Author Correction: Forearc carbon sink reduces long-term volatile recycling into the mantle.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

Author Correction: Forearc carbon sink reduces long-term volatile recycling into the mantle.

Change history: In this Article, the original affiliation 2 was not applicable and has been removed. In addition, in the Acknowledgements there was a statement missing and an error in a name. These errors have been corrected online.

Forearc carbon sink reduces long-term volatile recycling into the mantle.

Carbon and other volatiles in the form of gases, fluids or mineral phases are transported from Earth's surface into the mantle at convergent margins, where the oceanic crust subducts beneath the continental crust. The efficiency of this transfer has profound implications for the nature and scale of geochemical heterogeneities in Earth's deep mantle and shallow crustal reservoirs, as well as Earth's oxidation state. However, the proportions of volatiles released from the forearc and backarc are not well constrained compared to fluxes from the volcanic arc front. Here we use helium and carbon isotope data from deeply sourced springs along two cross-arc transects to show that about 91 per cent of carbon released from the slab and mantle beneath the Costa Rican forearc is sequestered within the crust by calcite deposition. Around an additional three per cent is incorporated into the biomass through microbial chemolithoautotrophy, whereby microbes assimilate inorganic carbon into biomass. We estimate that between 1.2 × 108 and 1.3 × 1010 moles of carbon dioxide per year are released from the slab beneath the forearc, and thus up to about 19 per cent less carbon is being transferred into Earth's deep mantle than previously estimated.

Pentoxifylline and tocopherol in the management of patients with osteoradionecrosis, the Portsmouth experience.

Osteoradionecrosis of the jaw remains the most problematic consequence of radiotherapy for the management of head and neck cancer. Treatment is often complex and multimodal. New theories on its pathophysiology have allowed the development of potential treatment modalities, including the use of pentoxifylline and tocopherol. In this retrospective case series we examined the outcomes of patients with ORN prescribed pentoxifylline and tocopherol.

Primary epithelial submandibular salivary gland tumours--review of management in a district general hospital setting.

Primary epithelial submandibular gland (SMG) tumours are uncommon, accounting for 8-12% of all salivary gland neoplasms, and most studies come from large specialised centres. There is little published about the relative frequency and outcome of SMG tumours treated in general hospitals. A retrospective study from two district general hospitals over a 10 year period (1996-2005). Seventeen benign (68%) and eight malignant (32%) tumours were included. A painless mass was the most common presentation. Pain and paraesthesia were not pathognomonic of malignancy. Pleomorphic adenoma accounted for all 17 benign tumours and adenoid cystic carcinoma was the commonest malignant tumour. Fine needle aspiration cytology (FNAC) accurately identified 78% of the benign tumours but none of the malignant tumours. Pre-operative imaging was also unable to distinguish malignant from benign tumours. Incomplete excision was reported in 20% of cases and was more common for malignant tumours. It may be difficult to distinguish benign from malignant SMG tumours on clinical examination and pre-operative investigations. Any suspected submandibular tumour should be considered for early treatment even when FNAC is suggestive of a benign tumour.

Factors influencing the occurrence of multicentric and 'recurrent' Warthin's tumour: a cross sectional study.

The multicentric nature of Warthin's tumour has been well recognised, though the factors predicting its occurrence and its influence on management remain speculative. In this cross sectional study, the authors analysed the presentation, management and outcome of solitary and multicentric Warthin's tumour, treated in the maxillofacial unit and investigated factors that could influence the occurrence of multicentric and recurrent tumours. Warthin's tumour was found in 24% (150/628) of patients presenting with parotid neoplasms and multicentric tumours were found in 13% (21/ 161) of parotidectomy specimens. Age, sex, side, site and smoking history were not predictors of multicentricity (P>0.40). Clinical examination (19%), imaging investigations (28%) and intra-operative palpation (33%) were poor at detecting multicentric tumours. Superficial parotidectomy was the most commonly performed operation. The recurrence rate was 0% in the solitary and 10% in the multicentric tumour group. Intra-operative rupture was not uncommon (11%), but was not associated with tumour recurrence (P= or >0.999). Incomplete excision (P=0.007) and multicentricity (P=0.026) were predictors of recurrence.

