistocene Transition (MPT), ca. 1200–800 000 years ago (ka), the Earth's glacial cycles changed from 41 to 100 kyr periodicity. The emergence of this longer ice age periodicity was accompanied by higher global ice volume in glacial periods and lower global ice volume in interglacial periods. Since there is no known change in external orbital forcing across the MPT, it is generally agreed that the cause of this transition is internal to the Earth system. Resolving the climate, carbon cycle, and cryosphere processes responsible for the MPT remains a major challenge in Earth and palaeoclimate science. To address this challenge, the international ice core community has prioritised recovery of an ice core record spanning the MPT interval. Here we present results from a simple generalised least-squares (GLS) model that predicts atmospheric CO2 out to 1.8 Myr. Our prediction utilises existing records of atmospheric carbon dioxide (CO2) from Antarctic ice cores spanning the past 800 kyr along with the existing LR04 benthic δ18Ocalcite stack (Lisiecki and Raymo, 2005; hereafter "benthic δ18O stack") from marine sediment cores. Our predictions assume that the relationship between CO2 and benthic δ18O over the past 800 000 years can be extended over the last 1.5 million years. The implicit null hypothesis is that there has been no fundamental change in feedbacks between atmospheric CO2 and the climate parameters represented by benthic δ18O , global ice volume, and ocean temperature. We test the GLS-model-predicted CO2 concentrations against observed blue ice CO2 concentrations, δ11B -based CO2 reconstructions from marine sediment cores, and δ13C of leaf-wax-based CO2 reconstructions (Higgins et al., 2015; Yan et al., 2019; Yamamoto et al., 2022). We show that there is no clear evidence from the existing blue ice or proxy CO2 data to reject our predictions or our associated null hypothesis. A definitive test and/or rejection of the null hypothesis may be provided following recovery and analysis of continuous oldest ice core records from Antarctica, which are still several years away. The record presented here should provide a useful comparison for the oldest ice core records and an opportunity for further constraints on the processes involved in the MPT. [ABSTRACT FROM AUTHOR]

Antarctica is the coldest, driest, highest, and windiest continent, and it is home to 70 research stations from 29 countries. Antarctica is a remote and harsh place, without many weather stations or people. This means scientists must come up with creative ways to learn about the continent's past climate. Scientists use sediment that builds up on the ocean floor to explore what Earth was like more than a million years ago; and they use satellites to learn about today's climate. But how can we know what happened in the time between? This is where ice can help! When snow falls in Antarctica, it builds up in layers that get squeezed into ice. These layers hold traces of the past climate. The ice in Antarctica is the oldest anywhere in the world. Hundreds of thousands of years ago until now. These studies help us to better understand the past climate and to predict the future climate. [ABSTRACT FROM AUTHOR]

During the Mid-Pleistocene Transition (MPT), ca. 1250–800 kya, the Earth's glacial cycles changed from 41 ky to 100 ky periodicity. The emergence of this longer ice-age periodicity was accompanied by higher global ice volume in glacial periods and lower global ice volume in interglacial periods. Since there is no known change in external orbital forcing across the MPT, it is generally agreed that the cause of this transition is internal to the earth system. Resolving the climate–carbon cycle–cryosphere dynamics processes responsible for the MPT remains a major challenge in ice core and climate science. To address this challenge, the international ice core community has prioritized recovery of an ice core record spanning the MPT interval. The results from such 'oldest ice' projects are still several years away. Our objective here it to make an advanced prediction of atmospheric CO2 out to 1.5 my. Our prediction utilizes existing records of atmospheric carbon dioxide (CO2) from Antarctic ice cores spanning the past 800 ky along with the existing benthic water stable isotope (ẟ18O) record from marine sediment cores. Our predictions assume that the relationship between CO2 and benthic ẟ18O over the past 800 thousand years can be extended over the last one and a half million years. The implied null hypothesis is that there has been no fundamental change in the global climate–carbon cycle–cryosphere feedback systems across the MPT. We find that our predicted CO2 record is significantly lower during glacial intervals than the existing blue-ice and boron isotope-based estimates of CO2 that pre-date the continuous 800 ky CO2 record. Our predicted glacial CO2 concentrations are ~9 ppm below glacial CO2 concentrations observed in blue ice data at ca. 1 mya and ~19 ppm below glacial CO2 concentrations reconstructed from boron isotopic data over ca ~1.1–1.25 mya. These results support rejection of our null hypothesis and provide quantitative evidence of a fundamental shift in the global climate–carbon cycle–cryosphere feedback systems across the MPT. However, the definitive test of the various theories explaining the MPT will be comparison of our predicted records with the forthcoming oldest ice core records. [ABSTRACT FROM AUTHOR]

