What are the real environmental impacts of Antarctic tourism? Unveiling their importance through a comprehensive meta-analysis.

Human activities in Antarctica were increasing before the COVID-19 pandemic, and tourism was not an exception. The growth and diversification of Antarctic tourism over the last few decades have been extensively studied. However, environmental impacts associated with this activity have received less attention despite an increasing body of scholarship examining environmental issues related to Antarctic tourism. Aside from raising important research questions, the potential negative effects of tourist visits in Antarctica are also an issue discussed by Antarctic Treaty Consultative Parties. This study presents the results of a meta-analysis of scholarly publications that synthesizes and updates our current knowledge of environmental impacts resulting from Antarctic tourism. A first publication database containing 233 records that focussed on this topic was compiled and subjected to a general bibliometric and content analysis. Further, an in-depth content analysis was performed on a subset of 75 records, which were focussed on showing specific research on Antarctic tourism impacts. The main topic, methods, management proposals, and research gaps highlighted by the respective authors of these 75 publications were assessed. The range of research topics addressed, the methods used - including the application of established research designs from the field of environmental impact assessment -, and the conclusions reached by the study authors are discussed. Interestingly, almost one third of the studies did not detect a direct relationship between tourism and significant negative effects on the environment. Cumulative impacts of tourism have received little attention, and long-term and comprehensive monitoring programs have been discussed only rarely, leading us to assume that such long-term programs are scarce. More importantly, connections between research and policy or management do not always exist. This analysis highlights the need for a comprehensive strategy to investigate and monitor the environmental impacts of tourism in Antarctica. A first specific research and monitoring programme to stimulate a debate among members of the Antarctic scientific and policy communities is proposed, with the ultimate goal of advancing the regulation and management of Antarctic tourism collaboratively.

Micromechanical Origin of Particle Size Segregation.

We computationally study the micromechanics of shear-induced size segregation and propose distinct migration mechanisms for individual large and small particles. While small particles percolate through voids without enduring contacts, large particles climb under shear through their crowded neighborhoods with anisotropic contact network. Particle rotation associated with shear is necessary for the upward migration of large particles. Segregation of large particles can be suppressed with inadequate friction, or with no rotation; increasing interparticle friction promotes the migration of large particles, but has little effect on the percolation of small particles.

Characterization of base roughness for granular chute flows.

Base roughness plays an important role in the dynamics of granular flows but is still poorly understood due to the difficulty of its quantification. For a bumpy base made of spheres, at least two factors should be considered in order to characterize its geometric roughness, namely, the size ratio of flow to base particles and the packing arrangement of base particles. In this paper, we propose an alternative definition of base roughness, R_{a}, as a function of both the size ratio and the distribution of base particles. This definition is generalized for random and regular packings of multilayered spheres. The range of possible values of R_{a} is presented, and optimal arrangements for maximizing base roughness are studied. Our definition is applied to granular chute flows in both two- and three-dimensional configurations, and is shown to successfully predict whether slip occurs at the base. A transition is observed from slip to nonslip conditions as R_{a} increases. Critical values of R_{a} are identified for the construction of a nonslip base at various angles of inclination.

Is locking plate fixation a better option than casting for distal radius fracture in elderly people?

OBJECTIVES: To compare the outcomes of locking plate fixation versus casting for displaced distal radius fracture with unstable fracture pattern in active Chinese elderly people. DESIGN: Historical cohort study. SETTING: Orthopaedic ward and clinic at Tseung Kwan O Hospital, Hong Kong. PATIENTS: Between 1 May 2010 and 31 October 2013, 57 Chinese elderly people aged 61 to 80 years were treated either operatively with locking plate fixation (n=26) or conservatively with cast immobilisation (n=31) for unstable displaced distal radius fracture. MAIN OUTCOME MEASURES: Clinical, radiological, and functional outcomes were assessed at 9 to 12 months after treatment. RESULTS: The functional outcome (based on the quick Disabilities of the Arm, Shoulder and Hand score) was significantly better in the locking plate fixation group than in the cast immobilisation group, while clinical and radiological outcomes were comparable with those in other similar studies. CONCLUSIONS: Locking plate fixation resulted in better functional outcome for displaced distal radius fracture with unstable fracture pattern in active Chinese elderly people aged 61 to 80 years. Further prospective study with long-term follow-up is recommended.