Multiple synchronous and metachronous neoplasms of the parotid gland: the Chichester experience.

Parotid neoplasms are usually solitary and multiple tumours occurring in an individual are uncommon. The incidence and implications of multiple synchronous and metachronous tumours remains relatively unknown. We reviewed the case notes of 606 patients who had parotidectomies for neoplastic lesions over a 30 year period and identified 30 patients (5%) with multiple primary tumours. There were 24 patients with synchronous tumours and 6 with metachronous tumours. Sixteen of the synchronous tumours (67%) were ipsilateral, whereas all six metachronous tumours were contralateral. Preoperative examination was effective at detecting bilateral tumours but poor at detecting multiple ipsilateral tumours. Multiple tumours were likely to be of the same histology (n=24, 80%) and Warthin's was by far the most common multiple tumour. Ipsilateral tumours of differing histological types and identical tumours other than Wartin's were uncommon. All but one patient had superficial parotidectomies and there were no recurrences.

Surgical management of incompletely excised basal cell carcinomas of the head and neck.

We made a retrospective audit of all basal cell carcinomas excised in the Maxillofacial Units at St. Richard's Hospital, Chichester and the Worthing and Southlands NHS Trust between 1990 and 1999. A total of 3795 BCCs were excised. Of these, 3560 were completely excised (93.8%) and 235 were incompletely excised (6.2%), which compares favourably with other series. Of these, 84 patients had further excision, 11 had radiotherapy, and 140 were kept under review. Residual tumour was present in 45% of the re-excised specimens. Of the 140 cases managed by observation, 21% recurred. Notably, 31% of patients in the observation cohort died of other causes without recurrence. Incomplete excision was significantly more likely (P < 0.001) if multiple lesions were excised at the time of operation. Involvement of multiple margins was not a significant risk factor for recurrence in the 'observed' cohort. This study shows that a flexible strategy, which balances observation, further excision and radiotherapy, is superior to any single approach.

Changing frequency of parotid gland neoplasms--analysis of 560 tumours treated in a district general hospital.

An analysis of all parotidectomies performed for neoplastic lesions in the maxillofacial unit at a district general hospital during a 26-year period between 1974-1999 was undertaken. The details analysed were age, sex, histology and temporal variations in the frequency of specific tumour types during the study period. A total of 538 parotidectomies performed on 529 patients in whom 560 tumours were present, formed the basis of this study. Marked variations were present in the age and sex distribution and relative frequency of specific tumour types in this study, when compared to previous reports. There were also differences in the age and sex distribution of pleomorphic adenoma and adenolymphoma (P <0.0001) in this study. The relative frequency of benign tumours and adenolymphoma increased, whereas that of pleomorphic adenoma decreased during the study period. In addition, there was a statistically significant decrease in the relative frequency of pleomorphic adenoma (P <0.0001) and an increase in adenolymphoma (P <0.0001) when comparisons were made with previous studies. This study from a defined population may be more representative of the true proportion of specific tumours in this population. The potential implications of the results on the investigation and treatment of parotid neoplasms is highlighted.

Evaluating cardiovascular disease prevention programs in African American communities.

This article reports on an evaluation of community cardiovascular disease prevention projects. The evaluation protocol involved a monitoring system for documenting community activities. It showed improvements in cardiovascular disease prevention services, community actions, planned products, and new or modified community programs to prevent cardiovascular disease. Reports from focus group sessions provided analyses of participants' perceived behaviors and satisfaction with eight community-based cardiovascular disease prevention projects in African American communities. Modest improvements in blood pressure, blood cholesterol, dietary intake, and physical activity among a convenience sample of participants in the community were noted.

Indications for third molar surgery.