During the Mid-Pleistocene Transition (MPT), ca. 1250-800 kya, the Earth's glacial cycles changed from 41 ky to 100 ky periodicity. The emergence of this longer ice-age periodicity was accompanied by higher global ice volume in glacial periods and lower global ice volume in interglacial periods. Since there is no known change in external orbital forcing across the MPT, it is generally agreed that the cause of this transition is internal to the earth system. Resolving the climate-carbon cycle-cryosphere dynamics processes responsible for the MPT remains a major challenge in ice core and climate science. To address this challenge, the international ice core community has prioritized recovery of an ice core record spanning the MPT interval. The results from such 'oldest ice' projects are still several years away. Our objective here it to make an advanced prediction of atmospheric CO2 out to 1.5 my. Our prediction utilizes existing records of atmospheric carbon dioxide (CO2) from Antarctic ice cores spanning the past 800 ky along with the existing benthic water stable isotope (&#94818O) record from marine sediment cores. Our predictions assume that the relationship between CO2 and benthic &#94818O over the past 800 thousand years can be extended over the last one and a half million years. The implied null hypothesis is that there has been no fundamental change in the global climate-carbon cycle-cryosphere feedback systems across the MPT. We find that our predicted CO2 record is significantly lower during glacial intervals than the existing blue-ice and boron isotope-based estimates of CO2 that pre-date the continuous 800 ky CO2 record. Our predicted glacial CO2 concentrations are ~9 ppm below glacial CO2 concentrations observed in blue ice data at ca. 1 mya and ~19 ppm below glacial CO2 concentrations reconstructed from boron isotopic data over ca ~1.1-1.25 mya. These results support rejection of our null hypothesis and provide quantitative evidence of a fundamental shift in the global climate-carbon cycle-cryosphere feedback systems across the MPT. However, the definitive test of the various theories explaining the MPT will be comparison of our predicted records with the forthcoming oldest ice core records. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate whether stemless shoulder implants in rheumatoid arthritis (RA) patients provide comparable functional outcomes to patients with osteoarthritis or post-traumatic arthritis. In addition, the study assessed for differences in incidence of radiolucent lines or proximal humeral bone loss during radiographic follow-up.Methods: Consecutive stemless shoulder arthroplasties performed in RA patients and a matched control group were retrospectively identified between February 2012 and 2018. Thirty-five patients were included in each group: 24 total shoulder arthroplasty (TSA) and 11 hemiarthroplasty (HA). Patients were evaluated annually using the Oxford Shoulder Score (OSS) and radiographically.Results: The mean OSS significantly improved in all groups until 24 months. The mean improvement for RA TSA and HA patients at 24 months was 19.86 (95% CI 10.66-29.05, p = 0.0004) and 19.71 (95% CI 7.33-32.31, p = 0.0084), respectively. The mean improvement in the control TSA and HA patients at 24 months was 20.86 (95% CI 17-24.71, p = 0.0001) and 17.86 (95% CI 1.36-34.35, p = 0.0381), respectively. During the study period, two patients in the RA TSA group (8%), one patient in the control TSA group (4%) and one patient in the control HA group (9%) required revision. The proportion of progressive proximal humeral bone loss after TSA was 33% in the RA group and 13% in the control group.Conclusion: Stemless shoulder implants can provide significant improvement in functional scores in RA patients in the short term. However, early bone loss around the humeral implant is a concern and the authors recommend long-term clinical and radiological follow-up. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the risk of neurological injury from the placement of a bicortical guidewire during subpectoral biceps tenodesis.Methods: Ten forequarter cadaver specimens were evaluated. A bicortical guidewire was placed, and measurements to important local neurological structures were made with digital calipers at open dissection.Results: The mean (range, SD) distances from the guidewire to the respective nerves was as follows: axillary nerve posteriorly, 15.7 mm (10-22 mm, 3.4); axillary nerve laterally, 18.7 mm (12-27 mm, 4.3); radial nerve posteriorly, 26.2 mm (16-35 mm, 7.0); radial nerve medially, 25 mm (16-33 mm, 4.4); and musculocutaneous nerve, 20.1 mm (12-26 mm, 5.2).Conclusions: There has been some disagreement in the literature regarding the proximity of a bicortical guidewire to the axillary nerve posteriorly. The results of this study concur with reports from several other authors and demonstrate that this nerve is at risk of iatrogenic injury when using this technique. The clinical relevance of this work is to allow surgeons to better understand the proximity of the nerve to a bicortical guidewire and to highlight that this risk is avoided with a unicortical technique. [ABSTRACT FROM AUTHOR]