Accessory radial collateral vascular bone graft for the management of nonunion of humeral shaft fracture after intramedullary nailing.

SUMMARY: An easy pedicle vascular bone graft technique for the management of nonunion of humeral shaft fracture is described. The distal and lateral part of the humerus, including the lateral epicondyle, is transferred to the nonunion site of the humerus. This vascular bone graft is based on the accessory radial collateral artery. It promotes healing of the nonunion.

Trans-triquetral dorsal perilunate fracture dislocation.

A rare case of trans-triquetral dorsal perilunate dislocation is described. It differs from the Mayfield and Johnson theory of progressive perilunar instability in greater arc injuries which states that the injury passes from the radial to the ulnar carpal bones and soft tissues in stages. This injury supports the concept of a reverse greater arc injury from ulnar to radial being possible with the radial carpal bones being spared in some cases.

Subcapital femoral neck fracture following successful trochanteric fracture treatment with a dynamic hip screw: a report of five cases.

A subcapital femoral neck fracture complicating a healed trochanteric fracture is rare. Such cases are managed in a rather heterogeneous manner, i.e. there exists a mixture of cases treated by either fixed angle devices or dynamic compression screws. We describe 5 patients who developed subcapital femoral neck fractures after healed trochanteric fractures treated with dynamic compression screws. The subjects' clinical data, operative records, and radiographs have been studied retrospectively and the literature reviewed. The risk factors for such a complication include being of advanced age, female, osteoporotic, and having a small femoral head and neck, and a basicervical type of fracture.

Acute dislocation of the elbow caused by a solitary osteochondroma of the proximal radius.

A young man presented with acute dislocation of the left elbow at the radio-capitellar articulation caused by trapping of the biceps tendon at the stalk of a solitary osteochondroma. There was no deformity of the ulna and radius shaft suggestive of a developmental growth disturbance of the forearm bones. Good reduction could be achieved by simple relocation of the biceps tendon. The osteochondroma was excised.

The crisscross injury mechanism in forearm injuries.

INTRODUCTION: A new mechanism of injury of the forearm bones, crisscross injury, is described. It is more common than the Essex-Lopresti fracture dislocation. The old concept of isolated injury of one side of the radioulnar joint may be challenged. It often occurs in Mason type II fracture dislocation of the radial head or dislocation of radioulnar joints. MATERIALS AND METHODS: The first part was a cadaveric study of the crisscross injury of forearms. The second part was a clinical study of the crisscross injury in some cases of Mason type II fracture radial head and double dislocation of the radioulnar joint. RESULTS: The cadaveric study confirmed a stable crisscross fracture dislocation injury with intact interosseous membrane. The clinical study echoed the presence of this injury by imaging techniques. CONCLUSION: The crisscross injury mechanism explains the mirror pathogenesis of the traumatic fracture dislocation of the distal and proximal radioulnar joints with intact shaft of the radius and ulna. Co-existing subluxation or dislocation of the other radioulnar articulation must not be overlooked in cases of fracture dislocation of one radioulnar joint. Two types of crisscross injury of forearm bones are proposed.

Short-stay in-patient rehabilitation of elderly patients with chronic obstructive pulmonary disease: prospective study.