Recent reports have suggested that the practice of prophylactic lower third molar surgery is widespread, possibly account for up to 50% of all patients treated. An objective effort to refute the findings of the previously published data was undertaken by the Maxillofacial Unit of a large district general hospital trust. A prospective study of 454 consecutive patients referred for third molar surgery demonstrated that in 96% of the patients, at least one nationally defined criteria for surgery was present. A concurrent retrospective audit of patients already on the waiting list for surgery identified that 97% had at least one valid criterion for surgery. Of those patients who presented with unilateral symptoms, over half had only the troublesome side removed. Only 11 out of 454 patients were accepted for treatment without a defined criterion, all of whom had partially erupted teeth. The evidence presented in the current study is compared with previously reported data and possible reasons for the variance are discussed.

Michigan physicians' perceptions of their role in managing obesity.

In a random sample of 211 primary-care physicians in Michigan, about 33% (n = 70) perceived their role in the prevention of obesity as coordinating and 39% (n = 82) as cooperative and of equal importance to that of other professionals. Perceived barriers to prevention of obesity were inadequate time to educate patients, method of reimbursement, and inadequate training in management of obesity. These results suggest that physicians' involvement in managing obesity can improve if they work closely with other health professionals.

Toward a symmetrical and an integrated framework of norms for nutrition communication in sub-Saharan Africa.

Nutrition is crucial to national development; an undernourished or a malnourished population is at risk for infectious diseases that may reduce its working and productive capacities. Sub-Saharan Africa leads the world in the proportion of its population that is chronically malnourished. This article presents a symmetrical and an integrated framework of norms for nutrition communication. It uses three nutrition communication projects in Africa to illustrate the application of those norms. Based on that review, it concludes that a community-based framework should emphasize at the outset--and throughout program implementation and evaluation--the importance of folk media (e.g., Africa's "oramedia") as both formative and summative norms for planning, implementing, and evaluating nutrition communication programs in Africa.

Controversies in third molar surgery--the national view on review strategies.

A national survey was conducted to establish the current practice of postoperative review of third molar surgery by the 255 fellows of the British Association of Oral and Maxillofacial Surgeons. Of the 216 complete responses, 134 say that they routinely reviewed all patients, while 67 did not. A further 15 fellows (7%) are currently considering their practice. Five (2%) stated that routine review should be compulsory and failure to do so was medically negligent. We conclude that a policy of selective rather than routine review is safe for most patients, but if a patient is under age, mentally retarded, taking psychoactive drugs, or has any other associated condition, then routine follow-up should be undertaken.

Labial sensory function following sagittal split osteotomy.

A retrospective assessment of labial sensory function following sagittal split osteotomy was undertaken by a combination of record analysis, postal questionnaire and objective sensory testing. Case records for 90 sides operated upon by a single consultant surgeon between 1979 and 1992 identified a prevalence of persisting sensory changed at 2 years of 6.7%. A higher incidence of sensory change was seen in patients treated with intermaxillary fixation/upper border wires than those managed with buccal monocortical miniplates. Postal questionnaire returns for 67 consultant operated sides identified a higher incidence of sensory change than recorded in the notes. 5.9% had long term persisting anaesthesia. Another 28% had more variable subtle sensory impairment. A similar relation to method of fixation was seen. An association between duration of temporary sensory change and magnitude of forward mandibular advance was noted. Objective sensory testing validated the subjectively reported sensory status but also identified many patients self-assessed as normal had some undetected sensory impairment. Possible mechanisms for the above findings and implications for clinical practice are presented.

Adaptive control for backward quadrupedal walking V. Mutable activation of bifunctional thigh muscles.