We assessed the proximity of neurological structures to arthroscopic portals in a cadaveric study and through a systematic review. Arthroscopy was performed on ten cadaveric wrists. Subsequently the specimens were dissected to isolate the superficial branch of the radial nerve, the dorsal branch of the ulnar nerve, the posterior interosseous nerve and the extensor tendons. We measured the distances from the nerves to common portals. For the systematic review Pubmed and EMBASE were searched on the 31 May 2014 for cadaveric studies reporting the proximity of neurological structures to any arthroscopic wrist portal. In the cadaveric study, partial injuries were seen to six extensor tendons and one posterior interosseous nerve; it was assumed this was due to creation of the portals. Seven published studies were included in the systematic review. The dorsal sensory branch of the ulnar nerve was found to be at risk by performing the 6 Ulnar, 6 Radial and ulnar midcarpal portals, the sensory branch of the radial nerve by the 1–2 and 3–4 portals and the posterior interosseous nerve by the 3–4 and 4–5 portals.Level of evidence: V [ABSTRACT FROM AUTHOR]

Members of the Haptophyta from British waters have been listed in a number of check-lists between 1953 and 1976 (Parke, 1953; Parke & Dixon, 1964, 1968, 1976), but there has been no attempt to draw the records together on a world-wide basis. However, a recent review of the classification system of the coccolithophorids included a check-list of all species thought to be extant from marine, coastal and freshwater habitats (Jordan & Kleijne, 1994). At the same time, two ambitious projects, the Encyclopaedia of Algal Genera (ed. B.C. Parker, in preparation) and the preparation of a CD-ROM retrieval system for information on algal and protist groups by the Expert-Centre for Taxonomic Identification (ETI), have required further collation of the available records (see Note 1), and, as a result, we have now extended the scheme of Jordan & Kleijne (1994) to include a global list of all extant haptophytes. [ABSTRACT FROM PUBLISHER]

Argues against some commentators' views on the task of Plato in the "Sophist." Suggestion that it is often thought that Plato sets himself as important task in the sophist; Issues which are not the concern of Plato in the "Sophist." Necessity of being guided in one's interpretation by the solution Plato offers to his problems; Serious problems presented by the view of some commentators; failure of Plato's contrast between otherness and opposition to support the other commonly held view of the problems Plato is facing in the Sophist." Introduction of a new interpretation of Plato's task, via a consideration of his stated intention to commit patricide and refute Parmenides' criticism of the road of enquiry followed by mortals.

The division Haptophyta is represented only by about 300 extant species showing wide diversity in morphology, biochemistry and ecology. They have a world-wide distribution and are numerically important in phytoplankton populations in nearly all marine environments. Evidence from the geological record shows that they have been the major constituent of calcareous deposits since the Late Triassic and, as they have evolved quickly through time, their coccoliths have always shown wide morphological diversity. In today's oceans they occasionally produce extensive blooms, visible by satellite imagery, which have ecological impact. As a consequence of these blooms the haptophyte algae arenow receiving greater attention, as their role in the global sulphurand carbon cycles may influence the world's climate, and their potential as nuisance bloom algae have implications for commercial fishingand the marine ecosystem. As it is likely that these organisms have always produced such blooms, these effects may have been in operationfor the last 200 million years. [ABSTRACT FROM AUTHOR]