OBJECTIVES: To evaluate the effectiveness of a short-stay in-patient rehabilitation programme. DESIGN: Prospective case-control cohort study. SETTING: Regional medical centre, Hong Kong. PATIENTS: One hundred and thirty symptomatic elderly patients with chronic obstructive pulmonary disease who had been treated for an acute respiratory illness in 1998. They were divided into two groups: the conventional treatment group, which received no rehabilitation (n=65), and the rehabilitation group (n=65). INTERVENTION: A short-stay in-patient rehabilitation programme was implemented, which included assessment, patient and caregiver education, an exercise regimen, physiotherapy, occupational therapy, and case conference. MAIN OUTCOME MEASURES: Length of stay, hospital re-admission rate, and admission-free interval. RESULTS: The mean length of stay in the rehabilitation ward was 6.2 days. The rate of hospital re-admission was significantly higher in the conventional treatment group than in the rehabilitation group, both within 28 days of discharge home (relative risk=3.33; 95% confidence interval, 2.32-4.56; P=0.019) and at 100 days after discharge (relative risk=2.47; 95% confidence interval, 1.78-3.48; P<0.001). The admission-free interval was significantly longer in the rehabilitation group than in the conventional treatment group (1.13 years vs 0.86 years; P<0.001). CONCLUSION: A short-stay in-patient rehabilitation programme is effective in reducing hospital re-admission rates. This type of rehabilitation service may be important for elderly patients, as well as for patients with more advanced disease and more functional deficits than others.

Unimuscular neuromuscular insult of the leg in partial anterior compartment syndrome in a patient with combined fractures.

A complicated case of ipsilateral fractures of the left femur and tibia after a road traffic accident is reported. The patient presented with numbness of the first web of his left foot and contracture of the extensor hallucis longus muscle, with fixed length deformity after intramedullary nailing of the femur and tibia. The extensor digitorum longus and tibialis anterior muscles were spared. Tinel's sign could be elicited at the mid-portion of the anterior compartment of the injured leg. This indicated that the distal half of the anterior tibial nerve (deep peroneal nerve), together with the extensor hallucis muscle of the anterior compartment of the leg, had been damaged. The subsequent management of this patient is described.

A new method of functional tendon transfer for the dysfunction of extensor hallucis longus.

A surgical technique of functional tendon transfer for the treatment of extensor hallucis longus (EHL) rupture is described. By using the extensor digitorum longus tendon of the second toe, the patient regains active dorsiflexion of the big toe and the deformity of the toe is corrected.

Chronic erosion injury of a digit by a ring: epidemiology, staging, treatment and prognosis.

A 71-year-old man who presented with chronic erosion of a digit by an ornamental ring is reported. The literature is reviewed; and the epidemiology, risk factors, staging, treatment and outcome are discussed.

Incidence of deep vein thrombosis after colorectal surgery in a Chinese population.

INTRODUCTION: Contemporary studies indicate that the incidence of deep vein thrombosis (DVT) is increasing in the Asian population. The present study aims to evaluate the incidence of postoperative DVT in Chinese patients undergoing surgery for colorectal malignancies. METHODS: Fifty-one consecutive patients with carcinoma of the rectum or sigmoid colon scheduled for resection were included in the study. None of the study subjects were given any form of DVT prophylaxis. Serial duplex ultrasound of both lower limbs were examined in the preoperative and postoperative periods. RESULTS: Three patients were excluded from the study because of the presence of DVT noted preoperatively. A total of 20/48 (41.7%) patients developed asymptomatic calf vein thrombosis. One out of 20 patients required anticoagulation because of thrombus propagation. None of the subjects showed signs or symptoms of DVT or pulmonary embolism. A total of 7/20 thrombi resolved completely at 4 weeks after operation. Only old age and smoking were identified as being associated with a higher incidence of DVT. Disseminated disease, type of operation, duration of operation and postoperative complications did not appear to be risk factors for DVT. CONCLUSION: A high incidence of asymptomatic calf vein thrombosis occurred after colorectal surgery for malignancies in Chinese. The majority did not progress even without anticoagulation.

All aboard the chip!

The Cambridge Healthtech Institute's Microarrays and Microchips conference was held in Tokyo, Japan, 4-5 June 2001.

Trephine bone grafting technique for the treatment of scaphoid nonunion.

A simple, minimally invasive trephine bone grafting technique for the treatment of scaphoid fracture nonunions is described. The method has a short surgical time, good results, and minimal donor site morbidity.