1. In this, the fifth article in a series to assess changes in posture, hindlimb dynamics, and muscle synergies associated with backward (BWD) quadrupedal walking, we compared the recruitment of three biarticular muscles of the cat's anterior thigh (anterior sartorius, SAa; medial sartorius, SAm; rectus femoris, RF) for forward (FWD) and BWD treadmill walking. Electromyography (EMG) records from these muscles, along with those of two muscles (semitendinosus, ST; anterior biceps femoris, ABF) studied previously in this series, were synchronized with kinematic data digitized from high-speed ciné film for unperturbed steps and steps in which a stumbling corrective reaction was elicited during swing. 2. During swing, the relative timing of EMG activity for the unifunctional SAm (hip and knee flexor) was similar for unperturbed steps of FWD and BWD walking. The SAm was active before paw lift off and remained active during most of swing (75%) for both forms of walking, but there was a marked decrease in EMG amplitude after paw off during BWD and not FWD swing. In contrast, the relative timing of EMG activity for the SAa and RF, two bifunctional muscles (hip flexors, knee extensors), was different for FWD and BWD swing. During FWD swing, the SAa and the RF (to a lesser extent) were coactive with the SAm; however, during BWD swing, the SAa and RF were active just before paw lift off and then inactive for the rest of swing until just before paw contact (see 3). Thus the swing-phase activity of the SAa and RF was markedly shorter for BWD than FWD swing. 3. Activity in SAa and RF was also different during FWD and BWD stance. The RF was consistently active from mid-to-late stance of FWD walking, and the SAa was also active during this period in some FWD steps. During the stance phase of BWD walking, however, the onset of activity in both muscles consistently shifted to early stance as both muscles became active just before paw contact (the E1 phase). Activity in RF consistently persisted through most of BWD stance. The duration of SAa recruitment during BWD stance was more variable across cats with offsets ranging from mid- to late stance. 4. The activation patterns of the biarticular anterior thigh muscles during stumbling corrective reactions were, in general, similar to their different activations during FWD and BWD swing. The initial response to a mechanical stimulus applied to the dorsum of the paw that obstructed FWD swing was an augmentation of knee flexion and increased activity in ST and SAm. A mechanical stimulus applied to the ventral surface of the paw to obstruct BWD swing resulted in an initial conversion of hip extension to flexion and a slowing of knee flexion. There was a corresponding recruitment of SAa and RF and an enhancement of background activity in SAm. 5. The two forms of walking are differentiated by posture and limb dynamics, yet muscles participating in the basic flexor and extensor synergies are unchanged. Although central pattern generating (CPG) circuits determine the basic timing of these synergies, changes in the duration and waveform of muscle activity may depend on unique interactions among the CPG, supraspinal inputs that set posture and the animal's goal (to walk BWD or FWD) and motion-related feedback from the hindlimb. Output mutability to each muscle may depend on the balance of this tripartite input; muscles with immutable patterns may rely heavily on input from CPG circuits, whereas muscles with mutable patterns may rely more on form-specific proprioceptive and supraspinal inputs.

Evidence of positive force feedback among hindlimb extensors in the intact standing cat.

1. The functional organization of heterogenic reflexes produced by activation of extensor force receptors (Golgi tendon organs) was studied in intact cats during stationary stance. Intramuscular stimulation (200 Hz, 20 ms) of hindlimb extensor muscles via chronically implanted electrodes was used to evoke weak muscle contractions and naturally activate Golgi tendon organ Ib afferents while cats stood unrestrained with each paw on a moveable triaxial force plate. 2. Intramuscular stimulation of every hindlimb extensor muscle tested in this study evoked excitatory responses that were widely distributed among hindlimb extensor muscles. Source and target specializations in the functional organization of this positive force feedback system were also observed. For example, stimulation of ankle extensors typically excited extensors and flexors at the ankle and hip (but not knee), whereas stimulation of hip extensors typically excited only extensors at all three joints. In addition, intramuscular stimulation of either lateral (LG) or medial (MG) gastrocnemius consistently inhibited soleus while exciting other extensors at the ankle and more proximal joints. 3. The electromyographic (EMG) reflex responses described above are attributed to the natural (via muscle contraction) activation of extensor group Ib afferents. Direct activation of intramuscular afferents by the stimulus was unlikely because there was no evidence that Ia afferents, which have the lowest electrical thresholds, were activated. Both the observed inhibition of the synergist, soleus, and the excitation of the antagonist, tibialis anterior, produced by gastrocnemius stimulation are opposite to the reflex effects that would be produced at the ankle by activation of gastrocnemius Ia afferents.(ABSTRACT TRUNCATED AT 250 WORDS)

Stance control in the chronic spinal cat.

1. A longitudinal study of the control of quiet and perturbed stance was conducted before and for 1 yr after complete spinal transection (T12) in a cat trained to stand on a moveable force platform. 2. With daily training, the spinal cat recovered full weight support and some intermittent control of lateral stability within 1 mo. Within the second month postspinalization, the spinal cat achieved the ability to maintain independent, unassisted stance (no external support or stimulation) for up to 45 s during quiet stance, as well as for 62-97% of the trials of horizontal translations of the support surface. 3. Control of lateral stability in the spinal cat was severely compromised, however, as eventually the spinal cat always lost its balance. Head movements and the tendency for the hindlimbs to initiate stepping movements were more destabilizing than platform translations. 4. Our preliminary results indicate that the recovery of partial lateral stability of the hindquarters in the spinal cat is the product of passive muscle properties and segmental reflexes, which, in isolation can provide only limited balance control in the chronic spinal cat.

A multivariate analysis of weight-loss behavior.

This study used a theoretical framework with multiple variables in multivariate analyses (factor, multiple regression, and path analyses) to investigate the sociopsychological predictors of weight loss. Responses from 309 participants of a comprehensive weight-loss program indicated that self-assurance was the most significant predictor of actual weight loss, followed by weeks completed. Other factors, such as program satisfaction and perceived importance, indirectly predicted weight loss through the intervening variables of self-assurance and weeks completed. Differences in the factors predicting weight loss were observed between completers and dropouts. The implications of these results for professionals concerned with weight control are discussed.

Functionally complex muscles of the cat hindlimb. I. Patterns of activation across sartorius.

The cat sartorius (SA) can be divided functionally into an anterior (SAa), knee extensor portion and a medial (SAm), knee flexor portion; it can be further subdivided anatomically by multiple nerve branches into parallel longitudinal columns that terminate in a distributed insertion at the knee with a continuous range of moment arms. Thus, SA may be controlled by a discrete number of motoneuron task groups reflecting a small number of central command signals or by a continuum of activation patterns associated with a continuum of moment arms. To resolve this question, the activation patterns across the width of the SA were recorded with an electrode array during three kinematically different movements--treadmill locomotion, scratching and paw shaking, in awake, unrestrained cats. Uniformity of activation along the longitudinal axis was also examined because individual muscle fibers do not extend the length of the SA. In addition, the cutaneous reflex responses were recorded throughout all regions of the SA during locomotion. Two fascial surface-patch arrays, each carrying 4-8 pairs of bipolar EMG electrodes, were sutured to the inner surface of the SA, one placed proximally and the other more distally. Each array sampled separate sites across the anterior to medial axis of SA. During locomotion, two basic EMG patterns were observed: the two burst-per-step-cycle pattern typical of SAa and the single burst pattern typical of SAm. There was an abrupt transition in the pattern of activation recorded in the two parts of SA during locomotion, and no continuum in the activation pattern was observed. Stimulation of both sural and saphenous cutaneous nerves during locomotion produced reflex responses that were uniformly distributed throughout SA, in contrast to the regional differences noted during unperturbed walking. Similarly, during scratching and paw shaking all parts of the SA were active simultaneously but with regional differences in EMG amplitude. The abrupt functional border between SAa and SAm coincided with the division of the SA into a knee flexor vs. a knee extensor. In all cases, the quantitative and qualitative differences in SAa and SAm EMGs were uniformly recorded throughout the entire extent of SAa or SAm; i.e., there was no segregation of activity within either SAa or SAm. Furthermore, the time course of EMG from each proximal recording site was nearly identical to the corresponding distal site, indicating no segregation of function along the longitudinal axis of SA. These results indicate that SAa and SAm constitute the smallest functional modules that can be recruited in SA.(ABSTRACT TRUNCATED AT 400 WORDS)